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Sample records for biological regeneration

  1. Fibroblast Growth Factors: Biology, Function, and Application for Tissue Regeneration

    OpenAIRE

    Ye-Rang Yun; Jong Eun Won; Eunyi Jeon; Sujin Lee; Wonmo Kang; Hyejin Jo; Jun-Hyeog Jang; Ueon Sang Shin; Hae-Won Kim

    2010-01-01

    Fibroblast growth factors (FGFs) that signal through FGF receptors (FGFRs) regulate a broad spectrum of biological functions, including cellular proliferation, survival, migration, and differentiation. The FGF signal pathways are the RAS/MAP kinase pathway, PI3 kinase/AKT pathway, and PLCγ pathway, among which the RAS/MAP kinase pathway is known to be predominant. Several studies have recently implicated the in vitro biological functions of FGFs for tissue regeneration. However, to obtain opt...

  2. Bioactive composite scaffolds for bone regeneration:from the process to the biological validation

    OpenAIRE

    Ronca, Alfredo

    2010-01-01

    In this work, we have discussed the preparation and characterization of composite scaffolds for bone regeneration. The scaffolds were made with different techniques: salt leaching / phase inversion,filament winding and stereolithography. The phase of preparation is followed by a characterization from a morphological, mechanical and biological point of view. Results were very promising especially regarding the biological response of the substrates that appear to be promising for future in v...

  3. Biologic Agents for Periodontal Regeneration and Implant Site Development

    Directory of Open Access Journals (Sweden)

    Fernando Suárez-López del Amo

    2015-01-01

    Full Text Available The advancement of molecular mediators or biologic agents has increased tremendously during the last decade in periodontology and dental implantology. Implant site development and reconstruction of the lost periodontium represent main fields in which these molecular mediators have been employed and investigated. Different growth factors trigger different reactions in the tissues of the periodontium at various cellular levels. Proliferation, migration, and differentiation constitute the main target areas of these molecular mediators. It was the purpose of this comprehensive review to describe the origin and rationale, evidence, and the most current understanding of the following biologic agents: Recombinant Human Platelet-Derived Growth Factor-BB (rhPDGF-BB, Enamel Matrix Derivate (EMD, Platelet-Rich Plasma (PRP and Platelet-Rich Fibrin (PRF, Recombinant Human Fibroblast Growth Factor-2 (rhFGF-2, Bone Morphogenic Proteins (BMPs, BMP-2 and BMP-7, Teriparatide PTH, and Growth Differential Factor-5 (GDF-5.

  4. Biologic Agents for Periodontal Regeneration and Implant Site Development

    Science.gov (United States)

    Suárez-López del Amo, Fernando; Monje, Alberto; Padial-Molina, Miguel; Tang, ZhiHui; Wang, Hom-Lay

    2015-01-01

    The advancement of molecular mediators or biologic agents has increased tremendously during the last decade in periodontology and dental implantology. Implant site development and reconstruction of the lost periodontium represent main fields in which these molecular mediators have been employed and investigated. Different growth factors trigger different reactions in the tissues of the periodontium at various cellular levels. Proliferation, migration, and differentiation constitute the main target areas of these molecular mediators. It was the purpose of this comprehensive review to describe the origin and rationale, evidence, and the most current understanding of the following biologic agents: Recombinant Human Platelet-Derived Growth Factor-BB (rhPDGF-BB), Enamel Matrix Derivate (EMD), Platelet-Rich Plasma (PRP) and Platelet-Rich Fibrin (PRF), Recombinant Human Fibroblast Growth Factor-2 (rhFGF-2), Bone Morphogenic Proteins (BMPs, BMP-2 and BMP-7), Teriparatide PTH, and Growth Differential Factor-5 (GDF-5). PMID:26509173

  5. Teleost fish scales: a unique biological model for the fabrication of materials for corneal stroma regeneration.

    Science.gov (United States)

    Takagi, Yasuaki; Ura, Kazuhiro

    2007-03-01

    The corneal stroma is composed of multiple lamellae, each containing closely packed collagen fibrils. The orientation of fibrils in a lamella is parallel, but those in different lamellae are orthogonal. As a result, the corneal stroma has a characteristic orthogonal plywood-like structure. Such a highly-regulated three-dimensional arrangement of collagen fibrils gives strength and transparency to the corneal stroma, but it also presents a challenge in the fabrication of materials to replace it. A bioinspired technology is required to process such materials, but the regulatory mechanism of collagen-fibril orientation is still unknown. The low regenerating activity of the corneal stroma seems to be a major factor preventing progress in this field of research. A similarly highly-ordered arrangement of collagen fibrils can be seen in the basal plates of teleost fish scales. Moreover, the scales have high regenerating ability. When a scale is mechanically lost, a new scale is rapidly regenerated. The cells that produce the basal plates are extremely activated; thus, production of the highly-ordered collagen fibrils is very rapid. Therefore, the regenerating scales should be a uniquely helpful biological model for studying the regulatory mechanism of collagen-fibril orientation. Fish-scale collagen has another advantage for use as a biomaterial: the low probability of zoonotic infection. Therefore, scale collagen is a most promising biomaterial for fabricating three-dimensionally arranged collagen fibers to substitute for the corneal stroma. Three tasks that must be clarified for the bioinspired production of a corneal substitute from fish scale collagen are proposed. PMID:17450830

  6. Evaluating the Bone Tissue Regeneration Capability of the Chinese Herbal Decoction Danggui Buxue Tang from a Molecular Biology Perspective

    OpenAIRE

    Wen-Ling Wang; Shi-Yuan Sheu; Yueh-Sheng Chen; Shung-Te Kao; Yuan-Tsung Fu; Tzong-Fu Kuo; Kuo-Yu Chen; Chun-Hsu Yao

    2014-01-01

    Large bone defects are a considerable challenge to reconstructive surgeons. Numerous traditional Chinese herbal medicines have been used to repair and regenerate bone tissue. This study investigated the bone regeneration potential of Danggui Buxue Tang (DBT), a Chinese herbal decoction prepared from Radix Astragali (RA) and Radix Angelicae Sinensis (RAS), from a molecular biology perspective. The optimal ratio of RA and RAS used in DBT for osteoblast culture was obtained by colorimetric and a...

  7. Biological conduit small gap sleeve bridging method for peripheral nerve injury:regeneration law of nerve ifbers in the conduit

    Institute of Scientific and Technical Information of China (English)

    Pei-xun Zhang; Li-ya A; Yu-hui Kou; Xiao-feng Yin; Feng Xue#; Na Han; Tian-bing Wang; Bao-guo Jiang

    2015-01-01

    The clinical effects of 2-mm small gap sleeve bridging of the biological conduit to repair periph-eral nerve injury are better than in the traditional epineurium suture, so it is possible to replace the epineurium suture in the treatment of peripheral nerve injury. This study sought to identify the regeneration law of nerve fibers in the biological conduit. A nerve regeneration chamber was constructed in models of sciatic nerve injury using 2-mm small gap sleeve bridging of a biodegradable biological conduit. The results showed that the biological conduit had good his-tocompatibility. Tissue and cell apoptosis in the conduit apparently lessened, and regenerating nerve ifbers were common. The degeneration regeneration law of Schwann cells and axons in the conduit was quite different from that in traditional epineurium suture. During the prime period for nerve fiber regeneration (2–8 weeks), the number of Schwann cells and nerve fibers was higher in both proximal and distal ends, and the effects of the small gap sleeve bridging method were better than those of the traditional epineurium suture. The above results provide an objec-tive and reliable theoretical basis for the clinical application of the biological conduit small gap sleeve bridging method to repair peripheral nerve injury.

  8. Biological conduit small gap sleeve bridging method for peripheral nerve injury: regeneration law of nerve fibers in the conduit

    Directory of Open Access Journals (Sweden)

    Pei-xun Zhang

    2015-01-01

    Full Text Available The clinical effects of 2-mm small gap sleeve bridging of the biological conduit to repair peripheral nerve injury are better than in the traditional epineurium suture, so it is possible to replace the epineurium suture in the treatment of peripheral nerve injury. This study sought to identify the regeneration law of nerve fibers in the biological conduit. A nerve regeneration chamber was constructed in models of sciatic nerve injury using 2-mm small gap sleeve bridging of a biodegradable biological conduit. The results showed that the biological conduit had good histocompatibility. Tissue and cell apoptosis in the conduit apparently lessened, and regenerating nerve fibers were common. The degeneration regeneration law of Schwann cells and axons in the conduit was quite different from that in traditional epineurium suture. During the prime period for nerve fiber regeneration (2-8 weeks, the number of Schwann cells and nerve fibers was higher in both proximal and distal ends, and the effects of the small gap sleeve bridging method were better than those of the traditional epineurium suture. The above results provide an objective and reliable theoretical basis for the clinical application of the biological conduit small gap sleeve bridging method to repair peripheral nerve injury.

  9. Biological characterization of cultured dermal papilla cells and hair follicle regeneration in vitro and in vivo

    Institute of Scientific and Technical Information of China (English)

    Lü Zhong-fa; CAI Sui-qing; WU Jin-jin; ZHENG Min

    2006-01-01

    Background Dermal papilla cells (DPC) are a group of mesenchyme-derived cells at the base of the hair follicle, where they regulate and control hair follicle growth through the expression and secretion of cytokines. Nevertheless, the role of DPC derived chemokines and other cytokines in the hair follicle biology remain speculative. In this study, we investigated the expression of basic fibroblast growth factor (bFGF), endothelin-1 (ET-1) and stem cell factor (SCF) in different passages of cultured DPC and their effects on the biological behaviour of DPC.Methods The expression of bFGF, ET-1 and SCF in different passages of cultured DPC and their possible effects on the biological behavior of DPC are investigated using in situ hybridization and immunochemistry. In addition, we performed transplantation of hair follicle cells into nude mice. The cultured DPC, dermal sheath cells and fibroblast of human scalp, respectively, were mixed with cells of the hair follicle epithelium in different ratios, and then were cultured in hair follicle organotypic cultures or implanted into the subcutis of nude mice.Results The expression of ET-1 and SCF in early passages of cultured DPC became stronger, but turned weaker and even negative in late passages (>6 passages). Hair follicle-like structures were formed after DPC combined with the cells of hair follicle epithelium cells in hair follicle organotypic cultures. When hair follicle organotypic cultures were implanted into the subcutis of nude mice, the relative intact hair follicles were formed. After the transplantation of hair follicle cells into the nude mice, the hair follicle-like structure was formed in the group that contained DPC mixed with hair follicle epithelium cells. However, no hair follicles were formed in the other two groups. It was found that the higher the expression of ET-1 and SCF in DPC, the stronger the ability of DPC to induce hair follicle regeneration.Conclusions The cultured DPC can induce hair follicle

  10. Endocrine Pancreas Development and Regeneration: Noncanonical Ideas From Neural Stem Cell Biology.

    Science.gov (United States)

    Masjkur, Jimmy; Poser, Steven W; Nikolakopoulou, Polyxeni; Chrousos, George; McKay, Ronald D; Bornstein, Stefan R; Jones, Peter M; Androutsellis-Theotokis, Andreas

    2016-02-01

    Loss of insulin-producing pancreatic islet β-cells is a hallmark of type 1 diabetes. Several experimental paradigms demonstrate that these cells can, in principle, be regenerated from multiple endogenous sources using signaling pathways that are also used during pancreas development. A thorough understanding of these pathways will provide improved opportunities for therapeutic intervention. It is now appreciated that signaling pathways should not be seen as "on" or "off" but that the degree of activity may result in wildly different cellular outcomes. In addition to the degree of operation of a signaling pathway, noncanonical branches also play important roles. Thus, a pathway, once considered as "off" or "low" may actually be highly operational but may be using noncanonical branches. Such branches are only now revealing themselves as new tools to assay them are being generated. A formidable source of noncanonical signal transduction concepts is neural stem cells because these cells appear to have acquired unusual signaling interpretations to allow them to maintain their unique dual properties (self-renewal and multipotency). We discuss how such findings from the neural field can provide a blueprint for the identification of new molecular mechanisms regulating pancreatic biology, with a focus on Notch, Hes/Hey, and hedgehog pathways. PMID:26798118

  11. Acceleration of Peripheral Nerve Regeneration through Asymmetrically Porous Nerve Guide Conduit Applied with Biological/Physical Stimulation

    OpenAIRE

    Kim, Jin Rae; Oh, Se Heang; Kwon, Gu Birm; Namgung, Uk; Song, Kyu Sang; Jeon, Byeong Hwa; Lee, Jin Ho

    2013-01-01

    Sufficient functional restoration of damaged peripheral nerves is a big clinical challenge. In this study, a nerve guide conduit (NGC) with selective permeability was prepared by rolling an asymmetrically porous polycaprolactone/Pluronic F127 membrane fabricated using a novel immersion precipitation method. Dual stimulation (nerve growth factor [NGF] as a biological stimulus and low-intensity pulse ultrasound [US] as a physical stimulus) was adapted to enhance nerve regeneration through an NG...

  12. TEMPORAL EVOLUTION OF SKELETAL REGENERATED TISSUE : WHAT CAN MECHANICAL INVESTIGATION ADD TO BIOLOGICAL?

    OpenAIRE

    Casanova, Remy; Mokoko, Didier; Pithioux, Martine; Pailler-Mattéi, Cyril; Zahouani, Hassan; Chabrand, Patrick

    2010-01-01

    The objective here was to experimentally characterise the temporal evolution of the structural and mechanical properties of large volume immature regenerated tissues. We studied these evolving tissues from their genesis in controlled mechanical conditions. We developed an animal model based on the periosteal properties leading to unloaded regenerated skeletal tissue. To characterize the temporal evolution of mechanical properties, we carried out indentation tests coupled with macroscopic exam...

  13. Biospheric Life Support - integrating biological regeneration into protection of humans in space.

    Science.gov (United States)

    Rocha, Mauricio; Iha, Koshun

    2016-07-01

    A biosphere stands for a set of biomes (regional biological communities) interacting in a materially closed (though energetically open) ecological system (CES). Earth's biosphere, the thin layer of life on the planet's surface, can be seen as a natural CES- where life "consumables" are regenerated/restored via biological, geological and chemical processes. In Life Sciences, artificial CESs- local ecosystems extracts with varying scales and degrees of closure, are considered convenient/representatives objects of study. For outer space, these concepts have been applied to the issue of life support- a significant consideration as long as distance from Earth increases. In the nineties, growing on the Russian expertise on biological life support, backed by a multidisciplinary science team, the famous Biosphere 2 appeared. That private project innovated, by assembling a set of Earth biomes samples- plus an organic ag one, inside a closed Mars base-like structure, next to 1.5 ha under glass, in Arizona, US. The crew of 8 inside completed their two years contract, though facing setbacks- the system failed, e.g., to produce enough food/air supplies. But their "failures"- if this word can be fairly applied to science endeavors, were as meaningful as their achievements for the future of life support systems (LSS) research. By this period, the Russians had accumulated experience in extended orbital stays, achieving biological outcomes inside their stations- e.g. complete wheat cycles. After reaching the Moon, the US administration decided to change national priorities, putting the space program as part of a "détente" policy, to relieve international tensions. Alongside the US space shuttle program, the Russians were invited to join the new International Space Station (ISS), bringing to that pragmatic project, also their physical/chemical LSS- top air/water regenerative technology at the time. Present US policy keeps the ISS operational, extending its service past its planned

  14. Biological regeneration of ferric (Fe3+) solution during desulphurisation of gaseous streams: effect of nutrients and support material.

    Science.gov (United States)

    Mulopo, Jean; Schaefer, L

    2015-01-01

    This paper evaluates the biological regeneration of ferric Fe3+ solution during desulphurisation of gaseous streams. Hydrogen sulphide (H2S) is absorbed into aqueous ferric sulphate solution and oxidised to elemental sulphur, while ferric ions Fe3+ are reduced to ferrous ions Fe2+. During the industrial regeneration of Fe3+, nutrients and trace minerals usually provided in a laboratory setup are not present and this depletion of nutrients may have a negative impact on the bacteria responsible for ferrous iron oxidation and may probably affect the oxidation rate. In this study, the effect of nutrients and trace minerals on ferrous iron oxidation have been investigated and the results showed that the presence of nutrients and trace minerals affects the efficiency of bacterial Fe2+oxidation. The scanning electron microscopy analysis of the geotextile support material was also conducted and the results showed that the iron precipitate deposits appear to play a direct role on the bacterial biofilm formation. PMID:26038932

  15. Can stem cells really regenerate the human heart? Use your noggin, dickkopf! Lessons from developmental biology

    OpenAIRE

    Sommer, Paula

    2013-01-01

    Abstract The human heart is the first organ to develop and its development is fairly well characterised. In theory, the heart has the capacity to regenerate, as its cardiomyocytes may be capable of cell division and the adult heart contains a cardiac stem cell niche, presumably capable of differentiating into cardiomyocytes and other cardiac-associated cell types. However, as with most other organs, these mechanisms are not activated upon serious injury. Several experimental options to induce...

  16. Wound models for periodontal and bone regeneration: the role of biologic research.

    Science.gov (United States)

    Sculean, Anton; Chapple, Iain L C; Giannobile, William V

    2015-06-01

    The ultimate goals of periodontal therapy remain the complete regeneration of those periodontal tissues lost to the destructive inflammatory-immune response, or to trauma, with tissues that possess the same structure and function, and the re-establishment of a sustainable health-promoting biofilm from one characterized by dysbiosis. This volume of Periodontology 2000 discusses the multiple facets of a transition from therapeutic empiricism during the late 1960s, toward regenerative therapies, which is founded on a clearer understanding of the biophysiology of normal structure and function. This introductory article provides an overview on the requirements of appropriate in vitro laboratory models (e.g. cell culture), of preclinical (i.e. animal) models and of human studies for periodontal wound and bone repair. Laboratory studies may provide valuable fundamental insights into basic mechanisms involved in wound repair and regeneration but also suffer from a unidimensional and simplistic approach that does not account for the complexities of the in vivo situation, in which multiple cell types and interactions all contribute to definitive outcomes. Therefore, such laboratory studies require validatory research, employing preclinical models specifically designed to demonstrate proof-of-concept efficacy, preliminary safety and adaptation to human disease scenarios. Small animal models provide the most economic and logistically feasible preliminary approaches but the outcomes do not necessarily translate to larger animal or human models. The advantages and limitations of all periodontal-regeneration models need to be carefully considered when planning investigations to ensure that the optimal design is adopted to answer the specific research question posed. Future challenges lie in the areas of stem cell research, scaffold designs, cell delivery and choice of growth factors, along with research to ensure appropriate gingival coverage in order to prevent gingival

  17. Biological characteristics of chicken anemia virus regenerated from clinical specimen by PCR.

    Science.gov (United States)

    van Santen, Vicky L; Toro, Haroldo; Hoerr, Frederic J

    2007-03-01

    Our previous genetic characterization of chicken anemia virus (CAV) in commercial broiler chickens in Alabama revealed a previously undetected polymorphism: a glutamine codon at VP1 position 22, in 7 of the 14 sequences. The novel glutamine codon was always found in association with a VP1 "hypervariable region" identical to CAV field isolates that replicate poorly in culture. The complete genome of CAV73, representative of the sequences with the novel polymorphism, was generated from cloned polymerase chain reaction (PCR) fragments amplified directly from naturally infected tissues. CAV73 had been detected in 31-day-old broilers submitted for examination for reasons unrelated to anemia. After electroporation of the cloned genomes into MDCC-CU147 lymphoblastoid cells, the regenerated CAV caused the culture to fail within 9 days, and the medium contained 5 X 10(6) TCID50 CAV/ml. Use of MDCC-CU147 cells was essential, as identical electroporation of MDCC-MSB1 cells failed to generate CAV able to destroy the culture within 8 wk. Regenerated CAV73 produced anemia and severe lymphocytic depletion of the thymus when inoculated into susceptible 3-day-old chickens and was reisolated from these chickens. Furthermore, it replicated in low- and high-passage MDCC-MSB1 cells similarly to a low-passage CAV field isolate that contains a different VP 1 "hypervariable region." The regeneration of CAV from PCR products directly from naturally infected carcasses, as performed in this study, provides a tool for the evaluation of distinct genetic polymorphisms that may be detected in specimens where infective virions are no longer available. Our results also provide some insight into the differential susceptibility of cell lines for low-passage CAV field isolates. PMID:17461269

  18. Evaluating the Bone Tissue Regeneration Capability of the Chinese Herbal Decoction Danggui Buxue Tang from a Molecular Biology Perspective

    Directory of Open Access Journals (Sweden)

    Wen-Ling Wang

    2014-01-01

    Full Text Available Large bone defects are a considerable challenge to reconstructive surgeons. Numerous traditional Chinese herbal medicines have been used to repair and regenerate bone tissue. This study investigated the bone regeneration potential of Danggui Buxue Tang (DBT, a Chinese herbal decoction prepared from Radix Astragali (RA and Radix Angelicae Sinensis (RAS, from a molecular biology perspective. The optimal ratio of RA and RAS used in DBT for osteoblast culture was obtained by colorimetric and alkaline phosphatase (ALP activity assays. Moreover, the optimal concentration of DBT for bone cell culture was also determined by colorimetric, ALP activity, nodule formation, Western blotting, wound-healing, and tartrate-resistant acid phosphatase activity assays. Consequently, the most appropriate weight ratio of RA to RAS for the proliferation and differentiation of osteoblasts was 5 : 1. Moreover, the most effective concentration of DBT was 1,000 μg/mL, which significantly increased the number of osteoblasts, intracellular ALP levels, and nodule numbers, while inhibiting osteoclast activity. Additionally, 1,000 μg/mL of DBT was able to stimulate p-ERK and p-JNK signal pathway. Therefore, DBT is highly promising for use in accelerating fracture healing in the middle or late healing periods.

  19. The 2~(nd) Guangzhou International Forum on the Frontier of Stem Cell and Regeneration Biology Invitations

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ The forum will focus on the following topics: reprogramming of stem cell, chemical biology researchin stem cell, applied research in embryonic and somatic stem cells, stem cell and drug R&D, developmentand mode animal research, stem cell biology and cloning. The Forum will invite members of the CASOverseas Innovation Team on stem cells and cloning, expert panel members of the national key projecton Development and Procreation, the nation's 973 Project chief scientists and other professionals of thearea from all over the world.

  20. Properties and in vitro biological evaluation of nano-hydroxyapatite/chitosan membranes for bone guided regeneration

    International Nuclear Information System (INIS)

    Nano-hydroxyapatite(n-HA)/chitosan(CS) composite membranes were prepared by solvent casting and evaporation methods for the function of guided bone regeneration (GBR). The effect of n-HA content and solvent evaporation temperature on the properties of the composite membranes was studied. The n-HA/CS membranes were analyzed by scanning electron microscopy, Fourier transformed infrared spectroscopy, X-ray diffraction, swelling measurement, mechanical test, cell culture and MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenylte-2H-tetrazolium bromide) assay. The results show that the surface roughness and micropores of the composite membranes increase with the rise of n-HA content, suitable for adhesion, crawl and growth of cells. The hydroxyapatite holds nano size and distributes uniformly in the composite membranes. Chemical bond interaction exists between Ca ions and -OH groups of n-HA and -NH2 or -OH groups of CS. The n-HA content and solvent evaporation temperature have obvious influence on the swelling ratio, tensile strength and elongation rate of the composite membranes. Cell culture and MTT assays show that n-HA and its content can affect the proliferation of cells. The n-HA/CS composite membranes have no negative effect on the cell morphology, viability and proliferation and possess good biocompatibility. This study makes the n-HA/CS composite membrane be a prospective biodegradable GBR membrane for future applications

  1. Biological evaluation of human hair keratin scaffolds for skin wound repair and regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Songmei; Sang, Lin [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China); Zhang, Yaping [Engineering Research Center of Biomass Materials, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Wang, Xiaoliang [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China); Li, Xudong, E-mail: xli20004@yahoo.com [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China)

    2013-03-01

    The cytocompatibility, in vivo biodegradation and wound healing of keratin biomaterials were investigated. For the purposes, three groups of keratin scaffolds were fabricated by freeze-drying reduced solutions at 2 wt.%, 4 wt.% and 8 wt.% keratins extracted from human hairs. These scaffolds exhibited evenly distributed high porous structures with pore size of 120-220 {mu}m and the porosity > 90%. NIH3T3 cells proliferated well on these scaffolds in culture lasting up to 22 days. Confocal micrographs stained with AO visually revealed cell attachment and infiltration as well as scaffold architectural stability. In vivo animal experiments were conducted with 4 wt.% keratin scaffolds. Early degradation of subcutaneously implanted scaffolds occurred at 3 weeks in the outermost surface, in concomitant with inflammatory response. At 5 weeks, the overall porous structure of scaffolds severely deteriorated while the early inflammatory response in the outermost surface obviously subsided. A faster keratin biodegradation was observed in repairing full-thickness skin defects. Compared with the blank control, keratin scaffolds gave rise to more blood vessels at 2 weeks and better complete wound repair at 3 weeks with a thicker epidermis, less contraction and newly formed hair follicles. These preliminary results suggest that human hair keratin scaffolds are promising dermal substitutes for skin regeneration. - Highlights: Black-Right-Pointing-Pointer Preparation of highly-interconnected human hair keratin scaffolds. Black-Right-Pointing-Pointer Long-term cell culturing and in vivo animal experiments with keratin scaffolds. Black-Right-Pointing-Pointer Biodegradation is dependent on implantation site and function Black-Right-Pointing-Pointer Early vascularization and better repair in treating full-thickness skin wounds. Black-Right-Pointing-Pointer A thicker epidermis, less contraction and newly formed hair follicles are observed.

  2. Biological evaluation of human hair keratin scaffolds for skin wound repair and regeneration

    International Nuclear Information System (INIS)

    The cytocompatibility, in vivo biodegradation and wound healing of keratin biomaterials were investigated. For the purposes, three groups of keratin scaffolds were fabricated by freeze-drying reduced solutions at 2 wt.%, 4 wt.% and 8 wt.% keratins extracted from human hairs. These scaffolds exhibited evenly distributed high porous structures with pore size of 120–220 μm and the porosity > 90%. NIH3T3 cells proliferated well on these scaffolds in culture lasting up to 22 days. Confocal micrographs stained with AO visually revealed cell attachment and infiltration as well as scaffold architectural stability. In vivo animal experiments were conducted with 4 wt.% keratin scaffolds. Early degradation of subcutaneously implanted scaffolds occurred at 3 weeks in the outermost surface, in concomitant with inflammatory response. At 5 weeks, the overall porous structure of scaffolds severely deteriorated while the early inflammatory response in the outermost surface obviously subsided. A faster keratin biodegradation was observed in repairing full-thickness skin defects. Compared with the blank control, keratin scaffolds gave rise to more blood vessels at 2 weeks and better complete wound repair at 3 weeks with a thicker epidermis, less contraction and newly formed hair follicles. These preliminary results suggest that human hair keratin scaffolds are promising dermal substitutes for skin regeneration. - Highlights: ► Preparation of highly-interconnected human hair keratin scaffolds. ► Long-term cell culturing and in vivo animal experiments with keratin scaffolds. ► Biodegradation is dependent on implantation site and function ► Early vascularization and better repair in treating full-thickness skin wounds. ► A thicker epidermis, less contraction and newly formed hair follicles are observed.

  3. The Mechanical and Biological Properties of Chitosan Scaffolds for Tissue Regeneration Templates Are Significantly Enhanced by Chitosan from Gongronella butleri

    Directory of Open Access Journals (Sweden)

    Hiroshi Tamura

    2009-04-01

    Full Text Available Chitosan with a molecular weight (MW of 104 Da and 13% degree of acetylation (DA was extracted from the mycelia of the fungus Gongronella butleri USDB 0201 grown in solid substrate fermentation and used to prepare scaffolds by the freeze-drying method. The mechanical and biological properties of the fungal chitosan scaffolds were evaluated and compared with those of scaffolds prepared using chitosans obtained from shrimp and crab shells and squid bone plates (MW 105-106 Da and DA 10-20%. Under scanning electron microscopy, it was observed that all scaffolds had average pore sizes of approximately 60-90 mm in diameter. Elongated pores were observed in shrimp chitosan scaffolds and polygonal pores were found in crab, squid and fungal chitosan scaffolds. The physico-chemical properties of the chitosans had an effect on the formation of pores in the scaffolds, that consequently influenced the mechanical and biological properties of the scaffolds. Fungal chitosan scaffolds showed excellent mechanical, water absorption and lysozyme degradation properties, whereas shrimp chitosan scaffolds (MW 106Da and DA 12% exhibited the lowest water absorption properties and lysozyme degradation rate. In the evaluation of biocompatibility of chitosan scaffolds, the ability of fibroblast NIH/3T3 cells to attach on all chitosan scaffolds was similar, but the proliferation of cells with polygonal morphology was faster on crab, squid and fungal chitosan scaffolds than on shrimp chitosan scaffolds. Therefore fungal chitosan scaffold, which has excellent mechanical and biological properties, is the most suitable scaffold to use as a template for tissue regeneration.

  4. Mass exchange in an experimental new-generation LSS model based on biological regeneration of envirnment

    Science.gov (United States)

    Tikhomirov, A.; Ushakova, S.; Gribovskaya, I.; Tirranen, L.; Manukovsky, N.; Zolotukhin, I.; Gros, J.; Lasseur, C.

    Experimental model of a biological life support system (LSS) was used to evaluate qualitative and quantitative parameters of inner mass exchange. The photosynthesizing block was the higher plants component (wheat, 3 radish), the heterotroph block consisted of the soil-like substrate (SLS) California worms, mushrooms and microbial microflora. In terms of gas composition the mass exchange process involved emission of oxygen by the photosynthesiz ing component and its uptake by the heterotroph component along with formation and maintaining the SLS structure, growth of mushrooms, California worms, human respiration and several other processes. Human presence in the system had the form of a "part of virtual human" that at regular intervals took part in the respiration gas exchange to get engaged in the respiration gas exchange in the course of calculated period of time. Experimental data demonstrated good agreement of ? 2 /? ? 2 balance which, in these gas components, was close to complete. Basic component in the water mass exchange were transpiration water and aqueous watering solution with mineral elements. Human consumption of the harvest biomass of plants (seeds and roots) was simulated by processing hese production by a genuine physical - chemicalt method of oxidizing to inorganic mineral compounds that were returned into the system and fully assimilated by the plants. Such an oxidation was achieved by "wet incineration" of organic biomass using hydrogen peroxide by a special process where high temperature and pressure are not needed, and hydrogen peroxide is produced from the water inside the system. The turnover was estimated in terms of individual biogenous elements. Specifically, experiments showed that in terms of sulfur, carbon and several other elements the closedness was almost 100%. Applications opportunities of the experimental biological system considered are under discussion.

  5. Biological regeneration of carrier material for the adsorption of halogen hydrocarbons in plants for cleaning up contaminated groundwater. Final report

    International Nuclear Information System (INIS)

    Halogen hydrocarbons and above all chlorinated hydrocarbons are widespread harmful substances in soils and in groundwater. When cleaning up groundwater contamination, the contaminants are brought into the gas phase by strip processes. From the gas phase, the contaminants can be adsorbed on different carrier materials, mostly active carbon. One was searching for ways to regenerate this adsorption material. The mixed culture from a sea sediment most suitable for the decomposition of chlorinated hydrocarbons was optimized regarding its decomposition performance and was later used on the technical scale. In the decomposition experiments on the large technical scale, the cultures were lodged on filling bodies which has a much higher amount of gaps. In this case, an optimum supply of the micro-organisms with oxygen and methane is guaranteed, which is used as co-substrate. No intermediate product was found in a gas chromatography examination. The biologically occupied stage is situated between a desorption column and the active carbon filters, and reduces the load of harmful substances which can no longer be brought into the gas phase by stripping out. This has the advantage that it can be integrated in existing plants and can be adapted to any case of contamination by lodging adapted micro-organisms on it. The basis for each application must be separately researched. (orig.)

  6. The regeneration of epidermal cells of Saintpaulia leaves as a new plant-tissue system for cellular radiation biology.

    Science.gov (United States)

    Engels, F M; van der Laan, F M; Leenhouts, H P; Chadwick, K H

    1980-09-01

    Investigation of the nucleus of epidermal cells of the petioles of Saintpaulia leaves by cytofluorimetry revealed that all cells are in a non-cycling pre DNA synthesis phase. Cultivation of dissected leaves results in a synchronous regeneration process of a defined number of cells. Five days after onset of cultivation the cells reach the first mitosis. The nuclear development during the regeneration process is described. Irradiation of the leaves results in a directly visible inhibition of this regenerating capability which is used to quantify cell survival in a tissue. The data show that the radiation response has a similar shape to that of the survival of single cells in culture. This response can be observed before the first mitosis of the cells and its application as a new plant tissue system for cellular radiation research is discussed. PMID:7012060

  7. Adipose tissue-organotypic culture system as a promising model for studying adipose tissue biology and regeneration

    OpenAIRE

    Toda, Shuji; Uchihashi, Kazuyoshi; Aoki, Shigehisa; Sonoda, Emiko; Yamasaki, Fumio; Piao, Meihua; Ootani, Akifumi; Yonemitsu, Nobuhisa; Sugihara, Hajime

    2009-01-01

    Adipose tissue consists of mature adipocytes, preadipocytes and mesenchymal stem cells (MSCs), but a culture system for analyzing their cell types within the tissue has not been established. We have recently developed “adipose tissue-organotypic culture system” that maintains unilocular structure, proliferative ability and functions of mature adipocytes for a long term, using three-dimensional collagen gel culture of the tissue fragments. In this system, both preadipocytes and MSCs regenerate...

  8. Heart Regeneration

    OpenAIRE

    Laflamme, Michael A.; Charles E. Murry

    2011-01-01

    Heart failure plagues industrialized nations, killing more people than any other disease. Heart failure usually results from a deficiency of cardiomyocytes, and a robust therapy to regenerate lost myocardium could help millions of patients a year. Heart regeneration is well documented in lower vertebrates and in developing mammals. After we are born, however, human heart regeneration becomes limited. In this article, Laflamme and Murry review the innate barriers to heart regeneration, the evi...

  9. Cryogenic regenerators

    International Nuclear Information System (INIS)

    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)

  10. Regeneración biológica: Secretos de la naturaleza Biological regeneration: Secrets of nature

    Directory of Open Access Journals (Sweden)

    Porfirio Hernández Ramírez

    2006-12-01

    capacity, both in the field of botany and of zoology. Among the new methods to improve the characteristics and dissemination of plants we find the regeneration techniques of plants in vitro, including the organogenesis and the somatic embriogenesis that give the possibility to form the so-called “artificial seeds”. In zoology, it has been observed the regenerative capacity of some animals, such as planarians, hydras, starfish and crustacean. Many vertebrates have lost, at least in a significant way, the regenerative potentiality of most of their organs and tissues. However, some have retained a marked regenerative ability, among them, the Teleostei, the Urodela (salamanders and tritons and other types of amphibia. The Chelonia, crocodriles and snakes have lost in general the capacity to regenerate lost parts. Alligators have the possibility to regenerate their tails. Mammals have also limitations, since they cannot regenerate extremities, organs and tissues as some inferior animals do. There are exceptions, as those found in stags, dolphins and some type of mice as the MRL mice. The human being expresses only some physiological regenerative processes, or before some injuries that are mainly manifested in the epidermal cells of the oral mucosa and of the respiratory tract, the blood cells, the hair, the nails, the muscular tissue, the skin and the bone tissue. The new knowledge on the stem cell opens a new era that offers man the possibility to influence therapeutically on the regeneration of organs and tissues

  11. Tissue regeneration with photobiomodulation

    Science.gov (United States)

    Tang, Elieza G.; Arany, Praveen R.

    2013-03-01

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

  12. Mass exchange in an experimental new-generation life support system model based on biological regeneration of environment

    Science.gov (United States)

    Tikhomirov, A. A.; Ushakova, S. A.; Manukovsky, N. S.; Lisovsky, G. M.; Kudenko, Yu. A.; Kovalev, V. S.; Gubanov, V. G.; Barkhatov, Yu. V.; Gribovskaya, I. V.; Zolotukhin, I. G.; Gros, J. B.; Lasseur, Ch.

    An experimental model of a biological life support system was used to evaluate qualitative and quantitative parameters of the internal mass exchange. The photosynthesizing unit included the higher plant component (wheat and radish), and the heterotrophic unit consisted of a soil-like substrate, California warms, mushrooms and microbial microflora. The gas mass exchange involved evolution of oxygen by the photosynthesizing component and its uptake by the heterotroph component along with the formation and maintaining of the SLS structure, growth of mushrooms and California worms, human respiration, and some other processes. Human presence in the system in the form of "virtual human" that at regular intervals took part in the respirative gas exchange during the experiment. Experimental data demonstrated good oxygen/carbon dioxide balance, and the closure of the cycles of these gases was almost complete. The water cycle was nearly 100% closed. The main components in the water mass exchange were transpiration water and the watering solution with mineral elements. Human consumption of the edible plant biomass (grains and roots) was simulated by processing these products by a unique physicochemical method of oxidizing them to inorganic mineral compounds, which were then returned into the system and fully assimilated by the plants. The oxidation was achieved by "wet combustion" of organic biomass, using hydrogen peroxide following a special procedure, which does not require high temperature and pressure. Hydrogen peroxide is produced from the water inside the system. The closure of the cycle was estimated for individual elements and compounds. Stoichiometric proportions are given for the main components included in the experimental model of the system. Approaches to the mathematical modeling of the cycling processes are discussed, using the data of the experimental model. Nitrogen, as a representative of biogmic elements, shows an almost 100% closure of the cycle inside

  13. Bone regeneration in dentistry

    OpenAIRE

    Tonelli, Paolo; Duvina, Marco; Barbato, Luigi; Biondi, Eleonora; Nuti, Niccolò; Brancato, Leila; Rose, Giovanna Delle

    2011-01-01

    The edentulism of the jaws and the periodontal disease represent conditions that frequently leads to disruption of the alveolar bone. The loss of the tooth and of its bone of support lead to the creation of crestal defects or situation of maxillary atrophy. The restoration of a functional condition involves the use of endosseous implants who require adequate bone volume, to deal with the masticatory load. In such situations the bone need to be regenerated, taking advantage of the biological p...

  14. Vertebrate-like regeneration in the invertebrate chordate amphioxus

    OpenAIRE

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

    2011-01-01

    An important question in biology is why some animals are able to regenerate, whereas others are not. The basal chordate amphioxus is uniquely positioned to address the evolution of regeneration. We report here the high regeneration potential of the European amphioxus Branchiostoma lanceolatum. Adults regenerate both anterior and posterior structures, including neural tube, notochord, fin, and muscle. Development of a classifier based on tail regeneration profiles predicts the assignment of yo...

  15. TO THE METHOD OF THE STUDYING OF REGENERATION ACTIVITY OF GRAPE CUTTINGS (SCIENTIFIC-RESEARCH WORK ON BIOLOGY IN SECONDARY SCHOOLS

    Directory of Open Access Journals (Sweden)

    Radchevskiy P. P.

    2014-09-01

    Full Text Available Methodological aspects of conduction of researches on study of regeneration activity of grape cuttings by students of secondary schools including by members of Small Agricultural Academy of Kuban are cited in the article

  16. Using natural radionuclides 210Po and 210Pb in GEOTRACES data from the North Atlantic to estimate particulate and biologically reactive trace element scavenging and regeneration

    Science.gov (United States)

    Rigaud, Sylvain; Church, Thomas

    2016-04-01

    situ 210Po scavenging, and may be related to surface biological productivity. Aeolian eastern sources of 210Pb in surface waters are evident as large excess of the largely conservative grandparent 226Ra, but deficient at depth with scavenging rates higher at ocean margins. At depth, 210Pb deficiency increases as does benthic scavenging, and eastward due to the increase of adsorption sites available plus a regional contribution of particle flux i. The benthic nepheloid layer (BNL) and the hydrothermal TAG plume distinctly enhance 210Pb scavenging due to increased surface adsorption on resuspended particles, or freshly formed precipitates. In contrast, 210Po does not appear to be significantly scavenged in these areas due to its relatively short half-life and the longer residence time of the particles. In the eastern boundary, enhanced surface production is evident, supported in part by lithogenic trace elements from nearby dust sources. Likewise biogenic trace elements are supplied from equatorial upwelling off Africa from benthic regeneration associated with benthic boundary scavenging.

  17. Biological Evaluation (In Vitro and In Vivo) of Bilayered Collagenous Coated (Nano Electrospun and Solid Wall) Chitosan Membrane for Periodontal Guided Bone Regeneration.

    Science.gov (United States)

    Lotfi, Ghogha; Shokrgozar, Mohammad Ali; Mofid, Rasoul; Abbas, Fatemeh Mashhadi; Ghanavati, Farzin; Baghban, Alireza Akbarzadeh; Yavari, Seyedeh Kimia; Pajoumshariati, Seyedramin

    2016-07-01

    The application of barrier membranes in guided bone regeneration (GBR) has become a commonly used surgical technique in periodontal research. The objectives of this study were to evaluate the in vitro biocompatibility and osteogenic differentiation of mesenchymal stem cells (MSCs) on two different collagenous coatings (nano electrospun fibrous vs. solid wall) of bilayered collagen/chitosan membrane and their histological evaluation on bone regeneration in rabbit calvarial defects. It was found that chitosan-nano electrospun collagen (CNC) membranes had higher proliferation/metabolic activity compared to the chitosan-collagen (CC) and pristine chitosan membranes. The qRT-PCR analysis demonstrated the CNC membranes induced significant expression of osteogenic genes (Osteocalcin, RUNX2 and Col-α1) in MSCs. Moreover, higher calcium content and alkaline phosphatase activity of MSCs were observed compared to the other groups. Histologic and histomorphometric evaluations were performed on the uncovered (negative control) as well as covered calvarial defects of ten adult white rabbits with different membranes (CNC, CC, BioGide (BG, positive control)) at 1 and 2 months after surgery. More bone formation was detected in the defects covered with CNC and BG membranes than those covered by CC and the negative control. No inflammation and residual biomaterial particles were observed on the membrane surface or in the surrounding tissues in the surgical areas. These results suggest that bilayer CNC membrane can have the potential for use as a GBR membrane material facilitating bone formation. PMID:26586588

  18. Biologic

    CERN Document Server

    Kauffman, L H

    2002-01-01

    In this paper we explore the boundary between biology and the study of formal systems (logic). In the end, we arrive at a summary formalism, a chapter in "boundary mathematics" where there are not only containers but also extainers ><, entities open to interaction and distinguishing the space that they are not. The boundary algebra of containers and extainers is to biologic what boolean algebra is to classical logic. We show how this formalism encompasses significant parts of the logic of DNA replication, the Dirac formalism for quantum mechanics, formalisms for protein folding and the basic structure of the Temperley Lieb algebra at the foundations of topological invariants of knots and links.

  19. Advanced Engineering Strategies for Periodontal Complex Regeneration

    OpenAIRE

    Chan Ho Park; Kyoung-Hwa Kim; Yong-Moo Lee; Yang-Jo Seol

    2016-01-01

    The regeneration and integration of multiple tissue types is critical for efforts to restore the function of musculoskeletal complex. In particular, the neogenesis of periodontal constructs for systematic tooth-supporting functions is a current challenge due to micron-scaled tissue compartmentalization, oblique/perpendicular orientations of fibrous connective tissues to the tooth root surface and the orchestration of multiple regenerated tissues. Although there have been various biological an...

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

    OpenAIRE

    Tiozzo, Stefano; Copley, Richard R.

    2015-01-01

    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 inde...

  1. Nanocomposites and bone regeneration

    Science.gov (United States)

    James, Roshan; Deng, Meng; Laurencin, Cato T.; Kumbar, Sangamesh G.

    2011-12-01

    This manuscript focuses on bone repair/regeneration using tissue engineering strategies, and highlights nanobiotechnology developments leading to novel nanocomposite systems. About 6.5 million fractures occur annually in USA, and about 550,000 of these individual cases required the application of a bone graft. Autogenous and allogenous bone have been most widely used for bone graft based therapies; however, there are significant problems such as donor shortage and risk of infection. Alternatives using synthetic and natural biomaterials have been developed, and some are commercially available for clinical applications requiring bone grafts. However, it remains a great challenge to design an ideal synthetic graft that very closely mimics the bone tissue structurally, and can modulate the desired function in osteoblast and progenitor cell populations. Nanobiomaterials, specifically nanocomposites composed of hydroxyapatite (HA) and/or collagen are extremely promising graft substitutes. The biocomposites can be fabricated to mimic the material composition of native bone tissue, and additionally, when using nano-HA (reduced grain size), one mimics the structural arrangement of native bone. A good understanding of bone biology and structure is critical to development of bone mimicking graft substitutes. HA and collagen exhibit excellent osteoconductive properties which can further modulate the regenerative/healing process following fracture injury. Combining with other polymeric biomaterials will reinforce the mechanical properties thus making the novel nano-HA based composites comparable to human bone. We report on recent studies using nanocomposites that have been fabricated as particles and nanofibers for regeneration of segmental bone defects. The research in nanocomposites, highlight a pivotal role in the future development of an ideal orthopaedic implant device, however further significant advancements are necessary to achieve clinical use.

  2. Advanced Engineering Strategies for Periodontal Complex Regeneration

    Directory of Open Access Journals (Sweden)

    Chan Ho Park

    2016-01-01

    Full Text Available The regeneration and integration of multiple tissue types is critical for efforts to restore the function of musculoskeletal complex. In particular, the neogenesis of periodontal constructs for systematic tooth-supporting functions is a current challenge due to micron-scaled tissue compartmentalization, oblique/perpendicular orientations of fibrous connective tissues to the tooth root surface and the orchestration of multiple regenerated tissues. Although there have been various biological and biochemical achievements, periodontal tissue regeneration remains limited and unpredictable. The purpose of this paper is to discuss current advanced engineering approaches for periodontal complex formations; computer-designed, customized scaffolding architectures; cell sheet technology-based multi-phasic approaches; and patient-specific constructs using bioresorbable polymeric material and 3-D printing technology for clinical application. The review covers various advanced technologies for periodontal complex regeneration and state-of-the-art therapeutic avenues in periodontal tissue engineering.

  3. [Regeneration of planarians: experimental object].

    Science.gov (United States)

    Sheĭman, I M; Kreshchenko, I D

    2015-01-01

    We discuss the expediency of using invertebrates, such as flatworms and planarians, as experimental objects. Free-living planarian flatworms (phylum Platyhelminthes, class Turbellaria) are invertebrate animals in which a bilateral symmetry appears for the first time in evolution and organs and tissues form. As the highest ecological link of the food chain--predators--these animals are characterized by a set of behavioral reactions controlled by a differentiated central nervous system. Planarians have unsurpassed ability to regenerate lost or damaged body parts. Owing to the ease of their breeding and their convenience for manipulations, these animals are used to study the influence of chemical and physical factors on the processes of life, growth, and reproduction. Currently, planarians are recognized as a model for biological research in the field of regeneration, stem cell biology, study of their proliferation and differentiation, as well as the regulatory mechanisms of morphogenetic processes. The genome of the planarian Schmidtea mediterranea was fully sequenced, which opened up the opportunity to work with this object at the molecular biological level. Furthermore, planarians are used in neurobiological and toxicological studies, in studying the evolutionary aspects of centralization of the nervous system, mechanisms of muscle contraction, and in the development of new antiparasitic drugs. This review aims to demonstrate the relevance and diversity of research conducted on simple biological objects--planarians--to awider audience to show the historical continuity of these studies and their wide geographical distribution and to focus on the studies carried out in Russia, which, as a rule, are not included in the foreign reviews on planarian regeneration. PMID:25898529

  4. REGene: a literature-based knowledgebase of animal regeneration that bridge tissue regeneration and cancer

    OpenAIRE

    Min Zhao; Bronwyn Rotgans; Tianfang Wang; Cummins, S. F.

    2016-01-01

    Regeneration is a common phenomenon across multiple animal phyla. Regeneration-related genes (REGs) are critical for fundamental cellular processes such as proliferation and differentiation. Identification of REGs and elucidating their functions may help to further develop effective treatment strategies in regenerative medicine. So far, REGs have been largely identified by small-scale experimental studies and a comprehensive characterization of the diverse biological processes regulated by RE...

  5. Pulp Regeneration: Current Approaches and Future Challenges

    Science.gov (United States)

    Yang, Jingwen; Yuan, Guohua; Chen, Zhi

    2016-01-01

    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. PMID:27014076

  6. 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.

  7. Stirling convertor regenerators

    CERN Document Server

    Ibrahim, Mounir B

    2011-01-01

    Stirling Convertor Regenerators addresses the latest developments and future possibilities in the science and practical application of Stirling engine regenerators and technology. Written by experts in the vanguard of alternative energy, this invaluable resource presents integral scientific details and design concepts associated with Stirling converter regenerators. Content is reinforced with novel insights and remarkable firsthand experience that the authors and their colleagues acquired while working at the National Aeronautics and Space Administration (NASA) and other leading organizations.

  8. Biological and Tribological Assessment of Poly(Ethylene Oxide Terephthalate)/Poly(Butylene Terephthalate), Polycaprolactone, and Poly (L\\DL) Lactic Acid Plotted Scaffolds for Skeletal Tissue Regeneration.

    Science.gov (United States)

    Hendrikson, Wilhelmus J; Zeng, Xiangqiong; Rouwkema, Jeroen; van Blitterswijk, Clemens A; van der Heide, Emile; Moroni, Lorenzo

    2016-01-21

    Additive manufactured scaffolds are fabricated from three commonly used biomaterials, polycaprolactone (PCL), poly (L\\DL) lactic acid (P(L\\DL)LA), and poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT). Scaffolds are compared biologically and tribologically. Cell-seeded PEOT/PBT scaffolds cultured in osteogenic and chondrogenic differentiation media show statistical significantly higher alkaline phosphatase (ALP) activity/DNA and glycosaminoglycans (GAG)/DNA ratios, followed by PCL and P(L\\DL)LA scaffolds, respectively. The tribological performance is assessed by determining the friction coefficients of the scaffolds at different loads and sliding velocities. With increasing load or decreasing sliding velocity, the friction coefficient value decreases. PEOT/PBT show to have the lowest friction coefficient value, followed by PCL and P(L\\DL)LA. The influence of the scaffold architecture is further determined with PEOT/PBT. Reducing of the fiber spacing results in a lower friction coefficient value. The best and the worst performing scaffold architecture are chosen to investigate the effect of cell culture on the friction coefficient. Matrix deposition is low in the cell-seeded scaffolds and the effect is, therefore, undetermined. Taken together, our studies show that PEOT/PBT scaffolds support better skeletal differentiation of seeded stromal cells and lower friction coefficient compared to PCL and P(L/DL)A scaffolds. PMID:26775915

  9. Discuss of Ethics Problems of Stem Cell Regeneration Biology Research and Clinical Application%干细胞再生生物学研究及临床应用的道德伦理问题探讨

    Institute of Scientific and Technical Information of China (English)

    郭玲; William Isaacs; 徐学红; 李忠光; 杨荣华; 薛雅卓; 王春慧; Hiroshi Takeshima; MengMeng Xu; 刘万红; Jianjie Ma

    2016-01-01

    Stem cells have a pluripotency to develop to over 250 different cells composed of human body.This characteristic makes stem cell regeneration biology a most attention field of today’s life science research.USA and European countries have been enforced long-term limit on human Stem Cell ( SC) research.One of the reasons is that there is no clear definition of the ethics of stem cell research and application.In this study, the discussions focus on: (1 Ethical issues in stem cell science and the moral issues in scientific research on the prospects of stem cell re-generative biology application.(2) Cloning human embryos in order to solve ethical issues in stem cells clinical application such as materials shortage of organ transplantation, human stem cell source and whether the"life wastes"have the right to survive and so on.(3) New Internation-al ethical guidelines should be in opposition to cover future ethical issues generated from the most recent stem cell researches.To clarify relation-ship between stem cell research, clinical application and ethic morality as soon as possible, accelerate the establishment of relevant laws and regu-lations is undoubtedly the urgent need to protect stem cell regeneration biology research for the benefit of human health in the world.%干细胞具有分化为人类个体中250余种细胞的特性,该特性使再生生物学成为当今生命科学研究中最受瞩目的领域。美国和欧洲国家对干细胞研究的监管十分严格,其中一个重要原因是干细胞研究应用的道德伦理尚没有明确的界定。本文就以下几个问题进行讨论:干细胞科学研究中的伦理道德问题,干细胞再生生物学应用前景引发的科研道德问题;克隆人类胚胎以解决器官移植的材料短缺,人类干细胞来源和“生命废料”是否具有生存权等干细胞临床应用的伦理学问题;制定的国际伦理准则或法则应该对未来干细胞成果引发的伦理问

  10. In vitro cell-biological performance and structural characterization of selective laser sintered and plasma surface functionalized polycaprolactone scaffolds for bone regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Van Bael, Simon, E-mail: simon.vanbael@mech.kuleuven.be [Department of Mechanical Engineering, Division of Production Engineering, Machine Design and Automation, Katholieke Universiteit Leuven, Celestijnenlaan 300b, 3001 Leuven (Belgium); Department of Mechanical Engineering, Division of Biomechanics and Engineering Design, Katholieke Universiteit Leuven, Celestijnenlaan 300c, bus 2419, 3001 Heverlee (Belgium); Prometheus, Division of Skeletal Tissue Engineering, Katholieke Universiteit Leuven, O and N 1, Herestraat 49, bus 813, 3000 Leuven (Belgium); Desmet, Tim [Polymer Chemistry and Biomaterials Research Group, Ghent University, Krijgslaan 281 S4 Bis, Ghent, 9000 (Belgium); Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering, Ghent University, Jozef Plateaustraat 22, 9000 Ghent (Belgium); Chai, Yoke Chin [Prometheus, Division of Skeletal Tissue Engineering, Katholieke Universiteit Leuven, O and N 1, Herestraat 49, bus 813, 3000 Leuven (Belgium); Pyka, Gregory [Prometheus, Division of Skeletal Tissue Engineering, Katholieke Universiteit Leuven, O and N 1, Herestraat 49, bus 813, 3000 Leuven (Belgium); Department of Metallurgy and Materials Engineering, Katholieke Universiteit Leuven, Kasteelpark Arenberg 44, bus 2450, 3001 Leuven (Belgium); Dubruel, Peter [Polymer Chemistry and Biomaterials Research Group, Ghent University, Krijgslaan 281 S4 Bis, Ghent, 9000 (Belgium); Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering, Ghent University, Jozef Plateaustraat 22, 9000 Ghent (Belgium); Kruth, Jean-Pierre [Department of Mechanical Engineering, Division of Production Engineering, Machine Design and Automation, Katholieke Universiteit Leuven, Celestijnenlaan 300b, 3001 Leuven (Belgium); Schrooten, Jan [Prometheus, Division of Skeletal Tissue Engineering, Katholieke Universiteit Leuven, O and N 1, Herestraat 49, bus 813, 3000 Leuven (Belgium)

    2013-08-01

    In the present study a structural characterization and in vitro cell-biological evaluation was performed on polycaprolactone (PCL) scaffolds that were produced by the additive manufacturing technique selective laser sintering (SLS), followed by a plasma-based surface modification technique, either non-thermal oxygen plasma or double protein coating, to functionalize the PCL scaffold surfaces. In the first part of this study pore morphology by means of 2D optical microscopy, surface chemistry by means of hydrophilicity measurement and X-ray photoelectron spectroscopy, strut surface roughness by means of 3D micro-computed tomography (CT) imaging and scaffold mechanical properties by means of compression testing were evaluated before and after the surface modifications. The results showed that both surface modifications increased the PCL scaffold hydrophilicity without altering the morphological and mechanical properties. In the second part of this study the in vitro cell proliferation and differentiation of human osteoprogenitor cells, over 14 days of culture in osteogenic and growth medium were investigated. The O{sub 2} plasma modification gave rise to a significant lower in vitro cell proliferation compared to the untreated and double protein coated scaffolds. Furthermore the double protein coating increased in vitro cell metabolic activity and cell differentiation compared to the untreated and O{sub 2} plasma PCL scaffolds when OM was used. - Highlights: • Polycaprolactone scaffolds are produced with selective laser sintering. • 2 types of plasma based surface functionalization were applied. • Plasma had no significant effect on strut roughness and pore morphology. • Plasma improved surface hydrophilicity. • In vitro cell differentiation increased with plasma protein coated functionalization.

  11. In vitro cell-biological performance and structural characterization of selective laser sintered and plasma surface functionalized polycaprolactone scaffolds for bone regeneration

    International Nuclear Information System (INIS)

    In the present study a structural characterization and in vitro cell-biological evaluation was performed on polycaprolactone (PCL) scaffolds that were produced by the additive manufacturing technique selective laser sintering (SLS), followed by a plasma-based surface modification technique, either non-thermal oxygen plasma or double protein coating, to functionalize the PCL scaffold surfaces. In the first part of this study pore morphology by means of 2D optical microscopy, surface chemistry by means of hydrophilicity measurement and X-ray photoelectron spectroscopy, strut surface roughness by means of 3D micro-computed tomography (CT) imaging and scaffold mechanical properties by means of compression testing were evaluated before and after the surface modifications. The results showed that both surface modifications increased the PCL scaffold hydrophilicity without altering the morphological and mechanical properties. In the second part of this study the in vitro cell proliferation and differentiation of human osteoprogenitor cells, over 14 days of culture in osteogenic and growth medium were investigated. The O2 plasma modification gave rise to a significant lower in vitro cell proliferation compared to the untreated and double protein coated scaffolds. Furthermore the double protein coating increased in vitro cell metabolic activity and cell differentiation compared to the untreated and O2 plasma PCL scaffolds when OM was used. - Highlights: • Polycaprolactone scaffolds are produced with selective laser sintering. • 2 types of plasma based surface functionalization were applied. • Plasma had no significant effect on strut roughness and pore morphology. • Plasma improved surface hydrophilicity. • In vitro cell differentiation increased with plasma protein coated functionalization

  12. Fgf regulates dedifferentiation during skeletal muscle regeneration in adult zebrafish.

    Science.gov (United States)

    Saera-Vila, Alfonso; Kish, Phillip E; Kahana, Alon

    2016-09-01

    Fibroblast growth factors (Fgfs) regulate critical biological processes such as embryonic development, tissue homeostasis, wound healing, and tissue regeneration. In zebrafish, Fgf signaling plays an important role in the regeneration of the spinal cord, liver, heart, fin, and photoreceptors, although its exact mechanism of action is not fully understood. Utilizing an adult zebrafish extraocular muscle (EOM) regeneration model, we demonstrate that blocking Fgf receptor function using either a chemical inhibitor (SU5402) or a dominant-negative transgenic construct (dnFGFR1a:EGFP) impairs muscle regeneration. Adult zebrafish EOMs regenerate through a myocyte dedifferentiation process, which involves a muscle-to-mesenchyme transition and cell cycle reentry by differentiated myocytes. Blocking Fgf signaling reduced cell proliferation and active caspase 3 levels in the regenerating muscle with no detectable levels of apoptosis, supporting the hypothesis that Fgf signaling is involved in the early steps of dedifferentiation. Fgf signaling in regenerating myocytes involves the MAPK/ERK pathway: inhibition of MEK activity with U0126 mimicked the phenotype of the Fgf receptor inhibition on both muscle regeneration and cell proliferation, and activated ERK (p-ERK) was detected in injured muscles by immunofluorescence and western blot. Interestingly, following injury, ERK2 expression is specifically induced and activated by phosphorylation, suggesting a key role in muscle regeneration. We conclude that the critical early steps of myocyte dedifferentiation in EOM regeneration are dependent on Fgf signaling. PMID:27267062

  13. Liver Development, Regeneration, and Carcinogenesis

    Directory of Open Access Journals (Sweden)

    Janet W. C. Kung

    2010-01-01

    Full Text Available The identification of putative liver stem cells has brought closer the previously separate fields of liver development, regeneration, and carcinogenesis. Significant overlaps in the regulation of these processes are now being described. For example, studies in embryonic liver development have already provided the basis for directed differentiation of human embryonic stem cells and induced pluripotent stem cells into hepatocyte-like cells. As a result, the understanding of the cell biology of proliferation and differentiation in the liver has been improved. This knowledge can be used to improve the function of hepatocyte-like cells for drug testing, bioartificial livers, and transplantation. In parallel, the mechanisms regulating cancer cell biology are now clearer, providing fertile soil for novel therapeutic approaches. Recognition of the relationships between development, regeneration, and carcinogenesis, and the increasing evidence for the role of stem cells in all of these areas, has sparked fresh enthusiasm in understanding the underlying molecular mechanisms and has led to new targeted therapies for liver cirrhosis and primary liver cancers.

  14. Strategies for lung regeneration

    Directory of Open Access Journals (Sweden)

    Thomas H. Petersen

    2011-05-01

    Full Text Available Due to the limited ability of the adult lung to regenerate and the frequency of lung disease, the lung is a tissue that can especially benefit from regenerative medicine. Prospects for lung regeneration have made great strides in the past year. In this review, we summarize recent progress and key challenges for approaches in lung regenerative medicine. With a focus on the matrix components critical for the development of regenerative lung tissues, we discuss possible cell sources for lung regeneration, key matrix effects on cell repopulation, and physical stimuli that will aid in the growth of lung tissues in vitro.

  15. In-situ regeneration measures after contamination due to a spill of light fuel oil

    International Nuclear Information System (INIS)

    An example is presented of how biological in-situ regeneration measures can reduce the cost level in all relevant cost factors of soil regeneration, i.e. constructional measures, landfilling, and standstill times. In consequence, the biological technology is considered to be much more efficient than coventional methods. (orig.)

  16. 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.

  17. Scaling and regeneration of self-organized patterns.

    Science.gov (United States)

    Werner, Steffen; Stückemann, Tom; Beirán Amigo, Manuel; Rink, Jochen C; Jülicher, Frank; Friedrich, Benjamin M

    2015-04-01

    Biological patterns generated during development and regeneration often scale with organism size. Some organisms, e.g., flatworms, can regenerate a rescaled body plan from tissue fragments of varying sizes. Inspired by these examples, we introduce a generalization of Turing patterns that is self-organized and self-scaling. A feedback loop involving diffusing expander molecules regulates the reaction rates of a Turing system, thereby adjusting pattern length scales proportional to system size. Our model captures essential features of body plan regeneration in flatworms as observed in experiments. PMID:25884138

  18. Model Systems for Cardiovascular Regenerative Biology

    OpenAIRE

    Garbern, Jessica C.; Mummery, Christine L.; Lee, Richard T.

    2013-01-01

    There is an urgent clinical need to develop new therapeutic approaches to treat heart failure, but the biology of cardiovascular regeneration is complex. Model systems are required to advance our understanding of biological mechanisms of cardiac regeneration as well as to test therapeutic approaches to regenerate tissue and restore cardiac function following injury. An ideal model system should be inexpensive, easily manipulated, easily reproducible, physiologically representative of human di...

  19. Regeneration under shelterwood

    OpenAIRE

    Erefur, Charlotta

    2007-01-01

    The objectives of this work were to quantify the effects of stand stem density (SSD), orientation and distance with respect to shelter tree, and fertilisation on the establishment of Pinus sylvestris L. and Picea abies (L.) Karst. regenerated by direct seeding and planting at different soil preparations. The field experiments were performed on South (64°14ʼN, 19°46ʼE, 225 m a.s.l.) and North (64°09ʼN, 19°36ʼE, 274 m a.s.l.) slopes in boreal Sweden. Regeneration and early growth in three stand ...

  20. 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...

  1. 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.

  2. Seed recovery and regeneration

    International Nuclear Information System (INIS)

    Magnetohydrodynamic's (MHD) electric power generation capability depends on Faraday's law of induction. An ionized gas, called plasma, passes through a fixed magnetic field. The plasma is produced by seeding flue gases at a temperature of around 2500 deg C with potassium carbonate or formate. In a coal-fired open cycle MHD power plant the potassium seed material is in direct contact with the polluted flue gas from coal combustion. The molten slag droplets will capture a certain amount of potassium. The sulphur dioxide in the flue gases will react with potassium to potassium sulphate. The spent seed material has to be recovered and reprocessed so that the potassium can be reused as seed material. We can distinguish a preprocessing and a regeneration step. Seed preprocessing removes the minerals and volatile coal constituents from the potassium salts. Seed regeneration transforms the purified potassium sulphate into potassium carbonate or formate. Eight regeneration processes have been evaluated. The processes that convert the sulphur of the coal into saleable sulphur or sulphuric acid are still at an early stage of development. Considering all pros and cons, the Formate/Econoseed process appears most suited for seed regeneration purposes in coal-fired MHD systems. For an advanced MHD power plant the mass flow rates of the flue gas and of the potassium containing off-product streams will be calculated. It will be shown that the sulphur content of coal will influence the economical efficiency of the power plant

  3. Regenerated Fe is tasty!

    Science.gov (United States)

    Nuester, J.; Twining, B. S.

    2012-12-01

    Bioavailability of nutrients is an essential factor controlling primary productivity in the ocean. In addition to macronutrients such as nitrogen and phosphorous, availability of the trace element iron unequivocally affects growth rates and community structure of phytoplankton and thereby primary productivity in many ocean regions. External sources of iron such as Aeolian dust, upwelling of Fe-rich waters, and hydrothermal are reduced in high-nutrient low-chlorophyll regions, and most Fe used by phytoplankton has been regenerated by zooplankton. While zooplankton regeneration of Fe was first shown two decades ago, major factors controlling this process such as chemical composition of prey and grazer taxonomy are not well constrained. As pH varies significantly in digestive systems between protozoa and mesozooplankton, we hypothesize that the extent and the bioavailability of regenerated Fe is a function of the digestive physiology. Furthermore, major element components such as silica for diatoms and calcium carbonate for cocolithophores may be able to buffer the pH of digestive systems of different grazer taxa. Such effects may further influence the magnitude and bioavailability of regenerated Fe. In order to constrain the effect of grazer taxonomy and chemical composition of prey on Fe bioavailability, 55Fe-labeled phytoplankton were fed to different grazers and unlabeled phytoplankton were subsequently inoculated to the filtrate of the grazing experiment in the regrowth phase of the experiment, and the uptake of 55Fe into the phytoplankton biomass was monitored over time. A parallel uptake experiment using inorganic 55Fe was used to compare the bioavailability of regenerated and inorganic Fe to the same phytoplankton species. Furthermore, some samples of the inorganic and the regenerated uptake experiments were treated with an oxalate rinse to remove any adsorbed Fe. This allowed us to estimate the adsorption of 55Fe from either source to the cell walls of

  4. 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.

  5. Regeneration of Zebrafish CNS: Adult Neurogenesis

    Directory of Open Access Journals (Sweden)

    Sukla Ghosh

    2016-01-01

    Full Text Available Regeneration in the animal kingdom is one of the most fascinating problems that have allowed scientists to address many issues of fundamental importance in basic biology. However, we came to know that the regenerative capability may vary across different species. Among vertebrates, fish and amphibians are capable of regenerating a variety of complex organs through epimorphosis. Zebrafish is an excellent animal model, which can repair several organs like damaged retina, severed spinal cord, injured brain and heart, and amputated fins. The focus of the present paper is on spinal cord regeneration in adult zebrafish. We intend to discuss our current understanding of the cellular and molecular mechanism(s that allows formation of proliferating progenitors and controls neurogenesis, which involve changes in epigenetic and transcription programs. Unlike mammals, zebrafish retains radial glia, a nonneuronal cell type in their adult central nervous system. Injury induced proliferation involves radial glia which proliferate, transcribe embryonic genes, and can give rise to new neurons. Recent technological development of exquisite molecular tools in zebrafish, such as cell ablation, lineage analysis, and novel and substantial microarray, together with advancement in stem cell biology, allowed us to investigate how progenitor cells contribute to the generation of appropriate structures and various underlying mechanisms like reprogramming.

  6. Regeneration of Zebrafish CNS: Adult Neurogenesis

    Science.gov (United States)

    Ghosh, Sukla; Hui, Subhra Prakash

    2016-01-01

    Regeneration in the animal kingdom is one of the most fascinating problems that have allowed scientists to address many issues of fundamental importance in basic biology. However, we came to know that the regenerative capability may vary across different species. Among vertebrates, fish and amphibians are capable of regenerating a variety of complex organs through epimorphosis. Zebrafish is an excellent animal model, which can repair several organs like damaged retina, severed spinal cord, injured brain and heart, and amputated fins. The focus of the present paper is on spinal cord regeneration in adult zebrafish. We intend to discuss our current understanding of the cellular and molecular mechanism(s) that allows formation of proliferating progenitors and controls neurogenesis, which involve changes in epigenetic and transcription programs. Unlike mammals, zebrafish retains radial glia, a nonneuronal cell type in their adult central nervous system. Injury induced proliferation involves radial glia which proliferate, transcribe embryonic genes, and can give rise to new neurons. Recent technological development of exquisite molecular tools in zebrafish, such as cell ablation, lineage analysis, and novel and substantial microarray, together with advancement in stem cell biology, allowed us to investigate how progenitor cells contribute to the generation of appropriate structures and various underlying mechanisms like reprogramming. PMID:27382491

  7. The “Stars and Stripes” Metaphor for Animal Regeneration-Elucidating Two Fundamental Strategies along a Continuum

    Directory of Open Access Journals (Sweden)

    Baruch Rinkevich

    2012-12-01

    Full Text Available A number of challenges have hindered the development of a unified theory for metazoan regeneration. To describe the full range of complex regeneration phenomena in Animalia, we suggest that metazoans that regenerate missing body parts exhibit biological attributes that are tailored along a morpho-spatial regeneration continuum, illustrated in its polar scenarios by the USA “stars and stripes” flag. Type 1 organisms (“T1, ‘stars’” are typical colonial organisms (but contain unitary taxa that are able to regenerate “whole new stars”, namely, whole bodies and colonial modules, through systemic induction and sometimes multiple regeneration foci (hollow regeneration spheres, resembling the blastula that compete for dominance. They regenerate soma and germ constituents with pluripotent adult stem cells and exhibit somatic-embryogenesis mode of ontogeny. Type 2 organisms (“T2, ‘stripes’” are capable of limited regeneration of somatic constituents via fate-restricted stem cells, and regenerate through centralized inductions that lead to a single regeneration front. T2 organisms are unitary and use preformistic mode of ontogeny. T1 and T2 organisms also differ in interpretation of what constitutes positional information. T2 organisms also execute alternative, less effective, regeneration designs (i.e., scar formation. We assigned 15 characteristics that distinguish between T1/T2 strategies: those involving specific regeneration features and those operating on biological features at the whole-organism level. Two model organisms are discussed, representing the two strategies of T1/T2 along the regeneration continuum, the Botrylloides whole body regeneration (T1 and the mouse digit-tip regeneration (T2 phenomena. The above working hypothesis also postulates that regeneration is a primeval attribute of metazoans. As specified, the “stars and stripes” paradigm allows various combinations of the biological features assigned to T1

  8. Morphology and Intrinsic Excitability of Regenerating Sensory and Motor Neurons Grown on a Line Micropattern

    OpenAIRE

    Benzina, Ouafa; Cloitre, Thierry; Martin, Marta; Raoul, Cédric; Gergely, Csilla; Scamps, Frédérique

    2014-01-01

    Axonal regeneration is one of the greatest challenges in severe injuries of peripheral nerve. To provide the bridge needed for regeneration, biological or synthetic tubular nerve constructs with aligned architecture have been developed. A key point for improving axonal regeneration is assessing the effects of substrate geometry on neuronal behavior. In the present study, we used an extracellular matrix-micropatterned substrate comprising 3 µm wide lines aimed to physically mimic the in vivo l...

  9. 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.

  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. 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.

  12. Determinants of axonal regeneration

    OpenAIRE

    Frisén, J

    1997-01-01

    Axons often regrow to their targets and lost functions may be restored after an injury in the peripheral nervous system. In contrast, axonal regeneration is generally very limited after injuries in the central nervous system, and functional impairment is usually permanent. The regenerative capacity depends on intrinsic neuronal factors as weil as the interaction of neurons with other cells. Glial cells may, in different situations, either support or inhibit axo...

  13. Problems concerning the microbiological regeneration of a site contaminated with used oil

    International Nuclear Information System (INIS)

    After outlining the basic facts of the used oil problem in Germany the report discusses: Biotransformation of hydrocarbons, polychlorinated biphenyls (PCB), pentachlorophenols (PCP), and volatile chlorocarbons; pollutants in soils; microbiological regeneration of groundwater and soil; accompanying procedures of biological regeneration. (HS)

  14. Gene expression profiling of intestinal regeneration in the sea cucumber

    Directory of Open Access Journals (Sweden)

    Méndez-Merced Ana T

    2009-06-01

    Full Text Available Abstract Background Among deuterostomes, the regenerative potential is maximally expressed in echinoderms, animals that can quickly replace most injured organs. In particular, sea cucumbers are excellent models for studying organ regeneration since they regenerate their digestive tract after evisceration. However, echinoderms have been sidelined in modern regeneration studies partially because of the lack of genome-wide profiling approaches afforded by modern genomic tools. For the last decade, our laboratory has been using the sea cucumber Holothuria glaberrima to dissect the cellular and molecular events that allow for such amazing regenerative processes. We have already established an EST database obtained from cDNA libraries of normal and regenerating intestine at two different regeneration stages. This database now has over 7000 sequences. Results In the present work we used a custom-made microchip from Agilent with 60-mer probes for these ESTs, to determine the gene expression profile during intestinal regeneration. Here we compared the expression profile of animals at three different intestinal regeneration stages (3-, 7- and 14-days post evisceration against the profile from normal (uneviscerated intestines. The number of differentially expressed probes ranged from 70% at p actins, and developmental genes, such as Wnt and Hox genes, show interesting expression profiles during regeneration. Conclusion Our findings set the base for future studies into the molecular basis of intestinal regeneration. Moreover, it advances the use of echinoderms in regenerative biology, animals that because of their amazing properties and their key evolutionary position, might provide important clues to the genetic basis of regenerative processes.

  15. Oscarella lobularis (Homoscleromorpha, Porifera) Regeneration: Epithelial Morphogenesis and Metaplasia.

    Science.gov (United States)

    Ereskovsky, Alexander V; Borisenko, Ilya E; Lapébie, Pascal; Gazave, Eve; Tokina, Daria B; Borchiellini, Carole

    2015-01-01

    morphogenesis during Oscarella regeneration could have important implications for our understanding of the diversity and evolution of regeneration mechanisms in metazoans, and is a strong basis for future investigations with molecular-biological approaches. PMID:26270639

  16. Biomechanical Stability of Dental Implants in Augmented Maxillary Sites: Results of a Randomized Clinical Study with Four Different Biomaterials and PRF and a Biological View on Guided Bone Regeneration

    Directory of Open Access Journals (Sweden)

    Troedhan Angelo

    2015-01-01

    Full Text Available Introduction. Bone regenerates mainly by periosteal and endosteal humoral and cellular activity, which is given only little concern in surgical techniques and choice of bone grafts for guided bone regeneration. This study investigates on a clinical level the biomechanical stability of augmented sites in maxillary bone when a new class of moldable, self-hardening calcium-phosphate biomaterials (SHB is used with and without the addition of Platelet Rich Fibrin (aPRF in the Piezotome-enhanced subperiosteal tunnel-technique (PeSPTT. Material and Methods. 82 patients with horizontal atrophy of anterior maxillary crest were treated with PeSPTT and randomly assigned biphasic (60% HA/40% bTCP or monophasic (100% bTCP SHB without or with addition of aPRF. 109 implants were inserted into the augmented sites after 8.3 months and the insertion-torque-value (ITV measured as clinical expression of the (biomechanical stability of the augmented bone and compared to ITVs of a prior study in sinus lifting. Results. Significant better results of (biomechanical stability almost by two-fold, expressed by higher ITVs compared to native bone, were achieved with the used biomaterials and more constant results with the addition of aPRF. Conclusion. The use of SHB alone or combined with aPRF seems to be favourable to achieve a superior (biomechanical stable restored alveolar bone.

  17. Approaches Towards Endogenous Pancreatic Regeneration

    OpenAIRE

    Banerjee, Meenal; Kanitkar, Meghana; Bhonde, Ramesh R.

    2005-01-01

    The phenomenon of pancreatic regeneration in mammals has been well documented. It has been shown that pancreatic tissue is able to regenerate in several species of mammal after surgical insult. This tissue is also known to have the potential to maintain or increase its β-cell mass in response to metabolic demands during pregnancy and obesity. Since deficiency in β-cell mass is the hallmark of most forms of diabetes, it is worthwhile understanding pancreatic regeneration in the context of this...

  18. URBAN REGENERATION PROCESSES IN RIGA

    OpenAIRE

    Guntis Šolks

    2013-01-01

    URBAN REGENERATION PROCESSES IN RIGA ANNOTATION Urban regeneration is characterized by various forms and implications and it is an important research issue for modern urban geography. Riga also has experienced various transformations since the reestablishment of the independence of Latvia. Urban regeneration have an important role in the urban transformation processes, what are providing the revitalization and reuse of urban brownfields, thus contributing to sustainable u...

  19. 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.

  20. Tissue Regeneration: A Silk Road.

    Science.gov (United States)

    Jao, Dave; Mou, Xiaoyang; Hu, Xiao

    2016-01-01

    Silk proteins are natural biopolymers that have extensive structural possibilities for chemical and mechanical modifications to facilitate novel properties, functions, and applications in the biomedical field. The versatile processability of silk fibroins (SF) into different forms such as gels, films, foams, membranes, scaffolds, and nanofibers makes it appealing in a variety of applications that require mechanically superior, biocompatible, biodegradable, and functionalizable biomaterials. There is no doubt that nature is the world's best biological engineer, with simple, exquisite but powerful designs that have inspired novel technologies. By understanding the surface interaction of silk materials with living cells, unique characteristics can be implemented through structural modifications, such as controllable wettability, high-strength adhesiveness, and reflectivity properties, suggesting its potential suitability for surgical, optical, and other biomedical applications. All of the interesting features of SF, such as tunable biodegradation, anti-bacterial properties, and mechanical properties combined with potential self-healing modifications, make it ideal for future tissue engineering applications. In this review, we first demonstrate the current understanding of the structures and mechanical properties of SF and the various functionalizations of SF matrices through chemical and physical manipulations. Then the diverse applications of SF architectures and scaffolds for different regenerative medicine will be discussed in detail, including their current applications in bone, eye, nerve, skin, tendon, ligament, and cartilage regeneration. PMID:27527229

  1. Progesterone and peripheral nerve regeneration

    Institute of Scientific and Technical Information of China (English)

    Fei Fan; Haichao Li; Yuwei Wang; Yanglin Zheng; Lianjun Jia; Zhihui Wang

    2006-01-01

    OBJECTIVE: To explore the effect of progesterone on peripheral nerve regeneration.DATA SOURCES: An online search of Medline and OVID databases was under taken to identify articles about progesterone and peripheral nerve regeneration published in English between January 1990 and June 2004 by using the keywords of "peripheral nerve, injury, progesterone, regeneration".STUDY SELECTION: The data were primarily screened, those correlated with progesterone and peripheral nerve regeneration were involved, and their original articles were further searched, the repetitive studies or reviews were excluded.DATA EXTRACTION: Totally 59 articles about progesterone and peripheral nerve regeneration were collected, and 26 of them were involved, the other 33 excluded ones were the repetitive studies or reviews.DATA SYNTHESIS: Recent researches found that certain amount of progesterone could be synthetized in peripheral nervous system, and the expression of progesterone receptor could be found in sensory neurons and Schwann cells. After combined with the receptor, endogenous and exogenous progesterone can accelerate the formation of peripheral nerve myelin sheath, also promote the axonal regeneration.CONCLUSION: Progesterone plays a role in protecting neurons, increasing the sensitivity of nerve tissue to nerve growth factor, and accelerating regeneration of nerve in peripheral nerve regeneration, which provides theoretical references for the treatment of demyelinated disease and nerve injury, as well as the prevention of neuroma, especially that the in vivo level of progesterone should be considered for the elderly people accompanied by neuropathy and patients with congenital luteal phase defect, which is of positive significance in guiding the treatment.

  2. The Basis of Muscle Regeneration

    Directory of Open Access Journals (Sweden)

    Antonio Musarò

    2014-01-01

    Full Text Available Muscle regeneration recapitulates many aspects of embryonic myogenesis and is an important homeostatic process of the adult skeletal muscle, which, after development, retains the capacity to regenerate in response to appropriate stimuli, activating the muscle compartment of stem cells, namely, satellite cells, as well as other precursor cells. Moreover, significant evidence suggests that while stem cells represent an important determinant for tissue regeneration, a “qualified” environment is necessary to guarantee and achieve functional results. It is therefore plausible that the loss of control over these cell fate decisions could lead to a pathological transdifferentiation, leading to pathologic defects in the regenerative process. This review provides an overview about the general aspects of muscle development and discusses the cellular and molecular aspects that characterize the five interrelated and time-dependent phases of muscle regeneration, namely, degeneration, inflammation, regeneration, remodeling, and maturation/functional repair.

  3. Intra-axonal myosin and actin in nerve regeneration.

    Science.gov (United States)

    McQuarrie, Irvine G; Lund, Linda M

    2009-10-01

    A focused review of sciatic nerve regeneration in the rat model, based on research conducted by the authors, is presented. We examine structural proteins carried distally in the axon by energy-requiring motor enzymes, using protein chemistry and molecular biology techniques in combination with immunohistochemistry. Relevant findings from other laboratories are cited and discussed. The general conclusion is that relatively large amounts of actin and tubulin are required to construct a regenerating axon and that these materials mainly originate in the parent axon. The motor enzymes that carry these proteins forward as macromolecules include kinesin and dynein but probably also include myosin. PMID:19927086

  4. Introduction to the Special Issue on Heart Regeneration and Rejuvenation

    Directory of Open Access Journals (Sweden)

    Richard P. Harvey

    2014-11-01

    Full Text Available Despite therapeutic advances that slow its progression, heart disease remains the world's leading cause of death. Until recently, the “Holy Grail” of cardiac biology, to regenerate the damaged heart, appeared to be a fantastical and quixotic quest. However, recent studies showing that the mammalian heart possesses an innate, albeit limited, regenerative capacity offer hope that effective cardiac regeneration may be an attainable goal. This Special Issue of Stem Cell Research reviews the remarkable progress that has been made in this field in the last few years.

  5. 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

  6. Insights to regenerate materials: learning from nature

    Science.gov (United States)

    García-Aznar, J. M.; Valero, C.; Gómez-Benito, M. J.; Javierre, E.

    2016-08-01

    Self-healing materials, both biological and engineered, integrate the ability to repair themselves and recover their functionality using the resources inherently available to them. Although significant advances have been made, in recent years, for the design of different concepts of self-healing materials, this work aims to provide some insights into how living materials are able to regenerate or heal when a fracture or injury occurs. The main sensors that regulate this adaptive and regenerative behavior are the cells. These are able to sense the mechanical alterations in their surroundings and regulate their activity in order to remove dead tissue and/or create new tissue. Therefore, understanding how cells are able to regenerate tissues under complex and multiphysics conditions can define the biomimetics guidelines to heal through inert or traditional engineering materials. In this work, we present a combination of experiments and different kinds of multiscale and multiphysics models in order to understand how mechanics regulate some mechanisms at cell and tissue level. This combination of results aims to gain insight into the development of novel strategies for self-healing materials, mimicking the behavior induced by cells and biological tissues.

  7. 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...

  8. Axonal regeneration through arterial grafts.

    OpenAIRE

    Anderson, P. N.; Turmaine, M.

    1986-01-01

    The left common peroneal nerves of adult inbred mice were severed and allowed to regenerate through the lumina of Y-shaped tubes comprising grafts of abdominal aorta and its bifurcation. Very little regeneration took place within the grafts unless the distal nerve stump was inserted into one limb of the Y-tube. Using syngeneic grafts virtually all the axons regenerating through the lumen grew down the limb of the Y-tube containing the distal nerve. Using non-syngeneic grafts, however, a subst...

  9. Biological effects

    International Nuclear Information System (INIS)

    Following an introduction into the field of cellular radiation effect considering the most important experimental results, the biological significance of the colony formation ability is brought out. The inactivation concept of stem cells does not only prove to be good, according to the present results, in the interpretation of the pathogenesis of acute radiation effects on moult tissue, it also enables chronicle radiation injuries to be interpreted through changes in the fibrous part of the organs. Radiation therapy of tumours can also be explained to a large extent by the radiation effect on the unlimited reproductiveness of tumour cells. The more or less similar dose effect curves for healthy and tumour tissue in practice lead to intermittent irradiation. The dependence of the intermittent doses and intervals on factors such as Elkind recovery, synchronisation, redistribution, reoxygenation, repopulation and regeneration are reviewed. (ORU/LH)

  10. Regenerable Contaminant Removal System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Regenerable Contaminant Removal System (RCRS) is an innovative method to remove sulfur and halide compounds from contaminated gas streams to part-per-billion...

  11. Tissue engineering in periodontal regeneration: A brief review

    Directory of Open Access Journals (Sweden)

    Sarita Dabra

    2012-01-01

    Full Text Available Periodontal disease is a major public health issue and the development of effective therapies to treat the disease and regenerate periodontal tissue is an important goal of today′s medicine. Regeneration of periodontal tissue is perhaps one of the most complex process to occur in the body. Langer and colleagues proposed tissue engineering as a possible technique for regenerating the lost periodontal tissues. Tissue engineering is a multidisciplinary field, which involves the application of the principles and methods of engineering and life sciences to help in the development of biological substitutes to restore, maintain or improve the function of damaged tissues and organs. A Google/Medline search was conducted and relevant literature evaluating the potential role of the tissue engineering in periodontal regeneration, which included histological studies and controlled clinical trials, was reviewed. A comprehensive search was designed. The articles were independently screened for eligibility. Articles with authentic controls and proper randomization and pertaining specifically to their role in periodontal regeneration were included. The available literature was analyzed and compiled. The analysis indicate tissue engineering to be a promising, as well as an effective novel approach to reconstruct and engineer the periodontal apparatus. Here, we represent several articles, as well as recent texts that make up a special and an in-depth review on the subject. The purpose behind writing this brief review has been to integrate the evidence of research related to tissue engineering so as to implement them in our daily practice.

  12. Effect of CO2 laser amputation on hydra regeneration

    Science.gov (United States)

    De Petrocellis, L.; Finizio, Andrea; Minei, R.; Mormile, Pasquale; Pierattini, Giovanni

    1994-08-01

    In order to investigate laser effects on biological specimens, Hydra, a coelenterate with high regeneration rate, was observed for ten days during regeneration after CO2 laser cutting. Control animals were cut with a razor blade immediately below the tentacle whorl under a dissecting microscope while they were in small glass petri dishes. They regenerated tentacles completely 8 to 10 days from the cutting. Hydra were cut in the same position with CO2 laser. As a first step, we studied the effect of the laser beam on the normal behaviour of hydra. For the cutting, we used four different power intensities: 0.5, 1.0, 1.5 and 2.0 W. At different power intensities the animals regenerated the tentacles. However in about 20% of the animals the amputation performed with 1 and 1.5 W originated a quicker regeneration of tentacles. No effect was observed on asexual reproduction of the polyps and therefore also no change of the bud index.

  13. Germline transgenic methods for tracking cells and testing gene function during regeneration in the axolotl.

    Science.gov (United States)

    Khattak, Shahryar; Schuez, Maritta; Richter, Tobias; Knapp, Dunja; Haigo, Saori L; Sandoval-Guzmán, Tatiana; Hradlikova, Kristyna; Duemmler, Annett; Kerney, Ryan; Tanaka, Elly M

    2013-01-01

    The salamander is the only tetrapod that regenerates complex body structures throughout life. Deciphering the underlying molecular processes of regeneration is fundamental for regenerative medicine and developmental biology, but the model organism had limited tools for molecular analysis. We describe a comprehensive set of germline transgenic strains in the laboratory-bred salamander Ambystoma mexicanum (axolotl) that open up the cellular and molecular genetic dissection of regeneration. We demonstrate tissue-dependent control of gene expression in nerve, Schwann cells, oligodendrocytes, muscle, epidermis, and cartilage. Furthermore, we demonstrate the use of tamoxifen-induced Cre/loxP-mediated recombination to indelibly mark different cell types. Finally, we inducibly overexpress the cell-cycle inhibitor p16 (INK4a) , which negatively regulates spinal cord regeneration. These tissue-specific germline axolotl lines and tightly inducible Cre drivers and LoxP reporter lines render this classical regeneration model molecularly accessible. PMID:24052945

  14. Augmenter of liver regeneration

    Directory of Open Access Journals (Sweden)

    Gandhi Chandrashekhar R

    2012-07-01

    Full Text Available Abstract ‘Augmenter of liver regeneration’ (ALR (also known as hepatic stimulatory substance or hepatopoietin was originally found to promote growth of hepatocytes in the regenerating or injured liver. ALR is expressed ubiquitously in all organs, and exclusively in hepatocytes in the liver. ALR, a survival factor for hepatocytes, exhibits significant homology with ERV1 (essential for respiration and viability protein that is essential for the survival of the yeast, Saccharomyces cerevisiae. ALR comprises 198 to 205 amino acids (approximately 22 kDa, but is post-translationally modified to three high molecular weight species (approximately 38 to 42 kDa found in hepatocytes. ALR is present in mitochondria, cytosol, endoplasmic reticulum, and nucleus. Mitochondrial ALR may be involved in oxidative phosphorylation, but also functions as sulfhydryl oxidase and cytochrome c reductase, and causes Fe/S maturation of proteins. ALR, secreted by hepatocytes, stimulates synthesis of TNF-α, IL-6, and nitric oxide in Kupffer cells via a G-protein coupled receptor. While the 22 kDa rat recombinant ALR does not stimulate DNA synthesis in hepatocytes, the short form (15 kDa of human recombinant ALR was reported to be equipotent as or even stronger than TGF-α or HGF as a mitogen for hepatocytes. Altered serum ALR levels in certain pathological conditions suggest that it may be a diagnostic marker for liver injury/disease. Although ALR appears to have multiple functions, the knowledge of its role in various organs, including the liver, is extremely inadequate, and it is not known whether different ALR species have distinct functions. Future research should provide better understanding of the expression and functions of this enigmatic molecule.

  15. Mucosal regeneration during radiotherapy

    International Nuclear Information System (INIS)

    Background and purpose: Regeneration of the aerodigestive mucosa is known to occur during conventionally fractionated radiotherapy. The circumstances surrounding its time of onset and magnitude are not well understood, however. Material and methods: Mucosal reactions were observed in 100 patients undergoing conventionally fractionated treatment at 2 Gy/day over 7 weeks and 88 receiving accelerated treatment at 1.8 Gy twice daily over 3(1(2)) weeks on the Trans Tasman Radiation Oncology Group head and neck cancer trials. Similar observations in 61 patients treated palliatively at dose rates between 0.8 and 240 Gy/h using ten 3.0-4.2 Gy fractions over 2 weeks are compared. Results: Several findings emerged from these studies: 1. Reactions evolved more quickly at oropharyngeal sites than in the hypopharynx. 2. Reactions at both sites evolved more rapidly at greater rates of dose accumulation. 3. The timing of reactions suggested the presence of a strong regenerative mucosal response that started before the manifestation of 'patchy' (grade II) mucosal reactions. 4. The regenerative response was strong enough to 'make good' damage accumulated at a rate of 2 Gy/day in over a third of cases. 5. The linear quadratic model without time correction failed to provide an adequate prediction of the frequency or intensity of mucosal reactions produced by any of the regimes. A simple model of the regenerative response is presented. Conclusions: This study suggests that the timing and magnitude of the regenerative response vary between sites and individuals but are linked to the amount of epithelial cellular depletion occurring during treatment

  16. Biología reproductiva y conservación: el caso de la regeneración de bosques templados y subtropicales de robles (Quercus spp. Plant reproductive biology and conservation: the case of temperate and subtropical oak forest regeneration

    Directory of Open Access Journals (Sweden)

    Fernando J. Pulido

    2002-03-01

    Full Text Available En este trabajo se revisan los resultados de 21 estudios experimentales sobre la regeneración de bosques de roble (Quercus spp. en los que se analizan al menos tres de las fases del ciclo reproductivo: fertilización, desarrollo de frutos viables, dispersión, consumo postdispersivo, germinación-emergencia de plántulas, establecimiento de juveniles y reclutamiento de adultos. La mayoría de las poblaciones estudiadas se encontraban en bosques templados de Norteamérica y Europa, repartidos de forma equitativa entre bosques de ambientes xéricos (incluidos los mediterráneos con especies perennes y habitualmente bajo explotación, y bosques de ambientes mésicos o montanos con especies generalmente caducifolias y escasamente alterados. Los estudios se clasificaron de acuerdo con los tipos de limitación de la regeneración encontrados por los autores, esto es, producción de semillas viables, presión de herbívoros y disponibilidad de sitios seguros. La revisión muestra que en la mayoría de los casos la regeneración se encontraba limitada por una combinación de factores, típicamente el consumo de bellotas y un ambiente abiótico desfavorable durante el establecimiento. La fecundidad de los árboles ha sido rara vez estudiada a pesar de que puede llegar ser en una limitación frecuente, al igual que ocurre con las limitaciones de la dispersión por animales. Finalmente, se analiza el grado de aplicación de la información ecológica acumulada a la solución de problemas de regeneración natural, y se discute su utilidad en comparación con las prácticas más comunes de regeneración artificial via plantacionesThis study presents a review of 21 experimental studies on oak (Quercus regeneration analysing at least three phases of the reproductive cycle, namely fertilization, viable fruit production, acorn dispersal, postdispersal predation, seedling emergence, sapling establishment, and adult recruitment. Most study cases came from North

  17. Bone morphogenetic proteins: Periodontal regeneration

    Directory of Open Access Journals (Sweden)

    Subramaniam M Rao

    2013-01-01

    Full Text Available Periodontitis is an infectious inflammatory disease that results in attachment loss and bone loss. Regeneration of the periodontal tissues entails de novo formation of cementum, periodontal ligament, and alveolar bone. Several different approaches are currently being explored to achieve complete, reliable, and reproducible regeneration of periodontal tissues. The therapeutic management of new bone formation is one of the key issues in successful periodontal regeneration. Bone morphogenetic proteins form a unique group of proteins within the transforming growth factor superfamily of genes and have a vital role in the regulation in the bone induction and maintenance. The activity of bone morphogenetic proteins was first identified in the 1960s, but the proteins responsible for bone induction were unknown until the purification and cloning of human bone morphogenetic proteins in the 1980s, because of their osteoinductive potential. Bone morphogenetic proteins have gained a lot of interest as therapeutic agents for treating periodontal defects. A systematic search for data related to the use of bone morphogenetic proteins for the regeneration of periodontal defects was performed to recognize studies on animals and human (PUBMED, MEDLINE, COCHRANE, and Google search. All the studies included showed noticeable regeneration of periodontal tissues with the use of BMP.

  18. Contemporaryperspective on endogenous myocardial regeneration

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Considering the complex nature of the adult heart,it is no wonder that innate regenerative processes,while maintaining adequate cardiac function, fall shortin myocardial jeopardy. In spite of these enchaining limitations, cardiac rejuvenation occurs as well asrestricted regeneration. In this review, the backgroundas well as potential mechanisms of endogenousmyocardial regeneration are summarized. We presentand analyze the available evidence in three subsequentsteps. First, we examine the experimental researchdata that provide insights into the mechanisms andorigins of the replicating cardiac myocytes, includingcell populations referred to as cardiac progenitor cells(i.e. , c-kit+ cells). Second, we describe the role ofclinical settings such as acute or chronic myocardialischemia, as initiators of pathways of endogenousmyocardial regeneration. Third, the hitherto conductedclinical studies that examined different approachesof initiating endogenous myocardial regeneration infailing human hearts are analyzed. In conclusion, wepresent the evidence in support of the notion thatregaining cardiac function beyond cellular replacementof dysfunctional myocardium via initiation of innateregenerative pathways could create a new perspectiveand a paradigm change in heart failure therapeutics.Reinitiating cardiac morphogenesis by reintroducingdevelopmental pathways in the adult failing heart mightprovide a feasible way of tissue regeneration. Basedon our hypothesis "embryonic recall", we present firstsupporting evidence on regenerative impulses in themyocardium, as induced by developmental processes.

  19. Voluntary exercise increases axonal regeneration from sensory neurons

    OpenAIRE

    Molteni, Raffaella; Zheng, Jun-Qi; Ying, Zhe; Gómez-Pinilla, Fernando; Twiss, Jeffery L

    2004-01-01

    Recent advances in understanding the role of neurotrophins on activity-dependent plasticity have provided insight into how behavior can affect specific aspects of neuronal biology. We present evidence that voluntary exercise can prime adult dorsal root ganglion neurons for increased axonal regeneration through a neurotrophin-dependent mechanism. Dorsal root ganglion neurons showed an increase in neurite outgrowth when cultured from animals that had undergone 3 or 7 days of exercise compared w...

  20. Development, regeneration, and evolution of feathers.

    Science.gov (United States)

    Chen, Chih-Feng; Foley, John; Tang, Pin-Chi; Li, Ang; Jiang, Ting Xin; Wu, Ping; Widelitz, Randall B; Chuong, Cheng Ming

    2015-01-01

    The feather is a complex ectodermal organ with hierarchical branching patterns. It provides functions in endothermy, communication, and flight. Studies of feather growth, cycling, and health are of fundamental importance to avian biology and poultry science. In addition, feathers are an excellent model for morphogenesis studies because of their accessibility, and their distinct patterns can be used to assay the roles of specific molecular pathways. Here we review the progress in aspects of development, regeneration, and evolution during the past three decades. We cover the development of feather buds in chicken embryos, regenerative cycling of feather follicle stem cells, formation of barb branching patterns, emergence of intrafeather pigmentation patterns, interplay of hormones and feather growth, and the genetic identification of several feather variants. The discovery of feathered dinosaurs redefines the relationship between feathers and birds. Inspiration from biomaterials and flight research further fuels biomimetic potential of feathers as a multidisciplinary research focal point. PMID:25387232

  1. Growth and Scaling during Development and Regeneration

    CERN Document Server

    Werner, Steffen

    2016-01-01

    Life presents fascinating examples of self-organization and emergent phenomena. In multi-cellular organisms, a multitude of cells interact to form and maintain highly complex body plans of well-defined size. In this thesis, we investigate theoretical feedback mechanisms for both self-organized body plan patterning and size control. The thesis is inspired by the astonishing scaling and regeneration abilities of flatworms. These worms can perfectly regrow their entire body plan even from tiny amputation fragments like the tip of the tail. Moreover, they can grow and actively de-grow by more than a factor of 40 in length depending on feeding conditions. These capabilities prompt for remarkable physical mechanisms of self-organized pattern formation and scaling. First, we explore the basic principles and challenges of pattern scaling in mechanisms previously proposed to describe biological pattern formation. Next, we present a novel class of patterning mechanisms yielding entirely self-organized and self-scaling ...

  2. EGFR signaling regulates cell proliferation, differentiation and morphogenesis during planarian regeneration and homeostasis.

    Science.gov (United States)

    Fraguas, Susanna; Barberán, Sara; Cebrià, Francesc

    2011-06-01

    Similarly to development, the process of regeneration requires that cells accurately sense and respond to their external environment. Thus, intrinsic cues must be integrated with signals from the surrounding environment to ensure appropriate temporal and spatial regulation of tissue regeneration. Identifying the signaling pathways that control these events will not only provide insights into a fascinating biological phenomenon but may also yield new molecular targets for use in regenerative medicine. Among classical models to study regeneration, freshwater planarians represent an attractive system in which to investigate the signals that regulate cell proliferation and differentiation, as well as the proper patterning of the structures being regenerated. Recent studies in planarians have begun to define the role of conserved signaling pathways during regeneration. Here, we extend these analyses to the epidermal growth factor (EGF) receptor pathway. We report the characterization of three epidermal growth factor (EGF) receptors in the planarian Schmidtea mediterranea. Silencing of these genes by RNA interference (RNAi) yielded multiple defects in intact and regenerating planarians. Smed-egfr-1(RNAi) resulted in decreased differentiation of eye pigment cells, abnormal pharynx regeneration and maintenance, and the development of dorsal outgrowths. In contrast, Smed-egfr-3(RNAi) animals produced smaller blastemas associated with abnormal differentiation of certain cell types. Our results suggest important roles for the EGFR signaling in controlling cell proliferation, differentiation and morphogenesis during planarian regeneration and homeostasis. PMID:21458439

  3. Looking Ahead to Engineering Epimorphic Regeneration of a Human Digit or Limb.

    Science.gov (United States)

    Quijano, Lina M; Lynch, Kristen M; Allan, Christopher H; Badylak, Stephen F; Ahsan, Tabassum

    2016-06-01

    Approximately 2 million people have had limb amputations in the United States due to disease or injury, with more than 185,000 new amputations every year. The ability to promote epimorphic regeneration, or the regrowth of a biologically based digit or limb, would radically change the prognosis for amputees. This ambitious goal includes the regrowth of a large number of tissues that need to be properly assembled and patterned to create a fully functional structure. We have yet to even identify, let alone address, all the obstacles along the extended progression that limit epimorphic regeneration in humans. This review aims to present introductory fundamentals in epimorphic regeneration to facilitate design and conduct of research from a tissue engineering and regenerative medicine perspective. We describe the clinical scenario of human digit healing, featuring published reports of regenerative potential. We then broadly delineate the processes of epimorphic regeneration in nonmammalian systems and describe a few mammalian regeneration models. We give particular focus to the murine digit tip, which allows for comparative studies of regeneration-competent and regeneration-incompetent outcomes in the same animal. Finally, we describe a few forward-thinking opportunities for promoting epimorphic regeneration in humans. PMID:26603349

  4. Microwave regeneration of molecular sieves

    International Nuclear Information System (INIS)

    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

  5. Unconventional food regeneration in space - Opportunities for microbial food production

    Science.gov (United States)

    Petersen, Gene R.; Schubert, Wayne W.; Seshan, P. K.; Dunlop, Eric H.

    1987-01-01

    The possible role of microbial species in regenerating food is considered, and three areas where microbial systems can be used in controlled ecological life support systems are discussed. Microbial species can serve as the biological portion of hybrid chemical/biological schemes for primary food products, as a means more fully to utilize waste materials from agronomical food production, and as a source of nutritional supplements to conventional plant foods. Work accomplished in each of these areas is described. The role of microgravity fermenters in this technology is addressed.

  6. Clinical implications of advances in liver regeneration

    OpenAIRE

    Kwon, Yong Jin; Lee, Kyeong Geun; Choi, Dongho

    2015-01-01

    Remarkable advances have been made recently in the area of liver regeneration. Even though liver regeneration after liver resection has been widely researched, new clinical applications have provided a better understanding of the process. Hepatic damage induces a process of regeneration that rarely occurs in normal undamaged liver. Many studies have concentrated on the mechanism of hepatocyte regeneration following liver damage. High mortality is usual in patients with terminal liver failure....

  7. Intravital imaging of hair follicle regeneration in the mouse.

    Science.gov (United States)

    Pineda, Cristiana M; Park, Sangbum; Mesa, Kailin R; Wolfel, Markus; Gonzalez, David G; Haberman, Ann M; Rompolas, Panteleimon; Greco, Valentina

    2015-07-01

    Hair follicles are mammalian skin organs that periodically and stereotypically regenerate from a small pool of stem cells. Hence, hair follicles are a widely studied model for stem cell biology and regeneration. This protocol describes the use of two-photon laser-scanning microscopy (TPLSM) to study hair regeneration within a living, uninjured mouse. TPLSM provides advantages over conventional approaches, including enabling time-resolved imaging of single hair follicle stem cells. Thus, it is possible to capture behaviors including apoptosis, proliferation and migration, and to revisit the same cells for in vivo lineage tracing. In addition, a wide range of fluorescent reporter mouse lines facilitates TPLSM in the skin. This protocol also describes TPLSM laser ablation, which can spatiotemporally manipulate specific cellular populations of the hair follicle or microenvironment to test their regenerative contributions. The preparation time is variable depending on the goals of the experiment, but it generally takes 30-60 min. Imaging time is dependent on the goals of the experiment. Together, these components of TPLSM can be used to develop a comprehensive understanding of hair regeneration during homeostasis and injury. PMID:26110716

  8. 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 ...... analyzed, emphasizing general aspects of active semiconductor waveguides....

  9. 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...

  10. An experimental study of passive regenerator geometries

    DEFF Research Database (Denmark)

    Engelbrecht, Kurt; Nielsen, Kaspar Kirstein; Pryds, Nini

    2011-01-01

    experimental uncertainty associated with magnetocaloric material properties, all regenerators are made of aluminum. The performance of corrugated plates and dimpled plates are compared to traditional flat plate regenerators for a range of cycle times and utilizations. Each regenerator is built using 18...

  11. Cytoskeletal regulation of dermal regeneration.

    Science.gov (United States)

    Strudwick, Xanthe L; Cowin, Allison J

    2012-01-01

    Wound healing results in the repair of injured tissues however fibrosis and scar formation are, more often than not the unfortunate consequence of this process. The ability of lower order vertebrates and invertebrates to regenerate limbs and tissues has been all but lost in mammals; however, there are some instances where glimpses of mammalian regenerative capacity do exist. Here we describe the unlocked potential that exists in mammals that may help us understand the process of regeneration post-injury and highlight the potential role of the actin cytoskeleton in this process. The precise function and regulation of the cytoskeleton is critical to the success of the healing process and its manipulation may therefore facilitate regenerative healing. The gelsolin family of actin remodelling proteins in particular has been shown to have important functions in wound healing and family member Flightless I (Flii) is involved in both regeneration and repair. Understanding the interactions between different cytoskeletal proteins and their dynamic control of processes including cellular adhesion, contraction and motility may assist the development of therapeutics that will stimulate regeneration rather than repair. PMID:24710556

  12. Mechanical device for tissue regeneration

    NARCIS (Netherlands)

    Herder, J.L.; Maij, E.

    2010-01-01

    The invention relates to a mechanical device for tissue- regeneration inside a patient, comprising means (2, 3) to place a scaffold for the tissue under mechanical stress. Said means comprise a first device-part (2) and a second device-part (3) which parts are arranged to be movable with respect to

  13. Regeneration from Injury and Resource Allocation in Sponges and Corals - a Review

    Science.gov (United States)

    Henry, Lea-Anne; Hart, Michael

    2005-05-01

    The ability of bottom-dwelling marine epifauna to regenerate injured or lost body parts is critical to the survival of individuals from disturbances that inflict wounds. Numerous studies on marine sponges (Phlyum Porifera) and corals (of the orders Scleractinia and Alcyonacea) suggest that regeneration is limited by many intrinsic (individual-dependent) and extrinsic (environment-dependent) factors, and that other life history processes may compete with regeneration for energetic and cellular resources. We review how intrinsic (size, age, morphology, genotype) and extrinsic (wound characteristics, water temperature, food availability, sedimentation, disturbance history, selection) factors limit regeneration in sponges and corals. We then review the evidence for impaired somatic growth and sexual reproduction, and altered outcomes of interactions (anti-predator defenses, competitive abilities, self- and non-self recognition abilities) with other organisms in regenerating sponges and corals. We demonstrate that smaller, older sponges and corals of decreasing morphological complexities tend to regenerate less well than others, and that regeneration can be modulated by genotype. Large wounds with small perimeters inflicted away from areas where resources are located tend to be regenerated less well than others, as are injuries inflicted when food is limited and when the animal has been previously or recently injured. We also demonstrate that regeneration strongly impairs somatic growth, reduces aspects of sexual reproduction, and decreases the ability for sponges and corals to defend themselves against predators, to compete, and to recognize conspecifics. Effects of limited regeneration and impaired life histories may manifest themselves in higher levels of biological assembly e.g., reduced accretion of epifaunal biomass, reduced recruitment and altered biotic associations, and thus affect marine community and ecosystem recovery from disturbances.

  14. Novel Therapeutic Effects of Non-thermal atmospheric pressure plasma for Muscle Regeneration and Differentiation

    OpenAIRE

    Jae Won Choi; Sung Un Kang; Yang Eun Kim; Ju Kyeong Park; Sang Sik Yang; Yeon Soo Kim; Yun Sang Lee; Yuijina Lee; Chul-Ho Kim

    2016-01-01

    Skeletal muscle can repair muscle tissue damage, but significant loss of muscle tissue or its long-lasting chronic degeneration makes injured skeletal muscle tissue difficult to restore. It has been demonstrated that non-thermal atmospheric pressure plasma (NTP) can be used in many biological areas including regenerative medicine. Therefore, we determined whether NTP, as a non-contact biological external stimulator that generates biological catalyzers, can induce regeneration of injured muscl...

  15. THE BIOLOGY OF FRACTURE HEALING

    OpenAIRE

    Marsell, Richard; Einhorn, Thomas A.

    2011-01-01

    The biology of fracture healing is a complex biological process that follows specific regenerative patterns and involves changes in the expression of several thousand genes. Although there is still much to be learned to fully comprehend the pathways of bone regeneration, the over-all pathways of both the anatomical and biochemical events have been thoroughly investigated. These efforts have provided a general understanding of how fracture healing occurs. Following the initial trauma, bone hea...

  16. 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...

  17. Cellular regeneration in bone marrow with synthesized semiconductor polymers by plasma

    International Nuclear Information System (INIS)

    In this work the intervention of polymers with capacity of conducting electric current for the regeneration of the spinal marrow in rats of laboratory is studied. It is a focus different from the one that up to now has taken in account since it involves medical, biological, physical and chemical sciences. Inside the properties of transporting electric charges, the polymers would have to respond before the biological media with ionic mechanisms of conduction, besides the electronic ones, to promote the regeneration of the spinal marrow. They should also be biocompatible to avoid the rejection of the media before the implantation. (Author)

  18. Financing Property's Contribution to Regeneration

    OpenAIRE

    Alastair Adair; Jim Berry; Stanley McGreal

    2003-01-01

    Attracting investment and finance into inner-city and other renewal areas poses particular difficulties and is frequently reliant on strong public-sector commitment through special incentives or other mechanisms to provide the conditions to lever private-sector activity. This paper initially links the concept of market failure and the rationale for regeneration and examines policy responses from UK, European and US perspectives, followed by a consideration of public- and private-sector financ...

  19. Progenitor Cells and Podocyte Regeneration

    OpenAIRE

    Shankland, Stuart J.; Pippin, Jeffrey W.; Duffield, Jeremy S.

    2014-01-01

    The very limited ability of adult podocytes to proliferate in vivo is clinically significant because: podocytes form a vascular barrier which is functionally critical to the nephron; podocyte hypoplasia is a characteristic of disease; and inadequate regeneration of podocytes is a major cause of persistent podocyte hypoplasia. Excessive podocyte loss or inadequate replacement leads to glomerulosclerosis in many progressive kidney diseases. Thus, restoration of podocyte cell density is almost c...

  20. Cell Therapy for Cardiovascular Regeneration

    OpenAIRE

    Takehara, Naofumi

    2013-01-01

    A great numbers of cardiovascular disease patients all over the world are suffering in the poor outcomes. Under this situation, cardiac regeneration therapy to reorganize the postnatal heart that is defined as a terminal differentiated-organ is a very important theme and mission for human beings. However, the temporary success of several clinical trials using usual cell types with uncertain cell numbers has provided the transient effect of cell therapy to these patients. We therefore should r...

  1. Regeneration of Pelargonium in vitro

    OpenAIRE

    Agnieszka Wojtania; Wiesław Szafrański

    2013-01-01

    Pelargonium sp. has been a subject of numerous studies to deterimine the effec tiveness of in vitro techniques to produce a large number of pathogen-free plants. Regeneration of pelargonium plants from the different initial explants as well via organogenesis as via somatic embryogenesis has been obtained. The most effective adventitious shoot formation has been achieved from shoot tips and axillary buds using cytokinin or cytokinin/auxin combinations. Leaf explants, whose general have lower o...

  2. Quo vadis, hair cell regeneration?

    OpenAIRE

    Brigande, John V; Heller, Stefan

    2009-01-01

    Hearing loss is a global health problem with profound socioeconomic impact. We contend that acquired hearing loss is mainly a modern disorder caused by man-made noise and modern drugs, among other causes. These factors, combined with increasing lifespan, have exposed a deficit in cochlear self-regeneration that was irrelevant for most of mammalian evolution. Nevertheless, the mammalian cochlea has evolved from phylogenetically older structures, which do have the capacity for self-repair. More...

  3. [Biological experiments on "Kosmos-1887"].

    Science.gov (United States)

    Alpatov, A M; I'lin, E A; Antipov, V V; Tairbekov, M G

    1989-01-01

    In the 13-ray space flight on Kosmos-1887 various experiments in the field of cell biology, genetics, biorhythm, developmental biology and regeneration were performed using bacteria, protozoa, plants, worms, insects, fish and amphibia. Paramecia showed enhanced cell proliferation, spheroidization and diminished protein content. Experiments on fruit-flies, newt oocytes and primate lymphocytes confirmed involvement of the cell genetic apparatus in responses to microgravity. Beetles exhibited a reduction of the length of the spontaneous period of freely running circadian rhythms. Carausius morosus developed latent changes in early embryogenesis which manifested at later stages of ontogenesis. Exposure to microgravity did not prevent recovery of injured tissues; moreover their regeneration may be accelerated after recovery. Biology research programs in future biosatellite flights are discussed. PMID:2512415

  4. Cell dedifferentiation and epithelial to mesenchymal transitions during intestinal regeneration in H. glaberrima

    Directory of Open Access Journals (Sweden)

    Rivera-Cruz Angélica

    2011-10-01

    Full Text Available Abstract Background Determining the type and source of cells involved in regenerative processes has been one of the most important goals of researchers in the field of regeneration biology. We have previously used several cellular markers to characterize the cells involved in the regeneration of the intestine in the sea cucumber Holothuria glaberrima. Results We have now obtained a monoclonal antibody that labels the mesothelium; the outer layer of the gut wall composed of peritoneocytes and myocytes. Using this antibody we studied the role of this tissue layer in the early stages of intestinal regeneration. We have now shown that the mesothelial cells of the mesentery, specifically the muscle component, undergo dedifferentiation from very early on in the regeneration process. Cell proliferation, on the other hand, increases much later, and mainly takes place in the mesothelium or coelomic epithelium of the regenerating intestinal rudiment. Moreover, we have found that the formation of the intestinal rudiment involves a novel regenerative mechanism where epithelial cells ingress into the connective tissue and acquire mesenchymal phenotypes. Conclusions Our results strongly suggest that the dedifferentiating mesothelium provides the initial source of cells for the formation of the intestinal rudiment. At later stages, cell proliferation supplies additional cells necessary for the increase in size of the regenerate. Our data also shows that the mechanism of epithelial to mesenchymal transition provides many of the connective tissue cells found in the regenerating intestine. These results present some new and important information as to the cellular basis of organ regeneration and in particular to the process of regeneration of visceral organs.

  5. Analysis of newly established EST databases reveals similarities between heart regeneration in newt and fish

    Directory of Open Access Journals (Sweden)

    Weis Patrick

    2010-01-01

    Full Text Available Abstract Background The newt Notophthalmus viridescens possesses the remarkable ability to respond to cardiac damage by formation of new myocardial tissue. Surprisingly little is known about changes in gene activities that occur during the course of regeneration. To begin to decipher the molecular processes, that underlie restoration of functional cardiac tissue, we generated an EST database from regenerating newt hearts and compared the transcriptional profile of selected candidates with genes deregulated during zebrafish heart regeneration. Results A cDNA library of 100,000 cDNA clones was generated from newt hearts 14 days after ventricular injury. Sequencing of 11520 cDNA clones resulted in 2894 assembled contigs. BLAST searches revealed 1695 sequences with potential homology to sequences from the NCBI database. BLAST searches to TrEMBL and Swiss-Prot databases assigned 1116 proteins to Gene Ontology terms. We also identified a relatively large set of 174 ORFs, which are likely to be unique for urodele amphibians. Expression analysis of newt-zebrafish homologues confirmed the deregulation of selected genes during heart regeneration. Sequences, BLAST results and GO annotations were visualized in a relational web based database followed by grouping of identified proteins into clusters of GO Terms. Comparison of data from regenerating zebrafish hearts identified biological processes, which were uniformly overrepresented during cardiac regeneration in newt and zebrafish. Conclusion We concluded that heart regeneration in newts and zebrafish led to the activation of similar sets of genes, which suggests that heart regeneration in both species might follow similar principles. The design of the newly established newt EST database allows identification of molecular pathways important for heart regeneration.

  6. Regeneration of nutrients and biological productivity in Antarctic waters

    Digital Repository Service at National Institute of Oceanography (India)

    Verlecar, X.N.; Somasundar, K.; Qasim, S.Z.

    similar to those of the coastal waters, salinity values were slightly higher near the Diver- mean, suggest that the fluctuation in the day-to-day occurrence of zooplankton may be due to predation by higher animals sucha~leal and penguins. The 1984 summer... before it is lost from the euphotic zone. Excretion from zoo plankton may also contribute to a substantial amount of N in the form of ammonia (Biggs 1982, Koike et al. 1986). Si, on the other hand, is progressively utilised by b a C INAEX V d INAEX I...

  7. Stem cell-based biological tooth repair and regeneration

    OpenAIRE

    Volponi, Ana Angelova; Pang, Yvonne; Sharpe, Paul T.

    2010-01-01

    Teeth exhibit limited repair in response to damage, and dental pulp stem cells probably provide a source of cells to replace those damaged and to facilitate repair. Stem cells in other parts of the tooth, such as the periodontal ligament and growing roots, play more dynamic roles in tooth function and development. Dental stem cells can be obtained with ease, making them an attractive source of autologous stem cells for use in restoring vital pulp tissue removed because of infection, in regene...

  8. Exact Regenerating Codes for Distributed Storage

    CERN Document Server

    V., Rashmi K; Kumar, P Vijay; Ramachandran, Kannan

    2009-01-01

    Erasure coding techniques are used to increase the reliability of distributed storage systems while minimizing storage overhead. The bandwidth required to repair the system after a node failure also plays a crucial role in the system performance. In [1] authors have shown that a tradeoff exists between storage and repair bandwidth. They also have introduced the scheme of regenerating codes which meet this tradeoff. In this paper, a scheme of Exact Regenerating Codes is introduced, which are regenerating codes with an additional property of regenerating back the same node upon failure. For the minimum bandwidth point, which is suitable for applications like distributed mail servers, explicit construction for exact regenerating codes is provided. A subspace approach is provided, using which the necessary and sufficient conditions for a linear code to be an exact regenerating code are derived. This leads to the uniqueness of our construction. For the minimum storage point which suits applications such as storage...

  9. 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.

  10. Regeneration of Pinus pinaster forests after wildfire

    OpenAIRE

    Castro, José; Bento, João Manuel; Rego, Francisco

    1990-01-01

    Wildfires are of extreme importance in Pinus pinaster forests of central and northern Portugal. Reforestation plans after wildfires are generally made without consideration for the possibility of natural regeneration. This paper addresses the question of the factors responsible for the occurrence of natural regeneration and concludes that litter accumulation, rock outcrops, slope, aspect, harvest, fire characteristics, and stand age are well related to the regeneration observed. Limitations o...

  11. Managing reindeer lichen during forest regeneration procedures

    OpenAIRE

    Roturier, Samuel

    2009-01-01

    In northern Sweden, conventional forest regeneration procedures applied in modern commercial forestry can disturb terricolous lichen (Cladina spp.) pastures. This has become a source of conflicts with Sámi reindeer herders. The overall aim of this thesis was to investigate forest regeneration strategies that may minimise the disturbance to, and promote the regeneration of, reindeer lichen pastures. The Sámi herders’ practices and knowledge related to the lichen resources were also analysed. E...

  12. Emerin increase in regenerating muscle fibers

    Directory of Open Access Journals (Sweden)

    S Squarzoni

    2009-06-01

    Full Text Available The fate of emerin during skeletal muscle regeneration was investigated in an animal model by means of crush injury. Immunofluorescence, immunoblotting and mRNA analysis demonstrated that emerin level is increased in regenerating rat muscle fibers with respect to normal mature myofibers. This finding suggests an involvement of emerin during the muscle fiber regeneration process, in analogy with its reported involvement in muscle cell differentiation in vitro. The impairment of skeletal muscle physiological regeneration or reorganization could be a possible pathogenetic mechanism for Emery Dreifuss muscular dystrophy.

  13. Plant regeneration: cellular origins and molecular mechanisms.

    Science.gov (United States)

    Ikeuchi, Momoko; Ogawa, Yoichi; Iwase, Akira; Sugimoto, Keiko

    2016-05-01

    Compared with animals, plants generally possess a high degree of developmental plasticity and display various types of tissue or organ regeneration. This regenerative capacity can be enhanced by exogenously supplied plant hormones in vitro, wherein the balance between auxin and cytokinin determines the developmental fate of regenerating organs. Accumulating evidence suggests that some forms of plant regeneration involve reprogramming of differentiated somatic cells, whereas others are induced through the activation of relatively undifferentiated cells in somatic tissues. We summarize the current understanding of how plants control various types of regeneration and discuss how developmental and environmental constraints influence these regulatory mechanisms. PMID:27143753

  14. HGF–Met Pathway in Regeneration and Drug Discovery

    Directory of Open Access Journals (Sweden)

    Kunio Matsumoto

    2014-10-01

    Full Text Available Hepatocyte growth factor (HGF is composed of an α-chain and a β-chain, and these chains contain four kringle domains and a serine protease-like structure, respectively. Activation of the HGF–Met pathway evokes dynamic biological responses that support morphogenesis (e.g., epithelial tubulogenesis, regeneration, and the survival of cells and tissues. Characterizations of conditional Met knockout mice have indicated that the HGF–Met pathway plays important roles in regeneration, protection, and homeostasis in various cells and tissues, which includes hepatocytes, renal tubular cells, and neurons. Preclinical studies designed to address the therapeutic significance of HGF have been performed on injury/disease models, including acute tissue injury, chronic fibrosis, and cardiovascular and neurodegenerative diseases. The promotion of cell growth, survival, migration, and morphogenesis that is associated with extracellular matrix proteolysis are the biological activities that underlie the therapeutic actions of HGF. Recombinant HGF protein and the expression vectors for HGF are biological drug candidates for the treatment of patients with diseases and injuries that are associated with impaired tissue function. The intravenous/systemic administration of recombinant HGF protein has been well tolerated in phase I/II clinical trials. The phase-I and phase-I/II clinical trials of the intrathecal administration of HGF protein for the treatment of patients with amyotrophic lateral sclerosis and spinal cord injury, respectively, are ongoing.

  15. 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. 

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

    OpenAIRE

    J. Škorpík

    2008-01-01

    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. 

  17. The urban question and regeneration

    OpenAIRE

    Bianchi A.

    2014-01-01

    The «urban regeneration» which is emerging today in Italy was founded in the wake of a line which has risen in Great Britain since the mid-70s of the twentieth century. Among the many European experiences, those of Glasgow and Bilbao are cited, where between the middle and the end of the '80s economic, social and cultural processes have triggered related to living within the cities, which have changed not only their physical appearance but also their functionality and the same structure. More...

  18. Bone regeneration and stem cells

    DEFF Research Database (Denmark)

    Arvidson, K; Abdallah, B M; Applegate, L A;

    2011-01-01

    This invited review covers research areas of central importance for orthopedic and maxillofacial bone tissue repair, including normal fracture healing and healing problems, biomaterial scaffolds for tissue engineering, mesenchymal and fetal stem cells, effects of sex steroids on mesenchymal stem...... cells, use of platelet rich plasma for tissue repair, osteogenesis and its molecular markers. A variety of cells in addition to stem cells, as well as advances in materials science to meet specific requirements for bone and soft tissue regeneration by addition of bioactive molecules, are discussed....

  19. Bacterial Cellulose-Hydroxyapatite Nanocomposites for Bone Regeneration

    OpenAIRE

    Saska, S.; H.S. Barud; Gaspar, A. M. M.; Marchetto, R.; Ribeiro, S. J. L.; Y. Messaddeq

    2011-01-01

    The aim of this study was to develop and to evaluate the biological properties of bacterial cellulose-hydroxyapatite (BC-HA) nanocomposite membranes for bone regeneration. Nanocomposites were prepared from bacterial cellulose membranes sequentially incubated in solutions of CaCl2 followed by Na2HPO4. BC-HA membranes were evaluated in noncritical bone defects in rat tibiae at 1, 4, and 16 weeks. Thermogravimetric analyses showed that the amount of the mineral phase was 40%–50% of the total wei...

  20. Recent advances in bone regeneration using adult stemcells

    Institute of Scientific and Technical Information of China (English)

    Hadar Zigdon-Giladi; Utai Rudich; Gal Michaeli Geller; Ayelet Evron

    2015-01-01

    Bone is a highly vascularized tissue reliant on theclose spatial and temporal association between bloodvessels and bone cells. Therefore, cells that participatein vasculogenesis and osteogenesis play a pivotalrole in bone formation during prenatal and postnatalperiods. Nevertheless, spontaneous healing of bonefracture is occasionally impaired due to insufficientblood and cellular supply to the site of injury. In thesecases, bone regeneration process is interrupted, whichmight result in delayed union or even nonunion ofthe fracture. Nonunion fracture is difficult to treatand have a high financial impact. In the last decade,numerous technological advancements in bone tissueengineering and cell-therapy opened new horizon inthe field of bone regeneration. This review starts withpresentation of the biological processes involved inbone development, bone remodeling, fracture healingprocess and the microenvironment at bone healingsites. Then, we discuss the rationale for using adultstem cells and listed the characteristics of the availablecells for bone regeneration. The mechanism of actionand epigenetic regulations for osteogenic differentiationare also described. Finally, we review the literature fortranslational and clinical trials that investigated the useof adult stem cells (mesenchymal stem cells, endothelialprogenitor cells and CD34+ blood progenitors) for boneregeneration.

  1. Regeneration, Plasticity, and Induced Molecular Programs in Adult Zebrafish Brain

    Science.gov (United States)

    Cosacak, Mehmet Ilyas; Papadimitriou, Christos; Kizil, Caghan

    2015-01-01

    Regenerative capacity of the brain is a variable trait within animals. Aquatic vertebrates such as zebrafish have widespread ability to renew their brains upon damage, while mammals have—if not none—very limited overall regenerative competence. Underlying cause of such a disparity is not fully evident; however, one of the reasons could be activation of peculiar molecular programs, which might have specific roles after injury or damage, by the organisms that regenerate. If this hypothesis is correct, then there must be genes and pathways that (a) are expressed only after injury or damage in tissues, (b) are biologically and functionally relevant to restoration of neural tissue, and (c) are not detected in regenerating organisms. Presence of such programs might circumvent the initial detrimental effects of the damage and subsequently set up the stage for tissue redevelopment to take place by modulating the plasticity of the neural stem/progenitor cells. Additionally, if transferable, those “molecular mechanisms of regeneration” could open up new avenues for regenerative therapies of humans in clinical settings. This review focuses on the recent studies addressing injury/damage-induced molecular programs in zebrafish brain, underscoring the possibility of the presence of genes that could be used as biomarkers of neural plasticity and regeneration. PMID:26417601

  2. Utilization of Guided Bone Regeneration Techniqes in Treatment of a Single Tooth Missing with Implant Supported Crown

    OpenAIRE

    Adamczyk, E.; Gladkowski, J.; Machnikowski, I.; Mierzwinska, E.; Spiechowicz, E.; Feder, T.; Wojtowicz, A.; Matenko, D.; Ciechowicz, K.

    2002-01-01

    Guided bone regeneration is developing very dynamically in dental surgery and in implantology. It relies on building up bone in places where it is lacking, utilizing a variety of grafting materials. Methods of guided bone regeneration utilize biological materials or synthetic specimens. The use of autogenous platelets rich plasma derived in the thromboforetic process (COBE spectra system) allows the employment of growth factors, which blood platelets contain in the formation of new bone tissu...

  3. Variation in Spot and Stripe Patterns in Original and Regenerated Zebrafish Caudal Fins.

    Science.gov (United States)

    Anorve-Andress, Kyle; Arcand, Amy Lucille; Borg, Bethanie R; Brown, Jayce Lee; Chartrand, Caitlin A; Frank, Marisohn L; Jansen, Jedediah N; Joyce, Michael J; Joyce, Michael T; Kinney, Joseph A; Kruggel, Spencer Lee; Lecy, Amanda D; Ma, Phyo; Malecha, Katchen M; Melgaard, Kelsey; Miller, Paula L; Nelson, Kristina K; Nieto Robles, Marvin; Perosino, Tianna Ruth; Peterson, Jenna Marie; Rollins, April Diane; Scherkenbach, Whitney Lee; Smith, Andrea L; Sodergren, Kelsey A; Stiller, Jacob Jo; Wehber, Kevin R; Liang, Jennifer Ostrom

    2016-08-01

    Tissue regeneration requires not only the replacement of lost cells and tissues, but also the recreation of morphologies and patterns. Skin pigment pattern is a relatively simple system that can allow researchers to uncover the underlying mechanisms of pattern formation. To gain insight into how pigment patterns form, undergraduate students in the senior level course Developmental Biology designed an experiment that assayed pigment patterns in original and regenerated caudal fins of wild-type, striped, and mutant, spotted zebrafish. A majority of the WT fins regenerated with a similar striped pattern. In contrast, the pattern of spots even in the original fins of the mutants varied among individual fish. Similarly, the majority of the spots in the mutants did not regenerate with the same morphology, size, or spacing as the original fins. This was true even when only a small amount of fin was removed, leaving most of the fin to potentially reseed the pattern in the regenerating tissue. This suggests that the mechanism that creates the wild-type, striped pattern persists to recreate the pattern during regeneration. The mechanism that creates the spots in the mutants, however, must include an unknown element that introduces variability. PMID:27096743

  4. β-cell preservation and regeneration for diabetes treatment: where are we now?

    OpenAIRE

    Karadimos, Michael J; Kapoor, Archana; El Khattabi, Ilham; Sharma, Arun

    2012-01-01

    Over the last decade, our knowledge of β-cell biology has expanded with the use of new scientific techniques and strategies. Growth factors, hormones and small molecules have been shown to enhance β-cell proliferation and function. Stem cell technology and research into the developmental biology of the pancreas have yielded new methods for in vivo and in vitro regeneration of β cells from stem cells and endogenous progenitors as well as transdifferentiation of non-β cells. Novel pharmacologic...

  5. Topical Application of Lithium Chloride on the Pulp Induces Dentin Regeneration

    OpenAIRE

    Ishimoto, Kazuya; Hayano, Satoru; Yanagita, Takeshi; Kurosaka, Hiroshi; Kawanabe, Noriaki; Itoh, Shinsuke; Ono, Mitsuaki; Kuboki, Takuo; Kamioka, Hiroshi; Yamashiro, Takashi

    2015-01-01

    We herein describe a novel procedure for dentin regeneration that mimics the biological processes of tooth development in nature. The canonical Wnt signaling pathway is an important regulator of the Dentin sialophosphoprotein (Dspp) expression. Our approach mimics the biological processes underlying tooth development in nature and focuses on the activation of canonical Wnt signaling to trigger the natural process of dentinogenesis. The coronal portion of the dentin and the underlying pulp was...

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

    International Nuclear Information System (INIS)

    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 CO2 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 CO2 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 CO2 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

  7. Progenitor Cells and Podocyte Regeneration

    Science.gov (United States)

    Shankland, Stuart J.; Pippin, Jeffrey W.; Duffield, Jeremy S.

    2014-01-01

    The very limited ability of adult podocytes to proliferate in vivo is clinically significant because: podocytes form a vascular barrier which is functionally critical to the nephron; podocyte hypoplasia is a characteristic of disease; and inadequate regeneration of podocytes is a major cause of persistent podocyte hypoplasia. Excessive podocyte loss or inadequate replacement leads to glomerulosclerosis in many progressive kidney diseases. Thus, restoration of podocyte cell density is almost certainly reliant on regeneration by podocyte progenitors. However such putative progenitors have remained elusive until recently. In this review we describe the developmental processes leading to podocyte and parietal epithelial cell (PEC) formation during glomerulogenesis. We compare evidence that in normal human kidneys PECs expressing ‘progenitor’ markers CD133 and CD24 can differentiate into podocytes in vitro and in vivo with evidence from animal models suggesting a more limited role of PEC-capacity to serve as podocyte progenitors in adults. We will highlight tantalizing new evidence that specialized vascular wall cells of afferent arterioles including those which produce renin in healthy kidney, provide a novel local progenitor source of new PECs and podocytes in response to podocyte hypoplasia in the adult, and draw comparisons with glomerulogenesis. PMID:25217270

  8. Microwave Regenerable Air Purification Device

    Science.gov (United States)

    Atwater, James E.; Holtsnider, John T.; Wheeler, Richard R., Jr.

    1996-01-01

    The feasibility of using microwave power to thermally regenerate sorbents loaded with water vapor, CO2, and organic contaminants has been rigorously demonstrated. Sorbents challenged with air containing 0.5% CO2, 300 ppm acetone, 50 ppm trichloroethylene, and saturated with water vapor have been regenerated, singly and in combination. Microwave transmission, reflection, and phase shift has also been determined for a variety of sorbents over the frequency range between 1.3-2.7 GHz. This innovative technology offers the potential for significant energy savings in comparison to current resistive heating methods because energy is absorbed directly by the material to be heated. Conductive, convective and radiative losses are minimized. Extremely rapid heating is also possible, i.e., 1400 C in less than 60 seconds. Microwave powered thermal desorption is directly applicable to the needs of Advance Life Support in general, and of EVA in particular. Additionally, the applicability of two specific commercial applications arising from this technology have been demonstrated: the recovery for re-use of acetone (and similar solvents) from industrial waste streams using a carbon based molecular sieve; and the separation and destruction of trichloroethylene using ZSM-5 synthetic zeolite catalyst, a predominant halocarbon environmental contaminant. Based upon these results, Phase II development is strongly recommended.

  9. Extracellular Control of Limb Regeneration

    Science.gov (United States)

    Calve, S.; Simon, H.-G.

    Adult newts possess the ability to completely regenerate organs and appendages. Immediately after limb loss, the extracellular matrix (ECM) undergoes dramatic changes that may provide mechanical and biochemical cues to guide the formation of the blastema, which is comprised of uncommitted stem-like cells that proliferate to replace the lost structure. Skeletal muscle is a known reservoir for blastema cells but the mechanism by which it contributes progenitor cells is still unclear. To create physiologically relevant culture conditions for the testing of primary newt muscle cells in vitro, the spatio-temporal distribution of ECM components and the mechanical properties of newt muscle were analyzed. Tenascin-C and hyaluronic acid (HA) were found to be dramatically upregulated in the amputated limb and were co-expressed around regenerating skeletal muscle. The transverse stiffness of muscle measured in situ was used as a guide to generate silicone-based substrates of physiological stiffness. Culturing newt muscle cells under different conditions revealed that the cells are sensitive to both matrix coating and substrate stiffness: Myoblasts on HA-coated soft substrates display a rounded morphology and become more elongated as the stiffness of the substrate increases. Coating of soft substrates with matrigel or fibronectin enhanced cell spreading and eventual cell fusion.

  10. Regeneration of Pelargonium in vitro

    Directory of Open Access Journals (Sweden)

    Agnieszka Wojtania

    2013-12-01

    Full Text Available Pelargonium sp. has been a subject of numerous studies to deterimine the effec tiveness of in vitro techniques to produce a large number of pathogen-free plants. Regeneration of pelargonium plants from the different initial explants as well via organogenesis as via somatic embryogenesis has been obtained. The most effective adventitious shoot formation has been achieved from shoot tips and axillary buds using cytokinin or cytokinin/auxin combinations. Leaf explants, whose general have lower organogenic potency, regenerate better in the presence of thidiazuron. This growth regulator stimulate the somatic embryos production from hypocotyl and cotyledone explants too. The main problem in tissue culture propagation of Pelargonium has been the high tendency to formation of vigorously growing callus with low organogenic potency and rapid senescence of cultures. Moreover, the significant differen ces in requirements to the medium composition (minerals, organic compounds and growth regulators between Pelargonium cultivars has been observed. This makes difficult to develop an universaI method of Pelargonium micropropagation.

  11. Biomaterials for orthopaedic implants and bone regeneration

    Science.gov (United States)

    Sargeant, Timothy David

    For bone regeneration, there is need for biodegradable, synthetic scaffolds that direct the formation of de novo mineralized tissue. Orthopaedic implants additionally require mechanical function. The work described herein attempts to address both of these needs. The general strategy involves integrating molecularly designed tissue engineering scaffolds with porous metallic foams to create hybrid materials to direct cellular behavior. Peptide amphiphiles (PAs) that self-assemble into nanofibers were designed to template hydroxyapatite mineral under biological conditions. The molecular design incorporated either serine (S) or phosphoserine S(P) and was mixed with RGDS-bearing PA to evaluate of the key parameters for mineral formation. This led to the discovery of nanoscale hydroxyapatite spheres templated on both S- and S(P)-bearing PA nanofibers. Stem cells were encapsulated in these gels and RT-PCR showed osteoblastic differentiation in all samples. Osteoblast maturation was increased in S-bearing PA compared to S(P)-bearing PA, although the reason is not yet understood. A method to create robust PA nanofiber coatings on NiTi was developed by optimizing the NiTi oxide surface chemistry, optimizing silane vapor deposition, and covalently attaching the PAs to the silanized substrate. The surfaces were characterized by XPS, SIMS, AFM, and fluorimetry. In vitro experiments demonstrated the importance of covalent attachment for cellular adhesion and proved the materials were not cytotoxic. Orthopaedic hybrid materials were created by triggering PA self-assembly within the interconnected pores of Ti foams developed by the Dunand research group. In vitro experiments demonstrate that pre-osteoblasts adhere to, proliferate on, and migrate into PA-Ti hybrids made with S(P)- and RGDS-bearing PA mixtures. The cells differentiate into mature osteoblasts and remain viable up to 28 days. In vivo studies using a rat model demonstrate osteointegration and boney ingrowth into bare

  12. 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.

  13. Current Bioengineering Methods for Whole Kidney Regeneration

    Directory of Open Access Journals (Sweden)

    Shuichiro Yamanaka

    2015-01-01

    Full Text Available Kidney regeneration is likely to provide an inexhaustible source of tissues and organs for immunosuppression-free transplantation. It is currently garnering considerable attention and might replace kidney dialysis as the ultimate therapeutic strategy for renal failure. However, anatomical complications make kidney regeneration difficult. Here, we review recent advances in the field of kidney regeneration, including (i the directed differentiation of induced pluripotent stem cells/embryonic stem cells into kidney cells; (ii blastocyst decomplementation; (iii use of a decellularized cadaveric scaffold; (iv embryonic organ transplantation; and (v use of a nephrogenic niche for growing xenoembryos for de novo kidney regeneration from stem cells. All these approaches represent potentially promising therapeutic strategies for the treatment of patients with chronic kidney disease. Although many obstacles to kidney regeneration remain, we hope that innovative strategies and reliable research will ultimately allow the restoration of renal function in patients with end-stage kidney disease.

  14. NOx adsorber and method of regenerating same

    Science.gov (United States)

    Endicott, Dennis L.; Verkiel, Maarten; Driscoll, James J.

    2007-01-30

    New technologies, such as NOx adsorber catalytic converters, are being used to meet increasingly stringent regulations on undesirable emissions, including NOx emissions. NOx adsorbers must be periodically regenerated, which requires an increased fuel consumption. The present disclosure includes a method of regenerating a NOx adsorber within a NOx adsorber catalytic converter. At least one sensor positioned downstream from the NOx adsorber senses, in the downstream exhaust, at least one of NOx, nitrous oxide and ammonia concentrations a plurality of times during a regeneration phase. The sensor is in communication with an electronic control module that includes a regeneration monitoring algorithm operable to end the regeneration phase when a time rate of change of the at least one of NOx, nitrous oxide and ammonia concentrations is after an expected plateau region begins.

  15. Regeneration of eye tissues is modulated by altered levels of gravity at 1g, 2g, and in microgravity during spaceflight

    Science.gov (United States)

    Grigoryan, Eleonora; Almeida, Eduardo; Mitashov, Victor

    The pursuit of human space exploration requires detailed knowledge of microgravity-related changes in fundamental biological processes, and their effects on health. Normal regeneration of organs and tissues is one such fundamental process that allows maintenance of vitality and function of living organisms. Animal models of tissue regeneration include the newt (Pleurodeles waltl, Urodela) eye, which has been extensively used by our team in Russian Bion and Foton microgravity experiments since 1985, and in recent NASA 2.5 meter diameter centrifuge hypergravity experiments. In total, these experiments allow us to draw several broad conclusions: Newt lens regeneration is significantly altered in microgravity and hypergravity relative to 1g controls. Lenses formed in microgravity are larger and more developed than those regenerated in 1g controls; Microgravity alterations of lens regeneration can persist after spaceflight, and continue to affect repeated removal and regeneration of the lens after return to 1g; Microgravity increases the numbers of early stage regenerative proliferating BrdU-labeled cells in dorsal iris progenitors and in the lens regenerate. Regeneration under hypergravity conditions at 2g inhibits lens regeneration, and often causes retinal detachment. Molecular mechanisms regulating lens regeneration rate include FGF2 signaling, (a key pathway for eye tissue development and regeneration), and an expression of stress-related proteins - HSPs. In conclusion, regeneration of lens and other eye tissues in the newt is sensitive to, and regulated by the level of gravity mechanotransduction and developmental signaling pathways, with microgravity favoring stem cell progenitor proliferation, and gravity at 1g promoting terminal differentiation, while hypergravity at 2g often causes damage of delicate regenerating tissues.

  16. Solar-regenerated desiccant dehumidification

    Science.gov (United States)

    Haves, P.

    1982-02-01

    The dehumidification requirements of buildings are discussed, and the most suitable desiccant material is identified as silica gel. Several conceptual designs for solar regenerated desiccant dehumidifiers using a solid desiccant are described. The construction and operation of a laboratory experiment to determine the performance of a packed bed of silica gel at low flow rate is described. The experimental results are presented and compared to the predictions of a simple computer model which assumes local equilibrium between the desiccant and the airstream. The simulations used to predict desiccant bed performance and the integration of the desiccant bed simulation with a simulation of the thermal performance of a passively cooled residence are described. Results for an average July day are presented. Sizing relationships derived from the simulation are described, and an economic analysis and recommendations for further work are presented.

  17. Advances in regeneration of dental pulp--a literature review.

    Science.gov (United States)

    Ajay Sharma, Lavanya; Sharma, Ajay; Dias, George J

    2015-05-01

    This review summarizes the biological response of dentin-pulp complexes to a variety of stimuli and responses to current treatment therapies and reviews the role of tissue engineering and its application in regenerative endodontics. An electronic search was undertaken based on keywords using Medline/PubMed, Embase, Web of Science and Ovid database resources up to March 2012 to identify appropriate articles, supplemented by a manual search using reference lists from relevant articles. Inclusion criteria were mainly based on different combinations of keywords and restricted to articles published in English language only. Biological approaches based on tissue engineering principles were found to offer the possibility of restoring natural tooth vitality, with distinct evidence that regeneration of lost dental tissues is possible. Studies to formulate an ideal restorative material with regenerative properties, however, are still under way. Further research with supporting clinical studies is required to identify the most effective and safe treatment therapy. PMID:23946258

  18. Insights on augmenter of liver regeneration cloning and function

    Institute of Scientific and Technical Information of China (English)

    Elisavet Gatzidou; Gregory Kouraklis; Stamatios Theocharis

    2006-01-01

    Hepatic stimulator substance (HSS) has been referred to as a liver-specific but species non-specific growth factor. Gradient purification and sequence analysis of HSS protein indicated that it contained the augmenter of liver regeneration (ALR), also known as hepatopoietin (HPO).ALR, acting as a hepatotrophic growth factor, specifically stimulated proliferation of cultured hepatocytes as well as hepatoma cells in vitro, promoted liver regeneration and recovery of damaged hepatocytes and rescued acute hepatic failure in vivo. ALR belongs to the new Erv1/Alr protein family, members of which are found in lower and higher eukaryotes from yeast to man and even in some double-stranded DNA viruses. The present review article focuses on the molecular biology of ALR, examining the ALR gene and its expression from yeast to man and the biological function of ALR protein. ALR protein seems to be non-liver-specific as was previously believed, increasing the necessity to extend research on mammalian ALR protein in different tissues, organs and developmental stages in conditions of normal and abnormal cellular growth.

  19. Biological Threats

    Science.gov (United States)

    ... Workplace Plans School Emergency Plans Main Content Biological Threats Biological agents are organisms or toxins that can ... for Disease Control and Prevention . Before a Biological Threat Unlike an explosion, a biological attack may or ...

  20. 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

  1. The Orchestra of Myocardial Regeneration

    OpenAIRE

    Siddiqi, S

    2014-01-01

    A glimpse on previous and current literature ignites the recognition of the luxurious era that cardiac science has reached. In particular, the past fifteen years have provided tremendous advancements in the field of myocardial biology with the characterization of cardiac stem cells, reprogramming of somatic cells, microRNA discovery, exosome-protocols and imaging modalities. In addition, conventional and outdated biological processes such as myocyte metabolism, cell cycle, and senescence are ...

  2. Urban Regeneration in the Twentieth Century

    OpenAIRE

    Mee, Alan

    2014-01-01

    Directed urban regeneration in Ireland only began in the later part of the twentieth century, driven by a combination of public policy, tax incentives, and pressure to respond to inner-city decay. The term urban regeneration here is taken to mean the conscious project, a publicly directed, area-based initiative to revitalize parts of the city in social, physical and economic terms. Generally this regeneration had a city-wide impact, and key sites or areas came to represent wider changes in ho...

  3. Chitosan Conduit for Peripheral Nerve Regeneration

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Chitosan, the N-deacetylated form of chitin, has good biocompatibility and biodegradability.This paper investigates the feasibility of using chitosan conduits for peripheral nerve regeneration.Cell culture experiments were used to test the material's cytotoxicity and affinity to nerve cells.Conduit implantation experiments were used to study the degradation of the material and the regeneration of injured sciatic nerves.The primary results indicate that chitosan has good mechanical properties, biocompatibility, and biodegradability and it may be a promising biomaterial for peripheral nerve regeneration.

  4. In situ regeneration of bioactive coatings enabled by an evolved Staphylococcus aureus sortase A

    Science.gov (United States)

    Ham, Hyun Ok; Qu, Zheng; Haller, Carolyn A.; Dorr, Brent M.; Dai, Erbin; Kim, Wookhyun; Liu, David R.; Chaikof, Elliot L.

    2016-04-01

    Surface immobilization of bioactive molecules is a central paradigm in the design of implantable devices and biosensors with improved clinical performance capabilities. However, in vivo degradation or denaturation of surface constituents often limits the long-term performance of bioactive films. Here we demonstrate the capacity to repeatedly regenerate a covalently immobilized monomolecular thin film of bioactive molecules through a two-step stripping and recharging cycle. Reversible transpeptidation by a laboratory evolved Staphylococcus aureus sortase A (eSrtA) enabled the rapid immobilization of an anti-thrombogenic film in the presence of whole blood and permitted multiple cycles of film regeneration in vitro that preserved its biological activity. Moreover, eSrtA transpeptidation facilitated surface re-engineering of medical devices in situ after in vivo implantation through removal and restoration film constituents. These studies establish a rapid, orthogonal and reversible biochemical scheme to regenerate selective molecular constituents with the potential to extend the lifetime of bioactive films.

  5. OPTIMIZATION RESULTS OF TEMPOROMANDIBULAR REPARATIVE REGENERATION BY NITINOL MATRICES (Experimental study

    Directory of Open Access Journals (Sweden)

    N. M. Dyuryagin

    2014-12-01

    Full Text Available Aim. Through the experiments on animals, mandibular fragments reparative regeneration and osteohistogenesis in the post-resection period using different ways of their optimization by artifi cial nitinol matrices were investigated.Materials and methods. Rabbits (two groups were subjected to similar resections of mandibular right branch fragments with articular head exarticulation. In the fi rst group (n = 10 extrafocal matrix structures placement option towards regeneration foci (sagittal dislocation was used, in the second one (n = 10 intrafocal matrix bone and periosteum nitinol constructions placement option was used.Results. In the fi rst group, the following reconstructive results were received: organ-like osteogenic regenerates fully displaced mandibular defects in 12 months. In the second group reconstructive results were the following: tissue-engineered composites fully displaced mandibular defects in 3 months. Biological, biometric, radiological, histological, immunohistochemical, morphometric, statistical methods were used to evaluate the results.Conclusion. Reparative regeneration and osteohistogenesis at extrafocal placement of artifi cial matrix structures are able to reconstruct independently mandibular fragments due to natural regeneration. Reparative regeneration and osteohistogenesis at intrafocal placement of artifi cial matrix structures are able to reconstruct independently mandibular fragments due to bone and periosteum tissue-engineered composites forming. Four-fold advantage of mandibular reconstruction dynamics by tissue-engineered composites being equal in functional effi ciency with natural regeneration results testifi es to their availability for usage in clinical practice.

  6. An ancient dental gene set governs development and continuous regeneration of teeth in sharks.

    Science.gov (United States)

    Rasch, Liam J; Martin, Kyle J; Cooper, Rory L; Metscher, Brian D; Underwood, Charlie J; Fraser, Gareth J

    2016-07-15

    The evolution of oral teeth is considered a major contributor to the overall success of jawed vertebrates. This is especially apparent in cartilaginous fishes including sharks and rays, which develop elaborate arrays of highly specialized teeth, organized in rows and retain the capacity for life-long regeneration. Perpetual regeneration of oral teeth has been either lost or highly reduced in many other lineages including important developmental model species, so cartilaginous fishes are uniquely suited for deep comparative analyses of tooth development and regeneration. Additionally, sharks and rays can offer crucial insights into the characters of the dentition in the ancestor of all jawed vertebrates. Despite this, tooth development and regeneration in chondrichthyans is poorly understood and remains virtually uncharacterized from a developmental genetic standpoint. Using the emerging chondrichthyan model, the catshark (Scyliorhinus spp.), we characterized the expression of genes homologous to those known to be expressed during stages of early dental competence, tooth initiation, morphogenesis, and regeneration in bony vertebrates. We have found that expression patterns of several genes from Hh, Wnt/β-catenin, Bmp and Fgf signalling pathways indicate deep conservation over ~450 million years of tooth development and regeneration. We describe how these genes participate in the initial emergence of the shark dentition and how they are redeployed during regeneration of successive tooth generations. We suggest that at the dawn of the vertebrate lineage, teeth (i) were most likely continuously regenerative structures, and (ii) utilised a core set of genes from members of key developmental signalling pathways that were instrumental in creating a dental legacy redeployed throughout vertebrate evolution. These data lay the foundation for further experimental investigations utilizing the unique regenerative capacity of chondrichthyan models to answer evolutionary

  7. Molecular mechanism of bone formation and regeneration

    Institute of Scientific and Technical Information of China (English)

    Akira Yamaguchi

    2008-01-01

    @@ Bone formation and regeneration are mediated by the coordinate action of various factors. Among these, bone morphogenetic protein (BMP) and runt-related gene 2 (Runx2) play crucial roles in bone formation.

  8. Regeneration in selected Cucurbita spp. germplasm

    OpenAIRE

    Gisbert Domenech, Maria Carmen; Nuez Viñals, Fernando; Picó Sirvent, María Belén

    2011-01-01

    Gisbert Domenech, MC.; Nuez Viñals, F.; Picó Sirvent, MB. (2011). Regeneration in selected Cucurbita spp. germplasm. Report- Cucurbit Genetics Cooperative. 33-34:53-54. http://hdl.handle.net/10251/62926.

  9. 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.

  10. An experimental study of passive regenerator geometries

    DEFF Research Database (Denmark)

    Engelbrecht, Kurt; Nielsen, Kaspar Kirstein; Pryds, Nini

    2011-01-01

    Active magnetic regenerative (AMR) systems are being investigated because they represent a potentially attractive alternative to vapor compression technology. The performance of these systems is dependent on the heat transfer and pressure drop performance of the regenerator geometry. Therefore th...

  11. De Novo Kidney Regeneration with Stem Cells

    Directory of Open Access Journals (Sweden)

    Shinya Yokote

    2012-01-01

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

  12. Organic solvent regeneration of granular activated carbon

    Science.gov (United States)

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

    1982-09-01

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

  13. 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

    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......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...

  14. Cooperative Regenerating Codes for Distributed Storage Systems

    OpenAIRE

    Shum, Kenneth W.

    2011-01-01

    When there are multiple node failures in a distributed storage system, regenerating the failed storage nodes individually in a one-by-one manner is suboptimal as far as repair-bandwidth minimization is concerned. If data exchange among the newcomers is enabled, we can get a better tradeoff between repair bandwidth and the storage per node. An explicit and optimal construction of cooperative regenerating code is illustrated.

  15. Regeneration in Echinoderms: repair, regrowth, cloning

    OpenAIRE

    MD Candia Carnevali

    2006-01-01

    Regenerative potential is expressed to a maximum extent in echinoderms. It is a commonphenomenon in all the classes, extensively employed to reconstruct external appendages and internalorgans often subjected to amputation, self-induced or traumatic, rapidly followed by completesuccessful re-growth of the lost parts. Regeneration has been studied in adult individuals as well as inlarvae. In armed echinoderms, regeneration of arms is obviously frequent: in many cases, thedetached body fragments...

  16. Denitrification of Spent Regenerated Brine Using Molasses

    OpenAIRE

    Tepuš, Brigita; Simonič, Marjana; Petrovič, Aleksandra; Filipič, Jasmina

    2014-01-01

    Spent BRINE from the regeneration of exhausted resins has to be properly treated before its disposal. The heterotrophic denitrification of regenerated brine was studied in present work. Molasses which served as a carbon source has until now not been applied during brine denitrification. The nitrate and nitrite consumptions were observed according to different ratios between total organic carbon and nitrate (TOC / NO3 ratios) and the influence of NaCl was studied during batch experiments. ...

  17. Proteomics based approach to understand tissue regeneration

    OpenAIRE

    Franco, Catarina de Matos Ferraz

    2011-01-01

    Most echinoderm species share an outstanding capacity for regeneration that is maintained throughout the adult animal lifespan. Regeneration allows these deuterostomes to recover from predation injuries or selfinduced arm autotomy, which are known to occur frequently in nature. Although echinoderms are extremely interesting in terms of their phylogenetic proximity to chordates, most areas of echinoderm research have been neglected in recent years. These wonderful animals quickly s...

  18. Study of Regenerated Plants Aspen from Callus

    OpenAIRE

    G. A. PETROVA; Kalashnikova, E. A.

    2014-01-01

    This article presents the results of an experiment for obtaining healthy seed aspen by micropropagation. The studies we have obtained from callus tissue regenerated plants aspen, various different growth rate. Were obtained two types of plants: plants, characterized by rapid growth and plants, which are characterized by slow growth. The data of biochemical studies on the content of soluble phenolic compounds in plants regenerated aspen. So plants with rapid growth during the five passages, th...

  19. Circadian Gene Networks In Bone Regeneration

    OpenAIRE

    Hassan, Nathaniel

    2012-01-01

    BACKGROUND: Previous studies suggested that vitamin D played a significant role in bone regeneration, facilitating the establishment of implant osseointegration. A whole genome microarray study further suggested that the vitamin D axis might involve circadian rhythm gene expression in the bone peripheral tissue.OBJECTIVES: To identify key gene networks involved with vitamin D receptor in the bone regeneration process and to explore any correlation with circadian rhythm gene expression in bone...

  20. Fluidic valve for reactor regeneration flow switching

    OpenAIRE

    Tesar, V

    2004-01-01

    An unusual and in many respects advantageous no-moving-part valve is described,developed for switching fluid flows in a through-flow reactor that requires a periodic regeneration by temporary replacement of the process fluid by another, regeneration fluid. The unusual feature of the valve is that it is axisymmetric, built integrally into the inlet part of the reactor body. The valve operation is based upon a monostable axisymmetric variant of the Coanda effect of jet attachment to a wall. ...

  1. Protoplast formation and regeneration in Lactobacillus delbrueckii

    OpenAIRE

    Singhvi, Mamta; Joshi, Dipti; Gaikaiwari, Shalaka; Digambar V. Gokhale

    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...

  2. The Architectural Practice of Regeneration

    Directory of Open Access Journals (Sweden)

    Tom Van Malderen

    2013-09-01

    Full Text Available In form and in content, cities are the epitome of diversity. This state is the result of the accumulation of layers of history, of construction, of demolition and reconstruction cycles. These tensions are the catalyst for the emergence of new urban forms and participate in the construction of heritage. As such they should be encouraged. As important as the existing fabric of the city is, its evolution to accommodate the ever-changing needs and fashions of its inhabitants is paramount. For regeneration to be successful it must inscribe itself in this process and it must be driven by an understanding of the environment where it occurs. This paper explores, through the lens of an architectural practice, some design processes and architectural proposals that have been generated by working on the Valletta harbours. It also discusses the necessary dynamics required to accommodate stakeholder engagement and planning policy while ensuring design quality and the perpetuation of the creative process inherent to the city. Finally, the paper introduces, as a possible future, the experiments and studies of the practice on the wider Valletta, putting into perspective the benefits of theoretical research combined with formal and aesthetic explorations of the harbour region.

  3. 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.

  4. Cell-based strategies for vascular regeneration.

    Science.gov (United States)

    Zou, Tongqiang; Fan, Jiabing; Fartash, Armita; Liu, Haifeng; Fan, Yubo

    2016-05-01

    Vascular regeneration is known to play an essential role in the repair of injured tissues mainly through accelerating the repair of vascular injury caused by vascular diseases, as well as the recovery of ischemic tissues. However, the clinical vascular regeneration is still challenging. Cell-based therapy is thought to be a promising strategy for vascular regeneration, since various cells have been identified to exert important influences on the process of vascular regeneration such as the enhanced endothelium formation on the surface of vascular grafts, and the induction of vessel-like network formation in the ischemic tissues. Here are a vast number of diverse cell-based strategies that have been extensively studied in vascular regeneration. These strategies can be further classified into three main categories, including cell transplantation, construction of tissue-engineered grafts, and surface modification of scaffolds. Cells used in these strategies mainly refer to terminally differentiated vascular cells, pluripotent stem cells, multipotent stem cells, and unipotent stem cells. The aim of this review is to summarize the reported research advances on the application of various cells for vascular regeneration, yielding insights into future clinical treatment for injured tissue/organ. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1297-1314, 2016. PMID:26864677

  5. Modeling planarian regeneration: a primer for reverse-engineering the worm.

    Directory of Open Access Journals (Sweden)

    Daniel Lobo

    Full Text Available A mechanistic understanding of robust self-assembly and repair capabilities of complex systems would have enormous implications for basic evolutionary developmental biology as well as for transformative applications in regenerative biomedicine and the engineering of highly fault-tolerant cybernetic systems. Molecular biologists are working to identify the pathways underlying the remarkable regenerative abilities of model species that perfectly regenerate limbs, brains, and other complex body parts. However, a profound disconnect remains between the deluge of high-resolution genetic and protein data on pathways required for regeneration, and the desired spatial, algorithmic models that show how self-monitoring and growth control arise from the synthesis of cellular activities. This barrier to progress in the understanding of morphogenetic controls may be breached by powerful techniques from the computational sciences-using non-traditional modeling approaches to reverse-engineer systems such as planaria: flatworms with a complex bodyplan and nervous system that are able to regenerate any body part after traumatic injury. Currently, the involvement of experts from outside of molecular genetics is hampered by the specialist literature of molecular developmental biology: impactful collaborations across such different fields require that review literature be available that presents the key functional capabilities of important biological model systems while abstracting away from the often irrelevant and confusing details of specific genes and proteins. To facilitate modeling efforts by computer scientists, physicists, engineers, and mathematicians, we present a different kind of review of planarian regeneration. Focusing on the main patterning properties of this system, we review what is known about the signal exchanges that occur during regenerative repair in planaria and the cellular mechanisms that are thought to underlie them. By establishing an

  6. The significance of nitrogen regeneration for new production within a filament of the Mauritanian upwelling system

    Science.gov (United States)

    Clark, Darren R.; Widdicombe, Claire E.; Rees, Andrew P.; Woodward, E. Malcolm S.

    2016-05-01

    The Lagrangian progression of a biological community was followed in a filament of the Mauritanian upwelling system, north-west Africa, during offshore advection. The inert dual tracers sulfur hexafluoride and helium-3 labelled a freshly upwelled patch of water that was mapped for 8 days. Changes in biological, physical, and chemical characteristics were measured, including phytoplankton productivity, nitrogen assimilation, and regeneration. Freshly upwelled water contained high nutrient concentrations but was depleted in N compared to Redfield stoichiometry. The highest rate of primary productivity was measured on the continental shelf, associated with high rates of nitrogen assimilation and a phytoplankton community dominated by diatoms and flagellates. Indicators of phytoplankton abundance and activity decreased as the labelled water mass transited the continental shelf slope into deeper water, possibly linked to the mixed layer depth exceeding the light penetration depth. By the end of the study, the primary productivity rate decreased and was associated with lower rates of nitrogen assimilation and lower nutrient concentrations. Nitrogen regeneration and assimilation took place simultaneously. Results highlighted the importance of regenerated NH4+ in sustaining phytoplankton productivity and indicate that the upwelled NO3- pool contained an increasing fraction of regenerated NO3- as it advected offshore. By calculating this fraction and incorporating it into an f ratio formulation, we estimated that of the 12.38 Tg C of annual regional production, 4.73 Tg C was exportable.

  7. Tissue Regeneration in the Classroom!

    Science.gov (United States)

    Hassoun, Lama; Hable, Whitney; Payne-Ferreira, Tracie L.

    2008-01-01

    Hands-on biological exploration has been shown to have a great impact on learning. When students "do" something, they remember more details than when they sit through a lecture describing the same activity. In this article, the authors present an exercise that has the potential to get all levels of students into the lab for practical experience…

  8. Biophysical stimulation of bone fracture repair, regeneration and remodelling

    Directory of Open Access Journals (Sweden)

    Chao E. Y.S.

    2003-12-01

    Full Text Available Biophysical stimulation to enhance bone fracture repair and bone regenerate maturation to restore its structural strength must rely on both the biological and biomechanical principle according to the local tissue environment and the type of mechanical stress to be born by the skeletal joint system. This paper reviews the possible interactions between biophysical stimuli and cellular responses in healing bone fractures and proceeds to speculate the prospects and limitations of different experimental models in evaluating and optimising such non-invasive interventions. It is important to realize that bone fracture repair has several pathways with various combinations of bone formation mechanisms, but there may only be one bone remodeling principle regulated by the hypothesis proposed by Wolff. There are different mechanical and biophysical stimuli that could provide effective augmentation of fracture healing and bone regenerate maturation. The key requirements of establishing these positive interactions are to define the precise cellular response to the stimulation signal in an in vitro environment and to use well-established animal models to quantify and optimise the therapeutic regimen in a time-dependent manner. This can only be achieved through research collaboration among different disciplines using scientific methodologies. In addition, the specific forms of biophysical stimulation and its dose effect and application timing must be carefully determined and validated. Technological advances in achieving focalized stimulus delivery with adjustable signal type and intensity, in the ability to monitor healing callus mechanical property non-invasively, and in the establishment of a robust knowledgebase to develop effective and reliable treatment protocols are the essential pre-requisites to make biophysical stimulation acceptable in the main arena of health care. Finally, it is important to bear in mind that successful fracture repair or bone

  9. Regeneration in brass wind instruments

    Science.gov (United States)

    Elliott, S. J.; Bowsher, J. M.

    1982-07-01

    This paper is concerned with the production of musical notes by the interaction between the lips of a player and a brass wind instrument. The mechanism of this non-linear oscillation, together with that in the voice and for woodwind instruments, is discussed and past theories reviewed. Each element in the interaction is then carefully delineated and reasonable approximations to the governing equations for the lip dynamics and flow conditions through the lip opening are deduced: the acoustic parameters of the instrument and pressure source from the lungs can be experimentally determined. In contrast to the case of woodwind instruments, for example, many of the important parameters controlling the interaction can vary over a wide range and are under the complete control of the player. The expressions describing each component of the interaction are then combined to form an overall theory of regeneration, following Helmholtz, which leads to a description of the conditions necessary for a note to be sustained, and to an expression describing the characteristic waveform of the mouthpiece pressure at low frequencies. Experimental measurements of this mouthpiece pressure are presented, together with measurements of the steady and alternating components of the pressure in the mouth, and of the velocity in the mouthpiece for blown notes on a trombone and trumpet. Good agreement was observed between the harmonics of the measured mouthpiece pressure and those deduced from theory. Measurements are presented of the intonation of a trombone, and the range and characteristics of notes "buzzed" on a mouthpiece alone are discussed. Finally the steady pressure in the mouth and the average flow down the instrument are used to calculate the average lip opening, and hence the effective mass of the moving parts of the lips for a variety of notes played on a trombone and trumpet.

  10. 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: EH - Ecology, Behaviour

  11. Mechanisms of lymphatic regeneration after tissue transfer.

    Directory of Open Access Journals (Sweden)

    Alan Yan

    Full Text Available INTRODUCTION: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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

  12. Small-Scale Fabrication of Biomimetic Structures for Periodontal Regeneration.

    Science.gov (United States)

    Green, David W; Lee, Jung-Seok; Jung, Han-Sung

    2016-01-01

    The periodontium is the supporting tissues for the tooth organ and is vulnerable to destruction, arising from overpopulating pathogenic bacteria and spirochaetes. The presence of microbes together with host responses can destroy large parts of the periodontium sometimes leading tooth loss. Permanent tissue replacements are made possible with tissue engineering techniques. However, existing periodontal biomaterials cannot promote proper tissue architectures, necessary tissue volumes within the periodontal pocket and a "water-tight" barrier, to become clinically acceptable. New kinds of small-scale engineered biomaterials, with increasing biological complexity are needed to guide proper biomimetic regeneration of periodontal tissues. So the ability to make compound structures with small modules, filled with tissue components, is a promising design strategy for simulating the anatomical complexity of the periodotium attachment complexes along the tooth root and the abutment with the tooth collar. Anatomical structures such as, intima, adventitia, and special compartments such as the epithelial cell rests of Malassez or a stellate reticulum niche need to be engineered from the start of regeneration to produce proper periodontium replacement. It is our contention that the positioning of tissue components at the origin is also necessary to promote self-organizing cell-cell connections, cell-matrix connections. This leads to accelerated, synchronized and well-formed tissue architectures and anatomies. This strategy is a highly effective preparation for tackling periodontitis, periodontium tissue resorption, and to ultimately prevent tooth loss. Furthermore, such biomimetic tissue replacements will tackle problems associated with dental implant support and perimimplantitis. PMID:26903872

  13. Role of tissue engineering in dental pulp regeneration

    Directory of Open Access Journals (Sweden)

    Shruti Sial

    2012-01-01

    Full Text Available Stem cells constitute the source of differentiated cells for the generation of tissues during development, and for regeneration of tissues that are diseased or injured postnatally. In recent years, stem cell research has grown exponentially owing to the recognition that stem cell-based therapies have the potential to improve the life of patients with conditions that span from Alzheimer′s disease to cardiac ischemia to bone or tooth loss. Growing evidence demonstrates that stem cells are primarily found in niches and that certain tissues contain more stem cells than others. Among these tissues, the dental pulp is considered a rich source of mesenchymal stem cells that are suitable for tissue engineering applications. It is known that dental pulp stem cells have the potential to differentiate into several cell types, including odontoblasts, neural progenitors, osteoblasts, chondrocytes, and adipocytes. The dental pulp stem cells are highly proliferative. Collectively, the multipotency, high proliferation rates, and accessibility make the dental pulp an attractive source of mesenchymal stem cells for tissue regeneration. This review discusses fundamental concepts of stem cell biology and tissue engineering within the context of regenerative dentistry.

  14. Small-Scale Fabrication of Biomimetic Structures for Periodontal Regeneration

    Directory of Open Access Journals (Sweden)

    David William Green

    2016-02-01

    Full Text Available The periodontium is the supporting tissues for the tooth organ and is vulnerable to destruction, arising from overpopulating pathogenic bacteria and spirochaetes. The presence of microbes together with host responses can destroy large parts of the periodontium sometimes leading tooth loss. Permanent tissue replacements are made possible with tissue engineering techniques. However, existing periodontal biomaterials cannot promote proper tissue architectures, necessary tissue volumes within the periodontal pocket and a water-tight barrier, to become clinically acceptable. New kinds of small-scale engineered biomaterials, with increasing biological complexity are needed to guide proper biomimetic regeneration of periodontal tissues. So the ability to make compound structures with small modules, filled with tissue components, is a promising design strategy for simulating the anatomical complexity of the periodotium attachement complexes along the tooth root and the abutment with the tooth collar. Anatomical structures such as, intima, adventitia and special compartments such as the epithelial cell rests of Malassez or a stellate reticulum niche need to be engineered from the start of regeneration to produce proper periodontium replacement.. It is our contention that the positioning of tissue components at the origin is also necessary to promote self-organising cell-cell connections, cell-matrix connections. This leads to accelerated, synchronized and well-formed tissue architectures and anatomies. This strategy is a highly effective preparation for tackling periodontitis, periodontium tissue resorption and to ultimately prevent tooth loss. Furthermore, such biomimetic tissue replacements will tackle problems associated with dental implant support and perimimplantitis.

  15. Bacterial Cellulose-Hydroxyapatite Nanocomposites for Bone Regeneration

    Directory of Open Access Journals (Sweden)

    S. Saska

    2011-01-01

    Full Text Available The aim of this study was to develop and to evaluate the biological properties of bacterial cellulose-hydroxyapatite (BC-HA nanocomposite membranes for bone regeneration. Nanocomposites were prepared from bacterial cellulose membranes sequentially incubated in solutions of CaCl2 followed by Na2HPO4. BC-HA membranes were evaluated in noncritical bone defects in rat tibiae at 1, 4, and 16 weeks. Thermogravimetric analyses showed that the amount of the mineral phase was 40%–50% of the total weight. Spectroscopy, electronic microscopy/energy dispersive X-ray analyses, and X-ray diffraction showed formation of HA crystals on BC nanofibres. Low crystallinity HA crystals presented Ca/P a molar ratio of 1.5 (calcium-deficient HA, similar to physiological bone. Fourier transformed infrared spectroscopy analysis showed bands assigned to phosphate and carbonate ions. In vivo tests showed no inflammatory reaction after 1 week. After 4 weeks, defects were observed to be completely filled in by new bone tissue. The BC-HA membranes were effective for bone regeneration.

  16. A Study of Regenerator for a Personal Stirling Refrigerator

    Science.gov (United States)

    Murakami, Kazuhiko; Otaka, Toshio; Sakamoto, Moriyoshi; Yamaguchi, Hajime; Ota, Masahiro

    Stirling cycle system is expected as a gentle system to the earth, because the working fluid is completely free from chlorine molecules. A regenerator is the most important element of the Stirling cycle system for the performances. Flow in a regenerator is very complicated because the regenerator is made of matrix. So we are studying about Stirling cycle systems, especially the regenerator for a personal Stirling refrigerator. In this report, flow in a regenerator for a personal Stirling refrigerators is studied by using an original experimental set-up. Flow velocities and pressures at the outside of a matrix in a regenerator were measured in a round pipe. Flow effects of inlet or outlet shape and area for a regenerator were examined in detail. Pressure loss were measured at sides of a regenerator and friction factors were expressed as empirical formulas for each conditions of inlet shape of regenerator or matrixes.

  17. 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.

  18. Unexpected regeneration in middle-aged mice.

    Science.gov (United States)

    Reines, Brandon; Cheng, Lily I; Matzinger, Polly

    2009-02-01

    Complete regeneration of damaged extremities, including both the epithelium and the underlying tissues, is thought to occur mainly in embryos, fetuses, and juvenile mammals, but only very rarely in adult mammals. Surprisingly, we found that common strains of mice are able to regenerate all of the tissues necessary to completely fill experimentally punched ear holes, but only if punched at middle age. Although young postweaning mice regrew the epithelium without typical pre-scar granulation tissue, they showed only minimal regeneration of connective tissues. In contrast, mice punched at 5-11 months of age showed true amphibian-like blastema formation and regrowth of cartilage, fat, and dermis, with blood vessels, sebaceous glands, hair follicles, and, in black mice, melanocytes. These data suggest that at least partial appendage regeneration may be more common in adult mammals than previously thought and call into question the common view that regenerative ability is lost with age. The data suggest that the age at which various inbred mouse strains become capable of epimorphic regeneration may be correlated with adult body weight. PMID:19226206

  19. Regeneration in Echinoderms: repair, regrowth, cloning

    Directory of Open Access Journals (Sweden)

    MD Candia Carnevali

    2006-06-01

    Full Text Available Regenerative potential is expressed to a maximum extent in echinoderms. It is a commonphenomenon in all the classes, extensively employed to reconstruct external appendages and internalorgans often subjected to amputation, self-induced or traumatic, rapidly followed by completesuccessful re-growth of the lost parts. Regeneration has been studied in adult individuals as well as inlarvae. In armed echinoderms, regeneration of arms is obviously frequent: in many cases, thedetached body fragments can undergo phenomena of partial or total regeneration independently of thedonor animal, and, in a few cases (asteroids, the individual autotomised arms can even regenerate toproduce new complete adults, offering superb examples of cloning strategies. In the species examinedso far most results throw light on aspects related to wound healing, growth, morphogenesis anddifferentiation, even though in most cases many crucial questions remain unanswered. The presentpaper provides an overview of the current understanding of the phenomenon and covers the mainbiological aspects of regeneration giving an idea of the “state of the art” across the phylum in terms ofexperimental approaches and representative models.

  20. 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.

  1. Microwave-assisted regeneration of activated carbon.

    Science.gov (United States)

    Foo, K Y; Hameed, B H

    2012-09-01

    Microwave heating was used in the regeneration of methylene blue-loaded activated carbons produced from fibers (PFAC), empty fruit bunches (EFBAC) and shell (PSAC) of oil palm. The dye-loaded carbons were treated in a modified conventional microwave oven operated at 2450 MHz and irradiation time of 2, 3 and 5 min. The virgin properties of the origin and regenerated activated carbons were characterized by pore structural analysis and nitrogen adsorption isotherm. The surface chemistry was examined by zeta potential measurement and determination of surface acidity/basicity, while the adsorptive property was quantified using methylene blue (MB). Microwave irradiation preserved the pore structure, original active sites and adsorption capacity of the regenerated activated carbons. The carbon yield and the monolayer adsorption capacities for MB were maintained at 68.35-82.84% and 154.65-195.22 mg/g, even after five adsorption-regeneration cycles. The findings revealed the potential of microwave heating for regeneration of spent activated carbons. PMID:22728787

  2. The chemical NMP as a potent BMP enhancer for bone tissue regeneration

    OpenAIRE

    San Miguel, B; Ghayor, C; Ehrbar, M.; Jung, R.E.; Zwahlen, R A; Hortschansky, P; Schmökel, H G; Weber, F. E.

    2009-01-01

    In medicine N-methylpyrrolidone (NMP) has a long track record as constituent in FDA approved medical devices and thus can be considered as safe and biological inactive small chemical. In the present study we report on the newly discovered pharmaceutical properties of NMP as it enhances bone regeneration in a rabbit calvarial defect model in vivo. At the cellular level, the pharmaceutical effect of NMP was confirmed, in particular, in combination with BMP-2, as NMP increased early and late mar...

  3. The physico-chemical properties and biostimulative activities of humic substances regenerated from lignite

    OpenAIRE

    David, Jan; Šmejkalová, Daniela; Hudecová, Šárka; Zmeškal, Oldřich; von Wandruszka, Ray; Gregor, Tomáš; Kučerík, Jiří

    2014-01-01

    The positive effect of humic acids on the growth of plant roots is well known, however, the mechanisms and role of their physical structure in these processes have not been fully explained yet. In this work, South-Moravian lignite was oxidized by means of nitric acid and hydrogen peroxide to produce a set of regenerated humic acids. The elemental composition, solid state stability and solution characteristics were determined and correlated in vitro with their biological activity. A modified h...

  4. Regeneration and calcification in the Spirobranchus lamarcki operculum: development and comparative genetics of a novel appendage

    OpenAIRE

    Szabó, Réka

    2015-01-01

    Regeneration, the replacement of lost or damaged body parts, and biomineralisation, the biologically controlled formation of minerals, are important and widespread abilities in the animal kingdom. Both phenomena have a complex evolutionary history; thus their study benefits from investigations in diverse animals. Spirobranchus (formerly Pomatoceros) lamarcki is a small tube-dwelling polychaete worm of the serpulid family. Serpulids have evolved a novel head appendage, the operculum, which fun...

  5. Advances in skin regeneration: application of electrospun scaffolds.

    Science.gov (United States)

    Norouzi, Mohammad; Boroujeni, Samaneh Moghadasi; Omidvarkordshouli, Noushin; Soleimani, Masoud

    2015-06-01

    The paucity of cellular and molecular signals essential for normal wound healing makes severe dermatological ulcers stubborn to heal. The novel strategies of skin regenerative treatments are focused on the development of biologically responsive scaffolds accompanied by cells and multiple biomolecules resembling structural and biochemical cues of the natural extracellular matrix (ECM). Electrospun nanofibrous scaffolds provide similar architecture to the ECM leading to enhancement of cell adhesion, proliferation, migration and neo tissue formation. This Review surveys the application of biocompatible natural, synthetic and composite polymers to fabricate electrospun scaffolds as skin substitutes and wound dressings. Furthermore, the application of biomolecules and therapeutic agents in the nanofibrous scaffolds viz growth factors, genes, antibiotics, silver nanoparticles, and natural medicines with the aim of ameliorating cellular behavior, wound healing, and skin regeneration are discussed. PMID:25721694

  6. The Molecular and Cellular Choreography of Appendage Regeneration.

    Science.gov (United States)

    Tanaka, Elly M

    2016-06-16

    Recent advances in limb regeneration are revealing the molecular events that integrate growth control, cell fate programming, and positional information to yield the exquisite replacement of the amputated limb. Parallel progress in several invertebrate and vertebrate models has provided a broader context for understanding the mechanisms and the evolution of regeneration. Together, these discoveries provide a foundation for describing the principles underlying regeneration of complex, multi-tissue structures. As such these findings should provide a wealth of ideas for engineers seeking to reconstitute regeneration from constituent parts or to elicit full regeneration from partial regeneration events. PMID:27315477

  7. Enhancing nerve regeneration in the peripheral nervous system using polymeric scaffolds, stem cell engineering and nanoparticle delivery system

    Science.gov (United States)

    Sharma, Anup Dutt

    Peripheral nerve regeneration is a complex biological process responsible for regrowth of neural tissue following a nerve injury. The main objective of this project was to enhance peripheral nerve regeneration using interdisciplinary approaches involving polymeric scaffolds, stem cell therapy, drug delivery and high content screening. Biocompatible and biodegradable polymeric materials such as poly (lactic acid) were used for engineering conduits with micropatterns capable of providing mechanical support and orientation to the regenerating axons and polyanhydrides for fabricating nano/microparticles for localized delivery of neurotrophic growth factors and cytokines at the site of injury. Transdifferentiated bone marrow stromal cells or mesenchymal stem cells (MSCs) were used as cellular replacements for lost native Schwann cells (SCs) at the injured nerve tissue. MSCs that have been transdifferentiated into an SC-like phenotype were tested as a substitute for the myelinating SCs. Also, genetically modified MSCs were engineered to hypersecrete brain- derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) to secrete therapeutic factors which Schwann cell secrete. To further enhance the regeneration, nerve growth factor (NGF) and interleukin-4 (IL4) releasing polyanhydrides nano/microparticles were fabricated and characterized in vitro for their efficacy. Synergistic use of these proposed techniques was used for fabricating a multifunctional nerve regeneration conduit which can be used as an efficient tool for enhancing peripheral nerve regeneration.

  8. Development of Thermosensitive Hydrogels of Chitosan, Sodium and Magnesium Glycerophosphate for Bone Regeneration Applications

    Science.gov (United States)

    Lisková, Jana; Bačaková, Lucie; Skwarczyńska, Agata L.; Musial, Olga; Bliznuk, Vitaliy; De Schamphelaere, Karel; Modrzejewska, Zofia; Douglas, Timothy E.L.

    2015-01-01

    Thermosensitive injectable hydrogels based on chitosan neutralized with sodium beta-glycerophosphate (Na-β-GP) have been studied as biomaterials for drug delivery and tissue regeneration. Magnesium (Mg) has been reported to stimulate adhesion and proliferation of bone forming cells. With the aim of improving the suitability of the aforementioned chitosan hydrogels as materials for bone regeneration, Mg was incorporated by partial substitution of Na-β-GP with magnesium glycerophosphate (Mg-GP). Chitosan/Na-β-GP and chitosan/Na-β-GP/Mg-GP hydrogels were also loaded with the enzyme alkaline phosphatase (ALP) which induces hydrogel mineralization. Hydrogels were characterized physicochemically with respect to mineralizability and gelation kinetics, and biologically with respect to cytocompatibility and cell adhesion. Substitution of Na-β-GP with Mg-GP did not negatively influence mineralizability. Cell biological testing showed that both chitosan/Na-β-GP and chitosan/Na-β-GP/Mg-GP hydrogels were cytocompatible towards MG63 osteoblast-like cells. Hence, chitosan/Na-β-GP/Mg-GP hydrogels can be used as an alternative to chitosan/Na-β-GP hydrogels for bone regeneration applications. However the incorporation of Mg in the hydrogels during hydrogel formation did not bring any appreciable physicochemical or biological benefit. PMID:25859630

  9. Development of Thermosensitive Hydrogels of Chitosan, Sodium and Magnesium Glycerophosphate for Bone Regeneration Applications

    Directory of Open Access Journals (Sweden)

    Jana Lisková

    2015-04-01

    Full Text Available Thermosensitive injectable hydrogels based on chitosan neutralized with sodium beta-glycerophosphate (Na-β-GP have been studied as biomaterials for drug delivery and tissue regeneration. Magnesium (Mg has been reported to stimulate adhesion and proliferation of bone forming cells. With the aim of improving the suitability of the aforementioned chitosan hydrogels as materials for bone regeneration, Mg was incorporated by partial substitution of Na-β-GP with magnesium glycerophosphate (Mg-GP. Chitosan/Na-β-GP and chitosan/Na-β-GP/Mg-GP hydrogels were also loaded with the enzyme alkaline phosphatase (ALP which induces hydrogel mineralization. Hydrogels were characterized physicochemically with respect to mineralizability and gelation kinetics, and biologically with respect to cytocompatibility and cell adhesion. Substitution of Na-β-GP with Mg-GP did not negatively influence mineralizability. Cell biological testing showed that both chitosan/Na-β-GP and chitosan/Na-β-GP/Mg-GP hydrogels were cytocompatible towards MG63 osteoblast-like cells. Hence, chitosan/Na-β-GP/Mg-GP hydrogels can be used as an alternative to chitosan/Na-β-GP hydrogels for bone regeneration applications. However the incorporation of Mg in the hydrogels during hydrogel formation did not bring any appreciable physicochemical or biological benefit.

  10. Tissue regeneration during tissue expansion and choosing an expander

    Directory of Open Access Journals (Sweden)

    K Agrawal

    2012-01-01

    Full Text Available This paper reviews the various aspects of tissue regeneration during the process of tissue expansion. "Creep" and mechanical and biological "stretch" are responsible for expansion. During expansion, the epidermis thickens, the dermis thins out, vascularity improves, significant angiogenesis occurs, hair telogen phase becomes shorter and the peripheral nerves, vessels and muscle fibres lengthen. Expansion is associated with molecular changes in the tissue. Almost all these biological changes are reversible after the removal of the expander.This study is also aimed at reviewing the difficulty in deciding the volume and dimension of the expander for a defect. Basic mathematical formulae and the computer programmes for calculating the dimension of tissue expanders, although available in the literature, are not popular. A user-friendly computer programme based on the easily available Microsoft Excel spread sheet has been introduced. When we feed the area of defect and base dimension of the donor area or tissue expander, this programme calculates the volume and height of the expander. The shape of the expander is decided clinically based on the availability of the donor area and the designing of the future tissue movement. Today, tissue expansion is better understood biologically and mechanically. Clinical judgement remains indispensable in choosing the size and shape of the tissue expander.

  11. All-optical signal processing and regeneration

    DEFF Research Database (Denmark)

    Wolfson, David

    2001-01-01

    of a detailed large-signal model. An important parameter for SOA-based gates is the input power dynamic range (IPDR) as it determines the cascadability of the devices. Guidelines on how to maximise the IPDR are therefore established. Important trends are that short SOAs with low confinement factors and a low...... to conventional wavelength conversion since conversion of an optical clock signal is used instead of CW light. An investigation of these advantages is carried out and the feasibility of the scheme is demonstrated at 20 Gbit/s. A description of interferometric wavelength converters (IWCs) is also given. The high...... attractive for all-optical regeneration. Experiments carried out at 40 Gbit/s demonstrate excellent performance for 2R regeneration, which is emphasised by a clear improvement of the optical signal-to-noise ratio and a noise suppression capability. 3R regeneration is also illustrated at 40 Gbit/s, where...

  12. A method for regenerating clarifying coal

    Energy Technology Data Exchange (ETDEWEB)

    Parfent' yeva, N.A.; Barteneva, A.G.; Khal' kin, Yu.I.; Kravchenko, E.A.; Minakova, V.I.; Norinskaya, T.I.; Shkarbanov, N.A.

    1984-01-01

    A method is patented for regenerating ''clarifying coal'' which includes processing of the coal by a reagent with heating and subsequent washing with water. The method is distinguished by the fact that in order to increase the degree of regeneration, 70 to 100 percent H2S04 or oleum is used as the reagent and the process is conducted at 150 to 160 degrees. Example. Ten grams of a clarifying coal collactivite with a moisture content of 20 degrees, used for clarifying a hydrolizate, is processed by 13 grams per milliliter of 70 percent H2S04 at 160 degrees for 10 minutes, after which the mixture is washed off by 250 milliliters of water through repeated curing with subsequent filtration to an acidity level of 0.1 percent. 8.7 grams of regenerated coal with a clarifying capability of 91.7 percent are produced.

  13. 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.

  14. Microwave-Regenerated Diesel Exhaust Particulate Filter

    Energy Technology Data Exchange (ETDEWEB)

    Nixdorf, Richard D. (Industrial Ceramic Solution, LLC); Green, Johney Boyd; Story, John M.; Wagner, Robert M. (Oak Ridge National Laboratory)

    2001-03-05

    Development of a microwave-regenerated particulate filter system has evolved from bench scale work to actual diesel engine experimentation. The filter system was initially evaluated on a stationary mounted 1.2-L diesel engine and was able to remove a significant amount of carbon particles from the exhaust. The ability of the microwave energy to regenerate or clean the filter was also demonstrated on this engine under idle conditions. Based on the 1.2-L experiments, improvements to the filter design and materials were implemented and the system was re-evaluated on a vehicle equipped with a 7.3-L diesel engine. The 7.3-L engine was selected to achieve heavy filter loading in a relatively short period of time. The purpose of these experiments was to evaluate filter-loading capacity, power requirements for regeneration, and filter regeneration efficiency. A more detailed evaluation of the filter was performed on a stationary mounted 1.9-L diesel engine. The effect of exhaust flow rate, loading, transients, and regeneration on filter efficiency was evaluated with this setup. In addition, gaseous exhaust emissions were investigated with and without an oxidation catalyst on the filter cartridge during loading and regeneration. (SAE Paper SAE-2001-01-0903 © 2001 SAE International. This paper is published on this website with permission from SAE International. As a user of this website, you are permitted to view this paper on-line, download this pdf file and print one copy of this paper at no cost for your use only. The downloaded pdf file and printout of this SAE paper may not be copied, distributed or forwarded to others or for the use of others.)

  15. Biologically active collagen-based scaffolds: advances in processing and characterization

    OpenAIRE

    Yannas, I.V.; Tzeranis, D. S.; Harley, B A; So, P. T. C.

    2010-01-01

    A small number of type I collagen–glycosaminoglycan scaffolds (collagen–GAG scaffolds; CGSs) have unusual biological activity consisting primarily in inducing partial regeneration of organs in the adult mammal. Two of these are currently in use in a variety of clinical settings. CGSs appear to induce regeneration by blocking the adult healing response, following trauma, consisting of wound contraction and scar formation. Several structural determinants of biological activity have been identif...

  16. 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 to be...... 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...

  17. Membrane reactors for continuous coenzyme regeneration

    Science.gov (United States)

    Wandrey, C.; Wichmann, R.

    1982-12-01

    The importance of continuous coenzyme regeneration is discussed with respect to chemical reaction engineering. The benefit of coenzymes covalently bound to water soluble polymers is especially stressed. The performance of membrane reactors for coenzyme regeneration is discussed in comparison with other reactor concepts. The coenzyme dependent production of L-amino acids from the corresponding alpha-keto acids is used to illustrate how precise turnover numbers as a function of enzyme/coenzyme ratio, initial substrate concentration, and conversion are obtained. Thus, it becomes possible to develop a concept for optimal operating points with respect to enzyme, coenzyme, and substrate costs per unit weight of product.

  18. Autoradiographic analysis of protein regeneration in striated skeleton muscle

    International Nuclear Information System (INIS)

    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.)

  19. 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...

  20. Analysis of noise suppression in cascaded all-optical regenerators

    DEFF Research Database (Denmark)

    Mørk, Jesper; Öhman, Filip; Bischoff, Svend

    2002-01-01

    We derive an approximate analytical expression for the BER of cascaded links with all-optical regenerators and use it for performing a general analysis of the interplay between noise and the non-linearity of the regenerator characteristic.......We derive an approximate analytical expression for the BER of cascaded links with all-optical regenerators and use it for performing a general analysis of the interplay between noise and the non-linearity of the regenerator characteristic....

  1. 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.

  2. Final cutting of shelterwood. Harvesting techniques and effects on the Picea abies regeneration

    International Nuclear Information System (INIS)

    During the last decade, environmental and biological aspects have grown increasingly important in forestry. At the same time conventional planting after clear-cutting has failed on many sites with a high ground water table, abundant competitive vegetation and frequent frosts. Therefore, on these sites the use of the shelterwood system for regeneration of Norway spruce (Picea abies [L.] Karst.) has increased in Sweden. The main objective of the thesis is to study if it is possible to final-cut shelterwoods at acceptable harvesting costs, logging damage and release effects in the regeneration. Final cutting of three shelterwoods (180-200 m3/ha) in Sweden were carried out with single- and double-grip harvester systems in 1-1.5 m high regeneration (6 400-26 700 seedlings/ha). In a fourth shelterwood (140-165 m3/ha), also situated in Sweden, conventional felling with a single-grip harvester was compared with a more concentrated felling according to a method named 'tossing the caber', where the trees were felled top-end first over the 1.2-1.3 m high regeneration (9 530-11 780 seedlings/ha) and into the striproad. No differences in productivity and cost between single- and double-grip harvesters in final cutting of shelterwood were found. Despite few stems/ha and extensive regeneration the harvesting cost was considered low (33.5 SEK/m3). Approximately one third of the seedlings suffered mortal logging damage, which was considered acceptable. No differences between conventional felling and the tossing the caber method were found regarding productivity, cost and damage to the regeneration. However, tossing the caber may be a more productive alternative in final cutting of pine-dominated shelterwood or seed tree stands. Seedling growth and survival after shelterwood removal was not influenced by the choice of harvester system. Seedling height and vitality were found to be good estimators of post-release survival and growth which, in total, was found to be acceptable in the

  3. The neonate versus adult mammalian immune system in cardiac repair and regeneration.

    Science.gov (United States)

    Sattler, Susanne; Rosenthal, Nadia

    2016-07-01

    The immune system is a crucial player in tissue homeostasis and wound healing. A sophisticated cascade of events triggered upon injury ensures protection from infection and initiates and orchestrates healing. While the neonatal mammal can readily regenerate damaged tissues, adult regenerative capacity is limited to specific tissue types, and in organs such as the heart, adult wound healing results in fibrotic repair and loss of function. Growing evidence suggests that the immune system greatly influences the balance between regeneration and fibrotic repair. The neonate mammalian immune system has impaired pro-inflammatory function, is prone to T-helper type 2 responses and has an immature adaptive immune system skewed towards regulatory T cells. While these characteristics make infants susceptible to infection and prone to allergies, it may also provide an immunological environment permissive of regeneration. In this review we will give a comprehensive overview of the immune cells involved in healing and regeneration of the heart and explore differences between the adult and neonate immune system that may explain differences in regenerative ability. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel. PMID:26801961

  4. A Tunable Silk Hydrogel Device for Studying Limb Regeneration in Adult Xenopus Laevis.

    Directory of Open Access Journals (Sweden)

    Anne Golding

    Full Text Available In certain amphibian models limb regeneration can be promoted or inhibited by the local wound bed environment. This research introduces a device that can be utilized as an experimental tool to characterize the conditions that promotes limb regeneration in the adult frog (Xenopus laevis model. In particular, this device was designed to manipulate the local wound environment via a hydrogel insert. Initial characterization of the hydrogel insert revealed that this interaction had a significant influence on mechanical forces to the animal, due to the contraction of the hydrogel. The material and mechanical properties of the hydrogel insert were a factor in the device design in relation to the comfort of the animal and the ability to effectively manipulate the amputation site. The tunable features of the hydrogel were important in determining the pro-regenerative effects in limb regeneration, which was measured by cartilage spike formation and quantified by micro-computed tomography. The hydrogel insert was a factor in the observed morphological outcomes following amputation. Future work will focus on characterizing and optimizing the device's observed capability to manipulate biological pathways that are essential for limb regeneration. However, the present work provides a framework for the role of a hydrogel in the device and a path forward for more systematic studies.

  5. Small Players Ruling the Hard Game: siRNA in Bone Regeneration.

    Science.gov (United States)

    Ghadakzadeh, Saber; Mekhail, Mina; Aoude, Ahmed; Hamdy, Reggie; Tabrizian, Maryam

    2016-03-01

    Silencing gene expression through a sequence-specific manner can be achieved by small interfering RNAs (siRNAs). The discovery of this process has opened the doors to the development of siRNA therapeutics. Although several preclinical and clinical studies have shown great promise in the treatment of neurological disorders, cancers, dominant disorders, and viral infections with siRNA, siRNA therapy is still gaining ground in musculoskeletal tissue repair and bone regeneration. Here we present a comprehensive review of the literature to summarize different siRNA delivery strategies utilized to enhance bone regeneration. With advancement in understanding the targetable biological pathways involved in bone regeneration and also the rapid progress in siRNA technologies, application of siRNA for bone regeneration has great therapeutic potential. High rates of musculoskeletal injuries and diseases, and their inevitable consequences, impose a huge financial burden on individuals and healthcare systems worldwide. © 2016 American Society for Bone and Mineral Research. PMID:26890411

  6. Entrepreneurship Education: Ireland's Solution to Economic Regeneration?

    Science.gov (United States)

    O'Connor, John; Fenton, Mary; Barry, Almar

    2012-01-01

    The significance of entrepreneurship has come into sharper focus as enterprise and innovation are being flagged as solutions to regenerate the Irish economy. The Irish Innovation Task Force believes that Ireland could become an "innovation hub", attracting foreign risk capital and international and indigenous entrepreneurs to start and grow…

  7. Regenerating evanescent waves from a silver superlens.

    Science.gov (United States)

    Fang, Nicholas; Liu, Zhaowei; Yen, Ta-Jen; Zhang, Xiang

    2003-04-01

    We investigated a precursor of superlensing: regenerating evanescent waves by excitation of a surface plasmon. Because the permittivity of a silver slab approaches -1, we experimentally observed a broadening of surface-plasmon bandwidth. Our study identifies a means to access deep subwavelength features by use of a metamaterial superlens. PMID:19461779

  8. Regenerating evanescent waves from a silver superlens

    Science.gov (United States)

    Fang, Nicholas; Liu, Zhaowei; Yen, Ta-Jen; Zhang, Xiang

    2003-04-01

    We investigated a precursor of superlensing: regenerating evanescent waves by excitation of a surface plasmon. Because the permittivity of a silver slab approaches -1, we experimentally observed a broadening of surface-plasmon bandwidth. Our study identifies a means to access deep subwavelength features by use of a metamaterial superlens.

  9. Planning and Implementation of Urban Regeneration

    DEFF Research Database (Denmark)

    Aunsborg, Christian; Sørensen, Michael Tophøj

    2008-01-01

    Worn down and more or less abandoned industrial and harbor areas became more and more visible in the Danish townscapes during the 1980s and 1990s. Some limited regeneration projects were carried through, but in general much public attention to these areas did not exist until the late 1990s where ...

  10. Heart regeneration in adult MRL mice

    OpenAIRE

    Leferovich, John M.; Bedelbaeva, Khamilia; Samulewicz, Stefan; Zhang, Xiang-Ming; Zwas, Donna; Lankford, Edward B.; Heber-Katz, Ellen

    2001-01-01

    The reaction of cardiac tissue to acute injury involves interacting cascades of cellular and molecular responses that encompass inflammation, hormonal signaling, extracellular matrix remodeling, and compensatory adaptation of myocytes. Myocardial regeneration is observed in amphibians, whereas scar formation characterizes cardiac ventricular wound healing in a variety of mammalian injury models. We have previously shown that the MRL mouse strain has an extraordinary ...

  11. Thymus: the next (re)generation.

    Science.gov (United States)

    Chaudhry, Mohammed S; Velardi, Enrico; Dudakov, Jarrod A; van den Brink, Marcel R M

    2016-05-01

    As the primary site of T-cell development, the thymus plays a key role in the generation of a strong yet self-tolerant adaptive immune response, essential in the face of the potential threat from pathogens or neoplasia. As the importance of the role of the thymus has grown, so too has the understanding that it is extremely sensitive to both acute and chronic injury. The thymus undergoes rapid degeneration following a range of toxic insults, and also involutes as part of the aging process, albeit at a faster rate than many other tissues. The thymus is, however, capable of regenerating, restoring its function to a degree. Potential mechanisms for this endogenous thymic regeneration include keratinocyte growth factor (KGF) signaling, and a more recently described pathway in which innate lymphoid cells produce interleukin-22 (IL-22) in response to loss of double positive thymocytes and upregulation of IL-23 by dendritic cells. Endogenous repair is unable to fully restore the thymus, particularly in the aged population, and this paves the way toward the need for exogenous strategies to help regenerate or even replace thymic function. Therapies currently in clinical trials include KGF, use of the cytokines IL-7 and IL-22, and hormonal modulation including growth hormone administration and sex steroid inhibition. Further novel strategies are emerging in the preclinical setting, including the use of precursor T cells and thymus bioengineering. The use of such strategies offers hope that for many patients, the next regeneration of their thymus is a step closer. PMID:27088907

  12. Methods of testing PET regenerates properties

    OpenAIRE

    2008-01-01

    The work presents an overview of the methods of testing poly(ethylene-terephthalate) (PET) regenerates: PET flakes, PET regranulates, PET preforms and PET bottles. All the methods have been included that are implemented for the quality testing of the mentioned products and allow constant control over the production process.

  13. Kidney regeneration and repair after transplantation

    NARCIS (Netherlands)

    M. Franquesa (Marcella); M. Flaquer (Maria); J.M. Cruzado; J. Grinyo (Josep)

    2013-01-01

    textabstractPURPOSE OF REVIEW: To briefly show which are the mechanisms and cell types involved in kidney regeneration and describe some of the therapies currently under study in regenerative medicine for kidney transplantation. RECENT FINDINGS: The kidney contains cell progenitors that under specif

  14. Ks0-regeneration at the UNK energies

    International Nuclear Information System (INIS)

    A contribution of bare odderon as the reggezied three-gluon exchange to Ks0-regeneration amplitudes f21 on hydrogen is estimated. At the UNK energies odderon is shown to manifest itself mainly in the phase φ21, yielding about 20 deg. 19 refs.; 6 figs

  15. Regenerated thermoluminescence in pre-irradiated phosphors

    International Nuclear Information System (INIS)

    In pre-irradiated phosphors, quartz, fine-grain pottery and CaF2:Dy (TLD-200), a regenerated thermoluminescence (R-TL) was observed after heavy irradiation. Its dependence on dose and time after heating was studied. A theoretical model is proposed to explain the phenomenon. Its implication on TL dating is discussed. (author)

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

    International Nuclear Information System (INIS)

    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. Adrenal regeneration hypertension prevented by thyroidectomy: a quantitative ultrastructural study of the regenerating adrenal cortex.

    OpenAIRE

    Conran, R. M.; Nickerson, P A

    1980-01-01

    Thyroparathyroidectomy (TPX) prevents adrenal regeneration hypertension (ARH) in female rats and concomitantly inhibits regeneration of the adrenal cortex. Removal of the thyroid gland plays the major role in preventing ARH inasmuch as parathyroidectomized adrenal-enucleated (PX-AE) rats became hypertensive, whereas thyroparathyroidectomized adrenal-enucleated rats (TPX-AE + PT) did not. Inhibition of adrenocortical regneration by TPX is reflected by a significant decrease in adrenal weight, ...

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

    OpenAIRE

    Isabel Carolina de Lima Guedes; Luiz Moreira Coelho Júnior; Antônio Donizette de Oliveira; José Márcio de Mello; José Luiz Pereira Rezende; Charles Plínio de Castro Silva

    2011-01-01

    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 fact...

  19. 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.

  20. Improved modelling of a parallel plate active magnetic regenerator

    DEFF Research Database (Denmark)

    Engelbrecht, Kurt; Tušek, J.; Nielsen, Kaspar Kirstein;

    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...

  1. Triphasic scaffolds for the regeneration of the bone-ligament interface.

    Science.gov (United States)

    Criscenti, G; Longoni, A; Di Luca, A; De Maria, C; van Blitterswijk, C A; Vozzi, G; Moroni, L

    2016-03-01

    A triphasic scaffold (TPS) for the regeneration of the bone-ligament interface was fabricated combining a 3D fiber deposited polycaprolactone structure and a polylactic co-glycolic acid electrospun. The scaffold presented a gradient of physical and mechanical properties which elicited different biological responses from human mesenchymal stem cells. Biological test were performed on the whole TPS and on scaffolds comprised of each single part of the TPS, considered as the controls. The TPS showed an increase of the metabolic activity with culturing time that seemed to be an average of the controls at each time point. The importance of differentiation media for bone and ligament regeneration was further investigated. Metabolic activity analysis on the different areas of the TPS showed a similar trend after 7 days in both differentiation media. Total alkaline phosphatase (ALP) activity analysis showed a statistically higher activity of the TPS in mineralization medium compared to the controls. A different glycosaminoglycans amount between the TPS and its controls was detected, displaying a similar trend with respect to ALP activity. Results clearly indicated that the integration of electrospinning and additive manufacturing represents a promising approach for the fabrication of scaffolds for the regeneration of tissue interfaces, such as the bone-to-ligament one, because it allows mimicking the structural environment combining different biomaterials at different scales. PMID:26824799

  2. Transplants in annelids, nemerteans and planarians: a tool for embryology, immunology, endocrinology and regeneration research

    Directory of Open Access Journals (Sweden)

    EE Zattara

    2015-09-01

    Full Text Available While transplantation procedures are often associated with biomedical applications, they are also an invaluable tool for basic research. This review focuses on how transplantation techniques have been used to understand the biology of three large lophotrochozoan phyla: Annelida, Nemertea and Platyhelmintha. I describe how transplantation paradigms have uncovered fundamental principles regarding the embryology, immunology, endocrinology and regeneration biology of representative species within these three groups. In particular, embryologists have used blastomere transplantations to show that both mosaic and regulative development occurs in animals within the phyla. Immunologists have used transplantation techniques to demonstrate that these invertebrates mount a variety of innate immune responses, some of which include surprising features that classically characterize adaptive immunity. Endocrinologists have used transplantation experiments to uncover hormonal requirements for sexual development and maturation. Meanwhile, regeneration biologists continue to address fundamental questions regarding tissue polarity, post-embryonic patterning, stem cell physiology, and the role of the nervous system in regeneration. Along with recent technical and conceptual advances, transplantation remains a powerful tool for invertebrate research.

  3. 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.

  4. Cellular regeneration in bone marrow with synthesized semiconductor polymers by plasma; Regeneracion celular en medula espinal con polimeros semiconductores sintetizados por plasma

    Energy Technology Data Exchange (ETDEWEB)

    Morales, J.; Olayo, R. [UAM-I, 09340 Mexico D.F. (Mexico); Alvarez, L.; Mondragon, R.; Morales, A. [UPIITA-IPN, 07000 Mexico D.F. (Mexico); Diaz, A.; Rios, C. [INNN, Mexico D.F. (Mexico); Salgado, H. [IMSS y Proyecto Camina A.C. Mexico D.F. (Mexico); Cruz, G.; Olayo, M.G. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2004-07-01

    In this work the intervention of polymers with capacity of conducting electric current for the regeneration of the spinal marrow in rats of laboratory is studied. It is a focus different from the one that up to now has taken in account since it involves medical, biological, physical and chemical sciences. Inside the properties of transporting electric charges, the polymers would have to respond before the biological media with ionic mechanisms of conduction, besides the electronic ones, to promote the regeneration of the spinal marrow. They should also be biocompatible to avoid the rejection of the media before the implantation. (Author)

  5. Effect of Picibanil (OK 432 on the Scavenging Effect of Free Radicals Produced during Liver Regeneration in the Rat

    Directory of Open Access Journals (Sweden)

    Okamoto,Ko

    1995-04-01

    Full Text Available We administered a biological response modifier Picibanil (OK-432, attenuated Streptococcus pyogenes, via the dorsal vein of the penis after 70% hepatectomy in rats, and clarified the scavenging effect of Picibanil on free radicals generated in the regenerating liver. A group of 5 rats was intravenously administered with 25 KE/kg of OK-432 after hepatectomy, while the control group was given saline after hepatectomy. Serum levels of aspartate aminotransferase and alanine aminotransferase and the value of thiobarbituric acid-reactive substances in serum and hepatic tissue after hepatectomy were serially measured, and these values were significantly lower in Picibanil treated animals than in control animals. Free radical production in the regenerating liver was also measured by electron spin resonance spectrometry, and OK-432 injection significantly reduced free radical production. These results suggested that OK-432 reduced hepatocellular damage in regenerating liver by inhibiting lipid peroxidation.

  6. Non-Uniform Heat Transfer in Thermal Regenerators

    DEFF Research Database (Denmark)

    Jensen, Jesper Buch

    regenerators (AMRs) with parallel plates. The results suggest that random variations in the regenerator geometries causes maldistributed fluid flow inside the regener- ators, which affects the regenerator performance. In order to study the heat transfer processes in regenerators with non-uniform geometries, 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......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...

  7. Modulation of tissue repair by regeneration enhancer elements.

    Science.gov (United States)

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

    2016-04-14

    How tissue regeneration programs are triggered by injury has received limited research attention. Here we investigate the existence of enhancer regulatory elements that are activated in regenerating tissue. Transcriptomic analyses reveal that leptin b (lepb) is highly induced in regenerating hearts and fins of zebrafish. Epigenetic profiling identified a short DNA sequence element upstream and distal to lepb that acquires open chromatin marks during regeneration and enables injury-dependent expression from minimal promoters. This element could activate expression in injured neonatal mouse tissues and was divisible into tissue-specific modules sufficient for expression in regenerating zebrafish fins or hearts. Simple enhancer-effector transgenes employing lepb-linked sequences upstream of pro- or anti-regenerative factors controlled the efficacy of regeneration in zebrafish. Our findings provide evidence for 'tissue regeneration enhancer elements' (TREEs) that trigger gene expression in injury sites and can be engineered to modulate the regenerative potential of vertebrate organs. PMID:27049946

  8. 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)

  9. 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

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

    Science.gov (United States)

    Lobo, Daniel; Levin, Michael

    2015-06-01

    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 provides an automated

  11. Brain and muscle Arnt-like 1 promotes skeletal muscle regeneration through satellite cell expansion

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Somik [Center for Diabetes Research, Department of Medicine, Houston Methodist Research Institute, Houston, TX 77030 (United States); Yin, Hongshan [Center for Diabetes Research, Department of Medicine, Houston Methodist Research Institute, Houston, TX 77030 (United States); Department of Cardiovascular Medicine, Third Affiliated Hospital, Hebei Medical University, Shijiazhuang 050051, Hebei (China); Nam, Deokhwa [Center for Diabetes Research, Department of Medicine, Houston Methodist Research Institute, Houston, TX 77030 (United States); Li, Yong [Department of Pediatric Surgery, Center for Stem Cell Research and Regenerative Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030 (United States); Ma, Ke, E-mail: kma@houstonmethodist.org [Center for Diabetes Research, Department of Medicine, Houston Methodist Research Institute, Houston, TX 77030 (United States)

    2015-02-01

    Circadian clock is an evolutionarily conserved timing mechanism governing diverse biological processes and the skeletal muscle possesses intrinsic functional clocks. Interestingly, although the essential clock transcription activator, Brain and muscle Arnt-like 1 (Bmal1), participates in maintenance of muscle mass, little is known regarding its role in muscle growth and repair. In this report, we investigate the in vivo function of Bmal1 in skeletal muscle regeneration using two muscle injury models. Bmal1 is highly up-regulated by cardiotoxin injury, and its genetic ablation significantly impairs regeneration with markedly suppressed new myofiber formation and attenuated myogenic induction. A similarly defective regenerative response is observed in Bmal1-null mice as compared to wild-type controls upon freeze injury. Lack of satellite cell expansion accounts for the regeneration defect, as Bmal1{sup −/−} mice display significantly lower satellite cell number with nearly abolished induction of the satellite cell marker, Pax7. Furthermore, satellite cell-derived primary myoblasts devoid of Bmal1 display reduced growth and proliferation ex vivo. Collectively, our results demonstrate, for the first time, that Bmal1 is an integral component of the pro-myogenic response that is required for muscle repair. This mechanism may underlie its role in preserving adult muscle mass and could be targeted therapeutically to prevent muscle-wasting diseases. - Highlights: • Bmal1 is highly inducible by muscle injury and myogenic stimuli. • Genetic ablation of Bmal1 significantly impairs muscle regeneration. • Bmal1 promotes satellite cell expansion during muscle regeneration. • Bmal1-deficient primary myoblasts display attenuated growth and proliferation.

  12. What is Known Regarding the Participation of Factor Nrf-2 in Liver Regeneration?

    Directory of Open Access Journals (Sweden)

    José A. Morales-González

    2015-05-01

    Full Text Available It has been known for years that, after chemical damage or surgical removal of its tissue, the liver initiates a series of changes that, taken together, are known as regeneration, which are focused on the recovery of lost or affected tissue in terms of the anatomical or functional aspect. The Nuclear factor-erythroid 2-related factor (Nrf-2 is a reduction-oxidation reaction (redox-sensitive transcriptional factor, with the basic leucine Zipper domain (bZIP motif, encoding the NFE2L2 gene. The Keap1-Nrf2-ARE pathway is transcendental in the regulation of various cellular processes, such as antioxidant defenses, redox equilibrium, the inflammatory process, the apoptotic processes, intermediate metabolism, detoxification, and cellular proliferation. Some reports have demonstrated the regulator role of Nrf-2 in the cellular cycle of the hepatocyte, as well as in the modulation of the antioxidant response and of apoptotic processes during liver regeneration. It has been reported that there is a delay in liver regeneration after Partial hepatectomy (PH in the absence of Nrf-2, and similarly as a regulator of hepatic cytoprotection due to diverse chemical or biological agents, and in diseases such as hepatitis, fibrosis, cirrhosis, and liver cancer. This regulator/protector capacity is due to the modulation of the Antioxidant response elements (ARE. It is postulated that oxidative stress (OS can participate in the initial stages of liver regeneration and that Nrf-2 can probably participate. Studies are lacking on the different initiation stages, maintenance, and the termination of liver regeneration alone or with ethanol.

  13. Brain and muscle Arnt-like 1 promotes skeletal muscle regeneration through satellite cell expansion

    International Nuclear Information System (INIS)

    Circadian clock is an evolutionarily conserved timing mechanism governing diverse biological processes and the skeletal muscle possesses intrinsic functional clocks. Interestingly, although the essential clock transcription activator, Brain and muscle Arnt-like 1 (Bmal1), participates in maintenance of muscle mass, little is known regarding its role in muscle growth and repair. In this report, we investigate the in vivo function of Bmal1 in skeletal muscle regeneration using two muscle injury models. Bmal1 is highly up-regulated by cardiotoxin injury, and its genetic ablation significantly impairs regeneration with markedly suppressed new myofiber formation and attenuated myogenic induction. A similarly defective regenerative response is observed in Bmal1-null mice as compared to wild-type controls upon freeze injury. Lack of satellite cell expansion accounts for the regeneration defect, as Bmal1−/− mice display significantly lower satellite cell number with nearly abolished induction of the satellite cell marker, Pax7. Furthermore, satellite cell-derived primary myoblasts devoid of Bmal1 display reduced growth and proliferation ex vivo. Collectively, our results demonstrate, for the first time, that Bmal1 is an integral component of the pro-myogenic response that is required for muscle repair. This mechanism may underlie its role in preserving adult muscle mass and could be targeted therapeutically to prevent muscle-wasting diseases. - Highlights: • Bmal1 is highly inducible by muscle injury and myogenic stimuli. • Genetic ablation of Bmal1 significantly impairs muscle regeneration. • Bmal1 promotes satellite cell expansion during muscle regeneration. • Bmal1-deficient primary myoblasts display attenuated growth and proliferation

  14. Calcium Sulfate and Platelet-Rich Plasma make a novel osteoinductive biomaterial for bone regeneration

    Directory of Open Access Journals (Sweden)

    Intini Francesco E

    2007-03-01

    Full Text Available Abstract Background With the present study we introduce a novel and simple biomaterial able to induce regeneration of bone. We theorized that nourishing a bone defect with calcium and with a large amount of activated platelets may initiate a series of biological processes that culminate in bone regeneration. Thus, we engineered CS-Platelet, a biomaterial based on the combination of Calcium Sulfate and Platelet-Rich Plasma in which Calcium Sulfate also acts as an activator of the platelets, therefore avoiding the need to activate the platelets with an agonist. Methods First, we tested CS-Platelet in heterotopic (muscle and orthotopic (bone bone regeneration bioassays. We then utilized CS-Platelet in a variety of dental and craniofacial clinical cases, where regeneration of bone was needed. Results The heterotopic bioassay showed formation of bone within the muscular tissue at the site of the implantation of CS-Platelet. Results of a quantitative orthotopic bioassay based on the rat calvaria critical size defect showed that only CS-Platelet and recombinant human BMP2 were able to induce a significant regeneration of bone. A non-human primate orthotopic bioassay also showed that CS-Platelet is completely resorbable. In all human clinical cases where CS-Platelet was used, a complete bone repair was achieved. Conclusion This study showed that CS-Platelet is a novel biomaterial able to induce formation of bone in heterotopic and orthotopic sites, in orthotopic critical size bone defects, and in various clinical situations. The discovery of CS-Platelet may represent a cost-effective breakthrough in bone regenerative therapy and an alternative or an adjuvant to the current treatments.

  15. Transcriptome atlas of eight liver cell types uncovers effects of histidine catabolites on rat liver regeneration

    Indian Academy of Sciences (India)

    C. F. Chang; J. Y. Fan; F. C. Zhang; J. Ma; C. S. Xu

    2010-12-01

    Eight liver cell types were isolated using the methods of Percoll density gradient centrifugation and immunomagnetic beads to explore effects of histidine catabolites on rat liver regeneration. Rat Genome 230 2.0 Array was used to detect the expression profiles of genes associated with metabolism of histidine and its catabolites for the above-mentioned eight liver cell types, and bioinformatic and systems biology approaches were employed to analyse the relationship between above genes and rat liver regeneration. The results showed that the urocanic acid (UA) was degraded from histidine in Kupffer cells, acts on Kupffer cells itself and dendritic cells to generate immune suppression by autocrine and paracrine modes. Hepatocytes, biliary epithelia cells, oval cells and dendritic cells can convert histidine to histamine, which can promote sinusoidal endothelial cells proliferation by GsM pathway, and promote the proliferation of hepatocytes and biliary epithelia cells by GqM pathway.

  16. Surface Functionalization of Titanium Alloy with miR-29b Nanocapsules To Enhance Bone Regeneration.

    Science.gov (United States)

    Meng, Yubin; Li, Xue; Li, Zhaoyang; Liu, Chaoyong; Zhao, Jin; Wang, Jianwei; Liu, Yunde; Yuan, Xubo; Cui, Zhenduo; Yang, Xianjin

    2016-03-01

    Titanium and its alloys have been widely used over the past 3 decades as implants for healing bone defects. Nevertheless, the bioinert property of titanium alloy limits its clinical application and surface modification method is frequently performed to improve the biological and chemical properties. Recently, the delivery of microRNA with osteogenesis capability has been recognized as a promising tool to enhance bone regeneration of implants. Here, we developed a biodegradable coating to modify the titanium surface in order to enhance osteogenic bioactivity. The previous developed nanocapsules were used as the building blocks, and then a bioactive titanium coating was designed to entrap the miR-29b nanocapsules. This coating was not only favorable for cell adhesion and growth but also provided sufficient microRNA transfection efficacy and osteoinductive potential, resulting in a significant enhancement of bone regeneration on the surface of bioinert titanium alloy. PMID:26887789

  17. Microelectronics-embedded channel bridging and signal regeneration of injured spinal cords

    Institute of Scientific and Technical Information of China (English)

    Zhigong Wang; Xiaosong Gu; Xiaoying Lü; Zhenglin Jiang; Wenyuan Li; Guangming Lü; Yufeng Wang; Xiaoyan Shen; Xintai Zhao; Huiling Wang; Zhenyu Zhang; Hongmei Shen; Yang Wu; Weixing Shen; Jingyang Zhang; Dong Chen; Xiaoyi Mao; Huaxiang Shen

    2009-01-01

    Due to the difficulty in spinal cord regeneration with biological methods, the microelectronic neural bridge, a new concept based on microelectronic technology, is presented. The microelectronic system has been realized in the forms of hybrid and integrated circuits. The integrated circuits for neural signal detection, stimulation, and regeneration are realized in a CMOS process. In animal experiments with 100 toads, 48 rats, and 3 rabbits, nerve signals have been successfully detected from spinal cords and sciatic nerves, and functional electrical stimulation has been carried out for spinal cords and sciatic nerves. When the microelectronic system is bridged between the controlling and stimulated nerve, the relevant motion of legs and nerve signal waveforms, which are stimulated by the evoked or spontaneous nerve signal through such a system, have been observed. Therefore, the feasibility of the presented method was demonstrated.

  18. Heterogeneous Catalyst Deactivation and Regeneration: A Review

    Directory of Open Access Journals (Sweden)

    Morris D. Argyle

    2015-02-01

    Full Text Available Deactivation of heterogeneous catalysts is a ubiquitous problem that causes loss of catalytic rate with time. This review on deactivation and regeneration of heterogeneous catalysts classifies deactivation by type (chemical, thermal, and mechanical and by mechanism (poisoning, fouling, thermal degradation, vapor formation, vapor-solid and solid-solid reactions, and attrition/crushing. The key features and considerations for each of these deactivation types is reviewed in detail with reference to the latest literature reports in these areas. Two case studies on the deactivation mechanisms of catalysts used for cobalt Fischer-Tropsch and selective catalytic reduction are considered to provide additional depth in the topics of sintering, coking, poisoning, and fouling. Regeneration considerations and options are also briefly discussed for each deactivation mechanism.

  19. In vitro regeneration of Basella alba L

    Science.gov (United States)

    Edney, Norris Allen; Rizvi, Muhammad A.; Rizvi, Narjis F.

    1989-01-01

    Basella alba L. is a tropical vine used as a vegetable in some Asian and African countries. It has potential as a nontraditional crop for small family farms. A short day plant, it blooms during the fall, provided the temperatures are mild. In the southeastern U.S., the short days of fall are associated with subfreezing temperatures, and plants are killed before blooming. Attempts were made to regenerate the plant using tissue culture techniques. Several trials were conducted with different media, hormones, and explants. It was found that nodal segments on Gamborg medium regenerated shoots. Interaction studies of auxins and cytokinins indicated that its endogeneous auxin content might be high because callus proliferated in almost all treatments and roots initiated even when the medium was not supplemented with an auxin.

  20. Regeneration of rat thymus after irradiation

    International Nuclear Information System (INIS)

    The regeneration processes were investigated in the rat thymus after heavy dose irradiation (6 and 8 Gy). The weight of thymus was gradually recovered to normal level in 6 Gy irradiated thymus, however it recovered only up to 65% of normal level in 8 Gy irradiated thymus. The ED2 positive macrophages were increased on day 3, and then gradually decreased to normal level in 6 Gy irradiated thymus. Inflammatory cytokines (IL-1β, IFN-γ and TNF-α) mRNA expressions were gradually recovered from day 7, however IL-6 mRNA was expressed transiently on day 7 after 8 Gy irradiation. These observations suggest that regeneration processes of irradiated thymus may be intimately regulated by cytokine networks. (author)

  1. 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.

  2. Hydroprocessing using regenerated spent heavy hydrocarbon catalyst

    International Nuclear Information System (INIS)

    This patent describes a process for hydroprocessing a hydrocarbon feedstock. It comprises: contacting the feedstock with hydrogen under hydroprocessing conditions with a hydroprocessing catalyst wherein the hydroprocessing catalyst contains a total contaminant metals build-up of greater than about 4 wt. % nickel plus vanadium, a hydrogenation component selected from the group consisting of Group VIB metals and Group VIII metals and is regenerated spent hydroprocessing catalyst regenerated by a process comprising the steps: partially decoking the spent catalyst in an initial coke-burning step; impregnating the partially decoked catalyst with a Group IIA metal-containing impregnation solution; and decoking the impregnated catalyst in a final coke-burning step wherein the impregnated catalyst is contacted with an oxygen-containing gas at a temperature of about 600 degrees F to about 1400 degrees F

  3. Biomimetic electrospun nanofibers for tissue regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Susan; Li Bojun; Ma Zuwei; Wei He; Chan Casey; Ramakrishna, Seeram [Nanoscience and Nanotechnology Initiative (NUSNNI), Faculty of Engineering, National University of Singapore, 117576 Singapore (Singapore)

    2006-09-15

    Nanofibers exist widely in human tissue with different patterns. Electrospinning nanotechnology has recently gained a new impetus due to the introduction of the concept of biomimetic nanofibers for tissue regeneration. The advanced electrospinning technique is a promising method to fabricate a controllable continuous nanofiber scaffold similar to the natural extracellular matrix. Thus, the biomedical field has become a significant possible application field of electrospun fibers. Although electrospinning has developed rapidly over the past few years, electrospun nanofibers are still at a premature research stage. Further comprehensive and deep studies on electrospun nanofibers are essential for promoting their biomedical applications. Current electrospun fiber materials include natural polymers, synthetic polymers and inorganic substances. This review briefly describes several typically electrospun nanofiber materials or composites that have great potential for tissue regeneration, and describes their fabrication, advantages, drawbacks and future prospects. (topical review)

  4. How x rays inhibit amphibian limb regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Maden, M.; Wallace, H.

    1976-07-01

    The effects of an inhibiting dose of 2,000 rad of x-rays on the regenerating limbs of axolotl larvae have been examined in a histological and cytological study. Particular attention was paid to the mitotic indices of normal and irradiated epidermal and blastemal cells. Both the characteristic pattern of epidermal mitotic stimulation which normally follows amputation and the later increase in blastemal mitoses are suppressed by irradiation. In most cells the effects are permanent, but in a small proportion a mitotic delay is induced and upon subsequent division chromosome damage in the form of micronuclei is revealed. Thus irradiated cells which do divide almost certainly die. These results are discussed in relation to other theories of x-ray inhibition of regeneration with particular reference to the view that irradiated cells can be reactivated.

  5. In vitro regeneration of salvia santolinifolia

    International Nuclear Information System (INIS)

    In vitro shoots of Salvia santolinifolia were produced under the influence of different types of cytokinins supplementation by nodal segments on MS media. Excised young nodal segments of Salvia santolinifolia obtained from adult field-grown plants, successfully regenerated plant lets through organogenesis. Addition of BA at 1.0, 2.0 and 3.0 mg/l produced maximum number and length of shoots. The multiplication of shoots was always slow in primary cultures and increased during subculture. Regenerated shoots produced roots on transfer to medium containing 2.5 mg/l of IBA. Plant lets thus obtained were grown in sterile soil and sand mixture (1:1). (author)

  6. Tissue regenerating functions of coagulation factor XIII

    DEFF Research Database (Denmark)

    Soendergaard, C; Kvist, P H; Seidelin, J B;

    2013-01-01

    The protransglutaminase factor XIII (FXIII) has recently gained interest within the field of tissue regeneration, as it has been found that FXIII significantly influences wound healing by exerting a multitude of functions. It supports haemostasis by enhancing platelet adhesion to damaged endothel......The protransglutaminase factor XIII (FXIII) has recently gained interest within the field of tissue regeneration, as it has been found that FXIII significantly influences wound healing by exerting a multitude of functions. It supports haemostasis by enhancing platelet adhesion to damaged...... endothelium, and by its cross-linking activity it stabilizes the formed fibrin clot. Furthermore, FXIII limits bacterial dissemination from the wound and incorporates macromolecules of importance for cellular infiltration supporting cell migration and survival. FXIII-mediated complex formation of the VEGF...

  7. Smed-Evi/Wntless is required for beta-catenin-dependent and -independent processes during planarian regeneration.

    Science.gov (United States)

    Adell, Teresa; Salò, Emili; Boutros, Michael; Bartscherer, Kerstin

    2009-03-01

    Planarians can regenerate a whole animal from only a small piece of their body, and have become an important model for stem cell biology. To identify regenerative processes dependent on Wnt growth factors in the planarian Schmidtea mediterranea (Smed), we analyzed RNAi phenotypes of Evi, a transmembrane protein specifically required for the secretion of Wnt ligands. We show that, during regeneration, Smed-evi loss-of-function prevents posterior identity, leading to two-headed planarians that resemble Smed-beta-catenin1 RNAi animals. In addition, we observe regeneration defects of the nervous system that are not found after Smed-beta-catenin1 RNAi. By systematic knockdown of all putative Smed Wnts in regenerating planarians, we identify Smed-WntP-1 and Smed-Wnt11-2 as the putative posterior organizers, and demonstrate that Smed-Wnt5 is a regulator of neuronal organization and growth. Thus, our study provides evidence that planarian Wnts are major regulators of regeneration, and that they signal through beta-catenin-dependent and -independent pathways. PMID:19211673

  8. 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. PMID:26074469

  9. [Spatial heterogeneity of natural regeneration in a spruce-fir mixed broadleaf-conifer forest in Changbai Mountains].

    Science.gov (United States)

    Li, Yan-Li; Yang, Hua; Kang, Xin-Gang; Wang, Yan; Yue, Gang; Shen, Lin

    2014-02-01

    Based on fieldwork on a plot of 60 m x 60 m in the Changbai Mountain area of Northeast China in August 2012, the spatial distribution pattern and heterogeneity of natural regeneration in the spruce-fir mixed broadleaf-conifer forest were analyzed using semi-variograms, fractal dimensions and Kriging interpolation methods. The results showed that Abies nephrolepis and Acer mono were the most common regeneration species, accounting for 87.4% of the total. The regeneration seedlings and saplings presented an aggregate distribution pattern with the biggest radius of 9.93 m. Distinct spatial autocorrelation existed among regeneration seedlings and saplings, with 88.7% of variation coming from structure factors (biological and ecological properties and environmental heterogeneity) and 11.3% from random factors. The spatial distribution of the regeneration seedlings and saplings presented anisotropy, with the smallest fractal dimension and strongest spatial heterogeneity from north to south, and the highest fractal dimension and weakest spatial heterogeneity from northeast to southwest. The spatial heterogeneity of heights of seedlings and saplings was greater than that of root collar diameters. The distance of spatial autocorrelation for tree root collar diameters was 29.97 m, and that for heights was 31.86 m. Random factors and structure factors were found to contribute equally to the spatial heterogeneity. PMID:24830227

  10. Heterogeneous Catalyst Deactivation and Regeneration: A Review

    OpenAIRE

    Morris D. Argyle; Calvin H. Bartholomew

    2015-01-01

    Deactivation of heterogeneous catalysts is a ubiquitous problem that causes loss of catalytic rate with time. This review on deactivation and regeneration of heterogeneous catalysts classifies deactivation by type (chemical, thermal, and mechanical) and by mechanism (poisoning, fouling, thermal degradation, vapor formation, vapor-solid and solid-solid reactions, and attrition/crushing). The key features and considerations for each of these deactivation types is reviewed in detail with referen...

  11. Understanding Urban Development Land: Accelerating Regeneration

    OpenAIRE

    Myers, D.; W. Mike; Peter, W

    2003-01-01

    Prolific urbanisation in Europe has lead to phenomenal growth in the geographical size and land use density of towns and cities. Inevitably, over time, the fabric (buildings and infrastructure) of the built environment becomes obsolete and needs replacing. This gives rise to debates relating to regeneration. It has become a political imperative in the UK, and Europe as a whole, to focus development activity on the previously developed sites within existing urban areas. In the UK this is known...

  12. Gene and cell therapy for muscle regeneration

    OpenAIRE

    Stilhano, Roberta Sessa; Martins, Leonardo; Ingham, Sheila Jean McNeill; Pesquero, João Bosco; Huard, Johnny

    2015-01-01

    Skeletal muscle injury and healing are multifactorial processes, involving three steps of healing: (1) degeneration and inflammation, (2) regeneration, and (3) fibrosis. Fibrous tissue hinders the muscle’s complete recovery and current therapies fail in achieving total muscle recovery. Gene and cell therapy (or both) are potential future treatments for severe muscular injuries. Stem cells’ properties associated with growth factors or/and cytokines can improve muscle healing and permit long-te...

  13. Dissociated Prostate Regeneration under the Renal Capsule.

    Science.gov (United States)

    Zong, Yang; Goldstein, Andrew S; Witte, Owen N

    2015-11-01

    Tissue recombination models are useful for studying cancer initiation, progression, and metastasis. They also provide an in vivo environment in which to investigate the functional role of stem cells in tissue repair. In this protocol, we describe in detail the dissociated prostate regeneration assay. Dissociated adult murine prostate cells are combined with embryonic urogenital sinus mesenchymal cells and implanted under the renal capsule. Morphological tissue structures with appropriate epithelial-stroma interactions are reconstituted in the grafts. PMID:26527760

  14. Innovative Approaches to Regenerate Enamel and Dentin

    OpenAIRE

    Petros Papagerakis; Xanthippi Chatzistavrou; Ma, Peter X.; Silvana Papagerakis

    2012-01-01

    The process of tooth mineralization and the role of molecular control of cellular behavior during embryonic tooth development have attracted much attention the last few years. The knowledge gained from the research in these fields has improved the general understanding about the formation of dental tissues and the entire tooth and set the basis for teeth regeneration. Tissue engineering using scaffold and cell aggregate methods has been considered to produce bioengineered dental tissues, whil...

  15. Enamel Regeneration - Current Progress and Challenges

    OpenAIRE

    Jayasudha,; 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 mimi...

  16. Heartbreak hotel: a convergence in cardiac regeneration.

    Science.gov (United States)

    Schneider, Michael D

    2016-05-01

    In February 2016, The Company of Biologists hosted an intimate gathering of leading international researchers at the forefront of experimental cardiovascular regeneration, with its emphasis on 'Transdifferentiation and Tissue Plasticity in Cardiovascular Rejuvenation'. As I review here, participants at the workshop revealed how understanding cardiac growth and lineage decisions at their most fundamental level has transformed the strategies in hand that presently energize the prospects for human heart repair. PMID:27143752

  17. Mechanobiology of healing and regeneration of bone

    OpenAIRE

    Vetter, Andreas Christian

    2010-01-01

    Knochen ist ein multifunktionales Organ und zugleich ein biologisches Material. In dieser Arbeit wird der Heilungsverlauf eines Knochenbruchs (als biologisches Material) näher untersucht mit Hilfe von Computermodellen. Im menschlichen Körper kommt es nach einem Bruch zu einer vollständigen Regeneration des Knochens, ohne dass eine Narbe nach der Heilung zurückbleibt. In grob 10% der Frakturen kommt es jedoch zu Komplikationen bis zu einem Nicht-Heilen des Bruches. Das Ziel von intensiver inte...

  18. Posterior regeneration in Isodiametra pulchra (Acoela, Acoelomorpha)

    OpenAIRE

    Perea-Atienza, Elena; Botta, Maria; Salvenmoser, Willi; Gschwentner, Robert; Egger, Bernhard; Kristof, Alen; Martinez, Pedro; Achatz, Johannes Georg

    2013-01-01

    Introduction Regeneration is a widespread phenomenon in the animal kingdom, but the capacity to restore damaged or missing tissue varies greatly between different phyla and even within the same phylum. However, the distantly related Acoelomorpha and Platyhelminthes share a strikingly similar stem-cell system and regenerative capacity. Therefore, comparing the underlying mechanisms in these two phyla paves the way for an increased understanding of the evolution of this developmental process. T...

  19. Reciprocal haunting : Pat Barker's Regeneration trilogy

    OpenAIRE

    Knutsen, Karen Patrick

    2008-01-01

    Pat Barker’s fictional account of the Great War, The Regeneration Trilogy, completed in 1995, is considered to be her most important work to date and has captured the imagination of the reading public as well as attracting considerable scholarly attention. Although the trilogy appears to be written in the realistic style of the traditional historical novel, Barker approaches the past with certain preoccupations from 1990s Britain and rewrites the past as seen through these contemporary lenses...

  20. Reciprocal Haunting : Pat Barker's Regeneration Trilogy

    OpenAIRE

    2008-01-01

    Pat Barker’s fictional account of the Great War, The Regeneration Trilogy, completed in 1995, is considered to be her most important work to date and has captured the imagination of the reading public as well as attracting considerable scholarly attention. Although the trilogy appears to be written in the realistic style of the traditional historical novel, Barker approaches the past with certain preoccupations from 1990s Britain and rewrites the past as seen through these contemporary lenses...

  1. Toward Therapeutic Pulmonary Alveolar Regeneration in Humans

    OpenAIRE

    Massaro, Donald; Massaro, Gloria DeCarlo

    2006-01-01

    In humans, age results in loss of pulmonary alveoli; menopause accelerates loss of diffusing capacity, an index of alveolar surface area; and disease (e.g., chronic obstructive pulmonary disease) results in loss of alveoli. Thus, an important goal for investigators is to generate knowledge that allows induction of pulmonary alveolar regeneration in humans. Our enthusiasm for this goal and our assessment of its feasibility are based on work in several laboratories over the last decade that has...

  2. Regeneration in the aging peripheral nervous system

    OpenAIRE

    Painter, Michio Wendell

    2014-01-01

    In the peripheral nervous system (PNS), aging is associated with a number of disorders, including a decline in regenerative capacity after injury. Although this decline has been observed in both rodents and humans for decades, the cellular and molecular underpinnings of this defect have remained elusive. As such, the goal of this thesis was to elucidate, at least in part, how aging impinges on axonal regeneration.

  3. Reprogramming for cardiac regeneration: strategies for innovation

    OpenAIRE

    Sanchís-Gomar, Fabián; Galera, Teresa; Lucía Mulas, Alejandro; Gallardo, María Esther

    2016-01-01

    It is well-known that the human myocardium has a low capacity for self-regeneration. This fact is especially important after acute myocardial infarction with subsequent heart failure and adverse tissue remodeling. New potential strategies have recently emerged for treating heart diseases, such as the possibility of generating large quantities of cardiomyocytes through genetic iPSC reprogramming, transdifferentiation for in vitro disease modeling, in vivo therapies or telomerase gene reactivat...

  4. Sustainable Urban Regeneration Based on Energy Balance

    OpenAIRE

    Sacha Silvester; Han Brezet; Arjan van Timmeren; Jonna Zwetsloot

    2012-01-01

    In this paper, results are reported of a technology assessment of the use and integration of decentralized energy systems and storage devices in an urban renewal area. First the general context of a different approach based on 'rethinking' and the incorporation of ongoing integration of coming economical and environmental interests on infrastructure, in relation to the sustainable urban development and regeneration from the perspective of the tripod people, technology and design is ...

  5. Retinal synaptic regeneration via microfluidic guiding channels

    OpenAIRE

    Ping-Jung Su; Zongbin Liu; Kai Zhang; Xin Han; Yuki Saito; Xiaojun Xia; Kenji Yokoi; Haifa Shen; Lidong Qin

    2015-01-01

    In vitro culture of dissociated retinal neurons is an important model for investigating retinal synaptic regeneration (RSR) and exploring potentials in artificial retina. Here, retinal precursor cells were cultured in a microfluidic chip with multiple arrays of microchannels in order to reconstruct the retinal neuronal synapse. The cultured retinal cells were physically connected through microchannels. Activation of electric signal transduction by the cells through the microchannels was demon...

  6. Economics of Naturally Regenerating, Heterogeneous Forests

    OpenAIRE

    Olli Tahvonen

    2015-01-01

    An economic model for naturally regenerating, heterogeneous forests is specified to yield both clear-cuts and continuous cover forestry endogenously. The model includes nonconvexities and any number of state variables but is, in its simplest form, a one-state variable problem. Clear-cuts with various rotation lengths and continuous harvesting appear as locally optimal solutions. Necessary and sufficient conditions for the local and global optimality of these two forest management types are ob...

  7. Regeneration of ZVS converter with Resonant inductor

    Directory of Open Access Journals (Sweden)

    J.Sivavara Prasad

    2011-09-01

    Full Text Available This paper presents an analysis of the regeneration of zero-voltage-switching converter with resonant inductor, quasi-resonant converters, and full-bridge zero-voltage-switched PWM Converter. The design of a clamping circuit considering a saturable resonant inductor is presented and compared with the design of a clamping circuit with a linear resonant inductor. A diode model with reverse recovery is employed to simulate the effects.

  8. Lyocell, The New Generation of Regenerated Cellulose

    OpenAIRE

    Éva Borbély

    2008-01-01

    For the majority of the last century, commercial routes to regenerated cellulosefibres have coped with the difficulties of making a good cellulose solution by using an easyto dissolve derivative (e.g. xanthane in the case of viscose rayon) or complex (e.g.cuprammonium rayon). For the purposes of this paper, advanced cellulosic fibres aredefined as those made from a process involving direct dissolution of cellulose. The firstexamples of such fibres have now been generically designaed as lyocel...

  9. The investigation of HTGR fuel regeneration process

    International Nuclear Information System (INIS)

    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

  10. Bioactive polymeric–ceramic hybrid 3D scaffold for application in bone tissue regeneration

    International Nuclear Information System (INIS)

    The regeneration of large bone defects remains a challenging scenario from a therapeutic point of view. In fact, the currently available bone substitutes are often limited by poor tissue integration and severe host inflammatory responses, which eventually lead to surgical removal. In an attempt to address these issues, herein we evaluated the importance of alginate incorporation in the production of improved and tunable β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) three-dimensional (3D) porous scaffolds to be used as temporary templates for bone regeneration. Different bioceramic combinations were tested in order to investigate optimal scaffold architectures. Additionally, 3D β-TCP/HA vacuum-coated with alginate, presented improved compressive strength, fracture toughness and Young's modulus, to values similar to those of native bone. The hybrid 3D polymeric–bioceramic scaffolds also supported osteoblast adhesion, maturation and proliferation, as demonstrated by fluorescence microscopy. To the best of our knowledge this is the first time that a 3D scaffold produced with this combination of biomaterials is described. Altogether, our results emphasize that this hybrid scaffold presents promising characteristics for its future application in bone regeneration. - Graphical abstract: B-TCP:HA–alginate hybrid 3D porous scaffolds for application in bone regeneration. - Highlights: • The produced hybrid 3D scaffolds are prone to be applied in bone tissue engineering. • Alginate coated 3D scaffolds present high mechanical and biological properties. • In vitro assays for evaluation of human osteoblast cell attachment in the presence of the scaffolds • The hybrid 3D scaffolds present suitable mechanical and biological properties for use in bone regenerative medicine

  11. Stem cells sources for intervertebral disc regeneration.

    Science.gov (United States)

    Vadalà, Gianluca; Russo, Fabrizio; Ambrosio, Luca; Loppini, Mattia; Denaro, Vincenzo

    2016-05-26

    Intervertebral disc regeneration field is rapidly growing since disc disorders represent a major health problem in industrialized countries with very few possible treatments. Indeed, current available therapies are symptomatic, and surgical procedures consist in disc removal and spinal fusion, which is not immune to regardable concerns about possible comorbidities, cost-effectiveness, secondary risks and long-lasting outcomes. This review paper aims to share recent advances in stem cell therapy for the treatment of intervertebral disc degeneration. In literature the potential use of different adult stem cells for intervertebral disc regeneration has already been reported. Bone marrow mesenchymal stromal/stem cells, adipose tissue derived stem cells, synovial stem cells, muscle-derived stem cells, olfactory neural stem cells, induced pluripotent stem cells, hematopoietic stem cells, disc stem cells, and embryonic stem cells have been studied for this purpose either in vitro or in vivo. Moreover, several engineered carriers (e.g., hydrogels), characterized by full biocompatibility and prompt biodegradation, have been designed and combined with different stem cell types in order to optimize the local and controlled delivery of cellular substrates in situ. The paper overviews the literature discussing the current status of our knowledge of the different stem cells types used as a cell-based therapy for disc regeneration. PMID:27247704

  12. Double Circulant Minimum Storage Regenerating Codes

    CERN Document Server

    Braso, Bernat Gaston

    2010-01-01

    Storage optimization in distributed environments is a major concern when talking about reliability in this kind of schemes. Although replication is the most used option, erasure coding is a more optimized one. However, erasure coding uses a lot of bandwidth to replace one node. In a dynamic scheme, where nodes enter and leave the system frequently, bandwidth use could be an important drawback. Regenerating Codes introduced by \\textit{Dimakis et al.} minimize the code repair problem by applying Network Coding to the distributed storage scheme. However finding the coefficients for the linear combinations used to replace a node is not easy, specially for the systematic case, and must be calculated for each new node fail. For the special case when the dimension $k$ and the redundancy $n-k$ of the system are the same, and the number of nodes participating in the regeneration phase is $d=k+1$, we purpose a new optimal family of Minimum Storage Regenerating codes where coefficients are precalculated and node regener...

  13. 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.

  14. Protein phosphorylation: Localization in regenerating optic axons

    International Nuclear Information System (INIS)

    A number of axonal proteins display changes in phosphorylation during goldfish optic nerve regeneration. (1) To determine whether the phosphorylation of these proteins was closely linked to their synthesis in the retinal ganglion cell body, cycloheximide was injected intraocularly into goldfish whose optic nerves had been regenerating for 3 weeks. Cycloheximide reduced the incorporation of [3H]proline and 32P orthophosphate into total nerve protein by 84% and 46%, respectively. Of the 20 individual proteins examined, 17 contained less than 15% of the [3H]proline label measured in corresponding controls, whereas 18 proteins contained 50% or more of the 32P label, suggesting that phosphorylation was largely independent of synthesis. (2) To determine whether the proteins were phosphorylated in the ganglion cell axons, axonal transport of proteins was blocked by intraocular injection of vincristine. Vincristine reduced [3H]proline labeling of total protein by 88% and 32P labeling by 49%. Among the individual proteins [3H]proline labeling was reduced by 90% or more in 18 cases but 32P labeling was reduced only by 50% or less. (3) When 32P was injected into the cranial cavity near the ends of the optic axons, all of the phosphoproteins were labeled more intensely in the optic tract than in the optic nerve. These results suggest that most of the major phosphoproteins that undergo changes in phosphorylation in the course of regeneration are phosphorylated in the optic axons

  15. Retinal synaptic regeneration via microfluidic guiding channels.

    Science.gov (United States)

    Su, Ping-Jung; Liu, Zongbin; Zhang, Kai; Han, Xin; Saito, Yuki; Xia, Xiaojun; Yokoi, Kenji; Shen, Haifa; Qin, Lidong

    2015-01-01

    In vitro culture of dissociated retinal neurons is an important model for investigating retinal synaptic regeneration (RSR) and exploring potentials in artificial retina. Here, retinal precursor cells were cultured in a microfluidic chip with multiple arrays of microchannels in order to reconstruct the retinal neuronal synapse. The cultured retinal cells were physically connected through microchannels. Activation of electric signal transduction by the cells through the microchannels was demonstrated by administration of glycinergic factors. In addition, an image-based analytical method was used to quantify the synaptic connections and to assess the kinetics of synaptic regeneration. The rate of RSR decreased significantly below 100 μM of inhibitor glycine and then approached to a relatively constant level at higher concentrations. Furthermore, RSR was enhanced by chemical stimulation with potassium chloride. Collectively, the microfluidic synaptic regeneration chip provides a novel tool for high-throughput investigation of RSR at the cellular level and may be useful in quality control of retinal precursor cell transplantation. PMID:26314276

  16. Liver regeneration - mechanisms and models to clinical application.

    Science.gov (United States)

    Forbes, Stuart J; Newsome, Philip N

    2016-08-01

    Liver regeneration has been studied for many decades and the mechanisms underlying regeneration of the normal liver following resection or moderate damage are well described. A large number of factors extrinsic (such as bile acids and circulating growth factors) and intrinsic to the liver interact to initiate and regulate liver regeneration. Less well understood, and more clinically relevant, are the factors at play when the abnormal liver is required to regenerate. Fatty liver disease, chronic scarring, prior chemotherapy and massive liver injury can all inhibit the normal programme of regeneration and can lead to liver failure. Understanding these mechanisms could enable the rational targeting of specific therapies to either reduce the factors inhibiting regeneration or directly stimulate liver regeneration. Although animal models of liver regeneration have been highly instructive, the clinical relevance of some models could be improved to bridge the gap between our in vivo model systems and the clinical situation. Likewise, modern imaging techniques such as spectroscopy will probably improve our understanding of whole-organ metabolism and how this predicts the liver's regenerative capacity. This Review describes briefly the mechanisms underpinning liver regeneration, the models used to study this process, and discusses areas in which failed or compromised liver regeneration is clinically relevant. PMID:27353402

  17. Spot the difference: Solving the puzzle of hidden pictures in the lizard genome for identification of regeneration factors.

    Science.gov (United States)

    Chung, Jin Woong

    2016-05-01

    All living things share some common life processes, such as growth and reproduction, and have the ability to respond to their environment. However, each type of organism has its own specialized way of managing biological events. Genetic sequences determine phenotypic and physiological traits. Based on genetic information, comparative genomics has been used to delineate the differences and similarities between various genomes, and significant progress has been made in understanding regenerative biology by comparing the genomes of a variety of lower animal models of regeneration, such as planaria, zebra fish, and newts. However, the genome of lizards has been relatively ignored until recently, even though lizards have been studied as an excellent amniote model of tissue regeneration. Very recently, whole genome sequences of lizards have been uncovered, and several attempts have been made to find regeneration factors based on genetic information. In this article, recent advances in comparative analysis of the lizard genome are introduced, and their biological implications and putative applications for regenerative medicine and stem cell biology are discussed. [BMB Reports 2016; 49(5): 249-254]. PMID:26949021

  18. Biology Notes.

    Science.gov (United States)

    School Science Review, 1982

    1982-01-01

    Presents procedures, exercises, demonstrations, and information on a variety of biology topics including labeling systems, biological indicators of stream pollution, growth of lichens, reproductive capacity of bulbous buttercups, a straw balance to measure transpiration, interaction of fungi, osmosis, and nitrogen fixation and crop production. (DC)

  19. Influence of input acoustic power on regenerator's performance

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Performance of a pulse tube cooler significantly depends on the efficient operation of its regenerator. Influence of input acoustic power on regenerator's performance is simulated and analyzed with simple harmonic analysis method. Given regenerator's dimensions and pressure ratio, there is an optimal input acoustic power for achieving a highest coefficient of performance, due to a compromise between relative time-averaged total energy flux in regenerator and relative acoustic power at regenerator's cold end. Additionally, optimal dimensions of regenerator are also estimated and presented for different input acoustic powers. The computed optimal diameter obviously increases with increase of input acoustic power, while the optimal length decreases slightly,and as a result, a larger input acoustic power requires a smaller aspect ratio (length over diameter).

  20. The progress in optic nerve regeneration, where are we?

    Institute of Scientific and Technical Information of China (English)

    Jennifer Wei Huen Shum; Kai Liu; Kwok-fai So

    2016-01-01

    Optic nerve regeneration is an important area of research. It can be used to treat patients suffering from optic neuropathy and provides insights into the treatment of numerous neurodegenerative diseases. There are many hurdles impeding optic regeneration in mammals. The mammalian central nervous system is non-permissive to regeneration and intrinsically lacks the capacity for axonal regrowth. Any axonal injury also triggers a vicious cycle of apoptosis. Understanding these hurdles provides us with a rough framework to appreciate the essential steps to bring about optic nerve regeneration: enhancing neuronal survival, axon regeneration, remyelination and establishing functional synapses to the original neuronal targets. In this review article, we will go through current potential treatments for optic nerve regeneration, which includes neurotrophic factor provision, inlfammatory stimulation, growth inhibition suppression, intracellular sig-naling modiifcation and modeling of bridging substrates.

  1. Development of an active magnetic regenerator for space applications

    Science.gov (United States)

    Chen, Weibo

    2014-07-01

    This paper discusses the design of a micromachined regenerator in an Active Magnetic Regenerative Refrigeration (AMRR) system for space applications. The AMRR system is designed to provide continuous remote/distributed cooling at about 2 K and reject heat at temperatures of about 15 K. This paper first discusses the general thermal and fluid performance requirements for an AMRR regenerator, a unique structured bed configuration that enables the regenerator to meet these requirements, and its thermal and fluid performance based on numerical analyses. The paper then discusses the general design consideration for the magnetic field driving the regenerator for optimal thermal performance, and the analysis processes to optimize the variation rate of the magnetic field in an actual superconducting magnet during the isothermal processes of the AMRR cycle to enhance the performance of an actual regenerator. The paper finally presents the thermal performance of the regenerator from such iterative design optimization processes.

  2. The molecular path to in vitro shoot regeneration.

    Science.gov (United States)

    Motte, Hans; Vereecke, Danny; Geelen, Danny; Werbrouck, Stefaan

    2014-01-01

    Plant regeneration through de novo shoot organogenesis in tissue culture is a critical step in most plant transformation and micropropagation procedures. Establishing an efficient regeneration protocol is an empirical process and requires optimization of multiple factors that influence the regeneration capacity. Here, we review the molecular process of shoot induction in a two-step regeneration protocol and focus on the role of auxins and cytokinins. First, during incubation on an auxin-rich callus induction medium (CIM), organogenic callus is produced that exhibits characteristics of a root meristem. Subsequent incubation on a cytokinin-rich shoot induction medium (SIM) induces root to shoot conversion. Through a detailed analysis of the different aspects of shoot regeneration, we try to reveal hinge points and novel candidate genes that may be targeted to increase shoot regeneration capacity in order to improve transformation protocols. PMID:24355763

  3. Treadmill Training Promotes Axon Regeneration in Injured Peripheral Nerves

    OpenAIRE

    Sabatier, Manning J.; Redmon, Natalie; Schwartz, Gail; English, Arthur W.

    2008-01-01

    Physical activity after spinal cord injury promotes improvements in motor function, but its effects following peripheral nerve injury are less clear. Although axons in peripheral nerves are known to regenerate better than those in the CNS, methods of accelerating regeneration are needed due to the slow overall rate of growth. Therefore we studied the effect of two weeks of treadmill locomotion on the growth of regenerating axons in peripheral nerves following injury. The common fibular nerves...

  4. Hydrogen peroxide primes heart regeneration with a derepression mechanism

    OpenAIRE

    Han, Peidong; Zhou, Xiao-Hai; Chang, Nannan; Xiao, Cheng-Lu; Yan, Shouyu; Ren, He; Yang, Xin-Zhuang; Zhang, Mei-Ling; Wu, Qing; Tang, Boyang; Diao, Ju-Peng; Zhu, Xiaojun; Zhang, Chuanmao; Li, Chuan-Yun; Cheng, Heping

    2014-01-01

    While the adult human heart has very limited regenerative potential, the adult zebrafish heart can fully regenerate after 20% ventricular resection. Although previous reports suggest that developmental signaling pathways such as FGF and PDGF are reused in adult heart regeneration, the underlying intracellular mechanisms remain largely unknown. Here we show that H2O2 acts as a novel epicardial and myocardial signal to prime the heart for regeneration in adult zebrafish. Live imaging of intact ...

  5. Interleukin-6 Mediates Angiotensinogen Gene Expression during Liver Regeneration

    OpenAIRE

    Hong-Shiee Lai; Wen-Hsi Lin; Shuo-Lun Lai; Hao-Yu Lin; Wen-Ming Hsu; Chia-Hung Chou; Po-Huang Lee

    2013-01-01

    BACKGROUND: Angiotensinogen is the precursor of angiotensin II, which is associated with ischemia-reperfusion injury. Angiotensin II reduces liver regeneration after hepatectomy and causes dysfunction and failure of reduced-size liver transplants. However, the regulation of angiotensinogen during liver regeneration is still unclear. AIMS: To investigate the regulation of angiotensinogen during liver regeneration for preventing angiotensin II-related ischemia-reperfusion injury during liver re...

  6. Enhancement of epidermal regeneration by biosynthetic epidermal growth factor

    OpenAIRE

    1986-01-01

    Epidermal regeneration depends on mitosis and migration of keratinocytes. Epidermal growth factor is known to stimulate growth of keratinocytes in vitro, thus it might be expected to promote wound healing. The results of this study show that topical application of biosynthetic human epidermal growth factor accelerates epidermal regeneration in split-thickness wounds and partial-thickness burns. The significant enhancement of epidermal regeneration suggests the potential for clinical use of ep...

  7. Regenerating the brain : lessons from the Red Spotted Newt

    OpenAIRE

    Berg, Daniel

    2012-01-01

    Unlike mammals, adult salamanders can regenerate their brain after injury in a process fuelled by neurogenesis. The aim of this thesis is to identify the cells that give rise to new neurons after injury and examine the mechanisms controlling the initiation and termination of brain regeneration in the newt. The reasons why newts can regenerate their brain while mammals cannot are unknown, and it has been argued that the presence of constantly proliferating cells is a prerequisi...

  8. Hedgehog Signaling Is Required for Effective Regeneration of Exocrine Pancreas

    OpenAIRE

    Fendrich, Volker; Esni, Farzad; GARAY, MARIA VERONICA R.; Feldmann, Georg; Habbe, Nils; Jensen, Jan Nygaard; Dor, Yuval; Stoffers, Doris; Jensen, Jan; Leach, Steven D.; Maitra, Anirban

    2008-01-01

    Although both endocrine and the exocrine pancreas display a significant capacity for tissue regeneration and renewal, the existence of progenitor cells in the adult pancreas remains uncertain. Using a model of cerulein-mediated injury and repair, we demonstrate that mature exocrine cells, defined by expression of an Elastase1 promoter, actively contribute to regenerating pancreatic epithelium through formation of metaplastic ductal intermediates. Acinar cell regeneration is associated with ac...

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

    OpenAIRE

    Jan Gessmann; Manfred Köller; Holger Godry; Thomas Armin Schildhauer; Dominik Seybold

    2012-01-01

    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 ...

  10. Regeneration of New Neurons is Preserved in Aged Vomeronasal Epithelia

    OpenAIRE

    Brann, Jessica H.; Firestein, Stuart

    2010-01-01

    During normal and diseased aging, it is thought the capacity for tissue regeneration and repair in neuronal tissues diminishes. In the peripheral olfactory system, stem cell reservoirs permit regeneration of olfactory and vomeronasal sensory neurons, a unique capacity among neurons. Following injury a large number of new neurons can be regenerated in a young animal. However, it is unknown whether this capacity for renewal exists in aged proliferative populations. Here we report that neuronal ...

  11. Challenges and Opportunities for Regeneration in the Peripheral Nervous System

    OpenAIRE

    Höke, Ahmet; Brushart, Thomas

    2009-01-01

    Regeneration in the peripheral nervous system offers unique opportunities and challenges to medicine. Compared to the central nervous system, peripheral axons can and do regenerate resulting in functional recovery, especially if the distance to target is short as in distal limb injuries. However, this regenerative capacity is often incomplete and functional recovery with proximal lesions is limited. Furthermore, regeneration of axons to the appropriate targets remains a challenge with inappro...

  12. Analysis of Regenerator for Reversed Stirling Cycle Which Various Geometry.

    OpenAIRE

    Vikram Patel; N.A.ranpura

    2013-01-01

    Analysis of regenerator deals with assumptions made for analysis and different equation use to predict the performance of regenerator Problem and sample calculation deals with problem and calculation of various parameter such as geometrical parameter heat transfer co-efficient and effectiveness, pressure drop loss of refrigerator effect due to ineffectiveness and pressure drop and other type of regenerator losses Result and discussion deals with the effect of mass flow rate mesh size standard...

  13. Research of Energy Regeneration Technology in Electric Vehicle

    Institute of Scientific and Technical Information of China (English)

    陈家新; 江建中; 汪信尧

    2003-01-01

    The theory of energy regeneration in electric vehicle (EV) has been introduced in most papers, but the mathematic model of EV energy regeneration system was little studied. In this paper the mathematic model of EV energy regeneration system is studied,and then the system ability under four control strategies is analyzed. In the end the system reliability is researched, and the calcula-tion model of system reliability is proposed.

  14. Altered Macrophage Phenotype Transition Impairs Skeletal Muscle Regeneration

    OpenAIRE

    Wang, Hanzhou; Melton, David W.; Porter, Laurel; Sarwar, Zaheer U.; McManus, Linda M.; Shireman, Paula K.

    2014-01-01

    Monocyte/macrophage polarization in skeletal muscle regeneration is ill defined. We used CD11b-diphtheria toxin receptor transgenic mice to transiently deplete monocytes/macrophages at multiple stages before and after muscle injury induced by cardiotoxin. Fat accumulation within regenerated muscle was maximal when ablation occurred at the same time as cardiotoxin-induced injury. Early ablation (day 1 after cardiotoxin) resulted in the smallest regenerated myofiber size together with increased...

  15. Quantum Biology

    Directory of Open Access Journals (Sweden)

    Alessandro Sergi

    2009-06-01

    Full Text Available A critical assessment of the recent developmentsof molecular biology is presented.The thesis that they do not lead to a conceptualunderstanding of life and biological systems is defended.Maturana and Varela's concept of autopoiesis is briefly sketchedand its logical circularity avoided by postulatingthe existence of underlying living processes,entailing amplification from the microscopic to the macroscopic scale,with increasing complexity in the passage from one scale to the other.Following such a line of thought, the currently accepted model of condensed matter, which is based on electrostatics and short-ranged forces,is criticized. It is suggested that the correct interpretationof quantum dispersion forces (van der Waals, hydrogen bonding, and so onas quantum coherence effects hints at the necessity of includinglong-ranged forces (or mechanisms for them incondensed matter theories of biological processes.Some quantum effects in biology are reviewedand quantum mechanics is acknowledged as conceptually important to biology since withoutit most (if not all of the biological structuresand signalling processes would not even exist. Moreover, it is suggested that long-rangequantum coherent dynamics, including electron polarization,may be invoked to explain signal amplificationprocess in biological systems in general.

  16. Dimensionless numerical model for simulation of active magnetic regenerator refrigerator

    Energy Technology Data Exchange (ETDEWEB)

    Sarlah, A.; Poredos, A. [Faculty of Mechanical Engineering, University of Ljubljana, Askerceva 6, SI-1000 Ljubljana (Slovenia)

    2010-09-15

    In order to obtain a better reliability, consistency and accuracy of results obtained with a numerical simulation of an AMRR (active magnetic regenerator refrigerator), a dimensionless numerical model was developed, which can equally be used for determination of regenerator's heat transfer coefficient and simulation of passive heat regenerators or AMRR operation. Regenerator's heat transfer coefficient {alpha}{sub f}, is a crucial input parameter in the simulation of AMRR operation and has a primal effect on the outcome of a solution. This paper deals with a derived dimensionless model and discusses errors involved when using different models for heat transfer coefficient and AMRR operation simulation. (author)

  17. Rodent models and imaging techniques to study liver regeneration.

    Science.gov (United States)

    Wei, Weiwei; Dirsch, Olaf; Mclean, Anna Lawson; Zafarnia, Sara; Schwier, Michael; Dahmen, Uta

    2015-01-01

    The liver has the unique capability of regeneration from various injuries. Different animal models and in vitro methods are used for studying the processes and mechanisms of liver regeneration. Animal models were established either by administration of hepatotoxic chemicals or by surgical approach. The administration of hepatotoxic chemicals results in the death of liver cells and in subsequent hepatic regeneration and tissue repair. Surgery includes partial hepatectomy and portal vein occlusion or diversion: hepatectomy leads to compensatory regeneration of the remnant liver lobe, whereas portal vein occlusion leads to atrophy of the ipsilateral lobe and to compensatory regeneration of the contralateral lobe. Adaptation of modern radiological imaging technologies to the small size of rodents made the visualization of rodent intrahepatic vascular anatomy possible. Advanced knowledge of the detailed intrahepatic 3D anatomy enabled the establishment of refined surgical techniques. The same technology allows the visualization of hepatic vascular regeneration. The development of modern histological image analysis tools improved the quantitative assessment of hepatic regeneration. Novel image analysis tools enable us to quantify reliably and reproducibly the proliferative rate of hepatocytes using whole-slide scans, thus reducing the sampling error. In this review, the refined rodent models and the newly developed imaging technology to study liver regeneration are summarized. This summary helps to integrate the current knowledge of liver regeneration and promises an enormous increase in hepatological knowledge in the near future. PMID:25402256

  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. PMID:26963675

  19. Irradiation inhibits the regeneration of aneurogenic limbs. [X radiation

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, H.; Maden, M.

    1976-03-01

    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.

  20. Regeneration of guinea PIG facial nerve: the effect of hypergravity

    Science.gov (United States)

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

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

  1. Regenerable Microbial Check Valve - Life cycle tests results

    Science.gov (United States)

    Atwater, James E.; Wheeler, Richard R., Jr.; Olivadoti, J. T.; Sauer, Richard L.; Flanagan, David T.

    1992-01-01

    Life cycle regeneration testing of the Microbial Check Valve (MCV) that is used on the Shuttle Orbiter to provide microbial control of potable water is currently in progress. Four beds are being challenged with simulated reclaimed waters and repeatedly regenerated. Preliminary results indicate that contaminant systems exhibit unique regeneration periodicities. Cyclic throughput diminishes with increasing cumulative flow. It is considered to be feasible to design a regenerable MCV system which will function without human intervention and with minimal resupply penalty for the 30 year life of the Space Station.

  2. Hair cell regeneration: Look to the future

    Science.gov (United States)

    Rubel, Edwin W.

    2005-04-01

    Less than 2 decades ago it was discovered that birds can regenerate hair cells in the auditory and vestibular parts of the inner ear after the native hair cells are destroyed by exposure to excessive noise or by mechanical trauma of aminoglycoside antibiotics. This discovery issued in a new era of hearing research-it suggested that some day it may be possible to actually restore hearing in people with congenital or acquired hearing loss due to the degeneration of sensory cells or supporting cells in the inner ear. Fifteen years is a very short time in the history of science. Consider the fact that we have actively sought chemical treatments to prevent or cure cancers for well over a half century and the ``war on Cancer,'' resulted in enormous public and private support. Progress has been great, and some forms of cancer can be treated with great success, but the overall 5-year survival rates have only risen from about 50% to 63%. Progress will continue and many more forms of cancer will be cured and prevented during the next half century. Similarly, during the first 15 years of hair cell regeneration research enormous progress has been made, and we now know that postnatal mammalian ears have the capacity to produce new hair cells. We are indeed a long way from restoring hearing through hair cell regeneration, but the future is pretty clear. I will review the progress of this field with an eye toward the future and what it means for treatments of today. In particular, I will address the potential cost versus benefits of bilateral implantation when applied to babies and young children.

  3. Adipose derived stem cells and nerve regeneration

    Institute of Scientific and Technical Information of China (English)

    Alessandro Faroni; Richard JP Smith; Adam J Reid

    2014-01-01

    Injuries to peripheral nerves are common and cause life-changing problems for patients along-side high social and health care costs for society. Current clinical treatment of peripheral nerve injuries predominantly relies on sacriifcing a section of nerve from elsewhere in the body to pro-vide a graft at the injury site. Much work has been done to develop a bioengineered nerve graft, precluding sacriifce of a functional nerve. Stem cells are prime candidates as accelerators of re-generation in these nerve grafts. This review examines the potential of adipose-derived stem cells to improve nerve repair assisted by bioengineered nerve grafts.

  4. Thermal regeneration in fix-bed reactors

    International Nuclear Information System (INIS)

    The thermal behaviour of a catalytic reactor with regeneration, from a simplified model is studied. Plug-flow is postulated to the reactor and a two-phase model for simulating heat transfer between the bed and the gas is used, disregarding the conduction terms. The computational results for an exothermal catalytic reaction are presented. The effect of the duration of the period and the inlet temperature of the gas in the bed temperature profiles is studied, as well as the evolution since the functioning until the steady state. (E.G.)

  5. Assessing social impacts in urban waterfront regeneration

    International Nuclear Information System (INIS)

    The target of this article is to identify the social impacts of urban waterfront regeneration. For this purpose, four different dimensions of social impacts in urban waterfront planning are presented: resources and identity, social status, access and activities and waterfront experience. The four social dimensions refer to the different ways of experiencing and using the edges of the sea, lake or river to make an understanding of their qualities to the community. The contents of this typology are illustrated by analysing some basic features of three different newly built waterfront areas in Helsinki. The article is based on post-evaluation

  6. Pancreatic regeneration: basic research and gene regulation.

    Science.gov (United States)

    Okita, Kenji; Mizuguchi, Toru; Shigenori, Ota; Ishii, Masayuki; Nishidate, Toshihiko; Ueki, Tomomi; Meguro, Makoto; Kimura, Yasutoshi; Tanimizu, Naoki; Ichinohe, Norihisa; Torigoe, Toshihiko; Kojima, Takashi; Mitaka, Toshihiro; Sato, Noriyuki; Sawada, Norimasa; Hirata, Koichi

    2016-06-01

    Pancreatic regeneration (PR) is an interesting phenomenon that could provide clues as to how the control of diabetes mellitus might be achieved. Due to the different regenerative abilities of the pancreas and liver, the molecular mechanism responsible for PR is largely unknown. In this review, we describe five representative murine models of PR and thirteen humoral mitogens that stimulate β-cell proliferation. We also describe pancreatic ontogenesis, including the molecular transcriptional differences between α-cells and β-cells. Furthermore, we review 14 murine models which carry defects in genes related to key transcription factors for pancreatic ontogenesis to gain further insight into pancreatic development. PMID:26148809

  7. How sex hormones promote skeletal muscle regeneration.

    Science.gov (United States)

    Velders, Martina; Diel, Patrick

    2013-11-01

    Skeletal muscle regeneration efficiency declines with age for both men and women. This decline impacts on functional capabilities in the elderly and limits their ability to engage in regular physical activity and to maintain independence. Aging is associated with a decline in sex hormone production. Therefore, elucidating the effects of sex hormone substitution on skeletal muscle homeostasis and regeneration after injury or disuse is highly relevant for the aging population, where sarcopenia affects more than 30 % of individuals over 60 years of age. While the anabolic effects of androgens are well known, the effects of estrogens on skeletal muscle anabolism have only been uncovered in recent times. Hence, the purpose of this review is to provide a mechanistic insight into the regulation of skeletal muscle regenerative processes by both androgens and estrogens. Animal studies using estrogen receptor (ER) antagonists and receptor subtype selective agonists have revealed that estrogens act through both genomic and non-genomic pathways to reduce leukocyte invasion and increase satellite cell numbers in regenerating skeletal muscle tissue. Although animal studies have been more conclusive than human studies in establishing a role for sex hormones in the attenuation of muscle damage, data from a number of recent well controlled human studies is presented to support the notion that hormonal therapies and exercise induce added positive effects on functional measures and lean tissue mass. Based on the fact that aging human skeletal muscle retains the ability to adapt to exercise with enhanced satellite cell activation, combining sex hormone therapies with exercise may induce additive effects on satellite cell accretion. There is evidence to suggest that there is a 'window of opportunity' after the onset of a hypogonadal state such as menopause, to initiate a hormonal therapy in order to achieve maximal benefits for skeletal muscle health. Novel receptor subtype selective

  8. An energy storage and regeneration system

    DEFF Research Database (Denmark)

    2006-01-01

    caverns. When the energy demand exceeds the power production capacity of the plant, the stored gases are burned and the thermal energy is converted into electricity in gas turbine generators. The regenerated electrical power is then used to supplement the output of the electric power plant to meet the......  The present invention relates to a method and a system for storing excess energy produced by an electric power plant during periods of lower energy demand than the power plant production capacity. The excess energy is stored by hydrolysis of water and storage of hydrogen and oxygen in underground...... higher level of energy demand....

  9. Control of Energy Regeneration for Electric Vehicle

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yi; MAO Xiao-jian; LI Li-ming; ZHUO Bn

    2008-01-01

    To extend electric vehicle (EV) running distance, the vehicle energy regeneration (ER) method and vehicle control strategy were designed based on the original vehicle braking system. The ER principle of direct current (DC) brushless motor was studied, the motor mathematical model and PI control method with torque close-loop were built. This control method was applied to pure EV and the real road tests were evaluated.The ER control does not make any significant uncomfortable influence brake feeling and can save about 10% battery energy based on 3 times economic commission for Europe (ECE) driving cycles.

  10. Genetic variability in regenerated Metarhizium flavoviride protoplasts

    Directory of Open Access Journals (Sweden)

    Júlia Kuklinsky-Sobral

    2004-03-01

    Full Text Available Protoplast isolation and regeneration were evaluated in two wild-type and two colour mutant strains of Metarhizium flavoviride. Cultivation in liquid medium, followed by mycelium treatment with Novozym 234 in the presence of KCl 0.7M as osmotic stabilizer, produced 5.05 x 10(6 to 1.15 x 10(7x mL-1 protoplasts. The percentage of regeneration ranged from 6.65 to 27.92%. Following protoplast regeneration, one strain produced spontaneously stable morphological variant colonies. Although colonies with altered morphology have been reported in bacteria following protoplast regeneration, this is the first time that the same is described in a filamentous fungus. The original strain and one derived variant were tested for sensitivity to the fungicides benomyl and captan.A formação e regeneração de protoplastos foram avaliadas em duas linhagens selvagens e duas linhagens mutantes para coloração de conídios em Metarhizium flavoviride. O cultivo em meio líquido seguido do tratamento do micélio com Novozym 234 na presença de KCl 0,7 M como estabilizador osmótico, resultou na produção de 5,05´10(6 a 1,15´10(7 protoplastos´mL-1. A porcentagem de regeneração das diferentes linhagens variou de 6,65 a 27,92%. Após a regeneração, uma das linhagens selvagens produziu espontaneamente variantes estáveis, com morfologia alterada. Embora variantes morfológicos já tenham sido observados após regeneração de protoplastos em bactérias, esta parece ser a primeira vez que tal ocorrência é descrita em fungos filamentosos. Um desses variantes, além da linhagem selvagem da qual ele foi originado, foi testado para sensibilidade aos fungicidas benomil e captano.

  11. Lyocell, The New Generation of Regenerated Cellulose

    Directory of Open Access Journals (Sweden)

    Éva Borbély

    2008-06-01

    Full Text Available For the majority of the last century, commercial routes to regenerated cellulosefibres have coped with the difficulties of making a good cellulose solution by using an easyto dissolve derivative (e.g. xanthane in the case of viscose rayon or complex (e.g.cuprammonium rayon. For the purposes of this paper, advanced cellulosic fibres aredefined as those made from a process involving direct dissolution of cellulose. The firstexamples of such fibres have now been generically designaed as lyocell fibres todistinguish them from rayons, and the first commercial lyocell fibre is Courtaulds’ Tencel.

  12. Bone marrow-derived fibroblast growth factor-2 induces glial cell proliferation in the regenerating peripheral nervous system

    OpenAIRE

    Ribeiro-Resende Victor; Carrier-Ruiz Alvaro; R Lemes Robertha M; Reis Ricardo A M; Mendez-Otero Rosalia

    2012-01-01

    Abstract Background Among the essential biological roles of bone marrow-derived cells, secretion of many soluble factors is included and these small molecules can act upon specific receptors present in many tissues including the nervous system. Some of the released molecules can induce proliferation of Schwann cells (SC), satellite cells and lumbar spinal cord astrocytes during early steps of regeneration in a rat model of sciatic nerve transection. These are the major glial cell types that s...

  13. Effect of Picibanil (OK 432) on the Scavenging Effect of Free Radicals Produced during Liver Regeneration in the Rat

    OpenAIRE

    Okamoto, Ko; Hamazaki,Keisuke; Iwagaki, Hiromi; Orita,Kunzo; Mori, Akitane

    1995-01-01

    We administered a biological response modifier Picibanil (OK-432), attenuated Streptococcus pyogenes, via the dorsal vein of the penis after 70% hepatectomy in rats, and clarified the scavenging effect of Picibanil on free radicals generated in the regenerating liver. A group of 5 rats was intravenously administered with 25 KE/kg of OK-432 after hepatectomy, while the control group was given saline after hepatectomy. Serum levels of aspartate aminotransferase and alanine aminotransferase and ...

  14. Quantum Biology

    CERN Document Server

    Sergi, Alessandro

    2009-01-01

    A critical assessment of the recent developments of molecular biology is presented. The thesis that they do not lead to a conceptual understanding of life and biological systems is defended. Maturana and Varela's concept of autopoiesis is briefly sketched and its logical circularity avoided by postulating the existence of underlying {\\it living processes}, entailing amplification from the microscopic to the macroscopic scale, with increasing complexity in the passage from one scale to the other. Following such a line of thought, the currently accepted model of condensed matter, which is based on electrostatics and short-ranged forces, is criticized. It is suggested that the correct interpretation of quantum dispersion forces (van der Waals, hydrogen bonding, and so on) as quantum coherence effects hints at the necessity of including long-ranged forces (or mechanisms for them) in condensed matter theories of biological processes. Some quantum effects in biology are reviewed and quantum mechanics is acknowledge...

  15. Pericytes: Multitasking Cells in the Regeneration of Injured, Diseased, and Aged Skeletal Muscle

    Directory of Open Access Journals (Sweden)

    Alexander Birbrair

    2014-09-01

    Full Text Available Pericytes are perivascular cells that envelop and make intimate connections with adjacent capillary endothelial cells. Recent studies show that they may have a profound impact in skeletal muscle regeneration, innervation, vessel formation, fibrosis, fat accumulation, and ectopic bone formation throughout life. In this review, we summarize and evaluate recent advances in our understanding of pericytes’ influence on adult skeletal muscle pathophysiology. We also discuss how further elucidating their biology may offer new approaches to the treatment of conditions characterized by muscle wasting.

  16. Calcium sulfate combined with guided tissue regeneration: A novel technique in treatment of gingival recessions

    Science.gov (United States)

    Mukherji, Arnav

    2016-01-01

    The presence of mucogingival problem around anterior teeth is a challenge to the clinician as not only biological and functional aspects has to be addressed but esthetic aspirations of the patient have to be met. The use of guided tissue regeneration (GTR) procedures for the treatment of gingival recession has shown encouraging results and is gaining clinical acceptance. However, maintenance of space under the membrane remains a problem for clinicians. Hence, this case study was an innovative attempt to evaluate the effect of adjunctive calcium sulfate placement along with collagen membrane GTR-based root coverage procedure. PMID:27307681

  17. Gene modulation associated with inhibition of liver regeneration in hepatitis B virus X transgenic mice

    Institute of Scientific and Technical Information of China (English)

    Malgorzata Sidorkiewicz; Jean-Philippe Jais; Guilherme Tralhao; Serban Morosan; Carlo Giannini; Nicolas Brezillon; Patrick Soussan; Oona Delpuech; Dina Kremsdorf

    2008-01-01

    AIM: To analyze the modulation of gene expression profile associated with inhibition of liver regeneration in hepatitis B X (HBx)-expressing transgenic mice.METHODS: Microarray technology was performed on liver tissue obtained from 4 control (LacZ) and 4 transgenic mice (HBx-LacZ), 48 h after partial hepatectomy. The significance of the normalized log-ratios was assessed for each gene, using robust Mests under an empirical Bayes approach. Microarray hybridization data was verified on selected genes by quantitative PCR.RESULTS: The comparison of gene expression patterns showed a consistent modulation of the expression of 26 genes, most of which are implicated in liver regeneration. Up-regulated genes included DNA repair proteins (Rad-52, MSH6) and transmembrane proteins (syndecan 4, tetraspanin), while down-regulated genes were connected to the regulation of transcription (histone deacetylase, Zfp90, MyoDl) and were involved in the cholesterol metabolic pathway and isoprenoidbiosynthesis (farnesyl diphosphate synthase, Cyp7b1, geranylgeranyl diphosphate synthase, SAA3).CONCLUSION: Our results provide a novel insight into the biological activities of HBx, implicated in the inhibition of liver regeneration.

  18. Novel applications of trophic factors, Wnt and WISP for neuronal repair and regeneration in metabolic disease

    Institute of Scientific and Technical Information of China (English)

    Kenneth Maiese

    2015-01-01

    Diabetes mellitus affects almost 350 million individuals throughout the globe resulting in sig-niifcant morbidity and mortality. Of further concern is the growing population of individuals that remain undiagnosed but are susceptible to the detrimental outcomes of this disorder. Dia-betes mellitus leads to multiple complications in the central and peripheral nervous systems that include cognitive impairment, retinal disease, neuropsychiatric disease, cerebral ischemia, and peripheral nerve degeneration. Although multiple strategies are being considered, novel target-ing of trophic factors, Wnt signaling, Wnt1 inducible signaling pathway protein 1, and stem cell tissue regeneration are considered to be exciting prospects to overcome the cellular mechanisms that lead to neuronal injury in diabetes mellitus involving oxidative stress, apoptosis, and au-tophagy. Pathways that involve insulin-like growth factor-1, ifbroblast growth factor, epidermal growth factor, and erythropoietin can govern glucose homeostasis and are intimately tied to Wnt signaling that involves Wnt1 and Wnt1 inducible signaling pathway protein 1 (CCN4) to foster control over stem cell proliferation, wound repair, cognitive decline,β-cell proliferation, vascular regeneration, and programmed cell death. Ultimately, cellular metabolism through Wnt signal-ing is driven by primary metabolic pathways of the mechanistic target of rapamycin and AMP activated protein kinase. These pathways offer precise biological control of cellular metabolism, but are exquisitely sensitive to the different components of Wnt signaling. As a result, unexpected clinical outcomes can ensue and therefore demand careful translation of the mechanisms that govern neural repair and regeneration in diabetes mellitus.

  19. Novel applications of trophic factors, Wnt and WISP for neuronal repair and regeneration in metabolic disease

    Directory of Open Access Journals (Sweden)

    Kenneth Maiese

    2015-01-01

    Full Text Available Diabetes mellitus affects almost 350 million individuals throughout the globe resulting in significant morbidity and mortality. Of further concern is the growing population of individuals that remain undiagnosed but are susceptible to the detrimental outcomes of this disorder. Diabetes mellitus leads to multiple complications in the central and peripheral nervous systems that include cognitive impairment, retinal disease, neuropsychiatric disease, cerebral ischemia, and peripheral nerve degeneration. Although multiple strategies are being considered, novel targeting of trophic factors, Wnt signaling, Wnt1 inducible signaling pathway protein 1, and stem cell tissue regeneration are considered to be exciting prospects to overcome the cellular mechanisms that lead to neuronal injury in diabetes mellitus involving oxidative stress, apoptosis, and autophagy. Pathways that involve insulin-like growth factor-1, fibroblast growth factor, epidermal growth factor, and erythropoietin can govern glucose homeostasis and are intimately tied to Wnt signaling that involves Wnt1 and Wnt1 inducible signaling pathway protein 1 (CCN4 to foster control over stem cell proliferation, wound repair, cognitive decline,β-cell proliferation, vascular regeneration, and programmed cell death. Ultimately, cellular metabolism through Wnt signaling is driven by primary metabolic pathways of the mechanistic target of rapamycin and AMP activated protein kinase. These pathways offer precise biological control of cellular metabolism, but are exquisitely sensitive to the different components of Wnt signaling. As a result, unexpected clinical outcomes can ensue and therefore demand careful translation of the mechanisms that govern neural repair and regeneration in diabetes mellitus.

  20. Cellular Response to a Novel Fetal Acellular Collagen Matrix: Implications for Tissue Regeneration

    Directory of Open Access Journals (Sweden)

    Robert C. Rennert

    2013-01-01

    Full Text Available Introduction. PriMatrix (TEI Biosciences Inc., Boston, MA, USA is a novel acellular collagen matrix derived from fetal bovine dermis that is designed for use in partial- and full-thickness wounds. This study analyzes the cellular response to PriMatrix in vivo, as well as the ability of this matrix to facilitate normal tissue regeneration. Methods. Five by five mm squares of rehydrated PriMatrix were implanted in a subcutaneous fashion on the dorsum of wild-type mice. Implant site tissue was harvested for histology, immunohistochemistry (IHC, and flow cytometric analyses at multiple time points until day 28. Results. PriMatrix implants were found to go through a biological progression initiated by a transient infiltrate of inflammatory cells, followed by mesenchymal cell recruitment and vascular development. IHC analysis revealed that the majority of the implanted fetal dermal collagen fibers persisted through day 28 but underwent remodeling and cellular repopulation to form tissue with a density and morphology consistent with healthy dermis. Conclusions. PriMatrix implants undergo progressive in vivo remodeling, facilitating the regeneration of histologically normal tissue through a mild inflammatory and progenitor cell response. Regeneration of normal tissue is especially important in a wound environment, and these findings warrant further investigation of PriMatrix in this setting.

  1. Scaffolds and cells for tissue regeneration: different scaffold pore sizes-different cell effects.

    Science.gov (United States)

    Bružauskaitė, Ieva; Bironaitė, Daiva; Bagdonas, Edvardas; Bernotienė, Eiva

    2016-05-01

    During the last decade biomaterial sciences and tissue engineering have become new scientific fields supplying rising demand of regenerative therapy. Tissue engineering requires consolidation of a broad knowledge of cell biology and modern biotechnology investigating biocompatibility of materials and their application for the reconstruction of damaged organs and tissues. Stem cell-based tissue regeneration started from the direct cell transplantation into damaged tissues or blood vessels. However, it is difficult to track transplanted cells and keep them in one particular place of diseased organ. Recently, new technologies such as cultivation of stem cell on the scaffolds and subsequently their implantation into injured tissue have been extensively developed. Successful tissue regeneration requires scaffolds with particular mechanical stability or biodegradability, appropriate size, surface roughness and porosity to provide a suitable microenvironment for the sufficient cell-cell interaction, cell migration, proliferation and differentiation. Further functioning of implanted cells highly depends on the scaffold pore sizes that play an essential role in nutrient and oxygen diffusion and waste removal. In addition, pore sizes strongly influence cell adhesion, cell-cell interaction and cell transmigration across the membrane depending on the various purposes of tissue regeneration. Therefore, this review will highlight contemporary tendencies in application of non-degradable scaffolds and stem cells in regenerative medicine with a particular focus on the pore sizes significantly affecting final recover of diseased organs. PMID:26091616

  2. Dental Pulp Stem Cells as a multifaceted tool for bioengineering and the regeneration of craniomaxillofacial tissues

    Directory of Open Access Journals (Sweden)

    Maitane eAurrekoetxea

    2015-10-01

    Full Text Available Dental pulp stem cells, or DPSC, are neural crest-derived cells with an outstanding capacity to differentiate along multiple cell lineages of interest for cell therapy. In particular, highly efficient osteo/dentinogenic differentiation of DPSC can be achieved using simple in vitro protocols, making these cells a very attractive and promising tool for the future treatment of dental and periodontal diseases. Among craniomaxillofacial organs, the tooth and salivary gland are two such cases in which complete regeneration by tissue engineering using DPSC appears to be possible, as research over the last decade has made substantial progress in experimental models of partial or total regeneration of both organs, by cell recombination technology. Moreover, DPSC seem to be a particularly good choice for the regeneration of nerve tissues, including injured or transected cranial nerves. In this context, the oral cavity appears to be an excellent testing ground for new regenerative therapies using DPSC. However, many issues and challenges need yet to be addressed before these cells can be employed in clinical therapy. In this review, we point out some important aspects on the biology of DPSC with regard to their use for the reconstruction of different craniomaxillofacial tissues and organs, with special emphasis on cranial bones, nerves, teeth, and salivary glands. We suggest new ideas and strategies to fully exploit the capacities of DPSC for bioengineering of the aforementioned tissues.

  3. Dental pulp stem cells as a multifaceted tool for bioengineering and the regeneration of craniomaxillofacial tissues.

    Science.gov (United States)

    Aurrekoetxea, Maitane; Garcia-Gallastegui, Patricia; Irastorza, Igor; Luzuriaga, Jon; Uribe-Etxebarria, Verónica; Unda, Fernando; Ibarretxe, Gaskon

    2015-01-01

    Dental pulp stem cells, or DPSC, are neural crest-derived cells with an outstanding capacity to differentiate along multiple cell lineages of interest for cell therapy. In particular, highly efficient osteo/dentinogenic differentiation of DPSC can be achieved using simple in vitro protocols, making these cells a very attractive and promising tool for the future treatment of dental and periodontal diseases. Among craniomaxillofacial organs, the tooth and salivary gland are two such cases in which complete regeneration by tissue engineering using DPSC appears to be possible, as research over the last decade has made substantial progress in experimental models of partial or total regeneration of both organs, by cell recombination technology. Moreover, DPSC seem to be a particularly good choice for the regeneration of nerve tissues, including injured or transected cranial nerves. In this context, the oral cavity appears to be an excellent testing ground for new regenerative therapies using DPSC. However, many issues and challenges need yet to be addressed before these cells can be employed in clinical therapy. In this review, we point out some important aspects on the biology of DPSC with regard to their use for the reconstruction of different craniomaxillofacial tissues and organs, with special emphasis on cranial bones, nerves, teeth, and salivary glands. We suggest new ideas and strategies to fully exploit the capacities of DPSC for bioengineering of the aforementioned tissues. PMID:26528190

  4. In-vitro regeneration studies of an important legume, Cicer arietinum: Hurdles and future prospects

    Directory of Open Access Journals (Sweden)

    Pragati Kumari

    2015-06-01

    Full Text Available There are several economically important grain legumes including chickpea that play significant role in nutrition of the rural and urban poor in developing world. Plants are subjected to a large number of stresses that may interfere with the normal growth and development. The model legumes are being developed as experimental systems to study a number of key biological questions using molecular tools including genomics and proteomics. Most of the functional genomics approaches rely upon the highthroughput transformation system useful for studying various gene identification strategies. The difficulty to transform a plant varies from species to species in legumes. There is limited success in exchange of the desirable characters by the classical and modern breeding technologies, in important pulse crop chickpea and biotechnological tools like plant tissue culture and genetic transformation techniques have emerged as a potential supplement. The major bottleneck is requirement of an in vitro manipulation of leguminosae members and the availability of reproducible, efficient and better plant regeneration methods. The regeneration and transformation of legumes particularly chickpea suffers due to recalcitrant nature towards rooting and transplantation of the in vitro regenerated plants. This becomes a limiting factor for the application of this technology towards designated mandate of crop improvement programs. This article discusses the hurdles and strategies for transformation of legumes in general and chickpea in particular.

  5. Ultraviolet irradiation initiates ectopic foot formation in regenerating hydra and promotes budding

    Indian Academy of Sciences (India)

    Saroj S Ghaskadbi; Leena Shetye; Shashi Chiplonkar; Surendra Ghaskadbi

    2005-03-01

    We have studied the effects of ultraviolet-C (UVC) and Ultraviolet-B (UVB) on growth and pattern formation in Pelmatohydra oligactis. UVC brings about a significant increase in budding in intact hydra while UVB does not exhibit such an effect. Excessive budding could be a response for survival at wavelengths that damage biological tissues. If the head or base piece of a bisected hydra is irradiated and recombined with the unirradiated missing part, regeneration proceeds normally indicating that exposure of a body part with either an intact head or foot to UVC does not influence pattern formation. Most significantly, in the middle piece, but not in the head or the base piece of a trisected hydra, UVC leads to initiation of ectopic feet formation in almost one third of the cases. Thus, UV irradiation interferes with pattern formation in regenerating hydra, possibly by changing positional values, and promotes budding in intact hydra. This is the first report on induction of ectopic feet formation by UV in regenerating hydra and opens up the possibility of using UV irradiation as a tool to understand pattern formation in the enigmatic hydra.

  6. Histomorphological evaluation of Compound bone of Granulated Ricinus in bone regeneration in rabbits

    International Nuclear Information System (INIS)

    Histological evaluation is an effective method in the behavioral description of the qualitative and quantitative implanted materials. The research validated the performance of Compound bone of Granulated Ricinus on bone regeneration with the histomorphological analysis results. Were selected 30 rabbits, females, divided into 3 groups of 10 animals (G1, G2, G3) with a postoperative time of 45, 70 and 120 days respectively. Each animal is undergone 2 bone lesions in the ilium, one implemented in the material: Compound bone of Granulated Ricinus and the other for control. After the euthanasia, the iliac bone was removed, identified and subjected to histological procedure. The evaluation histological, histomorphological results were interpreted and described by quantitative and qualitative analysis based facts verified in the three experimental groups evaluating the rate of absorption of the material in the tissue regeneration, based on the neo-bone formation. The histomorphologic results classified as a material biocompatible and biologically active. Action in regeneration by bone resorption occurs slowly and gradually. Knowing the time and rate of absorption and neo-formation bone biomaterial, which can be determined in the bone segment applicable in the clinical surgical area.

  7. In situ regeneration of bioactive coatings enabled by an evolved Staphylococcus aureus sortase A.

    Science.gov (United States)

    Ham, Hyun Ok; Qu, Zheng; Haller, Carolyn A; Dorr, Brent M; Dai, Erbin; Kim, Wookhyun; Liu, David R; Chaikof, Elliot L

    2016-01-01

    Surface immobilization of bioactive molecules is a central paradigm in the design of implantable devices and biosensors with improved clinical performance capabilities. However, in vivo degradation or denaturation of surface constituents often limits the long-term performance of bioactive films. Here we demonstrate the capacity to repeatedly regenerate a covalently immobilized monomolecular thin film of bioactive molecules through a two-step stripping and recharging cycle. Reversible transpeptidation by a laboratory evolved Staphylococcus aureus sortase A (eSrtA) enabled the rapid immobilization of an anti-thrombogenic film in the presence of whole blood and permitted multiple cycles of film regeneration in vitro that preserved its biological activity. Moreover, eSrtA transpeptidation facilitated surface re-engineering of medical devices in situ after in vivo implantation through removal and restoration film constituents. These studies establish a rapid, orthogonal and reversible biochemical scheme to regenerate selective molecular constituents with the potential to extend the lifetime of bioactive films. PMID:27073027

  8. Exosomes isolation protocols: facts and artifacts for cardiac regeneration.

    Science.gov (United States)

    Angelini, Francesco; Ionta, Vittoria; Rossi, Fabrizio; Pagano, Francesca; Chimenti, Isotta; Messina, Elisa; Giacomello, Alessandro

    2016-01-01

    In recent years, exosomes have attracted increasing scientific interest and are no longer considered just as containers for cell waste, but as important mediators of intercellular communication. Among many biomedical research topics, a possible direct role of exosomes in the regenerative medicine field has been underlined in recent studies, including those regarding the so called "paracrine hypothesis". In this perspective, a therapeutic role and/or use of exosomes for tissue regeneration seems to be plausible. However, the majority of the cells isolated and cultured in vitro are exposed to an exogenous exosomes source because of the wide use of foetal bovine serum as cell culture supplement. Bovine serum has been gradually considered as a major biological stimulus, but with still unknown outcome. In this review, we present the state of the art about the role of exosomes in regenerative medicine, particularly for the cardiovascular system. We also analyse the most commonly used exosome isolation techniques that, since their discovery, have undergone continuous development to reach the highest degree of scalability for future clinical translation. PMID:27100708

  9. Healing Osteoarthritis: Engineered Proteins Created for Therapeutic Cartilage Regeneration

    Directory of Open Access Journals (Sweden)

    Kevin M. Cherry

    2012-01-01

    Full Text Available Millions of people worldwide are afflicted with painfulosteoarthritis, which is characterized by degradationof articular cartilage found in major joints such as thehip or knee. Symptoms include inflammation, pain,and decreased mobility. Because cartilage has a limitedability to self-heal, researchers have focused efforts onmethods that trigger cartilage regeneration. Our approachis to develop an injectable, protein-based hydrogel withmechanical properties analogous to healthy articularcartilage. The hydrogel provides an environment for cellgrowth and stimulates new tissue formation. We utilizedrecombinant DNA technology to create multifunctional,elastomeric proteins. The recombinant proteins weredesigned with biologically active domains to influence cellbehavior and resilin structural domains that mimic thestiffness of native cartilage. Resilin, a protein found in thewing and leg joints of mosquitoes, provided inspiration forthe mechanical domain in the recombinant protein. Thenew resilin-based protein was expressed in E. coli bacteria.Forming hydrogels requires a large quantity of engineeredprotein, so parameters such as bacterial host, incubationtemperature, expression time, and induction method wereoptimized to increase the protein yield. Using salt toprecipitate the protein and exploiting resilin’s heat stability,27 mg/L of recombinant protein was recovered at 95%purity. The protein expression and purification protocolswere established by analyzing experimental samples onSDS-PAGE gels and by Western blotting. The mechanicalproperties and interactions with stem cells are currentlybeing evaluated to assess the potential of the resilin-basedhydrogel as a treatment for osteoarthritis.

  10. A metabolic link to skeletal muscle wasting and regeneration

    Directory of Open Access Journals (Sweden)

    René eKoopman

    2014-02-01

    Full Text Available Due to its essential role in movement, insulating the internal organs, generating heat to maintain core body temperature, and acting as a major energy storage depot, any impairment to skeletal muscle structure and function may lead to an increase in both morbidity and mortality. In the context of skeletal muscle, altered metabolism is directly associated with numerous pathologies and disorders, including diabetes, and obesity, while many skeletal muscle pathologies have secondary changes in metabolism, including cancer cachexia, sarcopenia and the muscular dystrophies. Furthermore, the importance of cellular metabolism in the regulation of skeletal muscle stem cells is beginning to receive significant attention. Thus, it is clear that skeletal muscle metabolism is intricately linked to the regulation of skeletal muscle mass and regeneration. The aim of this review is to discuss some of the recent findings linking a change in metabolism to changes in skeletal muscle mass, as well as describing some of the recent studies in developmental, cancer and stem-cell biology that have identified a role for cellular metabolism in the regulation of stem cell function, a process termed ‘metabolic reprogramming’.

  11. 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.

  12. Orthopaedic Interface Tissue Engineering for the Biological Fixation of Soft Tissue Grafts

    OpenAIRE

    Moffat, Kristen L.; Wang, I-Ning Elaine; Rodeo, Scott A.; Lu, Helen H.

    2009-01-01

    Interface tissue engineering is a promising new strategy aimed at the regeneration of tissue interfaces and ultimately enabling the biological fixation of soft tissue grafts utilized in orthopaedic repair and sports medicine. Many ligaments and tendons with direct insertions into subchondral bone exhibit a complex enthesis consisting of several distinct yet continuous regions of soft tissue, noncalcified fibrocartilage, calcified fibrocartilage and bone. Regeneration of this multi-tissue inte...

  13. Electrospun micro- and nanofiber tubes for functional nervous regeneration in sciatic nerve transections

    Directory of Open Access Journals (Sweden)

    Amadio Stefano

    2008-04-01

    Full Text Available Abstract Background Although many nerve prostheses have been proposed in recent years, in the case of consistent loss of nervous tissue peripheral nerve injury is still a traumatic pathology that may impair patient's movements by interrupting his motor-sensory pathways. In the last few decades tissue engineering has opened the door to new approaches;: however most of them make use of rigid channel guides that may cause cell loss due to the lack of physiological local stresses exerted over the nervous tissue during patient's movement. Electrospinning technique makes it possible to spin microfiber and nanofiber flexible tubular scaffolds composed of a number of natural and synthetic components, showing high porosity and remarkable surface/volume ratio. Results In this study we used electrospun tubes made of biodegradable polymers (a blend of PLGA/PCL to regenerate a 10-mm nerve gap in a rat sciatic nerve in vivo. Experimental groups comprise lesioned animals (control group and lesioned animals subjected to guide conduits implantated at the severed nerve stumps, where the tubular scaffolds are filled with saline solution. Four months after surgery, sciatic nerves failed to reconnect the two stumps of transected nerves in the control animal group. In most of the treated animals the electrospun tubes induced nervous regeneration and functional reconnection of the two severed sciatic nerve tracts. Myelination and collagen IV deposition have been detected in concurrence with regenerated fibers. No significant inflammatory response has been found. Neural tracers revealed the re-establishment of functional neuronal connections and evoked potential results showed the reinnervation of the target muscles in the majority of the treated animals. Conclusion Corroborating previous works, this study indicates that electrospun tubes, with no additional biological coating or drug loading treatment, are promising scaffolds for functional nervous regeneration. They

  14. Establishment of high frequency shoot regeneration system in Himalayan poplar (Populus ciliata Wall. ex Royle) from petiole explants using Thidiazuron cytokinin as plant growth regulator

    Institute of Scientific and Technical Information of China (English)

    G Aggarwal; A Gaur; D K Srivastava

    2015-01-01

    Populus species are important resources for industry and in scientific study on biological and agricul-tural systems. Our objective was to enhance the frequency of plant regeneration in Himalayan poplar (Populus ciliata wall. ex Royle). The effect of TDZ alone and in combi-nation with adenine and NAA was studied on the regen-eration potential of petiole explants. The explants were excised from Himalayan poplar plants grown in glass-houses. After surface sterilization the explants were cul-tured on shoot induction medium. High percentage shoot regeneration (86%) was recorded on MS medium sup-plemented with 0.004 mg L-1 TDZ and 79.7 mg L-1 adenine. The regenerated shoots for elongation and multi-plication were transferred to MS ? 0.5 mg L-1 BAP ? 0.2 mg L-1 IAA ? 0.3 mg L-1 GA3. Root re-generation from shoots developed in vitro was observed on MS medium supplemented with 0.10 mg L-1 IBA. Hi-malayan poplar plantlets could be produced within 2 months after acclimatization in a sterile mixture of sand and soil. We developed a high efficiency plant regeneration protocol from petiole explants of P. ciliata.

  15. Neural Ablation and Regeneration in Pain Practice.

    Science.gov (United States)

    Choi, Eun Ji; Choi, Yun Mi; Jang, Eun Jung; Kim, Ju Yeon; Kim, Tae Kyun; Kim, Kyung Hoon

    2016-01-01

    A nerve block is an effective tool for diagnostic and therapeutic methods. If a diagnostic nerve block is successful for pain relief and the subsequent therapeutic nerve block is effective for only a limited duration, the next step that should be considered is a nerve ablation or modulation. The nerve ablation causes iatrogenic neural degeneration aiming only for sensory or sympathetic denervation without motor deficits. Nerve ablation produces the interruption of axonal continuity, degeneration of nerve fibers distal to the lesion (Wallerian degeneration), and the eventual death of axotomized neurons. The nerve ablation methods currently available for resection/removal of innervation are performed by either chemical or thermal ablation. Meanwhile, the nerve modulation method for interruption of innervation is performed using an electromagnetic field of pulsed radiofrequency. According to Sunderland's classification, it is first and foremost suggested that current neural ablations produce third degree peripheral nerve injury (PNI) to the myelin, axon, and endoneurium without any disruption of the fascicular arrangement, perineurium, and epineurium. The merit of Sunderland's third degree PNI is to produce a reversible injury. However, its shortcoming is the recurrence of pain and the necessity of repeated ablative procedures. The molecular mechanisms related to axonal regeneration after injury include cross-talk between axons and glial cells, neurotrophic factors, extracellular matrix molecules, and their receptors. It is essential to establish a safe, long-standing denervation method without any complications in future practices based on the mechanisms of nerve degeneration as well as following regeneration. PMID:26839664

  16. Fiber optic-based regenerable biosensor

    Science.gov (United States)

    Sepaniak, Michael J.; Vo-Dinh, Tuan

    1993-01-01

    A fiber optic-based regenerable biosensor. The biosensor is particularly suitable for use in microscale work in situ. In one embodiment, the biosensor comprises a reaction chamber disposed adjacent the distal end of a waveguide and adapted to receive therein a quantity of a sample containing an analyte. Leading into the chamber is a plurality of capillary conduits suitable for introducing into the chamber antibodies or other reagents suitable for selective interaction with a predetermined analyte. Following such interaction, the contents of the chamber may be subjected to an incident energy signal for developing fluorescence within the chamber that is detectable via the optical fiber and which is representative of the presence, i.e. concentration, of the selected analyte. Regeneration of the biosensor is accomplished by replacement of the reagents and/or the analyte, or a combination of these, at least in part via one or more of the capillary conduits. The capillary conduits extend from their respective terminal ends that are in fluid communication with the chamber, away from the chamber to respective location(s) remote from the chamber thereby permitting in situ location of the chamber and remote manipulation and/or analysis of the activity with the chamber.

  17. Telocytes in cardiac regeneration and repair.

    Science.gov (United States)

    Bei, Yihua; Zhou, Qiulian; Sun, Qi; Xiao, Junjie

    2016-07-01

    Telocytes (TCs) are a novel type of stromal cells reported by Popescu's group in 2010. The unique feature that distinguishes TCs from other "classical" stromal cells is their extremely long and thin telopodes (Tps). As evidenced by electron microscopy, TCs are widely distributed in almost all tissues and organs. TCs contribute to form a three-dimensional interstitial network and play as active regulators in intercellular communication via homocellular/heterocellular junctions or shed vesicles. Interestingly, increasing evidence suggests the potential role of TCs in regenerative medicine. Although the heart retains some limited endogenous regenerative capacity, cardiac regenerative and repair response is however insufficient to make up the loss of cardiomyocytes upon injury. Developing novel strategies to increase cardiomyocyte renewal and repair is of great importance for the treatment of cardiac diseases. In this review, we focus on the role of TCs in cardiac regeneration and repair. We particularly describe the intercellular communication between TCs and cardiomyocytes, stem/progenitor cells, endothelial cells, and fibroblasts. Also, we discuss the current knowledge about TCs in cardiac repair after myocardial injury, as well as their potential roles in cardiac development and aging. TC-based therapy or TC-derived exosome delivery might be used as novel therapeutic strategies to promote cardiac regeneration and repair. PMID:26826525

  18. Urinary proteomic profiling reveals diclofenac-induced renal injury and hepatic regeneration in mice

    International Nuclear Information System (INIS)

    Diclofenac (DF) is a widely used non-steroidal anti-inflammatory drug for the treatment of rheumatic disorders, but is often associated with liver injury. We applied urinary proteomic profiling using MALDI-TOF MS to identify biomarkers for DF-induced hepatotoxicity in mice. Female CH3/HeOUJIco mice were treated with 75 mg/kg bw DF by oral gavage and 24 h urine was collected. Proteins identified in urine of DF-treated mice included epidermal growth factor, transthyretin, kallikrein, clusterin, fatty acid binding protein 1 and urokinase, which are related to liver regeneration but also to kidney injury. Both organs showed enhanced levels of oxidative stress (TBARS, p < 0.01). Kidney injury was confirmed by histology and increased Kim1 and Il-6 mRNA expression levels (p < 0.001 and p < 0.01). Liver histology and plasma ALT levels in DF-treated mice were not different from control, but mRNA expression of Stat3 (p < 0.001) and protein expression of PCNA (p < 0.05) were increased, indicating liver regeneration. In conclusion, urinary proteome analysis revealed that DF treatment in mice induced kidney and liver injury. Within 24 h, however, the liver was able to recover by activating tissue regeneration processes. Hence, the proteins found in urine of DF-treated mice represent kidney damage rather than hepatic injury. - Highlights: • The urinary proteome shows biological processes involved in adverse drug reactions. • Urine proteins of DF-treated mice relate to kidney injury rather than liver injury. • Liver regeneration, not liver injury, is apparent 24h after oral DF administration. • Pretreatment with LPS does not enhance DF-induced liver injury in mice

  19. Urinary proteomic profiling reveals diclofenac-induced renal injury and hepatic regeneration in mice

    Energy Technology Data Exchange (ETDEWEB)

    Swelm, Rachel P.L. van [Department of Pharmacology and Toxicology, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen (Netherlands); Laarakkers, Coby M.M. [Department of Laboratory Medicine, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen (Netherlands); Pertijs, Jeanne C.L.M.; Verweij, Vivienne; Masereeuw, Rosalinde [Department of Pharmacology and Toxicology, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen (Netherlands); Russel, Frans G.M., E-mail: F.Russel@pharmtox.umcn.nl [Department of Pharmacology and Toxicology, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen (Netherlands)

    2013-06-01

    Diclofenac (DF) is a widely used non-steroidal anti-inflammatory drug for the treatment of rheumatic disorders, but is often associated with liver injury. We applied urinary proteomic profiling using MALDI-TOF MS to identify biomarkers for DF-induced hepatotoxicity in mice. Female CH3/HeOUJIco mice were treated with 75 mg/kg bw DF by oral gavage and 24 h urine was collected. Proteins identified in urine of DF-treated mice included epidermal growth factor, transthyretin, kallikrein, clusterin, fatty acid binding protein 1 and urokinase, which are related to liver regeneration but also to kidney injury. Both organs showed enhanced levels of oxidative stress (TBARS, p < 0.01). Kidney injury was confirmed by histology and increased Kim1 and Il-6 mRNA expression levels (p < 0.001 and p < 0.01). Liver histology and plasma ALT levels in DF-treated mice were not different from control, but mRNA expression of Stat3 (p < 0.001) and protein expression of PCNA (p < 0.05) were increased, indicating liver regeneration. In conclusion, urinary proteome analysis revealed that DF treatment in mice induced kidney and liver injury. Within 24 h, however, the liver was able to recover by activating tissue regeneration processes. Hence, the proteins found in urine of DF-treated mice represent kidney damage rather than hepatic injury. - Highlights: • The urinary proteome shows biological processes involved in adverse drug reactions. • Urine proteins of DF-treated mice relate to kidney injury rather than liver injury. • Liver regeneration, not liver injury, is apparent 24h after oral DF administration. • Pretreatment with LPS does not enhance DF-induced liver injury in mice.

  20. The importance of fibronectin in development, regeneration and treatment: review article

    Directory of Open Access Journals (Sweden)

    Arash Abdolmaleki

    2015-08-01

    Full Text Available Fibronectin (FN is one of the essential component of the extra cellular matrix and their important role is as regulator of cellular activities and also fibronectin is an important scaffold for maintaining tissue. Fibronectin conformational changes expose additional binding sites that participate in fibril formation and in conversion of fibrils into a stabilized, insoluble form. In fact fibronectin is a connected glycoprotein disulfide dimer with sedimentation coefficient of approximately S 13 and 440 kDa molecular mass which is exist in many extracellular matrix and plasma with concentration of approximately 300 µg/ml that during the regeneration body tissues acts in severely regulated stages until regenerate the damaged tissue. Fibronectin has domains for interacting with other extra cellular matrix proteins, cell surface receptors, glycosaminoglycans (GAGs, and other FN molecules. This combination of domains allows FNs to bind simultaneously to cells and to molecules within the surrounding matrix. Also fibronectin have binding sites for collagen/ gelatin, heparin, fibrinogen, and other molecules. In the present study important roles of fibronectin in development, regeneration especially in nerves system and important role of it in treatment of some diseases have been reviewed. Present study has reviewed 77 publications by using of PubMed, NCBI, Elsevier, EBSCO and Nature databases for describing the important roles of fibronectin in biological systems. Studies have shown that fibronectin has diverse roles such as: cellular adhesion, embryonic differentiation, assembly of extra cellular matrix, connecting and cell growth, transformation as well as cell migration that each of this roles depends to fibronectins action site. Considering the important role of fibronectin in attachment of cancer cells to basal lamina, spread neoplasm, tissue regeneration and formation of extra cellular matrix better identification the properties as well as

  1. Emerging regenerative approaches for periodontal reconstruction: a systematic review from the AAP Regeneration Workshop.

    Science.gov (United States)

    Lin, Zhao; Rios, Hector F; Cochran, David L

    2015-02-01

    More than 30 years have passed since the first successful application of regenerative therapy for treatment of periodontal diseases. Despite being feasible, periodontal regeneration still faces numerous challenges, and complete restoration of structure and function of the diseased periodontium is often considered an unpredictable task. This review highlights developing basic science and technologies for potential application to achieve reconstruction of the periodontium. A comprehensive search of the electronic bibliographic database PubMed was conducted to identify different emerging therapeutic approaches reported to influence either biologic pathways and/or tissues involved in periodontal regeneration. Each citation was assessed based on its abstract, and the full text of potentially eligible reports was retrieved. Based on the review of the full papers, their suitability for inclusion in this report was determined. In principle, only reports from scientifically well-designed studies that presented preclinical in vivo (animal studies) or clinical (human studies) evidence for successful periodontal regeneration were included. Hence, in vitro studies, namely those conducted in laboratories without any live animals, were excluded. In case of especially recent and relevant reviews with a narrow focus on specific regenerative approaches, they were identified as such, and thereby the option of referring to them to summarize the status of a specific approach, in addition to or instead of listing each separately, was preserved. Admittedly, the presence of subjectivity in the selection of studies to include in this overview cannot be excluded. However, it is believed that the contemporary approaches described in this review collectively represent the current efforts that have reported preclinical or clinical methods to successfully enhance regeneration of the periodontium. Today's challenges facing periodontal regenerative therapy continue to stimulate important research

  2. Microwave assisted regeneration of soot filters

    International Nuclear Information System (INIS)

    Full text: Air pollution is a 'hot' issue nowadays, especially in metropolitan and heavily industrialized areas. Vehicular emissions are the largest source of atmospheric aerosols in metropolitan areas. The strong environmental legislation on gaseous emissions, both from gasoline and diesel engines, demands an urgent solution to eliminate the particulates and soot emission by vehicles, especially Diesel engines. There are several techniques available for elimination of soot emission, such as the use of cerium based fuel additives. A more conventional approach is of soot filters. The most important issue in using this technology is the regeneration of the filters after the soot particles are trapped. Self-regeneration is not usually possible due to high ignition temperature of Diesel soot. Despite the use of catalysts, in-situ regeneration of these filter elements is not always possible at the conventional operation temperature, in which case filter or exhaust heating is required. Currently, we have assessed the feasibility of using a microwave sensitive, catalytic material as a filter coating, thus allowing in-situ regeneration of the soot filter by exposing it periodically to a dielectric field. Microwave technique has distinct advantages of instantaneous operation, direct heating and fast switch on and off. Ideal susceptor materials for the present purpose are at the same time oxidation catalysts, thereby eliminating the need for additional combustion of any hydrocarbons present in the gas phase or carbon monoxide formed during soot combustion. Therefore we have opted to use La-M-Mn (M= Ce, Mg, Ca, Sr and Ba) based perovskites, as a potentially suitable coating material. These perovskites can be represented with the general structural formula AA'BO3. The substitution of A or B metal cations can be employed to systematically change the catalytic properties and possibly also the dielectric properties et-up. The structural properties of these perovskites have been

  3. A critical role for matrix metal loproteinases in liver regeneration

    NARCIS (Netherlands)

    Alwayn, Ian P. J.; Verbesey, Jennifer E.; Kim, Sendia; Roy, Roopali; Arsenault, Danielle A.; Greene, Arin K.; Novak, Katherine; Laforme, Andrea; Lee, Sang; Moses, Marsha A.; Puder, Mark

    2008-01-01

    Background. Matrix metalloproteinases (MMPs), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6) are mediators of liver regeneration. To determine whether MMPs are required for normal hepatic regeneration, we performed 67% hepatectomies on mice treated with a broad-spectrum MMP-inhibi

  4. Mobilising voluntary contributions in public urban regeneration – a review

    DEFF Research Database (Denmark)

    Larsen, Jacob Norvig; Jensen, Jesper Ole; Agger, Annika

    projects and associations be transferred to the context of publicly initiated urban regeneration?’ and ‘Does the urban regeneration offer potentials for developing voluntarism addressing problems in the local area?’. The paper is based on a review of literature on volunteerism, particularly in relation to...

  5. Advances in understanding the mechanism of zebrafish heart regeneration

    Directory of Open Access Journals (Sweden)

    Kazu Kikuchi

    2014-11-01

    Full Text Available The adult mammalian heart was once believed to be a post-mitotic organ without any capacity for regeneration, but recent findings have challenged this dogma. A modified view assigns the mammalian heart a measurable capacity for regeneration throughout its lifetime, with the implication that endogenous regenerative capacity can be therapeutically stimulated in the injury setting. Although extremely limited in adult mammals, the natural capacity for organ regeneration is a conserved trait in certain vertebrates. Urodele amphibians and teleosts are well-known examples of such animals that can efficiently regenerate various organs including the heart as adults. By understanding how these animals regenerate a damaged heart, one might obtain valuable insights into how regeneration can be augmented in injured human hearts. Among the regenerative vertebrate models, the teleost zebrafish, Danio rerio, is arguably the best characterized with respect to cardiac regenerative responses. Knowledge is still limited, but a decade of research in this model has led to results that may help to understand how cardiac regeneration is naturally stimulated and maintained. This review surveys recent advances in the field and discusses current understanding of the endogenous mechanisms of cardiac regeneration in zebrafish.

  6. Electro-assisted regeneration of ion exchange resins

    Institute of Scientific and Technical Information of China (English)

    Zhigang LIU; Ying WANG; Yansheng LI; Hui CHANG

    2008-01-01

    Electro-assisted regeneration (EAR) for the mixed bed of strongly acidic cation and weakly basic anion exchange resins with the Al(OH)3 suspension in a three-compartment cell was investigated. The desalina-tion experiments were carried out to evaluate the char-acteristic of the regenerated mixed resins. Experimental results showed that the efficiency of resin regeneration was strictly dependent on the voltage, regeneration time, and feed regenerant flow rate. The amount of the effluent reached 50 times the volume of the resins bed, and the conductivity was less than 1.0 μs/cm. Compared to the conventional ER, the total effluent volume of EAR was about 1000 mL more than that of ER under the same conditions, and the outlet conductivity was significantly lower. The desalination and regeneration reaction mechanisms of the mixed resins indicated the regeneration efficiency of resin with Al(OH)3 as the regenerant was much higher than that with H2O.

  7. A Comprehensive Transcriptomic and Proteomic Analysis of Hydra Head Regeneration.

    Science.gov (United States)

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

    2015-08-01

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

  8. Iodine laser with repeated use of a regenerated mixture

    Energy Technology Data Exchange (ETDEWEB)

    Gavrilina, L.K.; Katulin, V.A.; Korzhavina, N.N.; Leonov, Y.S.; Morozov, Y.I.; Nosach, V.Y.; Petrov, A.L.

    1979-07-01

    An iodine laser is described, pumped by radiation from an open high-current discharge and having a system for regenerating the spent mixture. The regeneration system makes it possible to reuse the SF/sub 6/ buffer gas many times, and it can be included in a closed cycle for replacing the active mixture in the laser chamber with a multiple discharge system.

  9. Effects of regenerator geometry on pulse tube refrigerator performance.

    Science.gov (United States)

    Lewis, M; Kuriyama, T; Xiao, J H; Radebaugh, R

    1998-01-01

    This paper gives results of the cooling performance of a double-inlet pulse tube refrigerator using various regenerators. The same pulse tube was used for all the experiments and measured 4.76 mm in diameter and 46.2 mm in length. A commercial linear compressor with a swept volume of 4 cm3 was used in these experiments. The operating conditions were held constant at a mean pressure of 2.0 MPa and a frequency of 54 Hz. Using finite difference software called REGEN3.1, developed at NIST, and recent experiment results, we optimized a series of regenerators based on dimensions, materials and screen packing. The values used for calculating the thermal conduction through stacked screens by REGEN3.1 were based on recent experimental results from NIST. The regenerator tubes were designed using 316 stainless steel and titanium materials. The regenerator matrices investigated were 400-mesh and 500-mesh stainless steel screen. The valve settings for both orifices were adjusted to minimize the no-load temperature for all regenerators. A cooling capacity curve from 0 to 3 W was also determined. The performance of the pulse tube refrigerator using the different regenerators is discussed. The experimental results from the various regenerators are evaluated and compared with their corresponding numerically calculated coefficient of performance (COP) and regenerator design as determined by REGEN3.1. PMID:11543212

  10. A Monolithic Perovskite Structure for Use as a Magnetic Regenerator

    DEFF Research Database (Denmark)

    Pryds, Nini; Clemens, Frank; Menon, Mohan; Nielsen, Pernille Hedemark; Brodersen, Karen; Bjørk, Rasmus; Bahl, Christian Robert Haffenden; Engelbrecht, Kurt; Nielsen, Kaspar Kirstein; Smith, Anders

    2011-01-01

    A La0.67Ca0.26Sr0.07Mn1.05O3 (LCSM) perovskite was prepared for the first time as a ceramic monolithic regenerator used in a regenerative magnetic refrigeration device. The parameters influencing the extrusion process and the performance of the regenerator, such as the nature of the monolith paste...

  11. Human regeneration: An achievable goal or a dream?

    Indian Academy of Sciences (India)

    Sukla Ghosh

    2016-03-01

    The main objective of regenerative medicine is to replenish cells or tissues or even to restore different body parts that are lost or damaged due to disease, injury and aging. Several avenues have been explored over many decades to address the fascinating problem of regeneration at the cell, tissue and organ levels. Here we discuss some of the primary approaches adopted by researchers in the context of enhancing the regenerating ability of mammals. Natural regeneration can occur in different animal species, and the underlying mechanism is highly relevant to regenerative medicine-based intervention. Significant progress has been achieved in understanding the endogenous regeneration in urodeles and fishes with the hope that they could help to reach our goal of designing future strategies for human regeneration.

  12. Role of metallothioneins in peripheral nerve function and regeneration

    DEFF Research Database (Denmark)

    Ceballos, D; Lago, N; Verdú, E; Penkowa, M; Carrasco, J; Navarro, X; Palmiter, R D; Hidalgo, J

    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...

  13. Serial analysis of gene expression (SAGE) in rat liver regeneration

    International Nuclear Information System (INIS)

    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

  14. Numerical modeling and analysis of the active magnetic regenerator

    DEFF Research Database (Denmark)

    Nielsen, Kaspar Kirstein

    In this thesis the active magnetic regenerator (AMR) is analyzed using various numerical tools and experimental devices. A 2-dimensional transient numerical model of the AMR is developed and implemented and it is used to investigate the in uence of a range of parameters on the performance of the...... investigated using the numerical AMR model. The results show indeed that the performance may be enhanced signicantly and it may thus be concluded that the performance of the AMR is dependent on a vast number of parameters (material composition, magnetic eld source, regenerator geometry, regenerator eciency...... 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...

  15. Delayed liver regeneration after partial hepatectomy in adiponectin knockout mice

    International Nuclear Information System (INIS)

    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.

  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 genetic regulation of the terminating phase of liver regeneration

    DEFF Research Database (Denmark)

    Nygård, Ingvild E.; Mortensen, Kim E.; Hedegaard, Jakob;

    2012-01-01

    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 the...... involvement of the caspase system at this time. Zinc Finger Protein (ZNF490) gene, with a potential negative effect on cell cycle progression, was only up-regulated at three and six weeks after PHx indicating a central role at this time. TGF-β regulation was not found to be significantly affected in the...... terminating phase of liver regeneration. Vasohibin 2 (VASH2) was down-regulated towards the end of regeneration, and may indicate a role in preventing a continued vascularization process. Conclusions CARD11, ZNF490 and VASH2 are differentially expressed in the termination phase of liver regeneration. The lack...

  18. Biological Oceanography

    Science.gov (United States)

    Abbott, M. R.

    1984-01-01

    Within the framework of global biogeochemical cycles and ocean productivity, there are two areas that will be of particular interest to biological oceanography in the 1990s. The first is the mapping in space time of the biomass and productivity of phytoplankton in the world ocean. The second area is the coupling of biological and physical processes as it affects the distribution and growth rate of phytoplankton biomass. Certainly other areas will be of interest to biological oceanographers, but these two areas are amenable to observations from satellites. Temporal and spatial variability is a regular feature of marine ecosystems. The temporal and spatial variability of phytoplankton biomass and productivity which is ubiquitous at all time and space scales in the ocean must be characterized. Remote sensing from satellites addresses these problems with global observations of mesocale (2 to 20 days, 10 to 200 km) features over a long period of time.

  19. Biological preconcentrator

    Science.gov (United States)

    Manginell, Ronald P.; Bunker, Bruce C.; Huber, Dale L.

    2008-09-09

    A biological preconcentrator comprises a stimulus-responsive active film on a stimulus-producing microfabricated platform. The active film can comprise a thermally switchable polymer film that can be used to selectively absorb and desorb proteins from a protein mixture. The biological microfabricated platform can comprise a thin membrane suspended on a substrate with an integral resistive heater and/or thermoelectric cooler for thermal switching of the active polymer film disposed on the membrane. The active polymer film can comprise hydrogel-like polymers, such as poly(ethylene oxide) or poly(n-isopropylacrylamide), that are tethered to the membrane. The biological preconcentrator can be fabricated with semiconductor materials and technologies.

  20. Stem Cell Transplantation for Pulpal Regeneration: A Systematic Review.

    Science.gov (United States)

    Fawzy El-Sayed, Karim M; Jakusz, Kimberley; Jochens, Arne; Dörfer, Christof; Schwendicke, Falk

    2015-10-01

    For treating pulpal pathological conditions, pulpal regeneration through transplanted stem/progenitor cells might be an alternative to conventional root canal treatment. A number of animal studies demonstrated beneficial effects of stem/progenitor cell transplantation for pulp-dentin complex regeneration, that is, pulpal tissue, neural, vascular, and dentinal regeneration. We systematically reviewed animal studies investigating stem/progenitor cell-mediated pulp-dentin complex regeneration. Studies quantitatively comparing pulp-dentin complex regeneration after transplantation of stem/progenitor cells versus no stem/progenitor cell transplantation controls in intraoral in vivo teeth animal models were analyzed. The following outcomes were investigated: regenerated pulp area per root canal total area, capillaries per total surface, regenerated dentinal area per total defect area, and nerves per total surface. PubMed and EMBASE were screened for studies published until July 2014. Cross-referencing and hand searching were used to identify further articles. Standardized mean differences (SMD) and 95% confidence intervals (95% CI) were calculated using random-effects meta-analysis. To assess possible bias, SYRCLE's risk of bias tool for animal studies was used. From 1364 screened articles, five studies (representing 64 animals) were included in the quantitative analysis. Risk of bias of all studies was high. Stem/progenitor cell-transplanted pulps showed significantly larger regenerated pulp area per root canal total area (SMD [95% CI]: 2.28 [0.35-4.21]) and regenerated dentin area per root canal total area (SMD: 6.91 [5.39-8.43]) compared with no stem/progenitor cell transplantation controls. Only one study reported on capillaries per or nerves per total surface and found both significantly increased in stem/progenitor cell-transplanted pulps compared with controls. Stem/progenitor cell transplantation seems to enhance pulp-dentin complex regeneration in animal models

  1. Tissue Regeneration in Urodela on Foton-M3

    Science.gov (United States)

    Grigoryan, E. N.; Poplinskaya, V. A.; Domaratskaya, E. I.; Novikova, Y. P.; Aleinikova, K. S.; Dvorochkin, N.; Almeida, E. A. C.

    2008-06-01

    In the experiment "Regeneration" flown on Foton-M3 in 2007 we continued our study of tissue and organ regeneration in Urodela. Special attention was given to the regulatory mechanisms that could induce peculiarities of regeneration during the spaceflight. The results obtained showed that lens regeneration in space-flown animals was synchronized and about 0.5 to 1 stage more advanced than in synchronous 1g controls. In both groups of animals cytokine FGFb expression increased in parallel with lens cell mitotic activity and was localized in the growth zone and iris of regenerating eyes. Lens regeneration was also accompanied by an increase of stress protein (HSP90) expression in retinal macroglia. Evaluation of HSP90 and FGFb expression by immuno-staining showed that it was higher in the eyes of space-flown animals than in synchronous controls. BrdU assay demonstrated incorporation of the precursor into populations of DNA synthesizing cells in both animal groups and mirrored cell growth in regenerating tissues. Tail regeneration in space-flown and synchronous control animals reached the stages IV to V. Computer morphometry showed that tail size parameters were similar though the tail area was slightly decreased in the space-flown newts. In contrast, remarkable changes in tail tip morphology were found between animal groups: flight and aquarium-control tail regenerates were identical in shape, while synchronous controls developed distinct dorsoventral asymmetry. Histological examinations suggested that morphogenetic differences were caused by different rates of epidermal cell growth in tail regenerates of newts exposed to microgravity and 1 g.

  2. Biotechnological applications in in vitro plant regeneration studies of broccoli (Brassica oleracea L. var. italica), an important vegetable crop.

    Science.gov (United States)

    Kumar, Pankaj; Srivastava, Dinesh Kumar

    2016-04-01

    Biotechnology holds promise for genetic improvement of important vegetable crops. Broccoli (Brassica oleracea L. var. italica) is an important vegetable crop of the family Brassicaceae. However, various biotic and abiotic stresses cause enormous crop yield losses during commercial cultivation of broccoli. Establishment of a reliable, reproducible and efficient in vitro plant regeneration system with cell and tissue culture is a vital prerequisite for biotechnological application of crop improvement programme. An in vitro plant regeneration technique refers to culturing, cell division, cell multiplication, de-differentiation and differentiation of cells, protoplasts, tissues and organs on defined liquid/solid medium under aseptic and controlled environment. Recent progress in the field of plant tissue culture has made this area one of the most dynamic and promising in experimental biology. There are many published reports on in vitro plant regeneration studies in broccoli including direct organogenesis, indirect organogenesis and somatic embryogenesis. This review summarizes those plant regeneration studies in broccoli that could be helpful in drawing the attention of the researchers and scientists to work on it to produce healthy, biotic and abiotic stress resistant plant material and to carry out genetic transformation studies for the production of transgenic plants. PMID:26721234

  3. Topical application of lithium chloride on the pulp induces dentin regeneration.

    Directory of Open Access Journals (Sweden)

    Kazuya Ishimoto

    Full Text Available We herein describe a novel procedure for dentin regeneration that mimics the biological processes of tooth development in nature. The canonical Wnt signaling pathway is an important regulator of the Dentin sialophosphoprotein (Dspp expression. Our approach mimics the biological processes underlying tooth development in nature and focuses on the activation of canonical Wnt signaling to trigger the natural process of dentinogenesis. The coronal portion of the dentin and the underlying pulp was removed from the first molars. We applied lithium chloride (LiCl, an activator of canonical Wnt signaling, on the amputated pulp surface to achieve transdifferentiation toward odontoblasts from the surrounding pulpal cells. MicroCT and microscopic analyses demonstrated that the topical application of LiCl induced dentin repair, including the formation of a complete dentin bridge. LiCl-induced dentin is a tubular dentin in which the pulp cells are not embedded within the matrix, as in primary dentin. In contrast, a dentin bridge was not induced in the control group treated with pulp capping with material carriers alone, although osteodentin without tubular formation was induced at a comparatively deeper position from the pulp exposure site. We also evaluated the influence of LiCl on differentiation toward odontoblasts in vitro. In the mDP odontoblast cell line, LiCl activated the mRNA expression of Dspp, Axin2 and Kallikrein 4 (Klk4 and downregulated the Osteopontin (Osp expression. These results provide a scientific basis for the biomimetic regeneration of dentin using LiCl as a new capping material to activate dentine regeneration.

  4. 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.

  5. Intervertebral disc (IVD): Structure, degeneration, repair and regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Whatley, Benjamin R.; Wen Xuejun, E-mail: xjwen@clemson.edu

    2012-02-01

    Low back pain affects a large portion of the population, resulting in high care costs for therapy and treatment. One primary cause of low back pain is the degeneration of the intervertebral disc (IVD) resulting in the compression of the spinal nerves and adjacent vertebrae. Exact causes of degeneration are unknown, but it is thought that natural aging, and both biological and genetic factors may play a significant role in the degenerative process. Conventional methods to alleviate low back pain include spinal fusion and artificial disc replacement. Traditional treatments through spinal fusion may eliminate pain yet do not restore disc function and lead to further degeneration of adjacent levels by altering disc biomechanics and natural kinematics. Recently, artificial IVD replacements have started to gain interest, with two IVD implants currently approved in the United States. Although these implants facilitate the preservation of motions and disc space height, they are unable to sustain compressive forces due to their lack of elasticity. In addition, the implants may produce wear debris that can cause osteolysis and other deleterious effects. As an alternative to these conventional approaches, tissue engineered IVD constructs offer the advantage of biointegration while preserving the essential attributes of natural motion and disc space restoration. There is a great need for the development of tissue engineered scaffolds that simulate the natural 3D morphology and microenvironment of the targeted tissue. Scaffolds should facilitate biological transport to satisfy nutrition and waste removal requirements within the IVD. The discrete tissue architectures of the nucleus pulposus (NP) and annulus fibrosus (AF) have posed great challenges to IVD tissue engineering. Current attempts have not been able to satisfy the biological functions and/or mechanical properties of native tissue. Therefore, these current scaffolds are far from satisfactory. This review highlights the

  6. Intervertebral disc (IVD): Structure, degeneration, repair and regeneration

    International Nuclear Information System (INIS)

    Low back pain affects a large portion of the population, resulting in high care costs for therapy and treatment. One primary cause of low back pain is the degeneration of the intervertebral disc (IVD) resulting in the compression of the spinal nerves and adjacent vertebrae. Exact causes of degeneration are unknown, but it is thought that natural aging, and both biological and genetic factors may play a significant role in the degenerative process. Conventional methods to alleviate low back pain include spinal fusion and artificial disc replacement. Traditional treatments through spinal fusion may eliminate pain yet do not restore disc function and lead to further degeneration of adjacent levels by altering disc biomechanics and natural kinematics. Recently, artificial IVD replacements have started to gain interest, with two IVD implants currently approved in the United States. Although these implants facilitate the preservation of motions and disc space height, they are unable to sustain compressive forces due to their lack of elasticity. In addition, the implants may produce wear debris that can cause osteolysis and other deleterious effects. As an alternative to these conventional approaches, tissue engineered IVD constructs offer the advantage of biointegration while preserving the essential attributes of natural motion and disc space restoration. There is a great need for the development of tissue engineered scaffolds that simulate the natural 3D morphology and microenvironment of the targeted tissue. Scaffolds should facilitate biological transport to satisfy nutrition and waste removal requirements within the IVD. The discrete tissue architectures of the nucleus pulposus (NP) and annulus fibrosus (AF) have posed great challenges to IVD tissue engineering. Current attempts have not been able to satisfy the biological functions and/or mechanical properties of native tissue. Therefore, these current scaffolds are far from satisfactory. This review highlights the

  7. Marine Biology

    Science.gov (United States)

    Dewees, Christopher M.; Hooper, Jon K.

    1976-01-01

    A variety of informational material for a course in marine biology or oceanology at the secondary level is presented. Among the topics discussed are: food webs and pyramids, planktonic blooms, marine life, plankton nets, food chains, phytoplankton, zooplankton, larval plankton and filter feeders. (BT)

  8. Biology Notes.

    Science.gov (United States)

    School Science Review, 1983

    1983-01-01

    Describes laboratory procedures, demonstrations, and classroom activities/materials, including water relation exercise on auxin-treated artichoke tuber tissue; aerobic respiration in yeast; an improved potometer; use of mobiles in biological classification, and experiments on powdery mildews and banana polyphenol oxidase. Includes reading lists…

  9. Plant regeneration and genetic transformation in Jatropha

    KAUST Repository

    Sujatha, M.

    2012-07-01

    Jatropha curcas, a non-edible oil bearing species with multiple uses, and considerable economic potential is emerging as a potential biofuel plant. The limited knowledge of this species, low and inconsistent yields, the narrow genetic variability, and vulnerability to insects and diseases are major constraints in successful cultivation of Jatropha as a biofuel crop. Hence, genetic improvement of Jatropha is essential by conventional and modern biotechnological tools to use as a viable alternative source of bio-diesel. Realising its potential as a bio-energy crop, in vitro regeneration methods have been established to meet the demand of large scale supply of superior clones, and also as a prelude for genetic improvement of the species through transgenic approaches. In this chapter, an overview of in vitro tissue culture and genetic transformation of Jatropha is discussed. © 2013 Springer Science+Business Media Dordrecht. All rights are reserved.

  10. Plant regeneration of Alstroemeria in vitro

    Directory of Open Access Journals (Sweden)

    Eleonora Gabryszewska

    2013-12-01

    Full Text Available The regenerative ability of explants from various organs of Alstroemeria plants was investigated. Rhizome apical and axillary tips cultured on the Murashige and Skoog medium with BA - 2. mgl-1 and NAA - 0,5 mgl-1 were the best among the tissue tested as initial explants. Five weeks after isolation the rhizome with 1-4 upright growing shoots were obtained. The types of rhizome explants influenced development and growth of lateral rhizomes and upright growing shoots. There were no significant differences in number of roots formed on various kind of rhizome explants. Rooting was strongly influenced by NAA. Subapical segments of vegetative stem, segments of flower pedicels and parts of ovary did not regenerate rhizome or roots but occasionally callus was formed on the medium with kinetin - 2 mgl-1 and NAA - 2 mgl-1. Segments excised from vegetative stem sporadically developed roots on the medium with NAA or IBA in concentrations 3 and 9 mgl-1.

  11. Effect of ageing on colonic mucosal regeneration

    Institute of Scientific and Technical Information of China (English)

    Ferenc Sipos; Katalin Leiszter; Zsolt Tulassay

    2011-01-01

    The physiologic and pathologic cellular and molecular changes occurring with age in the human colon affect both the inflammatory process leading to mucosal injury and the regenerative capacity of the epithelium. On the one hand, age-related telomere shortening and inflamm-ageing may lead to the development of colonic inflammation, which results in epithelial damage. On the other hand, the altered migration and function of regenerative stem cells, the age-related methylation of mucosal healing-associated genes, together with the alterations of growth factor signaling with age, may be involved in delayed mucosal regeneration. The connections of these alterations to the process of ageing are not fully known. The understanding and customtailored modification of these mechanisms are of great clinical importance with regard to disease prevention and modern therapeutic strategies. Here, we aim to summarize the age-related microscopic and molecular changes of the human colon, as well as their role in altered mucosal healing.

  12. Regeneration of ammonia borane spent fuel

    International Nuclear Information System (INIS)

    A necessary target in realizing a hydrogen (H2) economy, especially for the transportation sector, is its storage for controlled delivery, presumably to an energy producing fuel cell. In this vein, the U.S. Department of Energy's Centers of Excellence (CoE) in Hydrogen Storage have pursued different methodologies, including metal hydrides, chemical hydrides, and sorbents, for the expressed purpose of supplanting gasoline's current > 300 mile driving range. Chemical H2 storage has been dominated by one appealing material, ammonia borane (H3N-BH3, AB), due to its high gravimetric capacity of H2 (19.6 wt %) and low molecular weight (30.7 g mol-1). In addition, AB has both hydridic and protic moieties, yielding a material from which H2 can be readily released in contrast to the loss of H2 from C2H6 which is substantially endothermic. As such, a number of publications have described H2 release from amine boranes, yielding various rates depending on the method applied. The viability of any chemical H2 storage system is critically dependent on efficient recyclability, but reports on the latter subject are sparse, invoke the use of high energy reducing agents, and suffer from low yields. Our group is currently engaged in trying to find and fully demonstrate an energy efficient regeneration process for the spent fuel from H2 depleted AB with a minimum number of steps. Although spent fuel composition depends on the dehydrogenation method, we have focused our efforts on the spent fuel resulting from metal-based catalysis, which has thus far shown the most promise. Metal-based catalysts have produced the fastest rates for a single equivalent of H2 released from AB and up to 2.5 equiv. of H2 can be produced within 2 hours. While ongoing work is being carried out to tailor the composition of spent AB fuel, a method has been developed for regenerating the predominant product, polyborazylene (PB) which can be obtained readily from the decomposition of borazine or from nickel

  13. Animal models for meniscus repair and regeneration.

    Science.gov (United States)

    Deponti, Daniela; Di Giancamillo, Alessia; Scotti, Celeste; Peretti, Giuseppe M; Martin, Ivan

    2015-05-01

    The meniscus plays an important role in knee function and mechanics. Meniscal lesions, however, are common phenomena and this tissue is not able to achieve spontaneous successful repair, particularly in the inner avascular zone. Several animal models have been studied and proposed for testing different reparative approaches, as well as for studying regenerative methods aiming to restore the original shape and function of this structure. This review summarizes the gross anatomy, function, ultrastructure and biochemical composition of the knee meniscus in several animal models in comparison with the human meniscus. The relevance of the models is discussed from the point of view of basic research as well as of clinical translation for meniscal repair, substitution and regeneration. Finally, the advantages and disadvantages of each model for various research directions are critically discussed. PMID:23712959

  14. The effect of silymarin on hepatic regeneration after partial hepatectomy: is silymarin effective in hepatic regeneration?

    OpenAIRE

    Cetinkunar, Suleyman; Tokgoz, Serhat; Bilgin, Bulent Caglar; Erdem, Hasan; AKTIMUR, Recep; Can, Serpil; Erol, Huseyin Serkan; Isgoren, Atilla; Sozen, Selim; Polat, Yilmaz

    2015-01-01

    Aim: Silymarin from Silybum marianum was found to reduce liver injury. The aim of the present study was to investigate the effects of silymarin on hepatic regeneration in partially hepatectomized rats. Methods: Thirty Wistar-Albino rats were divided into 3 groups of 10 animals as sham, control and experimental groups. In the sham group (n=10) abdominal incision was closed after laparotomy. In the control group (n=10), the rats underwent 70% hepatectomy after laparotomy. In the experimental gr...

  15. Culture, regeneration and community: Reinventing the city

    Directory of Open Access Journals (Sweden)

    Donald Hyslop

    2012-08-01

    Full Text Available It is just over 12 years since the doors of Tate Modern in London were opened. In converting Gilbert Giles Scott’s Bankside Power Station into a museum we planned for two million visitors in the first year but received over five million – a number exceeding our wildest expectations. Year after year the high levels of attendance continues and now we are very much part of the cultural landscape, not only in the UK but across the world. This article explores the development, challenges and successes of what has become known as the Tate Modern ‘project’. While the museum and its collection is undoubtedly at the project's heart, it also involves a comprehensive strategy to utilise creative organisations and creative thinking in the development, regeneration and reinvention of a key area of a major world city. Central to this model of engaged working are a series of basic challenges: —how can the various needs of local communities, workers and tourists be balanced when developing an area? —how can cultural organisations and other businesses work together, and can culture be good for business? —what is the best way to engage and encourage political leadership and advocacy? —what is the best way to develop an organisation which not only works within local, national and international contexts but makes connections between them? —what are the opportunities to bring artists, creative forces and ideas into urban development and the places and spaces in which we live our everyday lives? It is hoped that this article will help us think about, imagine and practically develop the neighbourhoods and communities that we aspire to create. Keywords: Creative thinking, culture, urban regeneration and reinvention

  16. Electrochemical regeneration of spent ion exchange resin

    International Nuclear Information System (INIS)

    CAN-DECON™, CAN-DEREM™ and CAN-DEREM Plus™ processes developed by Atomic Energy of Canada Limited (AECL) are dilute regenerative chemical decontamination processes that employ ion exchange resin to remove dissolved metals and radionuclides and to regenerate the reagents. Depending on the system volume and oxide and radionuclide inventories, a large volume of spent ion exchange resin may be generated. Storage and long term disposal of spent resin may be one of the impediments to routine use of chemical decontamination processes. An electrochemical method is being developed by AECL for the regeneration of spent ion exchange resin generated during application of CAN-DECON, CAN-DEREM and CAN-DEREM Plus processes. In addition, some of the work being carried out is directed at methods for liquid waste treatment. This paper will describe the three-compartment electrochemical cell developed for laboratory tests. The cell consists of an anode, cathode and central compartment, the latter containing either solid spent resin or spent solution. The anode and the cathode compartments are separated from the central section by cation exchange membranes which allow cations to transport from anode to cathode compartments through the membranes. The paper will discuss the results of cyclic voltammetry tests performed in CAN-DEREM reagents to determine the iron redox potential in these electrolytes. The results of iron deposition tests performed in simulated spent CAN-DEREM reagents to study the current efficiency of iron deposition as a function of iron concentration, pH, cathode material and temperature will be presented. The results of tests of several commercial cation exchange membranes to study transport efficiency of iron through these membranes will also be discussed. (author)

  17. Hepatic resection and regeneration. Past and present

    International Nuclear Information System (INIS)

    Hepatic surgery has been performed on condition that the liver regenerates after hepatic resection, and the development of liver anatomy due to Glisson, Rex, and Couinaud has thrown light on hepatic surgery Understanding of feeding and drainage vessels became feasible for systemic hepatic resection; however, it seems to have been the most important problem to control the bleeding during hepatic resection. New types of devices such as cavitron ultrasonic surgical aspirator (CUSA) and Microwave coagulation were exploited to control blood loss during hepatic surgery. Pringle maneuver for exclusion feeding vessels of the liver and the decrease of central venous pressure during anesthesia enabled further decrease of blood loss. Nowadays, 3D-CT imaging may depict feeding and drainage vessels in relation to liver mass, and surgeons can simulate hepatic surgery in virtual reality before surgery, allowing hepatectomy to be performed without blood transfusion. Thus, hepatic resection has been a safe procedure, but there's been a significant research on how much of the liver can be resected without hepatic failure. A prediction scoring system based on ICGR15, resection rates, and age is mostly reliable in some criteria. Even if hepatectomy is performed with a good prediction score, the massive bleeding and associated infection may induce postoperative hepatic failure, while the criteria of postoperative hepatic failure have not yet established. Hepatic failure is supposed to be induced by the apoptosis of mature hepatocytes and necrosis originated from microcirculation disturbance of the liver. Prostaglandin E1 for the improvement of microcirculation, steroid for the inhibition of cytokines inducing apoptosis, and blood purification to exclude cytokines have been tried separately or concomitantly. New therapeutic approaches, especially hepatic regeneration from the stem cell, are expected. (author)

  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. A modeling study on the geometry of active magnetic regenerator

    Science.gov (United States)

    Numazawa, Takenori; Mastumoto, Koichi; Yanagisawa, Yoshinori; Nakagome, Hideki

    2012-06-01

    Magnetic refrigeration technology needs further development not just by the improvement of magnetocaloric properties but also the optimization of the cooling system design. One of the important problems in the cooling system design is the geometry of regenerator for the efficient heat transfer between magnetic material and fluid which is the major loss mechanism in cooling system. Two kinds of regenerators are widely used. One is flat plate regenerator which can offer the best heat transfer to pressure drop ratio [2] for common regenerator design; another is porous media regenerator which can obtain a large temperature span for the good heat transfer surface. But until now, only a few research papers actually study the regenerator geometry. This paper focuses on the influence of regenerator geometry to the performance of AMR system. The 1 dimension flat plat model and porous media model have been constructed and compared with entropy generation, cooling capacity, coefficient of performance by changing plate thickness and sphere size at frequency 0.25Hz, 0.5Hz, 1, aspect ratio 2, 7, 14. The result shows that the optimized sphere size will be around 0.2mm to 0.3mm. On the other hand, 0.1mm to 0.2mm thickness plate will be more efficient. Compared the 2 models, flat plate model can get a smaller entropy generation and achieve a higher cooling capacity.

  20. The Involvement of Heat Shock Proteins in Murine Liver Regeneration

    Institute of Scientific and Technical Information of China (English)

    Qing Shi; Zhongjun Dong; Haiming Wei

    2007-01-01

    Partial hepatectomy (PHx) in mammals is a very common experimental model to investigate the process of liver regeneration. The surgery itself could give birth to a series of stresses, such as the temporary raise of body temperature and the ischaemia-reperfusion injury. Heat shock proteins (HSPs) were a family of stress-inducible proteins involved in maintaining cell homeostasis and regulating the immune system. In our study, we intended to investigate the expression and role of HSPs in liver regeneration. Using RT-PCR and Western blotting, we determined the expression in regenerating liver of HSP27, HSP60, HSP70 and HSP90 in mRNA level and protein level, respectively, with mice treated with sham operation as controls. We also used quercertin as an inhibitior of HSPs to explore their effects on liver regeneration. We found that hepatic expression of HSPs increased at the early phase of liver regeneration and declined to the constitutively low level later. Moreover, quercetin pretreatment delayed the progress of liver regeneration in mice via inhibition of HSPs. The results indicated that HSPs played an important role in liver regeneration.

  1. Bone marrow-derived cell regulation of skeletal muscle regeneration.

    Science.gov (United States)

    Sun, Dongxu; Martinez, Carlo O; Ochoa, Oscar; Ruiz-Willhite, Lourdes; Bonilla, Jose R; Centonze, Victoria E; Waite, Lindsay L; Michalek, Joel E; McManus, Linda M; Shireman, Paula K

    2009-02-01

    Limb regeneration requires the coordination of multiple stem cell populations to recapitulate the process of tissue formation. Therefore, bone marrow (BM) -derived cell regulation of skeletal muscle regeneration was examined in mice lacking the CC chemokine receptor 2 (CCR2). Myofiber size, numbers of myogenic progenitor cells (MPCs), and recruitment of BM-derived cells and macrophages were assessed after cardiotoxin-induced injury of chimeric mice produced by transplanting BM from wild-type (WT) or CCR2(-/-) mice into irradiated WT or CCR2(-/-) host mice. Regardless of the host genotype, muscle regeneration and recruitment of BM-derived cells and macrophages were similar in mice replenished with WT BM, whereas BM-derived cells and macrophage accumulation were decreased and muscle regeneration was impaired in all animals receiving CCR2(-/-) BM. Furthermore, numbers of MPCs (CD34(+)/Sca-1(-)/CD45(-) cells) were significantly increased in mice receiving CCR2(-/-) BM despite the decreased size of regenerated myofibers. Thus, the expression of CCR2 on BM-derived cells regulated macrophage recruitment into injured muscle, numbers of MPC, and the extent of regenerated myofiber size, all of which were independent of CCR2 expression on host-derived cells. Future studies in regenerative medicine must include consideration of the role of BM-derived cells, possibly macrophages, in CCR2-dependent events that regulate effective skeletal muscle regeneration. PMID:18827026

  2. Mesoscopic biology

    Indian Academy of Sciences (India)

    G V Shivashankar

    2002-02-01

    In this paper we present a qualitative outlook of mesoscopic biology where the typical length scale is of the order of nanometers and the energy scales comparable to thermal energy. Novel biomolecular machines, governed by coded information at the level of DNA and proteins, operate at these length scales in biological systems. In recent years advances in technology have led to the study of some of the design principles of these machines; in particular at the level of an individual molecule. For example, the forces that operate in molecular interactions, the stochasticity involved in these interactions and their spatio-temporal dynamics are beginning to be explored. Understanding such design principles is opening new possibilities in mesoscopic physics with potential applications.

  3. Effect of SBD.4A--a defined multicomponent preparation of Angelica sinensis--in periodontal regeneration models.

    Science.gov (United States)

    Zhao, Hui; Alexeev, Alexei; Sharma, Vrushali; Guzman, Lorenzo Dave T; Bojanowski, Krzysztof

    2008-07-01

    Periodontitis is a major cause of tooth motility and loss, resulting in destruction of the supporting structures of the tooth, including periodontal ligaments and alveolar bone. Periodontal surgery can slow the progression of the disease, but is costly, invasive, limited by contraindications and technique-sensitive. Recently, non-invasive pharmacological treatments using proteinaceous biologicals have become available. Here, for the first time, the bone-regenerative capabilities of a non-proteinaceous biological--SBD.4A--a novel, stable multicomponent growth factor isolated from a medicinal plant Angelica sinensis are reported. SBD.4A was tested in osteoblast proliferation and differentiation systems, as well as in a fibroblast-secreted hyaluronic acid assay. Furthermore, SBD.4A was formulated in a slow release matrix and tested in the rat calvarial defect model. Apart from the previously reported strong stimulation of angiogenesis, fibroblast growth and collagen synthesis--the activities needed for periodontal regeneration--SBD.4A enhanced the deposition of hyaluronic acid and proliferation of osteoblasts in vitro, as well as bone regeneration in the rat calvarial defect model. Together, these results indicate the beneficial effect of SBD.4 on periodontal ligament and bone regeneration making the case for further development of this botanical growth factor. PMID:18389473

  4. Nanoparticles for Tendon Healing and Regeneration: Literature Review.

    Science.gov (United States)

    Parchi, Paolo D; Vittorio, Orazio; Andreani, Lorenzo; Battistini, Pietro; Piolanti, Nicola; Marchetti, Stefano; Poggetti, Andrea; Lisanti, Michele

    2016-01-01

    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. PMID:27597828

  5. 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

  6. Lens regeneration in mice under the influence of vitamin A

    Indian Academy of Sciences (India)

    Digvijay Singh Shekhawat; O P Jangir; Acharya Prakash; Suthar Pawan

    2001-12-01

    The effect of vitamin A has been studied on lens regeneration in young (7 days old) as well as adult mice. A longitudinal slit was made under local anesthesia in the cornea over the lens. The lens was extracted intact through the incision. Intraperitonial injection of vitamin A (0.05 ml of 30 IU/ml in young and 0.05 ml of 50 IU/ml in adult) was given to the operated animals. Vitamin A was found to induce lens regeneration in not only young but also in adult mice. Regenerated lenses were similar in shape, size, transparency and histological features to normal intact lenses.

  7. Nanotechnology and bio-functionalisation for peripheral nerve regeneration

    Institute of Scientific and Technical Information of China (English)

    Tina Sedaghati; Alexander M Seifalian

    2015-01-01

    There is a high clinical demand for new smart biomaterials, which stimulate neuronal cell pro-liferation, migration and increase cell-material interaction to facilitate nerve regeneration across these critical-sized defects. This article brielfy reviews several up-to-date published studies using Arginine-Glycine-Aspartic acid peptide sequence, nanocomposite based on polyhedral oligo-meric silsesquioxane nanoparticle and nanoifbrous scaffolds as promising strategies to enhance peripheral nerve regeneration by inlfuencing cellular behaviour such as attachment, spreading and proliferation. The aim is to establish the potent manipulations, which are simple and easy to employ in the clinical conditions for nerve regeneration and repair.

  8. Computer-tomographic characteristics of tibial distraction regenerate

    International Nuclear Information System (INIS)

    Computer tomography (CT) potentialities in examinations of patients over the course of distraction osteosynthesis and in assessment of the bone regenerate structure of different sites in various periods of its formation and maturation were studied in 25 patients in periods from 24 days to 5 years. CT permitted a visual and densitometric assessment of the developing bone regenerate surrounded by metal constructions. CT helps follow up all the periods of bone regenerate formation and maturation and permits the detection of deviations in this process, if any

  9. The significance of nitrogen regeneration for new production within a filament of the Mauritanian upwelling system

    Science.gov (United States)

    Clark, D. R.; Widdicombe, C. E.; Rees, A. P.; Woodward, E. M. S.

    2015-11-01

    The lagrangian progression of biogeochemical processes was followed in a filament of the Mauritanian upwelling system, North West Africa, during offshore advection. Inert duel tracers sulphur hexafluoride and helium-3 labelled a freshly upwelled patch of water that was mapped for 8 days. Changes in biological, physical and chemical characteristics were measured including phytoplankton productivity, nitrogen assimilation and regeneration. Freshly upwelled water contained high nutrient concentrations (NO3- = 9.0 ± 0.1 μmol L-1; PO43- = 0.7 ± 0.1 μmol L-1; Si = 2.7 ± 0.1 μmol L-1) but was depleted in N compared to Redfield stoichiometry (N:P = 13.9:1). A maximum primary productivity rate of 0.7 mol C m-2 d-1 was measured on the continental shelf, associated with N-assimilation rates of 43.8 nmol L-1 h-1 for NO3-, 32.8 nmol L-1 h-1 for NH4+ and a phytoplankton community dominated by diatoms and flagellates. Indicators of phytoplankton abundance and activity decreased as the labelled water mass transited the continental shelf slope into deeper water, possibly linked to the mixed layer depth exceeding the light penetration depth. By the end of the study, primary productivity rates of 0.1 mol C m-2 d-1 were measured, associated with N-assimilation rates of 3.9 nmol L-1 h-1 for NO3-, 6.1 nmol L-1 h-1 for NH4+ and lower nutrient concentrations (NO3- = 4.6 ± 0.3 μmol L-1; PO43- = 0.4 ± 0.1 μmol L-1; Si = 0.9 ± 0.1 μmol L-1). Nitrogen regeneration and assimilation took place simultaneously; NH4+ was regenerated at 9.4-85.0 nmol L-1 h-1; NH4+ was oxidised at 0.30-8.75 nmol L-1 h-1; NO2- was oxidised at 25.55-81.11 nmol L-1 h-1. Results highlight the importance of regenerated NH4+ in sustaining phytoplankton productivity and indicate that the upwelled NO3- pool contained an increasing fraction of regenerated NO3- as it advected offshore. By calculating this fraction and incorporating it into an f ratio formulation we estimated that of the 12.38 Tg C of annual

  10. The significance of nitrogen regeneration for new production within a filament of the Mauritanian upwelling system

    Directory of Open Access Journals (Sweden)

    D. R. Clark

    2015-11-01

    Full Text Available The lagrangian progression of biogeochemical processes was followed in a filament of the Mauritanian upwelling system, North West Africa, during offshore advection. Inert duel tracers sulphur hexafluoride and helium-3 labelled a freshly upwelled patch of water that was mapped for 8 days. Changes in biological, physical and chemical characteristics were measured including phytoplankton productivity, nitrogen assimilation and regeneration. Freshly upwelled water contained high nutrient concentrations (NO3− = 9.0 ± 0.1 μmol L−1; PO43− = 0.7 ± 0.1 μmol L−1; Si = 2.7 ± 0.1 μmol L−1 but was depleted in N compared to Redfield stoichiometry (N:P = 13.9:1. A maximum primary productivity rate of 0.7 mol C m−2 d−1 was measured on the continental shelf, associated with N-assimilation rates of 43.8 nmol L−1 h−1 for NO3−, 32.8 nmol L−1 h−1 for NH4+ and a phytoplankton community dominated by diatoms and flagellates. Indicators of phytoplankton abundance and activity decreased as the labelled water mass transited the continental shelf slope into deeper water, possibly linked to the mixed layer depth exceeding the light penetration depth. By the end of the study, primary productivity rates of 0.1 mol C m−2 d−1 were measured, associated with N-assimilation rates of 3.9 nmol L−1 h−1 for NO3−, 6.1 nmol L−1 h−1 for NH4+ and lower nutrient concentrations (NO3− = 4.6 ± 0.3 μmol L−1; PO43− = 0.4 ± 0.1 μmol L−1; Si = 0.9 ± 0.1 μmol L−1. Nitrogen regeneration and assimilation took place simultaneously; NH4+ was regenerated at 9.4–85.0 nmol L−1 h−1; NH4+ was oxidised at 0.30–8.75 nmol L−1 h−1; NO2− was oxidised at 25.55–81.11 nmol L−1 h−1. Results highlight the importance of regenerated NH4+ in sustaining phytoplankton productivity and indicate that the upwelled NO3− pool contained an increasing fraction of regenerated NO3− as it advected offshore. By calculating this fraction and

  11. Optimization of tyrosine-derived polycarbonate terpolymers for bone regeneration scaffolds

    Science.gov (United States)

    Resurreccion-Magno, Maria Hanshella C.

    surface post-fabrication. The scaffolds displayed (i) a bimodal pore architecture with micropores (biological supplement or with a minimal dose of rhBMP-2 induced comparable bone regeneration to a commercially available bone substitute in a non-rodent CSD animal model.

  12. Biological programming

    OpenAIRE

    Ramsden, Jeremy J.; Bándi, Gergely

    2010-01-01

    Biology offers a tremendous set of concepts that are potentially very powerfully usable for the software engineer, but they have been barely exploited hitherto. In this position paper we propose a fresh attempt to create the building blocks of a programming technology that could be as successful as life. A key guiding principle is to develop and make use of unambiguous definitions of the essential features of life.

  13. Biological radioprotector

    International Nuclear Information System (INIS)

    According to the patent description, the biological radioprotector is deuterium depleted water, DDW, produced by vacuum distillation with an isotopic content lower than natural value. It appears as such or in a mixture with natural water and carbon dioxide. It can be used for preventing and reducing the ionizing radiation effects upon humans or animal organisms, exposed therapeutically, professionally or accidentally to radiation. The most significant advantage of using DDW as biological radioprotector results from its way of administration. Indeed no one of the radioprotectors currently used today can be orally administrated, what reduces the patients' compliance to prophylactic administrations. The biological radioprotector is an unnoxious product obtained from natural water, which can be administrated as food additive instead of drinking water. Dose modification factor is according to initial estimates around 1.9, what is a remarkable feature when one takes into account that the product is toxicity-free and side effect-free and can be administrated prophylactically as a food additive. A net radioprotective action of the deuterium depletion was evidenced experimentally in laboratory animals (rats) hydrated with DDW of 30 ppm D/(D+H) concentration as compared with normally hydrated control animals. Knowing the effects of irradiation and mechanisms of the acute radiation disease as well as the effects of administration of radiomimetic chemicals upon cellular lines of fast cell division, it appears that the effects of administrating DDW result from stimulation of the immunity system. In conclusion, the biological radioprotector DDW presents the following advantages: - it is obtained from natural products without toxicity; - it is easy to be administrated as a food additive, replacing the drinking water; - besides radioprotective effects, the product has also immunostimulative and antitumoral effects

  14. Marine biology

    International Nuclear Information System (INIS)

    This book discusses both taxonomic and ecological topics on marine biology. Full coverage of marine organisms of all five kingdoms is provided, along with interesting and thorough discussion of all major marine habitats. Organization into six major parts allows flexibility. It also provides insight into important topics such as disposal of nuclear waste at sea, the idea that life began on the ocean floor, and how whales, krill, and people interact. A full-color photo chapter reviews questions, and exercises. The contents are: an overview marine biology: fundamental concepts/investigating life in the ocean; the physical ocean, the ocean floor, the nature of water, the nature and motion of ocean water; general ecology, conditions for life in the sea, biological productivity and energy transfer; marine organisms; monera, protista, mycota and metaphyta; the smaller marine animals, the large animals marine habitats, the intertidal zone/benthos of the continental shelf, the photic zone, the deep ocean, the ocean under stress, marine pollution, appendix a: the metric system and conversion factors/ appendix b: prefixes and suffixes/ appendix c: taxonomic classification of common marine organisms, and glossary, and index

  15. Marine biology

    Energy Technology Data Exchange (ETDEWEB)

    Thurman, H.V.; Webber, H.H.

    1984-01-01

    This book discusses both taxonomic and ecological topics on marine biology. Full coverage of marine organisms of all five kingdoms is provided, along with interesting and thorough discussion of all major marine habitats. Organization into six major parts allows flexibility. It also provides insight into important topics such as disposal of nuclear waste at sea, the idea that life began on the ocean floor, and how whales, krill, and people interact. A full-color photo chapter reviews questions, and exercises. The contents are: an overview marine biology: fundamental concepts/investigating life in the ocean; the physical ocean, the ocean floor, the nature of water, the nature and motion of ocean water; general ecology, conditions for life in the sea, biological productivity and energy transfer; marine organisms; monera, protista, mycota and metaphyta; the smaller marine animals, the large animals marine habitats, the intertidal zone/benthos of the continental shelf, the photic zone, the deep ocean, the ocean under stress, marine pollution, appendix a: the metric system and conversion factors/ appendix b: prefixes and suffixes/ appendix c: taxonomic classification of common marine organisms, and glossary, and index.

  16. Tingkat Insidensi Malaria di Wilayah Pemanasan Kelambu Berinsektisida Tahan Lama dan Wilayah Kontrol (MALARIA INCIDENCE RATE OF HEAT ASSISTED REGENERATION LONG LASTING INSECTICIDAL NETS AREA AND CONTROL

    Directory of Open Access Journals (Sweden)

    Etih Sudarnika

    2012-03-01

    Full Text Available Long lasting insecticidal nets (LLIN is one effective way to prevent malaria. Permethrin treatedLLIN is one type of LLIN which is recommended by WHO. Several studies have shown that these types ofLLIN requiring heat assisted regeneration after washing to enhance the biological activity of insecticidethat contained in the LLIN fibers. This study aimed to compare the incidence rates of malaria in childrenunder five years old who live in the intervention area (where the heat assisted regeneration on LLIN afterwashing was applied and control area (where the heat assisted regeneration on LLIN after washing wasnot applied. Data of malaria cases was collected from laboratory log book at all health centers in BangkaDistrict, in the period of June June 2007 until July 2008. Data were analyzed with Poisson regressionmodels. The results showed that the incidence rate of malaria in children under five years old was notsignificantly different between the treatment and control areas.

  17. Root Conditioning and Agents Effect in Regeneration of Periodontal Tissue

    Directory of Open Access Journals (Sweden)

    Kadkhoda Z

    1999-12-01

    Full Text Available Periodontitis affected root surfaces are hypermineralized and contaminated with cytotoxic and"nother biologically active substances."nThe instrumented surface will inervitably be coverd by a smear layer following root planing with or without flap."nSmear layer is resistant to saline rinsing, but may be removed with agents such as acids (e.g.citric acid, tetracyclines, EDTA, and laser."nLow pH aqueous solutions such as citric acid have been used in surgical periodontal therapy mainly for two reasons, It dissolves smear layer after a relatively short exposure time and it has been claimed to selectively remove root surface associated mineral exposing collagen to varying degrees. A root surface coated with collagen appears to be a preferred surface for fibroblast attachment, a cellular event fundamental to successful periodontal wound healing."nSeveral studies indicate the potential of tetracycline (TTE-HCL in periodontal regeneration. Its acidic pH suggest that it can be used as a demineralization agent and removing the smear layer and exposing collagen matrix of the dentin."nChalating agent (EDTA working at neutral pH appears preferable with respect to preserving the integrity of exposed collagen fibers, early colonization, and wound healing. In addition, etching at neutral pH has been reported preserve adjacent tissue- vitality, while etching at low pH necrotizes the fiap and adjacent periodontium."nClinical and subclinical studies have demonstrated laser waves can remove calculus and bacterial plaque and pocket epithelium and strile the root surface and can expose the dentin collagen and dentinal tublules, and leads to pronounce reducing of probing depth around teeth diseased with periodontitis.

  18. Proteomic analysis of blastema formation in regenerating axolotl limbs

    Directory of Open Access Journals (Sweden)

    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

  19. Experimental study on the inhibition of biological reduction of Fe(III)EDTA in NOx absorption solution*

    OpenAIRE

    Li, Wei; Wu, Cheng-zhi; Zhang, Shi-han; Shi, Yao; Lei, Le-cheng

    2005-01-01

    Scrubbing of NOx from the gas phase with Fe(II)EDTA has been shown to be highly effective. A new biological method can be used to convert NO to N2 and regenerate the chelating agent Fe(II)EDTA for continuous NO absorption. The core of this biological regeneration is how to effectively simultaneous reduce Fe(III)EDTA and Fe(II)EDTA-NO, two mainly products in the ferrous chelate absorption solution. The biological reduction rate of Fe(III)EDTA plays a main role for the NOx removal efficiency. I...

  20. Cooperative inputs of Bmp and Fgf signaling induce tail regeneration in urodele amphibians.

    Science.gov (United States)

    Makanae, Aki; Mitogawa, Kazumasa; Satoh, Akira

    2016-02-01

    Urodele amphibians have remarkable organ regeneration ability. They can regenerate not only limbs but also a tail throughout their life. It has been demonstrated that the regeneration of some organs are governed by the presence of neural tissues. For instance, limb regeneration cannot be induced without nerves. Thus, identifying the nerve factors has been the primary focus in amphibian organ regeneration research. Recently, substitute molecules for nerves in limb regeneration, Bmp and Fgfs, were identified. Cooperative inputs of Bmp and Fgfs can induce limb regeneration in the absence of nerves. In the present study, we investigated whether similar or same regeneration mechanisms control another neural tissue governed organ regeneration, i.e., tail regeneration, in Ambystoma mexicanum. Neural tissues in a tail, which is the spinal cord, could transform wound healing responses into organ regeneration responses, similar to nerves in limb regeneration. Furthermore, the identified regeneration inducer Fgf2+Fgf8+Bmp7 showed similar inductive effects. However, further analysis revealed that the blastema cells induced by Fgf2+Fgf8+Bmp7 could participate in the regeneration of several tissues, but could not organize a patterned tail. Regeneration inductive ability of Fgf2+Fgf8+Bmp7 was confirmed in another urodele, Pleurodeles waltl. These results suggest that the organ regeneration ability in urodele amphibians is controlled by a common mechanism. PMID:26703427

  1. Optimization of Regenerators for AMRR Systems

    Energy Technology Data Exchange (ETDEWEB)

    Nellis, Gregory [University of Wisconsin, Madison, WI (United States); Klein, Sanford [University of Wisconsin, Madison, WI (United States); Brey, William [University of Wisconsin, Madison, WI (United States); Moine, Alexandra [University of Wisconsin, Madison, WI (United States); Nielson, Kaspar [University of Wisconsin, Madison, WI (United States)

    2015-06-18

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

  2. Concise review: bridging the gap: bone regeneration using skeletal stem cell-based strategies-where are we now?

    DEFF Research Database (Denmark)

    Dawson, Jonathan I; Kanczler, Janos; Kassem, Moustapha; Oreffo, Richard O.C.

    2014-01-01

    Skeletal stem cells confer to bone its innate capacity for regeneration and repair. Bone regeneration strategies seek to harness and enhance this regenerative capacity for the replacement of tissue damaged or lost through congenital defects, trauma, functional/esthetic problems, and a broad range...... of diseases associated with an increasingly aged population. This review describes the state of the field and current steps to translate and apply skeletal stem cell biology in the clinic and the problems therein. Challenges are described along with key strategies including the isolation and ex vivo...... expansion of multipotential populations, the targeting/delivery of regenerative populations to sites of repair, and their differentiation toward bone lineages. Finally, preclinical models of bone repair are discussed along with their implications for clinical translation and the opportunities to harness...

  3. Application of Bladder Acellular Matrix in Urinary Bladder Regeneration: The State of the Art and Future Directions

    Directory of Open Access Journals (Sweden)

    Marta Pokrywczynska

    2015-01-01

    Full Text Available Construction of the urinary bladder de novo using tissue engineering technologies is the “holy grail” of reconstructive urology. The search for the ideal biomaterial for urinary bladder reconstruction has been ongoing for decades. One of the most promising biomaterials for this purpose seems to be bladder acellular matrix (BAM. In this review we determine the most important factors, which may affect biological and physical properties of BAM and its regeneration potential in tissue engineered urinary bladder. We also point out the directions in modification of BAM, which include incorporation of exogenous growth factors into the BAM structure. Finally, we discuss the results of the urinary bladder regeneration with cell seeded BAM.

  4. Ultradisperse Diamond Regeneration from Composite Electrolytes of Chromium Plating

    Science.gov (United States)

    Gubarevich, T. M.; Chernukho, L. E.; Kulik, V. P.; Shtempljuk, R. G.

    Composite chromium-diamond electroplating is one of the most UDD consuming technologies among UDD applications. The exploitation includes periodic cleaning of the chroming bath from accumulated anodic sludges and contaminants. During the cleaning, the UDD must be extracted from the sludges and regenerated for re-use. We have suggested technique for UDD regeneration from sludges containing up to 80% of insoluble Cr, Pb and Sb compounds. The process includes mechanic, colloidal-chemical and chemical treatments which provide a fairly pure material only with 1-3% of noncarbon; the calculated diamond yield is 85-90%. We have analyzed the contaminants in regenerated UDD for their dispersion, sedimentative and aggregative stability, adsorptive and structural characteristics of the surface. Regenerated diamond is applicable for re-use in electroplating technologies.

  5. Thymic regeneration in lethally x-irradiated mice

    International Nuclear Information System (INIS)

    The effects of a lethal dose of 750 rad of whole-body x irradiation on the murine lymphomyeloid complex have been investigated. During the first 4 days after exposure there was a marked decrease in the weight of the thymus, spleen, and lymph nodes and in the cellularity of the femoral bone marrow. Subsequently, a phase of thymic regeneration, maximal on the tenth day, was observed in the absence of detectable regeneration elsewhere in the lymphomyeloid complex. The thymus, from the third to the fifth days postirradiation, although very hypocellular, was a site of extensive tritiated thymidine incorporation indicating the presence of a precursor cell population undertaking DNA synthesis. No comparable changes in the tritiated thymidine incorporation of the spleen, lymph nodes or bone marrow were observed. Thymic regeneration in the absence of detectable regeneration elsewhere in the lymphomyeloid complex occurred over a range of doses within the lethal range in several strains of mice

  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......-law efficiency of 18% was obtained at a cooling load of 81.5 W, resulting in a temperature span of 15.5 K and a coefficient of performance of 3.6. A loss analysis is given, based on measured pumping power and shaft power together with theoretically estimated regenerator presssure drop. It is shown that......, 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 and...

  7. REGENERATION OF CHROMATED ALUMINUM DEOXIDIZERS. IMPROVED DIAPHRAGM FABRICATION AND PERFORMANCE

    Science.gov (United States)

    In the metal finishing industry highly concentrated hexavalent chromium solutions are used extensively to deoxidize aluminum surfaces prior to anodizing, conversion coatings, prepaint preparation, welding and adhesive bonding. A regeneration process was conceived and tested to re...

  8. Syndecan Promotes Axon Regeneration by Stabilizing Growth Cone Migration

    Directory of Open Access Journals (Sweden)

    Tyson J. Edwards

    2014-07-01

    Full Text Available Growth cones facilitate the repair of nervous system damage by providing the driving force for axon regeneration. Using single-neuron laser axotomy and in vivo time-lapse imaging, we show that syndecan, a heparan sulfate (HS proteoglycan, is required for growth cone function during axon regeneration in C. elegans. In the absence of syndecan, regenerating growth cones form but are unstable and collapse, decreasing the effective growth rate and impeding regrowth to target cells. We provide evidence that syndecan has two distinct functions during axon regeneration: (1 a canonical function in axon guidance that requires expression outside the nervous system and depends on HS chains and (2 an intrinsic function in growth cone stabilization that is mediated by the syndecan core protein, independently of HS. Thus, syndecan is a regulator of a critical choke point in nervous system repair.

  9. Monitoring of bone regeneration process by means of texture analysis

    International Nuclear Information System (INIS)

    An image analysis method is proposed for the monitoring of the regeneration of the tibial bone. For this purpose, 130 digitized radiographs of 13 patients, who had undergone tibial lengthening by the Ilizarov method, were studied. For each patient, 10 radiographs, taken at an equal number of postoperative successive time moments, were available. Employing available software, 3 Regions Of Interest (ROIs), corresponding to the: (a) upper, (b) central, and (c) lower aspect of the gap, where bone regeneration was expected to occur, were determined on each radiograph. Employing custom developed algorithms: (i) a number of textural features were generated from each of the ROIs, and (ii) a texture-feature based regression model was designed for the quantitative monitoring of the bone regeneration process. Statistically significant differences (p 2 = 0.9, p < 0.001). The suggested method may contribute to the monitoring of the tibial bone regeneration process.

  10. Genotypic variability for protoplast regeneration in Saintpaulia ionantha (H. Wendl.).

    Science.gov (United States)

    Winkelmann, T; Grunewaldt, J

    1995-08-01

    The behaviour of eleven Saintpaulia ionantha (H. Wendl.) genotypes in protoplast culture was compared. Isolation of protoplasts from young shootlets regenerated in vitro on leaf explants, yielded 0.7 to 1.8 × 10(6) protoplasts per gram fresh weight. In all cultivars and breeding lines tested, cell divisions were observed. The mean division frequencies varied between 1.0 and 5.0% after 14 days, and between 6.4 and 13.8% after 24 days of culture. In ten genotypes callussing and shoot regeneration were achieved. The difference between the genotypes in shoot regeneration rate, between 2 and 68%, was more pronounced. The comparison of four cytokinins indicated hat thidiazuron was most effective for shoot regeneration, but often resulted in poorer shoot quality than benzylaminopurine. PMID:24186626

  11. Receptor Tyrosine Kinases: Molecular Switches Regulating CNS Axon Regeneration

    Directory of Open Access Journals (Sweden)

    Vasanthy Vigneswara

    2012-01-01

    Full Text Available The poor or lack of injured adult central nervous system (CNS axon regeneration results in devastating consequences and poor functional recovery. The interplay between the intrinsic and extrinsic factors contributes to robust inhibition of axon regeneration of injured CNS neurons. The insufficient or lack of trophic support for injured neurons is considered as one of the major obstacles contributing to their failure to survive and regrow their axons after injury. In the CNS, many of the signalling pathways associated with neuronal survival and axon regeneration are regulated by several classes of receptor tyrosine kinases (RTK that respond to a variety of ligands. This paper highlights and summarises the most relevant recent findings pertinent to different classes of the RTK family of molecules, with a particular focus on elucidating their role in CNS axon regeneration.

  12. DESIGN OF EXACT REGENERATING HIERARCHICAL CODE FOR DISTRIBUTED STORAGE SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Hao Jie; Lu Yanbo; Liu Xinji; Xia Shutao

    2013-01-01

    Erasure code is widely used as the redundancy scheme in distributed storage system.When a storage node fails,the repair process often requires to transfer a large amount of data.Regenerating code and hierarchical code are two classes of codes proposed to reduce the repair bandwidth cost.Regenerating codes reduce the amount of data transferred by each helping node,while hierarchical codes reduce the number of nodes participating in the repair process.In this paper,we propose a "sub-code nesting framework" to combine them together.The resulting regenerating hierarchical code has low repair degree as hierarchical code and lower repair cost than hierarchical code.Our code can achieve exact regeneration of the failed node,and has the additional property of low updating complexity.

  13. Rat liver regeneration following ablation with irreversible electroporation.

    Science.gov (United States)

    Golberg, Alexander; Bruinsma, Bote G; Jaramillo, Maria; Yarmush, Martin L; Uygun, Basak E

    2016-01-01

    During the past decade, irreversible electroporation (IRE) ablation has emerged as a promising tool for the treatment of multiple diseases including hepatic cancer. However, the mechanisms behind the tissue regeneration following IRE ablation have not been investigated. Our results indicate that IRE treatment immediately kills the cells at the treatment site preserving the extracellular architecture, in effect causing in vivo decellularization. Over the course of 4 weeks, progenitor cell differentiation, through YAP and notch pathways, together with hepatocyte expansion led to almost complete regeneration of the ablated liver leading to the formation of hepatocyte like cells at the ablated zone. We did not observe significant scarring or tumor formation at the regenerated areas 6 months post IRE. Our study suggests a new model to study the regeneration of liver when the naïve extracellular matrix is decellularized in vivo with completely preserved extracellular architecture. PMID:26819842

  14. Advanced Regenerator for High Frequency Low Temperature Operation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The key element in producing an efficient low temperture cryocooler is the performance of the regenerator. It must have good heat transfer characteristics while...

  15. Simulated microgravity inhibits cell wall regeneration of Penicillium decumbens protoplasts

    Science.gov (United States)

    Zhao, C.; Sun, Y.; Yi, Z. C.; Rong, L.; Zhuang, F. Y.; Fan, Y. B.

    2010-09-01

    This work compares cell wall regeneration from protoplasts of the fungus Penicillium decumbens under rotary culture (simulated microgravity) and stationary cultures. Using an optimized lytic enzyme mixture, protoplasts were successfully released with a yield of 5.3 × 10 5 cells/mL. Under simulated microgravity conditions, the protoplast regeneration efficiency was 33.8%, lower than 44.9% under stationary conditions. Laser scanning confocal microscopy gave direct evidence for reduced formation of polysaccharides under simulated conditions. Scanning electron microscopy showed the delayed process of cell wall regeneration by simulated microgravity. The delayed regeneration of P. decumbens cell wall under simulated microgravity was likely caused by the inhibition of polysaccharide synthesis. This research contributes to the understanding of how gravitational loads affect morphological and physiological processes of fungi.

  16. Biological Databases

    Directory of Open Access Journals (Sweden)

    Kaviena Baskaran

    2013-12-01

    Full Text Available Biology has entered a new era in distributing information based on database and this collection of database become primary in publishing information. This data publishing is done through Internet Gopher where information resources easy and affordable offered by powerful research tools. The more important thing now is the development of high quality and professionally operated electronic data publishing sites. To enhance the service and appropriate editorial and policies for electronic data publishing has been established and editors of article shoulder the responsibility.

  17. Stem Cells as Vehicles for Youthful Regeneration of Aged Tissues

    OpenAIRE

    Rando, Thomas A; Wyss-Coray, Tony

    2014-01-01

    Stem cells hold great promise for regenerative therapies for a wide spectrum of diseases and disorders of aging by virtue of their ability to regenerate tissues and contribute to their homeostasis. Aging is associated with a marked decline in these functionalities of adult stem cells. As such, regeneration of aged tissues is both less efficient and less effective than that of young tissues. Recent studies have revealed the remarkably dynamic responses of stem cells to systemic signals, includ...

  18. Foam suppression and regeneration of spent surfactant solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kondrat, R.M.; Biletskiy, M.M.; Bosov, G.P.; Yatskiv, M.P.

    1983-01-01

    A system of a prototype industrial installation is described and the results of tests of the processes of foam absorption are cited in a system for preparing gas and regenerating spent surfactant (PAV) solutions as applied to conditions of pumping surfactants into wells to intensify the carry away of water. The fundamental possibility of controlling foam formation in a system for preparing gas and regenerating spent surfactant solutions in order to use the foaming reagents again is shown.

  19. Rapid Dye Regeneration Mechanism of Dye-Sensitized Solar Cells

    OpenAIRE

    Jeon, Jiwon; Park, Young Choon; Han, Sang Soo; GODDARD, William A.; Lee, Yoon Sup; Kim, Hyungjun

    2014-01-01

    During the light-harvesting process of dye-sensitized solar cells (DSSCs), the hole localized on the dye after the charge separation yields an oxidized dye, D^+. The fast regeneration of D^+ using the redox pair (typically the I^–/I_(3)^– couple) is critical for the efficient DSSCs. However, the kinetic processes of dye regeneration remain uncertain, still promoting vigorous debates. Here, we use molecular dynamics simulations to determine that the inner-sphere electron-transfer pathway provi...

  20. Development of efficient regeneration and transformation systems in Alstroemeria

    OpenAIRE

    Kim, J. B.

    2005-01-01

    This thesis describes an alternative regeneration system via somatic embryogenesis of leaves with axil tissue and the application of this system for genetic modification in Alstroemeria . Both compact embryogenic callus (CEC) and friable embryogenic callus (FEC) were induced from leaves with axil tissues. Alstroemeria plants were regenerated from somatic embryos induced from CEC and FEC within six to seven months. Protoplasts were successfully and efficiently isolated from FEC culture. After ...

  1. 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.

  2. Hyperactivated Stat3 boosts axon regeneration in the CNS.

    Science.gov (United States)

    Mehta, Saloni T; Luo, Xueting; Park, Kevin K; Bixby, John L; Lemmon, Vance P

    2016-06-01

    Axonal regeneration after spinal cord injury (SCI) is intrinsically and extrinsically inhibited by multiple factors. One major factor contributing to intrinsic regeneration failure is the inability of mature neurons in the central nervous system (CNS) to activate regeneration-associated transcription factors (TFs) post-injury. A prior study identified TFs overexpressed in neurons of the peripheral nervous system (PNS) compared to the CNS; some of these could be involved in the ability of PNS neurons to regenerate. Of these, signal transducer and activator of transcription 3 (STAT3), as well its downstream regeneration-associated targets, showed a significant upregulation in PNS neurons relative to CNS neurons, and a constitutively active variant of Stat3 (Stat3CA) promoted neurite growth when expressed in cerebellar neurons (Lerch et al., 2012; Smith et al., 2011). To further enhance STAT3's neurite outgrowth enhancing activity, Stat3CA was fused with a viral activation domain (VP16). VP16 hyperactivates TFs by recruiting transcriptional co-factors to the DNA binding domain (Hirai et al., 2010). Overexpression of this VP16-Stat3CA chimera in primary cortical neurons led to a significant increase of neurite outgrowth as well as Stat3 transcriptional activity in vitro. Furthermore, in vivo transduction of retinal ganglion cells (RGCs) with AAV constructs expressing VP16-Stat3CA resulted in regeneration of optic nerve axons after injury, to a greater degree than for those expressing Stat3CA alone. These findings confirm and extend the concept that overexpression of hyperactivated transcription factors identified as functioning in PNS regeneration can promote axon regeneration in the CNS. PMID:27060489

  3. In vitro regeneration of wild chervil (Anthriscus sylvestris L.)

    OpenAIRE

    Hendrawati, Oktavia; Hille, Jacques; Woerdenbag, Herman J.; Quax, Wim J.; Kayser, Oliver; Finer, J.

    2012-01-01

    Anthriscus sylvestris (L.) Hoffm. (Apiaceae) is a common wild plant that accumulates the lignan deoxypodophyllotoxin. Deoxypodophyllotoxin can be hydroxylated at the C-7 position in recombinant organisms yielding podophyllotoxin, which is used as a semi-synthetic precursor for the anticancer drugs, etoposide phosphate and teniposide. As in vitro regeneration of A. sylvestris has not yet been reported, development of a regeneration protocol for A. sylvestris would be useful as a micropropagati...

  4. In vitro regeneration of wild chervil ( Anthriscus sylvestris L.)

    OpenAIRE

    Hendrawati, Oktavia; Hille, Jacques; Woerdenbag, Herman J.; Quax, Wim J.; Kayser, Oliver

    2011-01-01

    Anthriscus sylvestris (L.) Hoffm. (Apiaceae) is a common wild plant that accumulates the lignan deoxypodophyllotoxin. Deoxypodophyllotoxin can be hydroxylated at the C-7 position in recombinant organisms yielding podophyllotoxin, which is used as a semi-synthetic precursor for the anticancer drugs, etoposide phosphate and teniposide. As in vitro regeneration of A. sylvestris has not yet been reported, development of a regeneration protocol for A. sylvestris would be useful as a micropropagati...

  5. The valuation of urban regeneration land: A contemporary perspective

    OpenAIRE

    N.E. Hutchison; N.E. Hutchinson; Adair, A.; Burgess, J

    2001-01-01

    A fundamental element of UK urban policy, as outlined in the Urban White Paper, is the redevelopment of inner city land (DETR, 2000). However the valuation of urban regeneration land, in connection with grant funding, is said to be one of the most vexed issues in the appraisal of projects (Beattie, 1991). This is due to a lack of transparency across valuation and property data in urban regeneration markets, shortcomings in traditional valuation methodologies (Adams et al, 1985) and complexiti...

  6. Molecular and cellular mechanisms of heart regeneration in zebrafish

    OpenAIRE

    Sleep Ronquillo, Eduard

    2010-01-01

    In contrast to mammals, zebrafish do have the ability to regenerate their heart after injury. A better understanding of how regenerationcompetent species do so should help developing strategies to enhance human cardiac regeneration. Here, by genetic lineage-tracing using an inducible Cre/lox system, we show that newly formed cardiomyocytes arise from the proliferation of differentiated heart muscle cells. These results argue against a significant contribution of stem or progenitor cells in th...

  7. Potential Use of Stem Cells for Kidney Regeneration

    OpenAIRE

    Takashi Yokoo; Kei Matsumoto; Shinya Yokote

    2011-01-01

    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 strat...

  8. Spatial patterns and processes in a regenerating mangrove forest

    OpenAIRE

    Pranchai, Aor

    2015-01-01

    The global effort to rehabilitate and restore destroyed mangrove forests is unable to keep up with the high mangrove deforestation rates which exceed the average pace of global deforestation by three to five times. Our knowledge of the underlying processes of mangrove forest regeneration is too limited in order to find suitable techniques for the restoration of degraded mangrove areas. The general objective of my dissertation was to improve mangrove restoration by understanding regeneration p...

  9. Regeneration patterns of Quercus suber according to montado management systems

    OpenAIRE

    Simões, M. Paula; Belo, Anabela F.; Fernandes, Mariana; Madeira, Manuel

    2016-01-01

    Traditional management of montado (dehesa) is an example of integration of sustainable land-use and biodiversity conservation. The whole system sustainability is currently threatened by the intensification of soil tilling to control shrub invasion and promote pastureland, the absence of tree natural regeneration being one of the most outstanding threats. A study to assess effects of management on tree regeneration at early stages was developed in a cork oak montado grazed by cattle, in southe...

  10. Role of Transcription Factors in Peripheral Nerve Regeneration

    OpenAIRE

    Patodia, Smriti; Raivich, Gennadij

    2012-01-01

    Following axotomy, the activation of multiple intracellular signaling cascades causes the expression of a cocktail of regeneration-associated transcription factors which interact with each other to determine the fate of the injured neurons. The nerve injury response is channeled through manifold and parallel pathways, integrating diverse inputs, and controlling a complex transcriptional output. Transcription factors form a vital link in the chain of regeneration, converting injury-induced str...

  11. Hydrocarbon-enhanced particulate filter regeneration via microwave ignition

    Science.gov (United States)

    Gonze, Eugene V.; Brown, David B.

    2010-02-02

    A regeneration method for a particulate filter includes estimating a quantity of particulate matter trapped within the particulate filter, comparing the quantity of particulate matter to a predetermined quantity, heating at least a portion of the particulate filter to a combustion temperature of the particulate matter, and introducing hydrocarbon fuel to the particulate filter. The hydrocarbon fuel facilitates combustion of the particulate matter to regenerate the particulate filter.

  12. Investigation on porous frequency of regenerator of microminiature thermoacoustic refrigerator

    Institute of Scientific and Technical Information of China (English)

    LIU Yi-cai; ZHOU Jie-min; ZHOU Nai-jun; LIAO Sheng-ming

    2005-01-01

    A new method was proposed to directly measure the effective resistance and distinguish the porous frequency in the regenerator of the microminiature thermoacoustic refrigerator. Measured results were compared with the flux gain factor and transmission loss of the real system. The results show that the agreement between the range of the porous frequency and frequency of the system is good, the method can be used to predict the porous frequency of the regenerator in production.

  13. Axon Regeneration in the Peripheral and Central Nervous Systems

    OpenAIRE

    Huebner, Eric A.; Strittmatter, Stephen M

    2009-01-01

    Axon regeneration in the mature mammalian central nervous system (CNS) is extremely limited after injury. Consequently, functional deficits persist after spinal cord injury (SCI), traumatic brain injury, stroke, and related conditions that involve axonal disconnection. This situation differs from that in the mammalian peripheral nervous system (PNS), where long- distance axon regeneration and substantial functional recovery can occur in the adult. Both extracellular molecules and the intrinsi...

  14. Cardiac Regeneration using Growth Factors: Advances and Challenges

    OpenAIRE

    Juliana de Souza Rebouças; Nereide Stela Santos-Magalhães; Fabio Rocha Formiga

    2016-01-01

    Abstract Myocardial infarction is the most significant manifestation of ischemic heart disease and is associated with high morbidity and mortality. Novel strategies targeting at regenerating the injured myocardium have been investigated, including gene therapy, cell therapy, and the use of growth factors. Growth factor therapy has aroused interest in cardiovascular medicine because of the regeneration mechanisms induced by these biomolecules, including angiogenesis, extracellular matrix remod...

  15. Bone Regeneration Mediated by Biomimetic Mineralization of a Nanofiber Matrix

    OpenAIRE

    Mata, Alvaro; Geng, Yanbiao; Henrikson, Karl; Aparicio, Conrado; Stock, Stuart; Satcher, Robert L.; Stupp, Samuel I.

    2010-01-01

    Rapid bone regeneration within a three-dimensional defect without the use of bone grafts, exogenous growth factors, or cells remains a major challenge. We report here on the use of self-assembling peptide nanostructured gels to promote bone regeneration that have the capacity to mineralize in biomimetic fashion. The main molecular design was the use of phosphoserine residues in the sequence of a peptide amphiphile known to nucleate hydroxyapatite crystals on the surfaces of nanofibers. We tes...

  16. Novel Plant Regeneration and Transient Gene Expression in Catharanthus roseus

    OpenAIRE

    Abdullah Makhzoum; Anica Bjelica; Genevieve Petit-Paly; Bernards, Mark A

    2015-01-01

    Catharanthus roseus genetic transformation represents a real challenge due, in part, to the lack of regeneration capability and this species’ recalcitrance to genetic transformation. In the present work, we demonstrate the regeneration of C. roseus plants from hypocotyls and cotyledons, using specific growth regulator conditions. Plants derived from hypocotyls and cotyledons were successfully acclimated and grown in the greenhouse. Furthermore, C. roseus meristem tissues were shown to have hi...

  17. Catharanthus roseus (L.) G. Don - plant regeneration and alkaloids content

    OpenAIRE

    Mirosława Furmanowa; Hanna Olędzka; Joanna Józefowicz; Agnieszka Pietrosiuk

    2014-01-01

    We describe here a regeneration of plantlets of Catharanthus roseus (L.) G. Don from shoot tips and axillary buds. Shoot tips were excised from 7-day-old seedlings and were incubated in solid Nitsch and Nitsch (NN) medium supplemented with kinetin, benzyladenine (BA), indole-3-butyric acid (IBA) and β-indolylacetic acid (IAA) in various combinations. After two months in culture, regenerated rooted plantlets were cut and transferred to a new medium; the explants contained shoot tips or axillar...

  18. Bone marrow-derived cell regulation of skeletal muscle regeneration

    OpenAIRE

    Sun, Dongxu; Martinez, Carlo O.; OCHOA, OSCAR; Ruiz-Willhite, Lourdes; Bonilla, Jose R.; Centonze, Victoria E.; Waite, Lindsay L.; Joel E. Michalek; McManus, Linda M.; Shireman, Paula K.

    2009-01-01

    Limb regeneration requires the coordination of multiple stem cell populations to recapitulate the process of tissue formation. Therefore, bone marrow (BM) -derived cell regulation of skeletal muscle regeneration was examined in mice lacking the CC chemokine receptor 2 (CCR2). Myofiber size, numbers of myogenic progenitor cells (MPCs), and recruitment of BM-derived cells and macrophages were assessed after cardiotoxin-induced injury of chimeric mice produced by transplanting BM from wild-type ...

  19. Optimization of Energy and Exergy Consumption in MEG Regeneration Processes

    OpenAIRE

    Billington, Henrik Reymert

    2009-01-01

    Monoethylene glycol (MEG) is commonly used for hydrate inhibition in fields that require continuous injection. Traditional processes for regeneration and reclamation of MEG require significant amounts of heat. Reclamation (salt removal) is usually done by complete evaporation of salty MEG in a flash separator under partial vacuum. Regeneration (water removal) is done by distillation. Heat integration in current processes is limited. The oil and gas industry is heading towards energy systems b...

  20. Identification of proteins in fluid collected from nerve regeneration chambers

    Directory of Open Access Journals (Sweden)

    Ye Yilin

    2014-01-01

    Full Text Available We examined whether there are novel neurotrophic factors (NTFs in nerve regeneration conditioned fluid (NRCF. Nerve regeneration chamber models were established in the sciatic nerves of 25 New Zealand rabbits, and NRCF was extracted from the chambers l week postoperatively. Proteins in NRCF were separated by native polyacrylamide gel electrophoresis (PAGE, and Western blot and ELISA were used to identify the proteins. A novel NTF was identified in a protein fraction corresponding to 220 kDa.

  1. Effect of Polycaprolactone Scaffold Permeability on Bone Regeneration In Vivo

    OpenAIRE

    Mitsak, Anna G.; Kemppainen, Jessica M.; Harris, Matthew T.; Hollister, Scott J

    2011-01-01

    Successful bone tissue engineering depends on the scaffold's ability to allow nutrient diffusion to and waste removal from the regeneration site, as well as provide an appropriate mechanical environment. Since bone is highly vascularized, scaffolds that provide greater mass transport may support increased bone regeneration. Permeability encompasses the salient features of three-dimensional porous scaffold architecture effects on scaffold mass transport. We hypothesized that higher permeabilit...

  2. The study of terbium regenerated bacterirhodopsin

    Institute of Scientific and Technical Information of China (English)

    XU; Bing; ZHANG; Yue; HU; Kunsheng

    2005-01-01

    The localization of Terbium (Tb3+) cations binding to deionized bacteriorhodopsin (bR) has been studied by using spectroscopic methods. It was found that adding Tb3+ cations to deionized bR affects the fluorescence lifetimes of tryptophan (Trp) in bR, the wavelength of fluorescence peak shifts "blue" and the peak value of fluorescence decreases. It was also found that adding one Tb3+ cation to deionized bR can restore the purple state from its blue state obviously. The measurements of absorbance, fluorescence and lifetime of fluorescence also show that when more than three Tb3+ cations are added, no further changes can be found. It is suggested that one Tb3+ specific binding site for the color-controlling is located on the exterior of the bR trimer structure to negatively charged lipids near Trp-10 and Trp-12. Three Tb3+ cations binding per bR is needed for the regenerated bR.

  3. Axonal PPARγ promotes neuronal regeneration after injury.

    Science.gov (United States)

    Lezana, Juan Pablo; Dagan, Shachar Y; Robinson, Ari; Goldstein, Ronald S; Fainzilber, Mike; Bronfman, Francisca C; Bronfman, Miguel

    2016-06-01

    PPARγ is a ligand-activated nuclear receptor best known for its involvement in adipogenesis and glucose homeostasis. PPARγ activity has also been associated with neuroprotection in different neurological disorders, but the mechanisms involved in PPARγ effects in the nervous system are still unknown. Here we describe a new functional role for PPARγ in neuronal responses to injury. We found both PPAR transcripts and protein within sensory axons and observed an increase in PPARγ protein levels after sciatic nerve crush. This was correlated with increased retrograde transport of PPARγ after injury, increased association of PPARγ with the molecular motor dynein, and increased nuclear accumulation of PPARγ in cell bodies of sensory neurons. Furthermore, PPARγ antagonists attenuated the response of sensory neurons to sciatic nerve injury, and inhibited axonal growth of both sensory and cortical neurons in culture. Thus, axonal PPARγ is involved in neuronal injury responses required for axonal regeneration. Since PPARγ is a major molecular target of the thiazolidinedione (TZD) class of drugs used in the treatment of type II diabetes, several pharmaceutical agents with acceptable safety profiles in humans are available. Our findings provide motivation and rationale for the evaluation of such agents for efficacy in central and peripheral nerve injuries. PMID:26446277

  4. Effortless effort in bone regeneration: a review.

    Science.gov (United States)

    Nazirkar, Girish; Singh, Shailendra; Dole, Vinaykumar; Nikam, Akhilesh

    2014-06-01

    Since the beginning of the 20th century, the concept of osteoconduction in bony changes in the oral cavity showed a wide range of biomaterials and their osteoinductive potential that emerged gradually and has to a large extent improved the quality of the bone prior to the placement of an implant. Alveolar bone loss is a major concern after tooth extraction in patients and therefore atraumatic extraction procedures should be followed to avoid further bone loss. To overcome the alveolar bone loss and to augment support for placing dental implants, many bone regenerative substitutes are available such as allografts, autografts, xenografts, synthetic biomaterials and osteoactive agents. In light of the steady progress in bone grafting techniques and graft materials, it has become possible to improve the volume, width, and height of bone in deficient areas of the oral cavity. These advances in regenerative dentistry thus facilitate an easy and convenient placement of an implant in an ideal position and angulations resulting in superior esthetics and function. Bone grafting materials and their substitutes are the alternative filler materials, which facilitate to reduce additional surgical procedures, risks, chances of cross infection involved in placing autografts and allografts into the bony structures. This review literature highlights various biomaterials that are helpful in bone healing and thus create an anatomically favorable base for ideal implant placement. How to cite the article: Nazirkar G, Singh S, Dole V, Nikam A. Effortless effort in bone regeneration: A review. J Int Oral Health 2014;6(3):120-4. PMID:25083047

  5. Bioengineered Lacrimal Gland Organ Regeneration in Vivo

    Directory of Open Access Journals (Sweden)

    Masatoshi Hirayama

    2015-07-01

    Full Text Available The lacrimal gland plays an important role in maintaining a homeostatic environment for healthy ocular surfaces via tear secretion. Dry eye disease, which is caused by lacrimal gland dysfunction, is one of the most prevalent eye disorders and causes ocular discomfort, significant visual disturbances, and a reduced quality of life. Current therapies for dry eye disease, including artificial tear eye drops, are transient and palliative. The lacrimal gland, which consists of acini, ducts, and myoepithelial cells, develops from its organ germ via reciprocal epithelial-mesenchymal interactions during embryogenesis. Lacrimal tissue stem cells have been identified for use in regenerative therapeutic approaches aimed at restoring lacrimal gland functions. Fully functional organ replacement, such as for tooth and hair follicles, has also been developed via a novel three-dimensional stem cell manipulation, designated the Organ Germ Method, as a next-generation regenerative medicine. Recently, we successfully developed fully functional bioengineered lacrimal gland replacements after transplanting a bioengineered organ germ using this method. This study represented a significant advance in potential lacrimal gland organ replacement as a novel regenerative therapy for dry eye disease. In this review, we will summarize recent progress in lacrimal regeneration research and the development of bioengineered lacrimal gland organ replacement therapy.

  6. Heart regeneration in adult MRL mice

    Science.gov (United States)

    Leferovich, John M.; Bedelbaeva, Khamilia; Samulewicz, Stefan; Zhang, Xiang-Ming; Zwas, Donna; Lankford, Edward B.; Heber-Katz, Ellen

    2001-08-01

    The reaction of cardiac tissue to acute injury involves interacting cascades of cellular and molecular responses that encompass inflammation, hormonal signaling, extracellular matrix remodeling, and compensatory adaptation of myocytes. Myocardial regeneration is observed in amphibians, whereas scar formation characterizes cardiac ventricular wound healing in a variety of mammalian injury models. We have previously shown that the MRL mouse strain has an extraordinary capacity to heal surgical wounds, a complex trait that maps to at least seven genetic loci. Here, we extend these studies to cardiac wounds and demonstrate that a severe transmural, cryogenically induced infarction of the right ventricle heals extensively within 60 days, with the restoration of normal myocardium and function. Scarring is markedly reduced in MRL mice compared with C57BL/6 mice, consistent with both the reduced hydroxyproline levels seen after injury and an elevated cardiomyocyte mitotic index of 10-20% for the MRL compared with 1-3% for the C57BL/6. The myocardial response to injury observed in these mice resembles the regenerative process seen in amphibians.

  7. Nanorheology of regenerated silk fibroin solution

    Indian Academy of Sciences (India)

    A Raghu; Sharath Ananthamurthy

    2008-06-01

    We have investigated the rheological properties of regenerated silk fibroin (RSF), a viscoelastic material at micro and nano length scales, by video microscopy. We describe here the principles and technique of video microscopy as a tool in such investigations. In this work, polystyrene beads were dispersed in the matrix of RSF polymer and the positions of the embedded beads diffusing were tracked using video microscopy. An optical tweezer was used to transport and locate the bead at any desired site within the micro-volume of the sample, to facilitate the subsequent free-bead video analysis. The position information of the beads was used to obtain the time dependant mean squared displacement (MSD) of the beads in the medium and hence to calculate the dynamic moduli of the medium. We present here the results of rheological measurements of the silk polymer network in solution over a frequency range, whose upper limit is the frame capture rate of our camera at full resolution. The technique is complementary to other microrheological techniques to characterize the material, but additionally enables one to characterize local inhomogeneities in the medium, features that get averaged out in bulk characterization procedures.

  8. Regeneration of ammonia borane spent fuel

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, Andrew David [Los Alamos National Laboratory; Davis, Benjamin L [Los Alamos National Laboratory; Gordon, John C [Los Alamos National Laboratory

    2009-01-01

    A necessary target in realizing a hydrogen (H{sub 2}) economy, especially for the transportation sector, is its storage for controlled delivery, presumably to an energy producing fuel cell. In this vein, the U.S. Department of Energy's Centers of Excellence (CoE) in Hydrogen Storage have pursued different methodologies, including metal hydrides, chemical hydrides, and sorbents, for the expressed purpose of supplanting gasoline's current > 300 mile driving range. Chemical H{sub 2} storage has been dominated by one appealing material, ammonia borane (H{sub 3}N-BH{sub 3}, AB), due to its high gravimetric capacity of H{sub 2} (19.6 wt %) and low molecular weight (30.7 g mol{sup -1}). In addition, AB has both hydridic and protic moieties, yielding a material from which H{sub 2} can be readily released in contrast to the loss of H{sub 2} from C{sub 2}H{sub 6} which is substantially endothermic. As such, a number of publications have described H{sub 2} release from amine boranes, yielding various rates depending on the method applied. The viability of any chemical H{sub 2} storage system is critically dependent on efficient recyclability, but reports on the latter subject are sparse, invoke the use of high energy reducing agents, and suffer from low yields. Our group is currently engaged in trying to find and fully demonstrate an energy efficient regeneration process for the spent fuel from H{sub 2} depleted AB with a minimum number of steps. Although spent fuel composition depends on the dehydrogenation method, we have focused our efforts on the spent fuel resulting from metal-based catalysis, which has thus far shown the most promise. Metal-based catalysts have produced the fastest rates for a single equivalent of H{sub 2} released from AB and up to 2.5 equiv. of H{sub 2} can be produced within 2 hours. While ongoing work is being carried out to tailor the composition of spent AB fuel, a method has been developed for regenerating the predominant product

  9. 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

  10. Temperature-Sensitive Mutations That Cause Stage-Specific Defects in Zebrafish Fin Regeneration

    OpenAIRE

    Johnson, S. L.; Weston, J A

    1995-01-01

    When amputated, the fins of adult zebrafish rapidly regenerate the missing tissue. Fin regeneration proceeds through several stages, including wound healing, establishment of the wound epithelium, recruitment of the blastema from mesenchymal cells underlying the wound epithelium, and differentiation and outgrowth of the regenerate. We screened for temperature-sensitive mutations that affect the regeneration of the fin. Seven mutations were identified, including five that fail to regenerate th...

  11. Gene-expression analysis of hair cell regeneration in the zebrafish lateral line

    OpenAIRE

    Jiang, Linjia; Romero-Carvajal, Andres; Haug, Jeff S.; Seidel, Christopher W.; Piotrowski, Tatjana

    2014-01-01

    Deafness is caused largely by the death of sensory hair cells in the inner ear. In contrast to nonmammalian vertebrates, human hair cells do not regenerate. Understanding the mechanisms that regulate hair cell regeneration in zebrafish may shed light on the factors that prevent hair cell regeneration in mammals. RNA-Seq analysis of regenerating sensory organs uncovered dynamic changes in the expression of signaling pathways during zebrafish hair cell regeneration. Unexpectedly, the Wnt/β-cate...

  12. pbx is required for pole and eye regeneration in planarians.

    Science.gov (United States)

    Chen, Chun-Chieh G; Wang, Irving E; Reddien, Peter W

    2013-02-01

    Planarian regeneration involves regionalized gene expression that specifies the body plan. After amputation, planarians are capable of regenerating new anterior and posterior poles, as well as tissues polarized along the anterior-posterior, dorsal-ventral and medial-lateral axes. Wnt and several Hox genes are expressed at the posterior pole, whereas Wnt inhibitory genes, Fgf inhibitory genes, and prep, which encodes a TALE-family homeodomain protein, are expressed at the anterior pole. We found that Smed-pbx (pbx for short), which encodes a second planarian TALE-family homeodomain transcription factor, is required for restored expression of these genes at anterior and posterior poles during regeneration. Moreover, pbx(RNAi) animals gradually lose pole gene expression during homeostasis. By contrast, pbx was not required for initial anterior-posterior polarized responses to wounds, indicating that pbx is required after wound responses for development and maintenance of poles during regeneration and homeostatic tissue turnover. Independently of the requirement for pbx in pole regeneration, pbx is required for eye precursor formation and, consequently, eye regeneration and eye replacement in homeostasis. Together, these data indicate that pbx promotes pole formation of body axes and formation of regenerative progenitors for eyes. PMID:23318641

  13. The role of the liver in liver regeneration

    International Nuclear Information System (INIS)

    Liver regeneration has been studied almost exclusively in the rat model, and the characteristic response after partial hepatectomy is well established. Large animals have been used to a limited extent, mainly because the measurement of regeneration has been prohibitively expensive. A suitable index of liver regeneration was sought in order to be able to utilise the advantages of a large animal like the pig. Activity of thymidine kinase, which phosphorylates thymidine prior to its incorporation into DNA, was evaluated by comparing it to 14C-thymidine incorporation after partial hepatectomy in the rat model. The changes in thymidine kinase activity correlated well with those in 14C-thymidine incorporation, thus validating use of the former as an index of liver regeneration. This study details a simple and reproducible model - that of 50% partial hepatectomy in the pig - and describes the regenerative response, using thymidine kinase activity as the index of regeneration. Enzyme activity increased on the second and reached a peak on the third post-operative day. The role of the liver in liver regeneration was also investigated by transplanting either a partially hepatectomised or an intact auxiliary liver in such a way that blood flowed through the transplanted liver and into the host liver

  14. Fuel economy: thermochemical regeneration and new method of coal gasification

    Energy Technology Data Exchange (ETDEWEB)

    Nosach, V.H.

    1982-02-01

    Heat regeneration and coal gasification are two means of increasing the efficiency of utilizing fossil fuel resources. Two methods of heat regeneration are discussed: air regeneration and a new method, thermochemical regeneration. Use of thermochemical regeneration in heat-utilizing aggregates has increased fuel efficiency by 15-20%, and the combined use of both heat regeneration methods is also highly effective. The increased use of coal is generally associated with the greater air pollution. The most effective method of controlling harmful atmospheric emissions by coal-fueled power plants is a two-stage combustion system with preliminary coal gasification to remove sulfur and ash and combustion of the pure gasification products. But the introduction of coal gasification has increased the need for designing new gas generators. The advantages of using coal gasification at electric power plants include increasing the reliability of steam generators, decreasing expenditures for transporting fuel, and more complete utilization of coal. Coal gasification also broadens the use of low-quality coal. Gasification of Siberian coal with the production of synthetic natural gas also lessens the problem of transporting energy resources from Siberia to central regions of the USSR. A continuous method has been developed for producing synthetic gas by steam gasification of coal without use of oxygen.

  15. Sensory hair cell death and regeneration in fishes

    Directory of Open Access Journals (Sweden)

    Gopinath Rajadinakaran

    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.

  16. Biological biomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Jorge-Herrero, E. [Servicio de Cirugia Experimental. Clinica Puerta de Hierro, Madrid (Spain)

    1997-05-01

    There are a number of situations in which substances of biological origin are employed as biomaterials. Most of them are macromolecules derived from isolated connective tissue or the connective tissue itself in membrane form, in both cases, the tissue can be used in its natural form or be chemically treated. In other cases, certain blood vessels can be chemically pretreated and used as vascular prostheses. Proteins such as albumin, collagen and fibrinogen are employed to coat vascular prostheses. Certain polysaccharides have also been tested for use in controlled drug release systems. Likewise, a number of tissues, such as dura mater, bovine pericardium, procine valves and human valves, are used in the preparation of cardiac prostheses. We also use veins from animals or humans in arterial replacement. In none of these cases are the tissues employed dissimilar to the native tissues as they have been chemically modified, becoming a new bio material with different physical and biochemical properties. In short, we find that natural products are being utilized as biomaterials and must be considered as such; thus, it is necessary to study both their chemicobiological and physicomechanical properties. In the present report, we review the current applications, problems and future prospects of some of these biological biomaterials. (Author) 84 refs.

  17. 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.

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

    International Nuclear Information System (INIS)

    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

  19. The transcription factor Sox11 promotes nerve regeneration through activation of the regeneration-associated gene Sprr1a

    OpenAIRE

    Jing, Xiaotang; Wang, Ting; Huang, Shaohua; Glorioso, Joseph C.; Albers, Kathryn M.

    2011-01-01

    Factors that enhance the intrinsic growth potential of adult neurons are key players in the successful repair and regeneration of neurons following injury. Injury-induced activation of transcription factors has a central role in this process because they regulate expression of regeneration-associated genes. Sox11 is a developmentally expressed transcription factor that is significantly induced in adult neurons in response to injury. Its function in injured neurons is however undefined. Here, ...

  20. In vitro evaluation of various bioabsorbable and nonresorbable barrier membranes for guided tissue regeneration

    Directory of Open Access Journals (Sweden)

    Smeets Ralf

    2008-10-01

    Full Text Available Abstract Background Different types of bioabsorbable and nonresorbable membranes have been widely used for guided tissue regeneration (GTR with its ultimate goal of regenerating lost periodontal structures. The purpose of the present study was to evaluate the biological effects of various bioabsorbable and nonresorbable membranes in cultures of primary human gingival fibroblasts (HGF, periodontal ligament fibroblasts (PDLF and human osteoblast-like (HOB cells in vitro. Methods Three commercially available collagen membranes [TutoDent® (TD, Resodont® (RD and BioGide® (BG] as well as three nonresorbable polytetrafluoroethylene (PTFE membranes [ACE (AC, Cytoplast® (CT and TefGen-FD® (TG] were tested. Cells plated on culture dishes (CD served as positive controls. The effect of the barrier membranes on HGF, PDLF as well as HOB cells was assessed by the Alamar Blue fluorometric proliferation assay after 1, 2.5, 4, 24 and 48 h time periods. The structural and morphological properties of the membranes were evaluated by scanning electron microscopy (SEM. Results The results showed that of the six barriers tested, TD and RD demonstrated the highest rate of HGF proliferation at both earlier (1 h and later (48 h time periods (P P ≤ 0.001. In HOB cell culture, the highest rate of cell proliferation was also calculated for TD at all time periods (P Conclusion Results from the present study suggested that GTR membrane materials, per se, may influence cell proliferation in the process of periodontal tissue/bone regeneration. Among the six membranes examined, the bioabsorbable membranes demonstrated to be more suitable to stimulate cellular proliferation compared to nonresorbable PTFE membranes.

  1. Aligned Nanofibers for Regenerating Arteries, Nerves, and Muscles

    Science.gov (United States)

    McClendon, Mark Trosper

    Cells are the fundamental unit of the human body, and therefore the ability to control cell behavior is the most important challenge in regenerative medicine. Peptides are the language of biology which is why synthetic peptide amphiphile (PA) molecules hold great potential as a biomaterial. The work presented in this dissertation explores a variety of liquid crystalline PA nanofibers as a means for directing cell growth. Shaping the alignment of these nanofiber networks requires a deep understanding of their rheological properties which presents a difficult challenge as they exist in complex solid and liquid environments. Using PA molecules that self-assemble into high aspect ratio nanofibers and liquid crystalline solutions, this work investigates the influence of shear flow on macroscopic and microscopic nanofiber alignment. To this end, a shear force applied to PA solutions was systematically varied while the alignment was probed using small angle x-ray scattering. Nanofibers were found to respond to shear flow by aligning parallel to the flow direction. By changing pH and PA chemical sequence it was observed that increasing the interfiber electrostatic repulsive interactions resulted in a greater dependence on shear rate. Nanofiber solutions having greater repulsion did not drastically increase in alignment when the applied strain was increased by two orders of magnitude (1 s -1 to 100 s-1), while solutions with nanofibers having less repulsion increased there alignment four fold with the same strain increase. say exactly what you mean by resulted in greater dependence: did it result in fibers aligning under lower shear rates or higher rates--give the results Anionic PA solutions typically used to encapsulate living cells at neutral pH were found to require minimal shear rates, nerve conduits, and these scaffolds were implanted in a rat sciatic nerve model. Histological and behavioral observations confirmed that PA implants sustained regeneration rates

  2. Creating biological nanomaterials using synthetic biology

    International Nuclear Information System (INIS)

    Synthetic biology is a new discipline that combines science and engineering approaches to precisely control biological networks. These signaling networks are especially important in fields such as biomedicine and biochemical engineering. Additionally, biological networks can also be critical to the production of naturally occurring biological nanomaterials, and as a result, synthetic biology holds tremendous potential in creating new materials. This review introduces the field of synthetic biology, discusses how biological systems naturally produce materials, and then presents examples and strategies for incorporating synthetic biology approaches in the development of new materials. In particular, strategies for using synthetic biology to produce both organic and inorganic nanomaterials are discussed. Ultimately, synthetic biology holds the potential to dramatically impact biological materials science with significant potential applications in medical systems. (review)

  3. Creating biological nanomaterials using synthetic biology

    Directory of Open Access Journals (Sweden)

    MaryJoe K Rice

    2014-01-01

    Full Text Available Synthetic biology is a new discipline that combines science and engineering approaches to precisely control biological networks. These signaling networks are especially important in fields such as biomedicine and biochemical engineering. Additionally, biological networks can also be critical to the production of naturally occurring biological nanomaterials, and as a result, synthetic biology holds tremendous potential in creating new materials. This review introduces the field of synthetic biology, discusses how biological systems naturally produce materials, and then presents examples and strategies for incorporating synthetic biology approaches in the development of new materials. In particular, strategies for using synthetic biology to produce both organic and inorganic nanomaterials are discussed. Ultimately, synthetic biology holds the potential to dramatically impact biological materials science with significant potential applications in medical systems.

  4. Sustainable Urban Regeneration Based on Energy Balance

    Directory of Open Access Journals (Sweden)

    Sacha Silvester

    2012-07-01

    Full Text Available In this paper, results are reported of a technology assessment of the use and integration of decentralized energy systems and storage devices in an urban renewal area. First the general context of a different approach based on 'rethinking' and the incorporation of ongoing integration of coming economical and environmental interests on infrastructure, in relation to the sustainable urban development and regeneration from the perspective of the tripod people, technology and design is elaborated. However, this is at different scales, starting mainly from the perspective of the urban dynamics. This approach includes a renewed look at the ‘urban metabolism’ and the role of environmental technology, urban ecology and environment behavior focus. Second, the potential benefits of strategic and balanced introduction and use of decentralized devices and electric vehicles (EVs, and attached generation based on renewables are investigated in more detail in the case study of the ‘Merwe-Vierhaven’ area (MW4 in the Rotterdam city port in the Netherlands. In order to optimize the energy balance of this urban renewal area, it is found to be impossible to do this by tuning the energy consumption. It is more effective to change the energy mix and related infrastructures. However, the problem in existing urban areas is that often these areas are restricted to a few energy sources due to lack of available space for integration. Besides this, energy consumption in most cases is relatively concentrated in (existing urban areas. This limits the potential of sustainable urban regeneration based on decentralized systems, because there is no balanced choice regarding the energy mix based on renewables and system optimization. Possible solutions to obtain a balanced energy profile can come from either the choice to not provide all energy locally, or by adding different types of storage devices to the systems. The use of energy balance based on renewables as a

  5. Quality assurance (QA) program in BNCT. RBE of 7 NCT beams for intestinal crypt regeneration in mice

    International Nuclear Information System (INIS)

    The epithermal neutron beams presently used for Neutron Capture Therapy (NCT) differ substantially in their composition (relative contribution of the different dose components to the total dose), in their dose rate (depending on the power of the reactor) as well as in their general feature (e.g. beam delivery system). Each of these elements might alter significantly the biological effectiveness of the beams. Therefore, the Relative Biological Effectiveness (RBE) of 7 NCT beams was intercompared, for a reference biological system (crypt regeneration in mice) and under well-defined irradiation conditions. This type of experiments - which should facilitate the exchange of radiobiological/clinical information - should take part of the Quality Assurance (QA) procedure of all NCT beams. (author)

  6. Tissue engineering and regeneration using biodegradable scaffolds.

    Science.gov (United States)

    Zhang, X; Zhang, Y

    2015-12-01

    A number of people across the world suffer from various diseases or genetic defects and many of these patients die because of the lack of the availability of ideal tissue substitute and/or treatment. An important aspect of the disease is its association with the loss of tissue function. Many end-stage diseases and/or complete organ failure often require total or partial organ transplantation to restore functionality. However, such transplantation surgeries are not always successful because of the organ/ tissue rejection and also the scarcity of donors. Regenerative medicine and tissue engineering aim to improve or repair the function of a dysfunctional tissue or organ. In spite of the many advances in tissue engineering methods, the field of regenerative medicine still awaits acceptable designs of bioscaffolds that are clinically tenable. Design of scaffolds and the nature of biomaterial used to make the scaffolds dictate cell behavior and function. Several approaches are currently being tried to optimize the design and improve the quality of the biomaterials. Innervation, vascularization and proper cell differentiation that are influenced by the biomaterials, are few challenges that need to be optimized along with the choice of stem cells that can be employed. Extracellular matrix scaffolds have proven to be a better choice for cartilage and bone repair while the fibrin, polyglycolate and polylactate etc are still being developed. Future research and technological innovations are still needed for a better choice of biomaterials that can support the tissue regeneration without causing any immune or inflammatory response from the host and which last for longer periods. PMID:25634586

  7. 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.

  8. The Role of Pannexin Hemichannels in Inflammation and Regeneration

    Directory of Open Access Journals (Sweden)

    Helen P. Makarenkova

    2014-02-01

    Full Text Available Tissue injury involves coordinated systemic responses including inflammatory response, targeted cell migration, cell-cell communication, stem cell activation and proliferation, and tissue regeneration. The inflammatory response is an important prerequisite for regeneration. Multiple studies suggest that extensive cell-cell communication during tissue regeneration is coordinated by purinergic signaling via extracellular ATP. Most recent data indicates that ATP release for such communication is mediated by hemichannels formed by connexins and pannexins. The Pannexin family consists of three vertebrate proteins (Panx 1, 2, and 3 that have low sequence homology with other gap junction proteins and were shown to form predominantly non-junctional plasma membrane hemichannels. Pannexin-1 (Panx1 channels function as an integral component of the P2X receptor (P2XR (purinergic signaling pathway and is arguably the major contributor to pathophysiological ATP release. Panx1 is expressed in many tissues, with highest levels detected in developing brain, retina and skeletal muscles. Panx1 channel expression and activity is reported to increase significantly following injury/inflammation and during regeneration and differentiation. Recent studies also report that pharmacological blockade of the Panx1 channel or genetic ablation of the Panx1 gene cause significant disruption of progenitor cell migration, proliferation, and tissue regeneration. These findings suggest that pannexins play important roles in activation of both post-injury inflammatory response and the subsequent process of tissue regeneration. Due to wide expression in multiple tissues and involvement in diverse signaling pathways, pannexins and connexins are currently being considered as therapeutic targets for traumatic brain or spinal cord injuries, ischemic stroke and cancer. The precise role of pannexins and connexins in the balance between tissue inflammation and regeneration needs to be

  9. Hepatic regeneration after sublethal partial liver irradiation in cirrhotic rats

    International Nuclear Information System (INIS)

    Our previous animal study had demonstrated that partial liver irradiation (IR) could stimulate regeneration in the protected liver, which supported the measurements adopted in radiotherapy planning for hepatocellular carcinoma. The purpose of this present study is to investigate whether cirrhotic liver repopulation could be triggered by partial liver IR. The cirrhosis was induced by thioacetamide (TAA) in rats. After cirrhosis establishment, TAA was withdrawn. In Experiment 1, only right-half liver was irradiated with single doses of 5 Gy, 10 Gy and 15 Gy, respectively. In Experiment 2, right-half liver was irradiated to 15 Gy, and the left-half to 2.5 Gy, 5 Gy and 7.5 Gy, respectively. The regeneration endpoints, including liver index (LI); mitotic index (MI); liver proliferation index (LPI); proliferating cell nuclear antigen-labeling index (PCNA-LI); serum hepatic growth factor (HGF), vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-α and interleukin (IL)-6, were evaluated on 0 day, 30-day, 60-day, 90-day, 120-day and 150-day after IR. Serum and in situ TGF-β1 were also measured. In both experimental groups, the IR injuries were sublethal, inducing no more than 9% animal deaths. Upon TAA withdrawal, hepatic regeneration decelerated in the controls. In Experiment 1 except for LI, all other regeneration parameters were significantly higher than those in controls for both right-half and left-half livers. In Experiment 2 all regeneration parameters were also higher compared with those in controls for both half livers. Serum HGF and VEGF were increased compared with that of controls. Both unirradiated and low dose-irradiated cirrhotic liver were able to regenerate triggered by sublethal partial liver IR and higher doses and IR to both halves liver triggered a more enhanced regeneration. (author)

  10. Altered macrophage phenotype transition impairs skeletal muscle regeneration.

    Science.gov (United States)

    Wang, Hanzhou; Melton, David W; Porter, Laurel; Sarwar, Zaheer U; McManus, Linda M; Shireman, Paula K

    2014-04-01

    Monocyte/macrophage polarization in skeletal muscle regeneration is ill defined. We used CD11b-diphtheria toxin receptor transgenic mice to transiently deplete monocytes/macrophages at multiple stages before and after muscle injury induced by cardiotoxin. Fat accumulation within regenerated muscle was maximal when ablation occurred at the same time as cardiotoxin-induced injury. Early ablation (day 1 after cardiotoxin) resulted in the smallest regenerated myofiber size together with increased residual necrotic myofibers and fat accumulation. However, muscle regeneration after late (day 4) ablation was similar to controls. Levels of inflammatory cells in injured muscle following early ablation and associated with impaired muscle regeneration were determined by flow cytometry. Delayed, but exaggerated, monocyte [CD11b(+)(CD90/B220/CD49b/NK1.1/Ly6G)(-)(F4/80/I-Ab/CD11c)(-)Ly6C(+/-)] accumulation occurred; interestingly, Ly6C(+) and Ly6C(-) monocytes were present concurrently in ablated animals and control mice. In addition to monocytes, proinflammatory, Ly6C(+) macrophage accumulation following early ablation was delayed compared to controls. In both groups, CD11b(+)F4/80(+) cells exhibited minimal expression of the M2 markers CD206 and CD301. Nevertheless, early ablation delayed and decreased the transient accumulation of CD11b(+)F4/80(+)Ly6C(-)CD301(-) macrophages; in control animals, the later tissue accumulation of these cells appeared to correspond to that of anti-inflammatory macrophages, determined by cytokine production and arginase activity. In summary, impairments in muscle regeneration were associated with exaggerated monocyte recruitment and reduced Ly6C(-) macrophages; the switch of macrophage/monocyte subsets is critical to muscle regeneration. PMID:24525152

  11. Structural Biology Fact Sheet

    Science.gov (United States)

    ... Home > Science Education > Structural Biology Fact Sheet Structural Biology Fact Sheet Tagline (Optional) Middle/Main Content Area What is structural biology? Structural biology is a field of science focused ...

  12. The maintenance and regeneration of the planarian excretory system are regulated by EGFR signaling.

    Science.gov (United States)

    Rink, Jochen C; Vu, Hanh Thi-Kim; Sánchez Alvarado, Alejandro

    2011-09-01

    The maintenance of organs and their regeneration in case of injury are crucial to the survival of all animals. High rates of tissue turnover and nearly unlimited regenerative capabilities make planarian flatworms an ideal system with which to investigate these important processes, yet little is known about the cell biology and anatomy of their organs. Here we focus on the planarian excretory system, which consists of internal protonephridial tubules. We find that these assemble into complex branching patterns with a stereotyped succession of cell types along their length. Organ regeneration is likely to originate from a precursor structure arising in the blastema, which undergoes extensive branching morphogenesis. In an RNAi screen of signaling molecules, we identified an EGF receptor (Smed-EGFR-5) as a crucial regulator of branching morphogenesis and maintenance. Overall, our characterization of the planarian protonephridial system establishes a new paradigm for regenerative organogenesis and provides a platform for exploring its functional and evolutionary homologies with vertebrate excretory systems. PMID:21828097

  13. Lyophilized Platelet-Rich Fibrin (PRF Promotes Craniofacial Bone Regeneration through Runx2

    Directory of Open Access Journals (Sweden)

    Qi Li

    2014-05-01

    Full Text Available Freeze-drying is an effective means to control scaffold pore size and preserve its composition. The purpose of the present study was to determine the applicability of lyophilized Platelet-rich fibrin (LPRF as a scaffold for craniofacial tissue regeneration and to compare its biological effects with commonly used fresh Platelet-rich fibrin (PRF. LPRF caused a 4.8-fold ± 0.4-fold elevation in Runt-related transcription factor 2 (Runx2 expression in alveolar bone cells, compared to a 3.6-fold ± 0.2-fold increase when using fresh PRF, and a more than 10-fold rise of alkaline phosphatase levels and mineralization markers. LPRF-induced Runx2 expression only occurred in alveolar bone and not in periodontal or dental follicle cells. LPRF also caused a 1.6-fold increase in osteoblast proliferation (p < 0.001 when compared to fresh PRF. When applied in a rat craniofacial defect model for six weeks, LPRF resulted in 97% bony coverage of the defect, compared to 84% for fresh PRF, 64% for fibrin, and 16% without scaffold. Moreover, LPRF thickened the trabecular diameter by 25% when compared to fresh PRF and fibrin, and only LPRF and fresh PRF resulted in the formation of interconnected trabeculae across the defect. Together, these studies support the application of lyophilized PRF as a biomimetic scaffold for craniofacial bone regeneration and mineralized tissue engineering.

  14. A Review of Gene Delivery and Stem Cell Based Therapies for Regenerating Inner Ear Hair Cells

    Directory of Open Access Journals (Sweden)

    Michael S. Detamore

    2011-09-01

    Full Text Available Sensory neural hearing loss and vestibular dysfunction have become the most common forms of sensory defects, affecting millions of people worldwide. Developing effective therapies to restore hearing loss is challenging, owing to the limited regenerative capacity of the inner ear hair cells. With recent advances in understanding the developmental biology of mammalian and non-mammalian hair cells a variety of strategies have emerged to restore lost hair cells are being developed. Two predominant strategies have developed to restore hair cells: transfer of genes responsible for hair cell genesis and replacement of missing cells via transfer of stem cells. In this review article, we evaluate the use of several genes involved in hair cell regeneration, the advantages and disadvantages of the different viral vectors employed in inner ear gene delivery and the insights gained from the use of embryonic, adult and induced pluripotent stem cells in generating inner ear hair cells. Understanding the role of genes, vectors and stem cells in therapeutic strategies led us to explore potential solutions to overcome the limitations associated with their use in hair cell regeneration.

  15. Morphogenetic Mechanisms in the Cyclic Regeneration of Hair Follicles and Deer Antlers from Stem Cells

    Directory of Open Access Journals (Sweden)

    Chunyi Li

    2013-01-01

    Full Text Available We have made comparisons between hair follicles (HFs and antler units (AUs—two seemingly unrelated mammalian organs. HFs are tiny and concealed within skin, whereas AUs are gigantic and grown externally for visual display. However, these two organs share some striking similarities. Both consist of permanent and cyclic/temporary components and undergo stem-cell-based organogenesis and cyclic regeneration. Stem cells of both organs reside in the permanent part and the growth centres are located in the temporary part of each respective organ. Organogenesis and regeneration of both organs depend on epithelial-mesenchymal interactions. Establishment of these interactions requires stem cells and reactive/niche cells (dermal papilla cells for HFs and epidermal cells for AUs to be juxtaposed, which is achieved through destruction of the cyclic part to bring the reactive cells into close proximity to the respective stem cell niche. Developments of HFs and AUs are regulated by similar endocrine (particularly testosterone and paracrine (particularly IGF1 factors. Interestingly, these two organs come to interplay during antlerogenesis. In conclusion, we believe that investigators from the fields of both HF and AU biology could greatly benefit from a comprehensive comparison between these two organs.

  16. Stem cells and related factors involved in facial nerve function regeneration.

    Science.gov (United States)

    Nelke, Kamil H; Łuczak, Klaudiusz; Pawlak, Wojciech; Łysenko, Lidia; Gerber, Hanna

    2015-01-01

    The facial nerve (VII) is one of the most important cranial nerves for head and neck surgeons. Its function is closely related to facial expressions that are individual for every person. After its injury or palsy, its functions can be either impaired or absent. Because of the presence of motor, sensory and parasympathetic fibers, the biology of its repair and function restoration depends on many factors. In order to achieve good outcome, many different therapies can be performed in order to restore as much of the nerve function as possible. When rehabilitation and physiotherapy are not sufficient, additional surgical procedures and therapies are taken into serious consideration. The final outcome of many of them is discussable, depending on nerve damage etiology. Stem cells in facial nerve repair are used, but long-term outcomes and results are still not fully known. In order to understand this therapeutic approach, clinicians and surgeons should understand the immunobiology of nerve repair and regeneration. In this review, potential stem cell usage in facial nerve regeneration procedures is discussed. PMID:26400886

  17. Perspectives for the treatment of sensorineural hearing loss by cellular regeneration of the inner ear.

    Science.gov (United States)

    Almeida-Branco, Mario S; Cabrera, Sonia; Lopez-Escamez, Jose A

    2015-01-01

    Sensorineural hearing loss is a caused by the loss of the cochlear hair cells with the consequent deafferentation of spiral ganglion neurons. Humans do not show endogenous cellular regeneration in the inner ear and there is no exogenous therapy that allows the replacement of the damaged hair cells. Currently, treatment is based on the use of hearing aids and cochlear implants that present different outcomes, some difficulties in auditory discrimination and a limited useful life. More advanced technology is hindered by the functional capacity of the remaining spiral ganglion neurons. The latest advances with stem cell therapy and cellular reprogramming have developed several possibilities to induce endogenous regeneration or stem cell transplantation to replace damaged inner ear hair cells and restore hearing function. With further knowledge of the cellular and molecular biology of the inner ear and its embryonic development, it will be possible to use induced stem cells as in vitro models of disease and as replacement cellular therapy. Investigation in this area is focused on generating cellular therapy with clinical use for the treatment of profound sensorineural hearing loss. PMID:25459416

  18. Liver regeneration - The best kept secret: A model of tissue injury response

    Directory of Open Access Journals (Sweden)

    Javier A. Cienfuegos

    2014-03-01

    Full Text Available Liver regeneration (LR is one of the most amazing tissue injury response. Given its therapeutic significance has been deeply studied in the last decades. LR is an extraordinary complex process, strictly regulated, which accomplishes the characteristics of the most evolutionary biologic systems (robustness and explains the difficulties of reshaping it with therapeutic goals. TH reproduces the physiological tissue damage response pattern, with a first phase of priming of the hepatocytes -cell-cycle transition G0-G1-, and a second phase of proliferation -cell-cycle S/M phases- which ends with the liver mass recovering. This process has been related with the tissue injury response regulators as: complement system, platelets, inflammatory cytokines (TNF-α, IL-1β, IL-6, growth factors (HGF, EGF, VGF and anti-inflammatory factors (IL-10, TGF-β. Given its complexity and strict regulation, illustrates the unique alternative to liver failure is liver transplantation. The recent induced pluripotential cells (iPS description and the mesenchymal stem cell (CD133+ plastic capability have aroused new prospects in the cellular therapy field. Those works have assured the cooperation between mesenchymal and epithelial cells. Herein, we review the physiologic mechanisms of liver regeneration.

  19. Chemical approaches to studying stem cell biology

    Institute of Scientific and Technical Information of China (English)

    Wenlin Li; Kai Jiang; Wanguo Wei; Yan Shi; Sheng Ding

    2013-01-01

    Stem cells,including both pluripotent stem cells and multipotent somatic stem cells,hold great potential for interrogating the mechanisms of tissue development,homeostasis and pathology,and for treating numerous devastating diseases.Establishment of in vitro platforms to faithfully maintain and precisely manipulate stem cell fates is essential to understand the basic mechanisms of stem cell biology,and to translate stem cells into regenerative medicine.Chemical approaches have recently provided a number of small molecules that can be used to control cell selfrenewal,lineage differentiation,reprogramming and regeneration.These chemical modulators have been proven to be versatile tools for probing stem cell biology and manipulating cell fates toward desired outcomes.Ultimately,this strategy is promising to be a new frontier for drug development aimed at endogenous stem cell modulation.

  20. 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

    relatively large pressure drop and almost fixed porosity make loss reductions and further optimization challenging. This paper proposes and focuses on packed screen regenerators, which may exhibit lower pressure drop and equivalent heat transfer performance to packed sphere regenerators. A 1D AMR model is......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...... 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....