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Sample records for bioprosthetic regenerate template

  1. Tropoelastin incorporation into a dermal regeneration template promotes wound angiogenesis.

    PubMed

    Wang, Yiwei; Mithieux, Suzanne M; Kong, Yvonne; Wang, Xue-Qing; Chong, Cassandra; Fathi, Ali; Dehghani, Fariba; Panas, Eleni; Kemnitzer, John; Daniels, Robert; Kimble, Roy M; Maitz, Peter K; Li, Zhe; Weiss, Anthony S

    2015-03-11

    Severe burn injury results in substantial skin loss and cannot be treated by autografts. The Integra Dermal Regeneration Template (IDRT) is the leading synthetic skin substitute because it allows for wound bed regeneration and wound healing. However, all substitutes suffer from slow blood vessel ingrowth and would benefit considerably from enhanced vascularization to nurture tissue repair. It is shown here that by incorporating the human elastic protein tropoelastin into a dermal regeneration template (TDRT) we can promote angiogenesis in wound healing. In small and large animal models comprising mice and pigs, the hybrid TDRT biomaterial and IDRT show similar contraction to autografts and decrease wound contraction compared to open wounds. In mice, TDRT accelerates early stage angiogenesis by 2 weeks, as evidenced by increased angiogenesis fluorescent radiant efficiency in live animal imaging and the expression of endothelial cell adhesion marker CD146. In the pig, a full thickness wound repair model confirms increased numbers of blood vessels in the regenerating areas of the dermis closest to the hypodermis and immediately below the epidermis at 2 weeks post-surgery. It is concluded that including tropoelastin in a dermal regeneration template has the potential to promote wound repair through enhanced vascularization. PMID:25469903

  2. Guided Cartilage Regeneration Using Resorbable Template

    PubMed Central

    Pomahac, Bohdan; Zuhaili, Baraa; Kudsi, Yusuf

    2008-01-01

    Objective: The reconstruction of a defect involving complex cartilaginous structures such as the ear and nose is a difficult problem. Cartilage donor sites are limited, and the shaping of an ear or nose is dependent upon the surgeon's skills and experience. In this report, we propose to use resorbable plates that can be shaped to serve as a template for cartilage healing. Methods: A shell composed of polylactic/polyglycolic acid copolymer sheet was molded into different shapes. Autologous ribs harvested from 2 New Zealand rabbits were slightly crushed and bent without breaking, and placed within the pre-shaped shell. The constructs were implanted into subcutaneous pockets in the flanks of the rabbits. After 8 weeks, the implanted cartilage constructs were taken out of the shell and analyzed by the gross macroscopic appearance for preservation of the shape and by histological means for analysis of cartilage viability. Results: All of the explanted cartilage constructs retained the same pre-implanted shape and contour. Upon histological examination with hematoxylin/eosin staining, the constructs were composed of a continuous layer of viable chondrocytes. Conclusions: Construction of complex cartilaginous structures is an operator-dependent, technically difficult problem. We propose to use a resorbable template for guiding the shape and healing of the desired cartilaginous construct. Preoperative scanning and precise 3-dimensional shaping of the template could achieve further improvement in the desired cartilaginous support of the reconstructed part. In this report, we document that cartilage enclosed in a resorbable template retains its shape and viability. We believe that a prefabricated shell may help simplify and standardize outcomes of ear or nose reconstruction. PMID:18213400

  3. [Early bioprosthetic mitral valve thrombosis].

    PubMed

    Tkaczyszyn, Michał; Olbrycht, Tomasz; Kustrzycka Kratochwil, Dorota; Sokolski, Mateusz; Sukiennik Kujawa, Małgorzata; Skiba, Jacek; Gemel, Marek; Banasiak, Waldemar; Jankowska, Ewa A; Ponikowski, Piotr

    2012-01-01

    We present a case of a 70 year-old woman operated due to severe mitral regurgitation. Early after surgery transthoracic echocardiography revealed the decreased effective orifice area of the implanted bioprosthetic valve and the stenotic features of transvalvular flow. Transesophageal echocardiography (TEE) disclosed a thrombotic cause of heterograft dysfunction. Due to the clinical deterioration and the unclear cause of prosthesis stenosis, the patient was reoperated. Intra-operatively bioprosthetic mitral valve thrombosis was confirmed. Precipitating factors of this rare complication including cardiac device related infective endocarditis (CDRIE) and the diagnostic applicability of TEE in this clinical scenario are discussed. PMID:22427084

  4. Bioprosthetic Mesh in Abdominal Wall Reconstruction

    PubMed Central

    Baumann, Donald P.; Butler, Charles E.

    2012-01-01

    Mesh materials have undergone a considerable evolution over the last several decades. There has been enhancement of biomechanical properties, improvement in manufacturing processes, and development of antiadhesive laminate synthetic meshes. The evolution of bioprosthetic mesh materials has markedly changed our indications and methods for complex abdominal wall reconstruction. The authors review the optimal properties of bioprosthetic mesh materials, their evolution over time, and their indications for use. The techniques to optimize outcomes are described using bioprosthetic mesh for complex abdominal wall reconstruction. Bioprosthetic mesh materials clearly have certain advantages over other implantable mesh materials in select indications. Appropriate patient selection and surgical technique are critical to the successful use of bioprosthetic materials for abdominal wall repair. PMID:23372454

  5. Vascularization of bioprosthetic valve material

    NASA Astrophysics Data System (ADS)

    Boughner, Derek R.; Dunmore-Buyze, Joy; Heenatigala, Dino; Lohmann, Tara; Ellis, Chris G.

    1999-04-01

    Cell membrane remnants represent a probable nucleation site for calcium deposition in bioprosthetic heart valves. Calcification is a primary failure mode of both bovine pericardial and porcine aortic heterograft bioprosthesis but the nonuniform pattern of calcium distribution within the tissue remains unexplained. Searching for a likely cellular source, we considered the possibility of a previously overlooked small blood vessel network. Using a videomicroscopy technique, we examined 5 matched pairs of porcine aortic and pulmonary valves and 14 samples from 6 bovine pericardia. Tissue was placed on a Leitz Metallux microscope and transilluminated with a 75 watt mercury lamp. Video images were obtained using a silicon intensified target camera equipped with a 431 nm interference filter to maximize contrast of red cells trapped in a capillary microvasculature. Video images were recorded for analysis on a Silicon Graphics Image Analysis work station equipped with a video frame grabber. For porcine valves, the technique demonstrated a vascular bed in the central spongiosa at cusp bases with vessel sizes from 6-80 micrometers . Bovine pericardium differed with a more uniform distribution of 7-100 micrometers vessels residing centrally. Thus, small blood vessel endothelial cells provide a potential explanation patterns of bioprosthetic calcification.

  6. Use of a bioartificial dermal regeneration template for skin restoration in combat casualty injuries.

    PubMed

    Seavey, Jonathan G; Masters, Zachary A; Balazs, George C; Tintle, Scott M; Sabino, Jennifer; Fleming, Mark E; Valerio, Ian L

    2016-01-01

    Military personnel who survive combat injuries frequently have large soft tissue wounds complicated by concomitant injuries and contamination. These devastating wounds present a therapeutic challenge to not only restore the protective skin barrier but also to preserve tendon and muscle excursion, provide protective padding around nerves and restore adequate joint motion. Accordingly, regenerative medicine modalities that can accomplish these goals are of great interest. The use of bioartificial dermal regeneration templates (DRT), such as Integra DRT (Integra Lifesciences Corporation, Plainsboro, NJ, USA), in the management of complex soft tissue injuries has an important role in the reconstruction of war wounds. These DRTs provide initial wound coverage and help establish a well-vascularized wound bed suitable for definitive soft tissue coverage. PMID:26681342

  7. Use of dermal regeneration template (Integra) for reconstruction of full-thickness complex oncologic scalp defects.

    PubMed

    Khan, Muhammad A A; Ali, Syed N; Farid, Mohammed; Pancholi, Megha; Rayatt, Sukh; Yap, Lok H

    2010-05-01

    The reconstruction of full-thickness scalp defects remains a surgical challenge. Different types of reconstruction had varying success including the use of dermal regeneration template (DRT). We reviewed the surgical outcome of 30 patients who underwent application of DRT for resurfacing of full-thickness scalp defects when the pericranium was excised and the outer cortex of the calvarial bone was burred after the excision of scalp neoplasm. This was a retrospective review of 30 patients who had scalp reconstruction with DRT undertaken by the senior author between October 2004 and June 2007. The mean age of patients in our series was 63 years (37-91 years). There were 14 men and 16 women. The indications for re-excision and DRT reconstruction in 28 patients were close margins and aggressive tumor type, whereas 2 patients had a recurrence. The mean defect size was 95 cm2 (16-275 cm2). The second stage of the reconstruction occurred on postoperative day 42 (postoperative days 27-62). The mean follow-up period was 14 months. Two patients had minor complications. For both stages, the combined average operative time was 128 minutes. The use of DRT is a rung of the reconstructive ladder that deserves consideration. In our series of 30 patients who required secondary reconstruction of complex scalp defects, the use of DRT has been seen to provide safe and durable soft-tissue cover for full-thickness scalp defects. The reduced operative time and inpatient stay are desirable characteristics particularly in elderly patients with multiple comorbidities. PMID:20485078

  8. A primer on wound healing in colorectal surgery in the age of bioprosthetic materials.

    PubMed

    Lundy, Jonathan B

    2014-12-01

    Wound healing is a complex, dynamic process that is vital for closure of cutaneous injuries, restoration of abdominal wall integrity after laparotomy closure, and to prevent anastomotic dehiscence after bowel surgery. Derangements in healing have been described in multiple processes including diabetes mellitus, corticosteroid use, irradiation for malignancy, and inflammatory bowel disease. A thorough understanding of the process of healing is necessary for clinical decision making and knowledge of the current state of the science may lead future researchers in developing methods to enable our ability to modulate healing, ultimately improving outcomes. An exciting example of this ability is the use of bioprosthetic materials used for abdominal wall surgery (hernia repair/reconstruction). These bioprosthetic meshes are able to regenerate and remodel from an allograft or xenograft collagen matrix into site-specific tissue; ultimately being degraded and minimizing the risk of long-term complications seen with synthetic materials. The purpose of this article is to review healing as it relates to cutaneous and intestinal trauma and surgery, factors that impact wound healing, and wound healing as it pertains to bioprosthetic materials. PMID:25435821

  9. A Primer on Wound Healing in Colorectal Surgery in the Age of Bioprosthetic Materials

    PubMed Central

    Lundy, Jonathan B.

    2014-01-01

    Wound healing is a complex, dynamic process that is vital for closure of cutaneous injuries, restoration of abdominal wall integrity after laparotomy closure, and to prevent anastomotic dehiscence after bowel surgery. Derangements in healing have been described in multiple processes including diabetes mellitus, corticosteroid use, irradiation for malignancy, and inflammatory bowel disease. A thorough understanding of the process of healing is necessary for clinical decision making and knowledge of the current state of the science may lead future researchers in developing methods to enable our ability to modulate healing, ultimately improving outcomes. An exciting example of this ability is the use of bioprosthetic materials used for abdominal wall surgery (hernia repair/reconstruction). These bioprosthetic meshes are able to regenerate and remodel from an allograft or xenograft collagen matrix into site-specific tissue; ultimately being degraded and minimizing the risk of long-term complications seen with synthetic materials. The purpose of this article is to review healing as it relates to cutaneous and intestinal trauma and surgery, factors that impact wound healing, and wound healing as it pertains to bioprosthetic materials. PMID:25435821

  10. One-Stage Reconstruction of Scalp after Full-Thickness Oncologic Defects Using a Dermal Regeneration Template (Integra)

    PubMed Central

    De Angelis, Barbara; Gentile, Pietro; Tati, Eleonora; Bottini, Davide J.; Bocchini, Ilaria; Orlandi, Fabrizio; Pepe, Giampiero; Segni, Chiara Di; Cervelli, Giulio; Cervelli, Valerio

    2015-01-01

    The use of Dermal Regeneration Template (DRT) can be a valid alternative for scalp reconstruction, especially in elderly patients where a rapid procedure with an acceptable aesthetic and reliable functional outcome is required. We reviewed the surgical outcome of 20 patients, 14 (70%) males and 6 (30%) females, who underwent application of DRT for scalp reconstruction for small defects (group A: mean defect size of 12.51 cm2) and for large defects (group B: mean defect size of 28.7 cm2) after wide excision of scalp neoplasm (basal cell carcinoma and squamous cell carcinoma). In group A, the excisions were performed to the galeal layer avoiding pericranium, and in group B the excisions were performed including pericranium layer with subsequent coverage of the exposed bone with local pericranial flap. In both the groups (A and B) after the excision of the tumor, the wound bed was covered with Dermal Regeneration Template. In 3 weeks we observed the complete healing of the wound bed by secondary intention with acceptable cosmetic results and stable scars. Scalp reconstruction using a DRT is a valid coverage technique for minor and major scalp defects and it can be conducted with good results in elderly patients with multiple comorbidities. PMID:26649312

  11. BIOPROSTHETIC HEART VALVES OF THE FUTURE

    PubMed Central

    Manji, Rizwan A.; Ekser, Burcin; Menkis, Alan H.; Cooper, David K.C.

    2014-01-01

    Glutaraldehyde-fixed bioprosthetic heart valves (GBHVs), derived from pigs or cows, undergo structural valve deterioration (SVD) over time, with calcification and eventual failure. It is generally accepted that SVD is due to chemical processes between glutaraldehyde and free calcium ions in the blood. Valve companies have made significant progress in decreasing SVD from calcification through various valve chemical treatments. However, there are still groups of patients (e.g., children and young adults) that have accelerated SVD of GBHV. Unfortunately, these patients are not ideal patients for valve replacement with mechanical heart valve prostheses as they are at high long-term risk from complications of the mandatory anticoagulation that is required. Thus, there is no “ideal” heart valve replacement for children and young adults. GBHVs represent a form of xenotransplantation, and there is increasing evidence that SVD seen in these valves is at least in part associated with xenograft rejection. We review the evidence that suggests that xenograft rejection of GBHVs is occurring, and that calcification of the valve may be related to this rejection. Furthermore, we review recent research into the transplantation of live porcine organs in nonhuman primates that may be applicable to GBHVs, and consider the potential use of genetically-modified pigs as sources of bioprosthetic heart valves. PMID:24444036

  12. Nontuberculous Mycobacteria: An Underestimated Cause of Bioprosthetic Valve Infective Endocarditis.

    PubMed

    Bouchiat, Coralie; Saison, Julien; Boisset, Sandrine; Flandrois, Jean-Pierre; Issartel, Bertrand; Dauwalder, Olivier; Benito, Yvonne; Jarraud, Sophie; Grando, Jacqueline; Boibieux, Andre; Dumitrescu, Oana; Delahaye, François; Farhat, Fadi; Thivolet-Bejui, Françoise; Frieh, Jean-Philippe; Vandenesch, François

    2015-04-01

    Background.  Atypical mycobacteria, or nontuberculous mycobacteria (NTM), have been barely reported as infective endocarditis (IE) agents. Methods.  From January 2010 to December 2013, cardiac valve samples sent to our laboratory as cases of blood culture-negative suspected IE were analyzed by 16S rDNA polymerase chain reaction (PCR). When positive for NTM, hsp PCR allowed species identification. Demographic, clinical, echocardiographic, histopathological, and Ziehl-Neelsen staining data were then collected. Results.  Over the study period, 6 of 370 cardiac valves (belonging to 5 patients in 3 hospitals) were positive for Mycobacterium chelonae (n = 5) and Mycobacterium lentiflavum (n = 1) exclusively on bioprosthetic material. The 5 patients presented to the hospital for heart failure without fever 7.1-18.9 months (median 13.1 months) after biological prosthetic valve implantation. Echocardiography revealed paravalvular regurgitation due to prosthesis dehiscence in all patients. Histopathological examination of the explanted material revealed inflammatory infiltrates in all specimens, 3 of which were associated with giant cells. Gram staining and conventional cultures remained negative, whereas Ziehl-Neelsen staining showed acid-fast bacilli in all patients. Allergic etiology was ruled out by antiporcine immunoglobulin E dosages. These 5 cases occurred exclusively on porcine bioprosthetic material, revealing a statistically significant association between bioprosthetic valves and NTM IE (P < .001). Conclusions.  The body of evidence confirmed the diagnosis of prosthetic IE. The statistically significant association between bioprosthetic valves and NTM IE encourages systematic Ziehl-Neelsen staining of explanted bioprosthetic valves in case of early bioprosthesis dysfunction, even without an obvious sign of IE. In addition, we strongly question the cardiac bioprosthesis conditioning process after animal sacrifice. PMID:26213691

  13. Nontuberculous Mycobacteria: An Underestimated Cause of Bioprosthetic Valve Infective Endocarditis

    PubMed Central

    Bouchiat, Coralie; Saison, Julien; Boisset, Sandrine; Flandrois, Jean-Pierre; Issartel, Bertrand; Dauwalder, Olivier; Benito, Yvonne; Jarraud, Sophie; Grando, Jacqueline; Boibieux, Andre; Dumitrescu, Oana; Delahaye, François; Farhat, Fadi; Thivolet-Bejui, Françoise; Frieh, Jean-Philippe; Vandenesch, François

    2015-01-01

    Background. Atypical mycobacteria, or nontuberculous mycobacteria (NTM), have been barely reported as infective endocarditis (IE) agents. Methods. From January 2010 to December 2013, cardiac valve samples sent to our laboratory as cases of blood culture-negative suspected IE were analyzed by 16S rDNA polymerase chain reaction (PCR). When positive for NTM, hsp PCR allowed species identification. Demographic, clinical, echocardiographic, histopathological, and Ziehl-Neelsen staining data were then collected. Results. Over the study period, 6 of 370 cardiac valves (belonging to 5 patients in 3 hospitals) were positive for Mycobacterium chelonae (n = 5) and Mycobacterium lentiflavum (n = 1) exclusively on bioprosthetic material. The 5 patients presented to the hospital for heart failure without fever 7.1–18.9 months (median 13.1 months) after biological prosthetic valve implantation. Echocardiography revealed paravalvular regurgitation due to prosthesis dehiscence in all patients. Histopathological examination of the explanted material revealed inflammatory infiltrates in all specimens, 3 of which were associated with giant cells. Gram staining and conventional cultures remained negative, whereas Ziehl-Neelsen staining showed acid-fast bacilli in all patients. Allergic etiology was ruled out by antiporcine immunoglobulin E dosages. These 5 cases occurred exclusively on porcine bioprosthetic material, revealing a statistically significant association between bioprosthetic valves and NTM IE (P < .001). Conclusions. The body of evidence confirmed the diagnosis of prosthetic IE. The statistically significant association between bioprosthetic valves and NTM IE encourages systematic Ziehl-Neelsen staining of explanted bioprosthetic valves in case of early bioprosthesis dysfunction, even without an obvious sign of IE. In addition, we strongly question the cardiac bioprosthesis conditioning process after animal sacrifice. PMID:26213691

  14. [Valve-in-valve with Portico valve for a degenerative bioprosthetic surgical valve (Biocor)].

    PubMed

    Latini, Roberto Adriano; Testa, Luca; Brambilla, Nedy; Tusa, Maurizio; Bedogni, Francesco

    2016-04-01

    In the last years, a general shift toward the use of surgical bioprosthetic aortic valves rather than mechanical valves with subsequent less use of anticoagulant therapy has been observed. However, bioprosthetic valves have limited durability. Reoperation, the current standard of care for these patients, carries a high surgical risk, especially because patients are elderly and with numerous comorbidities. Recently, transcatheter aortic valve replacement within a failed bioprosthetic valve (valve-in-valve procedure) has proven feasible. We here describe a case of valve-in-valve procedure with a Portico valve placed in a purely insufficient bioprosthetic valve (Biocor). PMID:27093211

  15. Bioprosthetic Aortic Valve Endocarditis in Association with Enterococcus durans

    PubMed Central

    Di Gioacchino, Lorena; Balestrini, Fabrizio

    2016-01-01

    Enterococci are common organisms associated with endocarditis, but infection by Enterococcus durans is very rare. To our knowledge, only 3 cases have been reported in the medical literature, and all 3 have involved native valves. Here we publish the first reported case (to our knowledge) of E. durans endocarditis in association with a bioprosthetic aortic valve. After the organism and its antibiotic susceptibility were identified, the 74-year-old male patient was treated successfully with teicoplanin and gentamicin, over a course of 6 weeks. PMID:27127436

  16. A Genomics-Based Model for Prediction of Severe Bioprosthetic Mitral Valve Calcification.

    PubMed

    Ponasenko, Anastasia V; Khutornaya, Maria V; Kutikhin, Anton G; Rutkovskaya, Natalia V; Tsepokina, Anna V; Kondyukova, Natalia V; Yuzhalin, Arseniy E; Barbarash, Leonid S

    2016-01-01

    Severe bioprosthetic mitral valve calcification is a significant problem in cardiovascular surgery. Unfortunately, clinical markers did not demonstrate efficacy in prediction of severe bioprosthetic mitral valve calcification. Here, we examined whether a genomics-based approach is efficient in predicting the risk of severe bioprosthetic mitral valve calcification. A total of 124 consecutive Russian patients who underwent mitral valve replacement surgery were recruited. We investigated the associations of the inherited variation in innate immunity, lipid metabolism and calcium metabolism genes with severe bioprosthetic mitral valve calcification. Genotyping was conducted utilizing the TaqMan assay. Eight gene polymorphisms were significantly associated with severe bioprosthetic mitral valve calcification and were therefore included into stepwise logistic regression which identified male gender, the T/T genotype of the rs3775073 polymorphism within the TLR6 gene, the C/T genotype of the rs2229238 polymorphism within the IL6R gene, and the A/A genotype of the rs10455872 polymorphism within the LPA gene as independent predictors of severe bioprosthetic mitral valve calcification. The developed genomics-based model had fair predictive value with area under the receiver operating characteristic (ROC) curve of 0.73. In conclusion, our genomics-based approach is efficient for the prediction of severe bioprosthetic mitral valve calcification. PMID:27589735

  17. Challenging transfemoral valve-in-valve implantation in a degenerated stentless bioprosthetic aortic valve.

    PubMed

    Halapas, A; Chrissoheris, M; Spargias, Konstantinos

    2014-08-01

    Bioprosthetic heart valves are often preferred over mechanical valves as they may preclude the need for anticoagulation. Reoperation is the standard treatment for structural failure of bioprosthetic valves; however, it carries significant risk especially in inoperable elderly patients. Valve-in-valve (ViV) transcatheter aortic valve replacement (TAVR) seems to be an effective and promising procedure in patients with degenerated bioprosthetic aortic valves avoiding the risks associated with the use of cardioplegia and redo cardiac surgery. We report an interesting case of a high-risk 74-year-old patient with a degenerated Sorin Freedom Solo stentless valve treated successfully with ViV TAVR. PMID:25091103

  18. Evaluation of an ultra-lightweight, single-patient-use negative pressure wound therapy system over dermal regeneration template and skin grafts.

    PubMed

    Gabriel, Allen; Thimmappa, Brinda; Rubano, Christopher; Storm-Dickerson, Toni

    2013-08-01

    As the use of negative pressure wound therapy (NPWT) over skin grafts has increased, traditional methods of NPWT system reimbursement and application are increasingly being challenged. A simplified method of accessing and operating NPWT in the outpatient setting is needed, particularly in cases where immediate outpatient use of NPWT is optimal. We evaluated use of a new ultra-lightweight, off-the-shelf, disposable, single-patient-use NPWT system (SP-NPWT; V.A.C.Via™ Therapy, KCI USA, Inc., San Antonio, TX) over dermal regeneration template (DRT) and/or skin grafts. SP-NPWT was initiated over a DRT and/or skin graft in 33 patients with 41 graft procedures. Endpoints were recorded and compared to a historical control group of 25 patients with 28 grafts bolstered with traditional rental NPWT (V.A.C.® Therapy, KCI USA, Inc.). Average length of inpatient hospital stay was 0·0 days for the SP-NPWT group and 6·0 days for the control group (P < 0·0001). The average duration of SP-NPWT post-DRT or skin graft was 5·6 days for the SP-NPWT group and 7·0 days for the control (P < 0·0001). Preliminary data suggest that, compared to traditional NPWT, off-the-shelf SP-NPWT may provide a quicker, seamless transition to home, resulting in decreased hospital stay and potential cost savings. PMID:22682307

  19. Regenerated cellulose membrane as bio-template for in-situ growth of visible-light driven C-modified mesoporous titania.

    PubMed

    Mohamed, Mohamad Azuwa; W Salleh, W N; Jaafar, Juhana; Mohd Hir, Zul Adlan; Rosmi, Mohamad Saufi; Abd Mutalib, Muhazri; Ismail, Ahmad Fauzi; Tanemura, Masaki

    2016-08-01

    Visible light driven C-doped mesoporous TiO2 (C-MTiO2) nanorods have been successfully synthesized through green, low cost, and facile approach by sol-gel bio-templating method using regenerated cellulose membrane (RCM) as nanoreactor. In this study, RCM was also responsible to provide in-situ carbon sources for resultant C-MTiO2 nanorods in acidified sol at low temperatures. The composition, crystallinity, surface area, morphological structure, and optical properties of C-MTiO2 nanorods, respectively, had been characterized using FTIR, XRD, N2 adsorption/desorption, TEM, UV-vis-NIR, and XPS spectroscopy. The results suggested that the growth of C-MTiO2 nanorods was promoted by the strong interaction between the hydroxyl groups of RCMs and titanium ion. Optical and XPS analysis confirmed that carbon presence in TiO2 nanorods were responsible for band-gap narrowing, which improved the visible light absorption capability. Photocatalytic activity measurements exhibited the capability of C-MTiO2 nanorods in degradation of methyl orange in aqueous solution, with 96.6% degradation percentage under visible light irradiation. PMID:27112862

  20. Biomechanical and structural properties of the explanted bioprosthetic valve leaflets.

    PubMed

    Purinya, B; Kasyanov, V; Volkolakov, J; Latsis, R; Tetere, G

    1994-01-01

    Porcine bioprosthesis were treated with 0.625% glutaraldehyde and stabilized under changing pressure from 4 to 30 mmHg. Bovine pericardium and 12 biovalves (of age between 14 days and 80 months) after implantation in the human body were investigated (7 porcine PB and 5 pericardial bioprosthesis--PCB). Circumferential and radial strips from porcine aortic valve leaflets, bovine pericardium and bioprosthetic leaflets were studied in light, transmitting and scanning electron microscopy. Uniaxial load tests were carried out to examine the deformability and strength of these tissues. Microscopic examination of the biovalves revealed that the PB and PCB tissue retained its original architecture, but with alterations in detailed structure. The collagen bundles stuck together with vacuolization between them. There were some areas of the collagen structure fragmentation which could lead to complete necrosis. Eighty months after implantation in patients, the PCB became more extensible and its ultimate strain increases 2.5 times. Ultimate stress decreases in the radial direction from 9.43 to 2.88 MPa, and in the circumferential direction from 9.43 to 6.44 MPa. Forty-eight months after implantation, PB tissue's ultimate stress decreases in the circumferential direction from 4.06 to 1.99 MPa. At the same time ultimate strain increases from 13 to 22%. This study is to improve the methods of tissue stabilization in 0.625% glutaraldehyde solution for the first 48 h at cyclic, changing construction of biovalves soft supporting stent after 48 h. PMID:8106530

  1. Simulated bioprosthetic heart valve deformation under quasi-static loading.

    PubMed

    Sun, Wei; Abad, Ajay; Sacks, Michael S

    2005-11-01

    For more than 40 years, the replacement of diseased natural heart valves with prosthetic devices has dramatically extended the quality and length of the lives of millions of patients worldwide. However, bioprosthetic heart valves (BHV) continue to fail due to structural failure resulting from poor tissue durability and faulty design. Clearly, an in-depth understanding of the biomechanical behavior of BHV at both the tissue and functional prosthesis levels is essential to improving BHV design and to reduce rates of failure. In this study, we simulated quasi-static BHV leaflet deformation under 40, 80, and 120 mm Hg quasi-static transvalvular pressures. A Fung-elastic material model was used that incorporated material parameters and axes derived from actual leaflet biaxial tests and measured leaflet collagen fiber structure. Rigorous experimental validation of predicted leaflet strain field was used to validate the model results. An overall maximum discrepancy of 2.36% strain between the finite element (FE) results and experiment measurements was obtained, indicating good agreement between computed and measured major principal strains. Parametric studies utilizing the material parameter set from one leaflet for all three leaflets resulted in substantial variations in leaflet stress and strain distributions. This result suggests that utilization of actual leaflet material properties is essential for accurate BHV FE simulations. The present study also underscores the need for rigorous experimentation and accurate constitutive models in simulating BHV function and design. PMID:16438226

  2. Bioprosthetic valve degeneration due to cholesterol deposition in a patient with a normal lipid profile

    PubMed Central

    Price, Leslie; Sniderman, Allan; Omerglu, Attila; Lachapelle, Kevin

    2007-01-01

    Hypercholesterolemia has been identified as a risk factor for bioprosthetic valvular degeneration, and it has been suggested that statin therapy reduces this risk. The case of a 77-year-old man with low levels of low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B who developed marked LDL-C crystal deposition and a severe foreign body giant cell reaction 21.5 years after aortic bioprosthetic replacement is reported. This observation confirms that cholesterol deposition contributes to bioprosthetic valve degeneration, but that this can occur even in patients with low levels of LDL-C. It suggests that the characteristics of the valve are more critical than the patient’s level of LDL-C. PMID:17347697

  3. Assessing anticalcification treatments in bioprosthetic tissue by using the New Zealand rabbit intramuscular model.

    PubMed

    Wright, Gregory A; Faught, Joelle M; Olin, Jane M

    2009-06-01

    The objective of this work was to demonstrate that the New Zealand White (NZW) rabbit intramuscular model can be used for detecting calcification in bioprosthetic tissue and to compare the calcification in the rabbit to that of native human valves. The rabbit model was compared with the commonly used Sprague-Dawley rat subcutaneous model. Eighteen rabbits and 18 rats were used to assess calcification in bioprosthetic tissue over time (7, 14, 30, and 90 d). The explanted rabbit and rat tissue discs were measured for calcium by using atomic absorption and Raman spectroscopy. Calcium deposits on the human valve explants were assessed by using Raman spectroscopy. The results showed that the NZW rabbit model is robust for detecting calcification in a shorter duration (14 d), with less infection complications, more space to implant tissue groups (thereby reducing animal use numbers), and a more metabolically and mechanically dynamic environment than the rat subcutaneous model . The human explanted valves and rabbit explanted tissue both showed Raman peaks at 960 cm(-1) which is representative of hydroxyapatite. Hydroxyapatite is the final calcium and phosphate species in the calcification of bioprosthetic heart valves and rabbit intramuscular implants. The NZW rabbit intramuscular model is an effective model for assessing calcification in bioprosthetic tissue. PMID:19619417

  4. Donkey pericardium as an alternative bioprosthetic heart valve material.

    PubMed

    Chen, Shanliang; Xu, Li; Liu, Yuxi; Li, Quan; Wang, Dong; Wang, Xuemei; Liu, Tianqi

    2013-03-01

    This study comparatively evaluates the characteristics of glutaraldehyde-treated acellular bovine and donkey pericardium using histological and electronic microscopic observation techniques, shrinkage temperature, and mechanical properties, as well as determining calcium and phosphorus content at 4 and 8 weeks after the subcutaneous implantation of donkey and bovine pericardium in Wistar rats. Donkey pericardium was significantly thinner compared with bovine pericardium (1.622 ±  0.161 mm vs. 4.027 ± 0.401 mm, P < 0.0001) and was associated with significantly greater tensile strength (14.21 ±  3.81 MPa vs. 3.78 ± 1.20 MPa, P = 0.001) and elastic modulus (81.67 ± 20.41 MPa vs. 21.67 ± 11.69 MPa, P <  0.0001) over bovine pericardium. Shrinkage temperature of donkey pericardium was similar to that of bovine pericardium (87.43 ± 0.55°C vs. 87.50 ± 0.36°C, P =  0.810). No differences between groups were observed for maximum load (donkey: 21.64 ± 7.02 KN/m vs. bovine: 15.05 ± 4.50 KN/m, P = 0.082) and tear strength (donkey: 11.54 ± 5.33 MPa vs. bovine: 10.69 ±  3.77 MPa, P = 0.757). Calcium content was significantly lower in donkey pericardium compared with bovine pericardium at 4 weeks (690.15 ± 191.27 µg/g vs. 1381.73 ± 62.52 µg/g, P = 0.001) and 8 weeks (205.24 ± 62.40 µg/g vs. 910.48 ± 398.29 µg/g, P = 0.037). This preliminary study has confirmed that glutaraldehyde-tanned donkey pericardium, demonstrating reduced calcification and increased tensile strength, may provide a suitable bioprosthetic valve substitute. PMID:23145868

  5. Premature Bioprosthetic Aortic Valve Degeneration Associated with Allergy to Galactose-Alpha-1,3-Galactose.

    PubMed

    Hawkins, Robert B; Frischtak, Helena L; Kron, Irving L; Ghanta, Ravi K

    2016-07-01

    We present the cases of two patients with bioprosthetic aortic valves who developed an allergy to alpha-gal. Each had premature degeneration of their bioprosthesis and demonstrated rapidly increasing transvalvular gradients after development of their allergy. Each underwent successful replacement with a mechanical aortic valve within 1-2 years of symptom onset. doi: 10.1111/jocs.12764 (J Card Surg 2016;31:446-448). PMID:27238083

  6. Templating hydrogels.

    PubMed

    Texter, John

    2009-03-01

    Templating processes for creating polymerized hydrogels are reviewed. The use of contact photonic crystals and of non-contact colloidal crystalline arrays as templates are described and applications to chemical sensing and device fabrication are illustrated. Emulsion templating is illustrated in the formation of microporous membranes, and templating on reverse emulsions and double emulsions is described. Templating in solutions of macromolecules and micelles is discussed and then various applications of hydrogel templating on surfactant liquid crystalline mesophases are illustrated, including a nanoscale analogue of colloidal crystalline array templating, except that the bead array in this case is a cubic array of nonionic micelles. The use of particles as templates in making core-shell and hollow microgel beads is described, as is the use of membrane pores as another illustration of confinement templating. PMID:19816529

  7. Bioprosthetic versus mechanical prostheses for valve replacement in end-stage renal disease patients: systematic review and meta-analysis

    PubMed Central

    Zhao, Dong Fang; Zhou, Jessie J.; Karagaratnam, Aran; Phan, Steven; Yan, Tristan D.

    2016-01-01

    Background Patients with end-stage renal disease (ESRD) indicated for dialysis are increasingly requiring cardiac valve surgery. The choice of bioprosthetic or mechanic valve prosthesis for such patients requires careful risk assessment. A systematic review and meta-analysis was performed to assess current evidence available. Methods A comprehensive search from six electronic databases was performed from their inception to February 2015. Results from patients with ESRD undergoing cardiac surgery for bioprosthetic or mechanical valve replacement were identified. Results Sixteen studies with 8,483 patients with ESRD undergoing cardiac valve replacement surgery were included. No evidence of publication bias was detected. Prior angioplasty by percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery was significantly higher in the bioprosthetic group compared to the mechanical group (16.0% vs. 12.0%, P=0.04); all other preoperative baseline patient characteristics were similar. There was no significant difference in 30-day mortality or all-cause mortality between the two comparisons. Compared with the mechanical group, the frequency of bleeding (5.2% vs. 6.4%, P=0.04) and risk of thromboembolism (2.7% vs. 12.8%, P=0.02) were significantly lower in the bioprosthetic group. There were similar rates of reoperation and valve endocarditis. Conclusions The present study demonstrated that patients with ESRD undergoing bioprosthetic or mechanical valve replacement had similar mid-long term survival. The bioprosthetic group had lower rates of bleeding and thromboembolism. Further studies are required to differentiate the impact of valve location. The presented results may be applicable for ESRD patients requiring prosthetic valve replacement. PMID:27162649

  8. [Pannus Formation Two Years after Bioprosthetic Aortic Valve Implantation;Report of a Case].

    PubMed

    Ono, Kimiyo; Kuroda, Hiroaki

    2015-08-01

    We report a case of early deterioration of the bioprosthetic aortic valve 23 months postoperatively. A 77-year-old man who had undergone aortic valve replacement with a 23-mm Epic valve( St. Jude Medical [SJM])presented to us after a syncopal episode. Echocardiography revealed severe aortic stenosis, and redo aortic valve replacement with a 21-mm SJM mechanical valve was performed. All 3 cusps of the tissue valve were thickened by fibrous pannus overgrowth. Neither calcification nor invasion of inflammatory cells was observed. The cause of pannus formation at such an early stage after implantation remains unknown. PMID:26329714

  9. Experimental validation of the fluid-structure interaction simulation of a bioprosthetic aortic heart valve.

    PubMed

    Kemp, I; Dellimore, K; Rodriguez, R; Scheffer, C; Blaine, D; Weich, H; Doubell, A

    2013-09-01

    Experiments performed on a 19 mm diameter bioprosthetic valve were used to successfully validate the fluid-structure interaction (FSI) simulation of an aortic valve at 72 bpm. The FSI simulation was initialized via a novel approach utilizing a Doppler sonogram of the experimentally tested valve. Using this approach very close quantitative agreement (≤12.5%) between the numerical predictions and experimental values for several key valve performance parameters, including the peak systolic transvalvular pressure gradient, rapid valve opening time and rapid valve closing time, was obtained. The predicted valve leaflet kinematics during opening and closing were also in good agreement with the experimental measurements. PMID:23907849

  10. Severe Bioprosthetic Mitral Valve Stenosis and Heart Failure in a Young Woman with Systemic Lupus Erythematosus.

    PubMed

    Wartak, Siddharth; Akkad, Isaac; Sadiq, Adnan; Crooke, Gregory; Moskovits, Manfred; Frankel, Robert; Hollander, Gerald; Shani, Jacob

    2016-01-01

    A 23-year-old African American woman with a past medical history of systemic lupus erythematous (SLE), secondary hypertension, and end stage renal disease (ESRD) on hemodialysis for eight years was stable until she developed symptomatic severe mitral regurgitation with preserved ejection fraction. She underwent a bioprosthetic mitral valve replacement (MVR) at outside hospital. However, within a year of her surgery, she presented to our hospital with NYHA class IV symptoms. She was treated for heart failure but in view of her persistent symptoms and low EF was considered for heart and kidney transplant. This was a challenge in view of her history of lupus. We presumed that her stenosis of bioprosthetic valve was secondary to lupus and renal disease. We hypothesized that her low ejection fraction was secondary to mitral stenosis and potentially reversible. We performed a dobutamine stress echocardiogram, which revealed an improved ejection fraction to more than 50% and confirmed preserved inotropic contractile reserve of her myocardium. Based on this finding, she underwent a metallic mitral valve and tricuspid valve replacement. Following surgery, her symptoms completely resolved. This case highlights the pathophysiology of lupus causing stenosis of prosthetic valves and low ejection cardiomyopathy. PMID:27610249

  11. Optimal thromboprophylaxis following bioprosthetic aortic valve replacement: still a matter of debate?

    PubMed Central

    Mydin, Muhammad I.; Dimitrakakis, Georgios; Younis, Jenan; Nowell, Justin; Athanasiou, Thanos; Kourliouros, Antonios

    2012-01-01

    Optimal thromboprophylaxis following bioprosthetic aortic valve replacement (AVR) remains controversial. The main objective, which is the effective prevention of central nervous or peripheral embolic events, especially in the early postoperative period, will have to be weighed against the haemorrhagic risk that is associated with the utilization of different antithrombotic regimes. Most governing bodies in cardiovascular medicine have issued recommendations on thromboprophylaxis after the surgical implantation of aortic bioprostheses. However, the level of evidence to support these recommendations remains low, largely due to the inherent limitations of conducting appropriately randomized and adequately powered clinical research in this area. It is apparent from the recent surveys and large registries that there is a great variability in antithrombotic practice at an institutional or individual-clinician level reflecting this controversy and the lack of robust evidence. While organizational, financial or conceptual limitations could hinder the conduct and availability of conclusive research on optimal thromboprophylaxis after aortic bioprosthesis, it is imperative that all evidence is presented in a systematic way in order to assist the decision-making for the modern clinician. In this review, we provide an outline of the current recommendations for thromboprophylaxis, followed by a comprehensive and analytical presentation of all comparative studies examining anticoagulation vs. antiplatelet therapy after bioprosthetic AVR. PMID:22493097

  12. Severe Bioprosthetic Mitral Valve Stenosis and Heart Failure in a Young Woman with Systemic Lupus Erythematosus

    PubMed Central

    Wartak, Siddharth; Sadiq, Adnan; Crooke, Gregory; Moskovits, Manfred; Frankel, Robert; Hollander, Gerald; Shani, Jacob

    2016-01-01

    A 23-year-old African American woman with a past medical history of systemic lupus erythematous (SLE), secondary hypertension, and end stage renal disease (ESRD) on hemodialysis for eight years was stable until she developed symptomatic severe mitral regurgitation with preserved ejection fraction. She underwent a bioprosthetic mitral valve replacement (MVR) at outside hospital. However, within a year of her surgery, she presented to our hospital with NYHA class IV symptoms. She was treated for heart failure but in view of her persistent symptoms and low EF was considered for heart and kidney transplant. This was a challenge in view of her history of lupus. We presumed that her stenosis of bioprosthetic valve was secondary to lupus and renal disease. We hypothesized that her low ejection fraction was secondary to mitral stenosis and potentially reversible. We performed a dobutamine stress echocardiogram, which revealed an improved ejection fraction to more than 50% and confirmed preserved inotropic contractile reserve of her myocardium. Based on this finding, she underwent a metallic mitral valve and tricuspid valve replacement. Following surgery, her symptoms completely resolved. This case highlights the pathophysiology of lupus causing stenosis of prosthetic valves and low ejection cardiomyopathy. PMID:27610249

  13. Time-frequency and time-scale techniques for the classification of native and bioprosthetic heart valve sounds.

    PubMed

    Bentley, P M; Grant, P M; McDonnell, J T

    1998-01-01

    The determination of diagnostic features in recorded heart sounds was investigated with Carpentier-Edwards (CE) bioprosthetic valves. Morphological features, extracted using the Choi-Williams distribution, achieved between 96 and 61% correct classification. The time-scale wavelet-transform feature set achieved 100% correct classification with native valve populations, and 87% with the CE replacements. PMID:9444847

  14. An immersogeometric variational framework for fluid–structure interaction: application to bioprosthetic heart valves

    PubMed Central

    Kamensky, David; Hsu, Ming-Chen; Schillinger, Dominik; Evans, John A.; Aggarwal, Ankush; Bazilevs, Yuri; Sacks, Michael S.; Hughes, Thomas J. R.

    2014-01-01

    In this paper, we develop a geometrically flexible technique for computational fluid–structure interaction (FSI). The motivating application is the simulation of tri-leaflet bioprosthetic heart valve function over the complete cardiac cycle. Due to the complex motion of the heart valve leaflets, the fluid domain undergoes large deformations, including changes of topology. The proposed method directly analyzes a spline-based surface representation of the structure by immersing it into a non-boundary-fitted discretization of the surrounding fluid domain. This places our method within an emerging class of computational techniques that aim to capture geometry on non-boundary-fitted analysis meshes. We introduce the term “immersogeometric analysis” to identify this paradigm. The framework starts with an augmented Lagrangian formulation for FSI that enforces kinematic constraints with a combination of Lagrange multipliers and penalty forces. For immersed volumetric objects, we formally eliminate the multiplier field by substituting a fluid–structure interface traction, arriving at Nitsche’s method for enforcing Dirichlet boundary conditions on object surfaces. For immersed thin shell structures modeled geometrically as surfaces, the tractions from opposite sides cancel due to the continuity of the background fluid solution space, leaving a penalty method. Application to a bioprosthetic heart valve, where there is a large pressure jump across the leaflets, reveals shortcomings of the penalty approach. To counteract steep pressure gradients through the structure without the conditioning problems that accompany strong penalty forces, we resurrect the Lagrange multiplier field. Further, since the fluid discretization is not tailored to the structure geometry, there is a significant error in the approximation of pressure discontinuities across the shell. This error becomes especially troublesome in residual-based stabilized methods for incompressible flow, leading

  15. Fluid–structure interaction analysis of bioprosthetic heart valves: Significance of arterial wall deformation

    PubMed Central

    Hsu, Ming-Chen; Kamensky, David; Bazilevs, Yuri; Sacks, Michael S.; Hughes, Thomas J. R.

    2014-01-01

    We propose a framework that combines variational immersed-boundary and arbitrary Lagrangian–Eulerian (ALE) methods for fluid–structure interaction (FSI) simulation of a bioprosthetic heart valve implanted in an artery that is allowed to deform in the model. We find that the variational immersed-boundary method for FSI remains robust and effective for heart valve analysis when the background fluid mesh undergoes deformations corresponding to the expansion and contraction of the elastic artery. Furthermore, the computations presented in this work show that the arterial wall deformation contributes significantly to the realism of the simulation results, leading to flow rates and valve motions that more closely resemble those observed in practice. PMID:25580046

  16. Evolving Bioprosthetic Tissue Calcification Can Be Quantified Using Serial Multislice CT Scanning

    PubMed Central

    Meuris, B.; De Praetere, H.; Coudyzer, W.; Flameng, W.

    2013-01-01

    Background. We investigated the value of serial multislice CT scanning for in vivo determination of evolving tissue calcification in three separate experimental settings. Materials and Methods. Bioprosthetic valve tissue was implanted in three different conditions: (1) glutaraldehyde-fixed porcine stentless conduits in pulmonary position (n = 6); (2) glutaraldehyde-fixed stented pericardial valves in mitral position (n = 3); and (3) glutaraldehyde-fixed pericardial tissue as patch in the jugular vein and carotid artery (n = 16). Multislice CT scanning was performed at various time intervals. Results. In stentless conduits, the distribution of wall calcification can be reliably quantified with CT. After 20 weeks, the CT-determined mean calcium volume was 1831 ± 581 mm³, with a mean wall calcium content of 89.8 ± 44.4 μg/mg (r2 = 0.68). In stented pericardial valves implanted in mitral position, reliable determination of tissue mineralization is disturbed by scattering caused by the (continuously moving) alloy of the stent material. Pericardial patches in the neck vessels revealed progressive mineralization, with a significant increase in mean HU and calcium volume at 8 weeks after implantation, rising up to a level of 131.1 ± 39.6 mm³ (mean calcium volume score) and a mean calcium content of 19.1 ± 12.3 μg/mg. Conclusion. The process of bioprosthetic tissue mineralization can be visualized and quantified in vivo using multislice CT scanning. This allows determination of the kinetics of tissue mineralization with intermediate in vivo evaluations. PMID:24089616

  17. Evaluation of bioprosthetic heart valve failure using a matrix-fibril shear stress transfer approach.

    PubMed

    Anssari-Benam, Afshin; Barber, Asa H; Bucchi, Andrea

    2016-02-01

    A matrix-fibril shear stress transfer approach is devised and developed in this paper to analyse the primary biomechanical factors which initiate the structural degeneration of the bioprosthetic heart valves (BHVs). Using this approach, the critical length of the collagen fibrils l c and the interface shear acting on the fibrils in both BHV and natural aortic valve (AV) tissues under physiological loading conditions are calculated and presented. It is shown that the required critical fibril length to provide effective reinforcement to the natural AV and the BHV tissue is l c  = 25.36 µm and l c  = 66.81 µm, respectively. Furthermore, the magnitude of the required shear force acting on fibril interface to break a cross-linked fibril in the BHV tissue is shown to be 38 µN, while the required interfacial force to break the bonds between the fibril and the surrounding extracellular matrix is 31 µN. Direct correlations are underpinned between these values and the ultimate failure strength and the failure mode of the BHV tissue compared with the natural AV, and are verified against the existing experimental data. The analyses presented in this paper explain the role of fibril interface shear and critical length in regulating the biomechanics of the structural failure of the BHVs, for the first time. This insight facilitates further understanding into the underlying causes of the structural degeneration of the BHVs in vivo. PMID:26715134

  18. The influence of leaflet skin friction and stiffness on the performance of bioprosthetic aortic valves.

    PubMed

    Dellimore, K; Kemp, I; Scheffer, C; Weich, H; Doubell, A

    2013-12-01

    Leaflet skin friction and stiffness were found to have a significant influence on the systolic performance of a 19 mm diameter bioprosthetic aortic valve based on fluid-structure interaction simulations at a heart rate of 72 bpm. Four different leaflet skin friction coefficients (0.0, 9.2 × 10(-4), 4.8 × 10(-2) and 4.8 × 10(-1)) were simulated along with three different leaflet elastic moduli (3.0 × 10(6), 3.5 × 10(6), 4.0 × 10(6) N m(-2)). Higher leaflet skin friction was found to increase the magnitude of the systolic transvalvular pressure gradient and the peak velocity through the valve, as well as decrease the valve orifice area. The results for the leaflet opening and closing kinematics also showed that higher leaflet skin friction combined with higher leaflet stiffness produces longer rapid valve opening, closing and ejection times, as well as smaller valve orifice areas. These results are consistent with clinical findings for calcified aortic valves and suggest that valve performance under stenotic conditions is strongly influenced by the combined effect of increasing leaflet stiffness and surface roughness caused by calcification. PMID:24264225

  19. Dynamic in vitro quantification of bioprosthetic heart valve leaflet motion using structured light projection.

    PubMed

    Iyengar AKS; Sugimoto, H; Smith, D B; Sacks, M S

    2001-11-01

    Quantification of heart valve leaflet deformation during the cardiac cycle is essential in understanding normal and pathological valvular function, as well as in the design of replacement heart valves. Due to the technical complexities involved, little work to date has been performed on dynamic valve leaflet motion. We have developed a novel experimental method utilizing a noncontacting structured laser-light projection technique to investigate dynamic leaflet motion. Using a simulated circulatory loop, a matrix of 150-200 laser light points were projected over the entire leaflet surface. To obtain unobstructed views of the leaflet surface, a stereo system of high-resolution boroscopes was used to track the light points at discrete temporal points during the cardiac cycle. The leaflet surface at each temporal point was reconstructed in three dimensions, and fit using our biquintic hermite finite element approach (Smith et al., Ann. Biomed. Eng. 26:598-611, 2001). To demonstrate our approach, we utilized a bovine pericardial bioprosthetic heart valve, which revealed regions of complex flexural deformation and substantially different shapes during the opening and closing phases. In conclusion, the current method has high spatial and temporal resolution and can reconstruct the entire surface of the cusp simultaneously. Because it is completely noncontacting, this approach is applicable to studies of fatigue and bioreactor technology for tissue engineered heart valves. PMID:11791679

  20. Regeneration inducers in limb regeneration.

    PubMed

    Satoh, Akira; Mitogawa, Kazumasa; Makanae, Aki

    2015-08-01

    Limb regeneration ability, which can be observed in amphibians, has been investigated as a representative phenomenon of organ regeneration. Recently, an alternative experimental system called the accessory limb model was developed to investigate early regulation of amphibian limb regeneration. The accessory limb model contributed to identification of limb regeneration inducers in urodele amphibians. Furthermore, the accessory limb model may be applied to other species to explore universality of regeneration mechanisms. This review aims to connect the insights recently gained to emboss universality of regeneration mechanisms among species. The defined molecules (BMP7 (or2) + FGF2 + FGF8) can transform skin wound healing to organ (limb) regeneration responses. The same molecules can initiate regeneration responses in some species. PMID:26100345

  1. Effects of cyclic flexural fatigue on porcine bioprosthetic heart valve heterograft biomaterials.

    PubMed

    Mirnajafi, Ali; Zubiate, Brett; Sacks, Michael S

    2010-07-01

    Although bioprosthetic heart valves (BHV) remain the primary treatment modality for adult heart valve replacement, continued problems with durability remain. Several studies have implicated flexure as a major damage mode in porcine-derived heterograft biomaterials used in BHV fabrication. Although conventional accelerated wear testing can provide valuable insights into BHV damage phenomena, the constituent tissues are subjected to complex, time-varying deformation modes (i.e., tension and flexure) that do not allow for the control of the amount, direction, and location of flexure. Thus, in this study, customized fatigue testing devices were developed to subject circumferentially oriented porcine BHV tissue strips to controlled cyclic flexural loading. By using this approach, we were able to study layer-specific structural damage induced by cyclic flexural tensile and compressive stresses alone. Cycle levels of 10 x 10(6), 25 x 10(6), and 50 x 10(6) were used, with resulting changes in flexural stiffness and collagen structure assessed. Results indicated that flexural rigidity was markedly reduced after only 10 x 10(6) cycles, and progressively decayed at a lower rate with cycle number thereafter. Moreover, the against-curvature fatigue direction induced the most damage, suggesting that the ventricularis and fibrosa layers have low resistance to cyclic flexural compressive and tensile loads, respectively. The histological analyses indicated progressive collagen fiber delamination as early as 10 x 10(6) cycles but otherwise no change in gross collagen orientation. Our results underscore that porcine-derived heterograft biomaterials are very sensitive to flexural fatigue, with delamination of the tissue layers the primary underlying mechanism. This appears to be in contrast to pericardial BHV, wherein high tensile stresses are considered to be the major cause of structural failure. These findings point toward the need for the development of chemical fixation

  2. Multiclassifier system with hybrid learning applied to the control of bioprosthetic hand.

    PubMed

    Kurzynski, Marek; Krysmann, Maciej; Trajdos, Pawel; Wolczowski, Andrzej

    2016-02-01

    In this paper the problem of recognition of the intended hand movements for the control of bio-prosthetic hand is addressed. The proposed method is based on recognition of electromiographic (EMG) and mechanomiographic (MMG) biosignals using a multiclassifier system (MCS) working in a two-level structure with a dynamic ensemble selection (DES) scheme and original concepts of competence function. Additionally, feedback information coming from bioprosthesis sensors on the correct/incorrect classification is applied to the adjustment of the combining mechanism during MCS operation through adaptive tuning competences of base classifiers depending on their decisions. Three MCS systems operating in decision tree structure and with different tuning algorithms are developed. In the MCS1 system, competence is uniformly allocated to each class belonging to the group indicated by the feedback signal. In the MCS2 system, the modification of competence depends on the node of decision tree at which a correct/incorrect classification is made. In the MCS3 system, the randomized model of classifier and the concept of cross-competence are used in the tuning procedure. Experimental investigations on the real data and computer-simulated procedure of generating feedback signals are performed. In these investigations classification accuracy of the MCS systems developed is compared and furthermore, the MCS systems are evaluated with respect to the effectiveness of the procedure of tuning competence. The results obtained indicate that modification of competence of base classifiers during the working phase essentially improves performance of the MCS system and that this improvement depends on the MCS system and tuning method used. PMID:25982067

  3. Bio-fabrication and physiological self-release of tissue equivalents using smart peptide amphiphile templates.

    PubMed

    Gouveia, Ricardo M; Hamley, Ian W; Connon, Che J

    2015-10-01

    In this study we applied a smart biomaterial formed from a self-assembling, multi-functional synthetic peptide amphiphile (PA) to coat substrates with various surface chemistries. The combination of PA coating and alignment-inducing functionalised substrates provided a template to instruct human corneal stromal fibroblasts to adhere, become aligned and then bio-fabricate a highly-ordered, multi-layered, three-dimensional tissue by depositing an aligned, native-like extracellular matrix. The newly-formed corneal tissue equivalent was subsequently able to eliminate the adhesive properties of the template and govern its own complete release via the action of endogenous proteases. Tissues recovered through this method were structurally stable, easily handled, and carrier-free. Furthermore, topographical and mechanical analysis by atomic force microscopy showed that tissue equivalents formed on the alignment-inducing PA template had highly-ordered, compact collagen deposition, with a two-fold higher elastic modulus compared to the less compact tissues produced on the non-alignment template, the PA-coated glass. We suggest that this technology represents a new paradigm in tissue engineering and regenerative medicine, whereby all processes for the bio-fabrication and subsequent self-release of natural, bio-prosthetic human tissues depend solely on simple template-tissue feedback interactions. PMID:26411438

  4. Transcatheter aortic valve implantation for failing surgical aortic bioprosthetic valve: from concept to clinical application and evaluation (part 1).

    PubMed

    Piazza, Nicolo; Bleiziffer, Sabine; Brockmann, Gernot; Hendrick, Ruge; Deutsch, Marcus-André; Opitz, Anke; Mazzitelli, Domenico; Tassani-Prell, Peter; Schreiber, Christian; Lange, Rüdiger

    2011-07-01

    With an aging population, improvement in life expectancy, and significant increase in the use of bioprosthetic valves, structural valve deterioration will become more and more prevalent. The operative mortality for an elective redo aortic valve surgery is reported to range from 2% to 7%, but this percentage can increase to more than 30% in high-risk and nonelective patients. Because transcatheter aortic valve (TAV)-in-surgical aortic valve (SAV) implantation represents a minimally invasive alternative to conventional redo surgery, it may prove to be safer and just as effective as redo surgery. Of course, prospective comparisons with a large number of patients and long-term follow-up are required to confirm these potential advantages. It is axiomatic that knowledge of the basic construction and dimensions, radiographic identification, and potential failure modes of SAV bioprostheses is fundamental in understanding key principles involved in TAV-in-SAV implantation. The goals of this paper are: 1) to review the classification, physical characteristics, and potential failure modes of surgical bioprosthetic aortic valves; and 2) to discuss patient selection and procedural techniques relevant to TAV-in-SAV implantation. PMID:21777879

  5. A case in which biventricular assist device support was required after aortic valve replacement with a bioprosthetic valve.

    PubMed

    Koizumi, Kiyoshi; Yozu, Ryohei; Shin, Hankei; Tsutsumi, Kozi; Enoki, Chiharu; Iino, Yoshimi; Matayoshi, Toru; Morita, Masanori

    2003-01-01

    We report the case of a 45-year-old man with severe aortic regurgitation. The patient underwent aortic valve replacement with a bioprosthetic valve, but was unable to be weaned from cardiopulmonary bypass (CPB). Intraoperative coronary angiography revealed stenosis of the right coronary orifice, so an intra-aortic balloon pump was inserted and coronary artery bypass grafting to the right coronary artery was conducted; however, weaning from CPB again failed. Left ventricular assist using a Gyro centrifugal pump was performed between the left atrium and left femoral artery, along with right ventricular assist using a Nikkiso centrifugal pump between the right atrium and pulmonary artery. Flow rates averaged from 2.0 to 2.8 l/min for the left-side ventricular assist device (VAD) and 2.1-3.8 l/min for the right-side VAD. The bypass rate reached approximately 70% at maximum. No thromboembolic events were documented during VAD support. The patient underwent explantation of VADs on postoperative day 4. No thrombus was identified on the bioprosthetic aortic valve by transesophageal echocardiography. The left-side pump displayed no thrombus, while the right-side pump had a small thrombus at the shaft. The patient was discharged from the hospital and was alive as of 2 year postoperatively. To the best of our knowledge, no clinical study has yet compared the antithrombotic properties of two centrifugal pumps in one patient where mechanical support was performed for the same duration and flow rate. PMID:14598107

  6. Amyloid deposits in bioprosthetic cardiac valves after long-term implantation in man. A new localization of amyloidosis.

    PubMed Central

    Goffin, Y. A.; Gruys, E.; Sorenson, G. D.; Wellens, F.

    1984-01-01

    Congo red staining with microscopic examination under polarized light was performed in 30 porcine bioprosthetic cardiac valves and one autologous fascia lata valve explanted from 31 patients in order to detect the presence of amyloid. Microdeposits of amyloid were present in the sewing ring of the fascia lata valve and in 10 porcine bioprostheses, and this finding was confirmed by transmission electron microscopy in 3 porcine bioprostheses. All amyloid-laden porcine valves had been implanted for at least 33 months before removal, and all except two showed dysfunction and/or severe degeneration of cuspal tissue. Statistical analyses failed to establish any correlation between the presence of amyloid and patient-related factors. In a majority of porcine bioprostheses amyloid was permanganate-sensitive and tryptophan-positive. The pathogenesis of this new form of heart valve amyloidosis might consist in penetration of human macrophages in deteriorated bioprosthetic cusps and their interaction with blood-borne amyloid precursors. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 PMID:6421168

  7. Bone Marrow–Derived Mesenchymal Stem Cells Enhance Bacterial Clearance and Preserve Bioprosthetic Integrity in a Model of Mesh Infection

    PubMed Central

    Criman, Erik T.; Kurata, Wendy E.; Matsumoto, Karen W.; Aubin, Harry T.; Campbell, Carmen E.

    2016-01-01

    Background: The reported incidence of mesh infection in contaminated operative fields is as high as 30% regardless of the material used. Recently, mesenchymal stem cells (MSCs) have been shown to possess favorable immunomodulatory properties and improve tissue incorporation when seeded onto bioprosthetics. The aim of this study was to evaluate whether seeding noncrosslinked bovine pericardium (Veritas Collagen Matrix) with allogeneic bone marrow–derived MSCs improves infection resistance in vivo after inoculation with Escherichia coli (E. coli). Methods: Rat bone marrow–derived MSCs at passage 3 were seeded onto bovine pericardium and cultured for 7 days before implantation. Additional rats (n = 24) were implanted subcutaneously with MSC-seeded or unseeded mesh and inoculated with 7 × 105 colony-forming units of E. coli or saline before wound closure (group 1, unseeded mesh/saline; group 2, unseeded mesh/E. coli; group 3, MSC-seeded mesh/E. coli; 8 rats per group). Meshes were explanted at 4 weeks and underwent microbiologic and histologic analyses. Results: MSC-seeded meshes inoculated with E. coli demonstrated superior bacterial clearance and preservation of mesh integrity compared with E. coli–inoculated unseeded meshes (87.5% versus 0% clearance; p = 0.001). Complete mesh degradation concurrent with abscess formation was observed in 100% of rats in the unseeded/E. coli group, which is in contrast to 12.5% of rats in the MSC-seeded/E. coli group. Histologic evaluation determined that remodeling characteristics of E. coli–inoculated MSC-seeded meshes were similar to those of uninfected meshes 4 weeks after implantation. Conclusions: Augmenting a bioprosthetic material with stem cells seems to markedly enhance resistance to bacterial infection in vivo and preserve mesh integrity. PMID:27482490

  8. PROTEIN TEMPLATES IN HARD TISSUE ENGINEERING

    PubMed Central

    George, Anne; Ravindran, Sriram

    2010-01-01

    Biomineralization processes such as formation of bones and teeth require controlled mineral deposition and self-assembly into hierarchical biocomposites with unique mechanical properties. Ideal biomaterials for regeneration and repair of hard tissues must be biocompatible, possess micro and macroporosity for vascular invasion, provide surface chemistry and texture that facilitate cell attachment, proliferation, differentiation of lineage specific progenitor cells, and induce deposition of calcium phosphate mineral. To expect in-vivo like cellular response several investigators have used extracellular matrix proteins as templates to recreate in-vivo microenvironment for regeneration of hard tissues. Recently, several novel methods of designing tissue repair and restoration materials using bioinspired strategies are currently being formulated. Nanoscale structured materials can be fabricated via the spontaneous organization of self-assembling proteins to construct hierarchically organized nanomaterials. The advantage of such a method is that polypeptides can be specifically designed as building blocks incorporated with molecular recognition features and spatially distributed bioactive ligands that would provide a physiological environment for cells in-vitro and in-vivo. This is a rapidly evolving area and provides a promising platform for future development of nanostructured templates for hard tissue engineering. In this review we try to highlight the importance of proteins as templates for regeneration and repair of hard tissues as well as the potential of peptide based nanomaterials for regenerative therapies. PMID:20802848

  9. The template update problem.

    PubMed

    Matthews, Iain; Ishikawa, Takahiro; Baker, Simon

    2004-06-01

    Template tracking dates back to the 1981 Lucas-Kanade algorithm. One question that has received very little attention, however, is how to update the template so that it remains a good model of the tracked object. We propose a template update algorithm that avoids the "drifting" inherent in the naive algorithm. PMID:18579941

  10. Liver Regeneration

    PubMed Central

    Michalopoulos, George K.

    2009-01-01

    Liver regeneration after partial hepatectomy is a very complex and well-orchestrated phenomenon. It is carried out by the participation of all mature liver cell types. The process is associated with signaling cascades involving growth factors, cytokines, matrix remodeling, and several feedbacks of stimulation and inhibition of growth related signals. Liver manages to restore any lost mass and adjust its size to that of the organism, while at the same time providing full support for body homeostasis during the entire regenerative process. In situations when hepatocytes or biliary cells are blocked from regeneration, these cell types can function as facultative stem cells for each other. PMID:17559071

  11. Cartilage Regeneration

    PubMed Central

    Tuan, Rocky S.; Chen, Antonia F.; Klatt, Brian A.

    2016-01-01

    Cartilage damaged by trauma has a limited capacity to regenerate. Current methods for treating small chondral defects include palliative treatment with arthroscopic debridement and lavage, reparative treatment with marrow stimulation techniques (e.g. microfracture), and restorative treatment, including osteochondral grafting and autologous chondrocyte implantation. Larger defects are treated by osteochondral allografting or total joint replacements. However, the future of treating cartilage defects lies in providing biologic solutions through cartilage regeneration. Laboratory and clinical studies have examined the treatment of larger lesions using tissue engineered cartilage. Regenerated cartilage can be derived from various cell types, including chondrocytes, mesenchymal stem cells, and pluripotent stem cells. Common scaffolding materials include proteins, carbohydrates, synthetic materials, and composite polymers. Scaffolds may be woven, spun into nanofibers, or configured as hydrogels. Chondrogenesis may be enhanced with the application of chondroinductive growth factors. Finally, bioreactors are being developed to enhance nutrient delivery and provide mechanical stimulation to tissue-engineered cartilage ex vivo. The multi-disciplinary approaches currently being developed to produce cartilage promise to bring the dream of cartilage regeneration in clinical use to reality. PMID:23637149

  12. Optimizing the tensile properties of polyvinyl alcohol hydrogel for the construction of a bioprosthetic heart valve stent.

    PubMed

    Wan, W K; Campbell, G; Zhang, Z F; Hui, A J; Boughner, D R

    2002-01-01

    Although bioprosthetic heart valves offer the benefits of a natural opening and closing, better hemodynamics, and avoidance of life-long anticoagulant therapy, they nevertheless tend to fail in 10-15 years from tears and calcification. Several authors, including the present ones, have identified the rigid stent as a factor contributing to these failures. The ultimate solution is an artificial heart valve that has mechanical properties that allow it to move in conformity with the aortic root during the cardiac cycle, has superior hemodynamics, is nonthrombogenic, will last more than 20 years, and mitigates the need for anticoagulants. We have identified a polymer, polyvinyl alcohol (PVA) hydrogel, that has mechanical properties similar to soft tissue. The purpose of this research is to match the tensile properties of PVA to the porcine aortic root and to fabricate a stent prototype for a bioprosthetic heart valve with the use of the PVA hydrogel. Specimens of 15% w/w PVA were prepared by processing through 1-6 cycles of freezing (-20 degrees C) at 0.2 degrees C/min freeze rate and thawing (+20 degrees C) at different thawing rates (0.2 degrees C/min and 1 degrees C/min), for different holding times (1 and 6 h) at -20 degrees C. Subsequently tensile tests and stress-relaxation tests were conducted on the specimens. The different holding times at -20 degrees C demonstrated no difference in the result. The slower thawing rate improved the tensile properties but did not produce significant changes on the stress-relaxation properties. The nonlinear stress-strain curve for the PVA after the fourth freeze-thaw cycle matched the porcine aortic root within the physiological pressure range. The stress-relaxation curve for PVA also approximated the shape of the aortic root. The complex geometry of an artificial heart valve stent was successfully injection molded. These results, in combination with other preliminary findings for biocompatibility and fatigue behavior, suggest

  13. Programmable imprint lithography template

    DOEpatents

    Cardinale, Gregory F.; Talin, Albert A.

    2006-10-31

    A template for imprint lithography (IL) that reduces significantly template production costs by allowing the same template to be re-used for several technology generations. The template is composed of an array of spaced-apart moveable and individually addressable rods or plungers. Thus, the template can be configured to provide a desired pattern by programming the array of plungers such that certain of the plungers are in an "up" or actuated configuration. This arrangement of "up" and "down" plungers forms a pattern composed of protruding and recessed features which can then be impressed onto a polymer film coated substrate by applying a pressure to the template impressing the programmed configuration into the polymer film. The pattern impressed into the polymer film will be reproduced on the substrate by subsequent processing.

  14. Simulation of long-term fatigue damage in bioprosthetic heart valves: effects of leaflet and stent elastic properties

    PubMed Central

    Martin, Caitlin

    2014-01-01

    One of the major failure modes of bioprosthetic heart valves (BHVs) is noncalcific structural deterioration due to fatigue of the tissue leaflets; yet, the mechanisms of fatigue are not well understood. BHV durability is primarily assessed based on visual inspection of the leaflets following accelerated wear testing. In this study, we developed a computational framework to simulate BHV leaflet fatigue, which is both efficient and quantitative, making it an attractive alternative to traditional accelerated wear testing. We utilize a phenomenological soft tissue fatigue damage model developed previously to describe the stress softening and permanent set of the glutaraldehyde-treated bovine pericardium leaflets in BHVs subjected to cyclic loading. A parametric study was conducted to determine the effects of altered leaflet and stent elastic properties on the fatigue of the leaflets. The simulation results show that heterogeneity of the leaflet elastic properties, poor leaflet coaptation, and little stent-tip deflection may accelerate leaflet fatigue, which agrees with clinical findings. Therefore, the developed framework may be an invaluable tool for evaluating leaflet durability in new tissue valve designs, including traditional BHVs as well as new transcatheter valves. PMID:24092257

  15. Simulation of long-term fatigue damage in bioprosthetic heart valves: effects of leaflet and stent elastic properties.

    PubMed

    Martin, Caitlin; Sun, Wei

    2014-08-01

    One of the major failure modes of bioprosthetic heart valves (BHVs) is noncalcific structural deterioration due to fatigue of the tissue leaflets; yet, the mechanisms of fatigue are not well understood. BHV durability is primarily assessed based on visual inspection of the leaflets following accelerated wear testing. In this study, we developed a computational framework to simulate BHV leaflet fatigue, which is both efficient and quantitative, making it an attractive alternative to traditional accelerated wear testing. We utilize a phenomenological soft tissue fatigue damage model developed previously to describe the stress softening and permanent set of the glutaraldehyde-treated bovine pericardium leaflets in BHVs subjected to cyclic loading. A parametric study was conducted to determine the effects of altered leaflet and stent elastic properties on the fatigue of the leaflets. The simulation results show that heterogeneity of the leaflet elastic properties, poor leaflet coaptation, and little stent-tip deflection may accelerate leaflet fatigue, which agrees with clinical findings. Therefore, the developed framework may be an invaluable tool for evaluating leaflet durability in new tissue valve designs, including traditional BHVs as well as new transcatheter valves. PMID:24092257

  16. Templates, Numbers & Watercolors.

    ERIC Educational Resources Information Center

    Clemesha, David J.

    1990-01-01

    Describes how a second-grade class used large templates to draw and paint five-digit numbers. The lesson integrated artistic knowledge and vocabulary with their mathematics lesson in place value. Students learned how draftspeople use templates, and they studied number paintings by Charles Demuth and Jasper Johns. (KM)

  17. Regenerator seal

    NASA Technical Reports Server (NTRS)

    Davis, Leonard C. (Inventor); Pacala, Theodore (Inventor); Sippel, George R. (Inventor)

    1981-01-01

    A method for manufacturing a hot side regenerator cross arm seal assembly having a thermally stablilized wear coating with a substantially flat wear surface thereon to seal between low pressure and high pressure passages to and from the hot inboard side of a rotary regenerator matrix includes the steps of forming a flat cross arm substrate member of high nickel alloy steel; fixedly securing the side edges of the substrate member to a holding fixture with a concave surface thereacross to maintain the substrate member to a slightly bent configuration on the fixture surface between the opposite ends of the substrate member to produce prestress therein; applying coating layers on the substrate member including a wear coating of plasma sprayed nickel oxide/calcium flouride material to define a wear surface of slightly concave form across the restrained substrate member between the free ends thereon; and thereafter subjecting the substrate member and the coating thereon to a heat treatment of 1600.degree. F. for sixteen hours to produce heat stabilizing growth in the coating layers on the substrate member and to produce a thermally induced growth stress in the wear surface that substantially equalizes the prestress in the substrate whereby when the cross arm is removed from the fixture surface following the heat treatment step a wear face is formed on the cross arm assembly that will be substantially flat between the ends.

  18. Dynamic and fluid–structure interaction simulations of bioprosthetic heart valves using parametric design with T-splines and Fung-type material models

    PubMed Central

    Kamensky, David; Xu, Fei; Kiendl, Josef; Wang, Chenglong; Wu, Michael C. H.; Mineroff, Joshua; Reali, Alessandro; Bazilevs, Yuri; Sacks, Michael S.

    2015-01-01

    This paper builds on a recently developed immersogeometric fluid–structure interaction (FSI) methodology for bioprosthetic heart valve (BHV) modeling and simulation. It enhances the proposed framework in the areas of geometry design and constitutive modeling. With these enhancements, BHV FSI simulations may be performed with greater levels of automation, robustness and physical realism. In addition, the paper presents a comparison between FSI analysis and standalone structural dynamics simulation driven by prescribed transvalvular pressure, the latter being a more common modeling choice for this class of problems. The FSI computation achieved better physiological realism in predicting the valve leaflet deformation than its standalone structural dynamics counterpart. PMID:26392645

  19. Dynamic and fluid-structure interaction simulations of bioprosthetic heart valves using parametric design with T-splines and Fung-type material models

    NASA Astrophysics Data System (ADS)

    Hsu, Ming-Chen; Kamensky, David; Xu, Fei; Kiendl, Josef; Wang, Chenglong; Wu, Michael C. H.; Mineroff, Joshua; Reali, Alessandro; Bazilevs, Yuri; Sacks, Michael S.

    2015-06-01

    This paper builds on a recently developed immersogeometric fluid-structure interaction (FSI) methodology for bioprosthetic heart valve (BHV) modeling and simulation. It enhances the proposed framework in the areas of geometry design and constitutive modeling. With these enhancements, BHV FSI simulations may be performed with greater levels of automation, robustness and physical realism. In addition, the paper presents a comparison between FSI analysis and standalone structural dynamics simulation driven by prescribed transvalvular pressure, the latter being a more common modeling choice for this class of problems. The FSI computation achieved better physiological realism in predicting the valve leaflet deformation than its standalone structural dynamics counterpart.

  20. Bias and variability of diagnostic spectral parameters extracted from closing sounds produced by bioprosthetic valves implanted in the mitral position.

    PubMed

    Cloutier, G; Durand, L G; Guardo, R; Sabbah, H N; Stein, P D

    1989-08-01

    A method is proposed to estimate the bias and variability of eight diagnostic spectral parameters extracted from mitral closing sounds produced by bioprosthetic heart valves. These spectral parameters are: the frequency of the dominant (F1) and second dominant (F2) spectral peaks, the highest frequency of the spectrum found at -3 dB (F-3), -10 dB (F-10) and -20 dB (F-20) below the highest peak, the relative integrated area above -20 dB of the dominant peak (RIA20), the bandwidth at -3 dB of the dominant spectral peak (BW3), and the ratio of F1 divided by BW3 (Q1). The bias and variability of four spectral techniques were obtained by comparing parameters extracted from each technique with the parameters of a spectral "standard." This "standard" consisted of 19 normal mitral sound spectra computed analytically by evaluating the Z transform of a sum of decaying sinusoids on the unit circle. Truncation of the synthesized mitral signals and addition of random noise were used to simulate the physiological characteristics of the closing sounds. Results show that the fast Fourier transform method with rectangular window provides the best estimates of F1 and Q1, that the Steiglitz-McBride method with maximum entropy (pole-zero modeling with four poles and four zeros) can best evaluate F2, F-20, RIA20 and BW3, and that the all-pole modeling with covariance method (16 poles) is best suited to compute F-3. It was also shown that both the all-pole modeling and the Steiglitz-McBride methods can be used to estimate F-10. It is concluded that a single algorithm would not provide the best estimates of all spectral parameters. PMID:2759640

  1. Comparison of David V valve-sparing root replacement and bioprosthetic valve conduit for aortic root aneurysm

    PubMed Central

    DeNino, Walter F.; Toole, John Matthew; Rowley, Christopher; Stroud, Martha R.; Ikonomidis, John S.

    2015-01-01

    Objective Valve sparing root replacement (VSRR) is an attractive option for the management of aortic root aneurysms with a normal native aortic valve. Therefore, we reviewed our experience with a modification of the David V VSRR and compared it with stented pericardial bioprosthetic valve conduit (BVC) root replacement in an age-matched cohort of older patients. Methods A total of 48 VSRRs were performed at our institution, excluding those on bicuspid aortic valves. We compared these cases with 15 aortic root replacements performed using a BVC during the same period. Subgroup analysis was performed comparing 16 VSRR cases and 15 age-matched BVC cases. Results The greatest disparity between the VSRR and BVC groups was age (53 vs 69 years, respectively; P < .0005). The matched patients were similar in terms of baseline demographics and differed only in concomitant coronary artery bypass grafting (2 VSRR vs 7 BVC patients; P = .036). None of the VSRR and 3 of the BVC procedures were performed for associated dissection (P = .101). Postoperative aortic insufficiency grade was significantly different between the 2 groups (P = .004). The cardiopulmonary bypass, crossclamp, and circulatory arrest times were not different between the VSRR and BVC groups (174 vs 187 minutes, P = .205; 128 vs 133 minutes, P = .376; and 10 vs 13 minutes, respectively; P = .175). No differences were found between the 2 groups with respect to postoperative complications. One postoperative death occurred in the BVC group and none in the VSRR group. The postoperative length of stay and aortic valve gradients were less in the VSRR group (6 vs 8 days, P = .038; 6 vs 11.4 mm Hg, P = .001). The intensive care unit length of stay was significantly less in the VSRR group (54 vs 110 hours, P = .001). Conclusions VSRR is an effective alternative to the BVC for aortic root aneurysm. PMID:25173127

  2. Heart regeneration.

    PubMed

    Breckwoldt, Kaja; Weinberger, Florian; Eschenhagen, Thomas

    2016-07-01

    Regenerating an injured heart holds great promise for millions of patients suffering from heart diseases. Since the human heart has very limited regenerative capacity, this is a challenging task. Numerous strategies aiming to improve heart function have been developed. In this review we focus on approaches intending to replace damaged heart muscle by new cardiomyocytes. Different strategies for the production of cardiomyocytes from human embryonic stem cells or human induced pluripotent stem cells, by direct reprogramming and induction of cardiomyocyte proliferation are discussed regarding their therapeutic potential and respective advantages and disadvantages. Furthermore, different methods for the transplantation of pluripotent stem cell-derived cardiomyocytes are described and their clinical perspectives are discussed. 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:26597703

  3. Virus templated metallic nanoparticles.

    PubMed

    Aljabali, Alaa A A; Barclay, J Elaine; Lomonossoff, George P; Evans, David J

    2010-12-01

    Plant viruses are considered as nanobuilding blocks that can be used as synthons or templates for novel materials. Cowpea mosaic virus (CPMV) particles have been shown to template the fabrication of metallic nanoparticles by an electroless deposition metallization process. Palladium ions were electrostatically bound to the virus capsid and, when reduced, acted as nucleation sites for the subsequent metal deposition from solution. The method, although simple, produced highly monodisperse metallic nanoparticles with a diameter of ca. ≤35 nm. CPMV-templated particles were prepared with cobalt, nickel, iron, platinum, cobalt-platinum and nickel-iron. PMID:20877898

  4. STAR Grantee 101 template

    EPA Science Inventory

    The presentation covers the standard Terms and Conditions, from reporting, to Human Subject research, to publication disclaimers, and offers some resources to find helpful information. Some slides are intended as a template, where project officers can enter specific information (...

  5. Plug and drill template

    NASA Technical Reports Server (NTRS)

    Orella, S.

    1979-01-01

    Device installs plugs and then drills them after sandwich face sheets are in place. Template guides drill bit into center of each concealed plug thereby saving considerable time and fostering weight reduction with usage of smaller plugs.

  6. Virus templated metallic nanoparticles

    NASA Astrophysics Data System (ADS)

    Aljabali, Alaa A. A.; Barclay, J. Elaine; Lomonossoff, George P.; Evans, David J.

    2010-12-01

    Plant viruses are considered as nanobuilding blocks that can be used as synthons or templates for novel materials. Cowpea mosaic virus (CPMV) particles have been shown to template the fabrication of metallic nanoparticles by an electroless deposition metallization process. Palladium ions were electrostatically bound to the virus capsid and, when reduced, acted as nucleation sites for the subsequent metal deposition from solution. The method, although simple, produced highly monodisperse metallic nanoparticles with a diameter of ca. <=35 nm. CPMV-templated particles were prepared with cobalt, nickel, iron, platinum, cobalt-platinum and nickel-iron.Plant viruses are considered as nanobuilding blocks that can be used as synthons or templates for novel materials. Cowpea mosaic virus (CPMV) particles have been shown to template the fabrication of metallic nanoparticles by an electroless deposition metallization process. Palladium ions were electrostatically bound to the virus capsid and, when reduced, acted as nucleation sites for the subsequent metal deposition from solution. The method, although simple, produced highly monodisperse metallic nanoparticles with a diameter of ca. <=35 nm. CPMV-templated particles were prepared with cobalt, nickel, iron, platinum, cobalt-platinum and nickel-iron. Electronic supplementary information (ESI) available: Additional experimental detail, agarose gel electrophoresis results, energy dispersive X-ray spectra, ζ-potential measurements, dynamic light scattering data, nanoparticle tracking analysis and an atomic force microscopy image of Ni-CPMV. See DOI: 10.1039/c0nr00525h

  7. Mechanical Versus Bioprosthetic Aortic Valve Replacement in Middle-Aged Adults: A Systematic Review and Meta-Analysis.

    PubMed

    Zhao, Dong Fang; Seco, Michael; Wu, James J; Edelman, James B; Wilson, Michael K; Vallely, Michael P; Byrom, Michael J; Bannon, Paul G

    2016-07-01

    The choice of a bioprosthetic valve (BV) or mechanical valve (MV) in middle-aged adults undergoing aortic valve replacement is a complex decision that must account for numerous prosthesis and patient factors. A systematic review and meta-analysis was performed to compare long-term survival, major adverse prosthesis-related events, anticoagulant-related events, major bleeding, reoperation, and structural valve degeneration in middle-aged patients receiving a BV or MV. A comprehensive search from six electronic databases was performed from their inception to February 2016. Results from patients aged less than 70 years undergoing aortic valve replacement with a BV or MV were included. There were 12 studies involving 8,661 patients. Baseline characteristics were similar. There was no significant difference in long-term survival among patients aged 50 to 70 or 60 to 70 years. Compared with MVs, BVs had significantly fewer long-term anticoagulant-related events (hazard ratio [HR] 0.54, p = 0.006) and bleeding (HR 0.48, p < 0.00001) but significantly greater major adverse prosthesis-related events (HR 1.82, p = 0.02), including reoperation (HR 2.19, p < 0.00001). The present meta-analysis found no significant difference in survival between BVs and MVs in patients aged 50 to 70 or 60 to 70 years. Compared with MVs, BVs have reduced risk of major bleeding and anticoagulant-related events but increased risk of structural valve degeneration and reoperation. However, the mortality consequences of reoperation appear lower than that of major bleeding, and recent advances may further lower the reoperation rate for BV. Therefore, this review supports the current trend of using BVs in patients more than 60 years of age. PMID:26794881

  8. Templated blue phases.

    PubMed

    Ravnik, Miha; Fukuda, Jun-ichi

    2015-11-21

    Cholesteric blue phases of a chiral liquid crystal are interesting examples of self-organised three-dimensional nanostructures formed by soft matter. Recently it was demonstrated that a polymer matrix introduced by photopolymerization inside a bulk blue phase not only stabilises the host blue phase significantly, but also serves as a template for blue phase ordering. We show with numerical modelling that the transfer of the orientational order of the blue phase to the surfaces of the polymer matrix, together with the resulting surface anchoring, can account for the templating behaviour of the polymer matrix inducing the blue phase ordering of an achiral nematic liquid crystal. Furthermore, tailoring the anchoring conditions of the polymer matrix surfaces can bring about orientational ordering different from those of bulk blue phases, including an intertwined complex of the polymer matrix and topological line defects of orientational order. Optical Kerr response of templated blue phases is explored, finding large Kerr constants in the range of K = 2-10 × 10(-9) m V(-2) and notable dependence on the surface anchoring strength. More generally, the presented numerical approach is aimed to clarify the role and actions of templating polymer matrices in complex chiral nematic fluids, and further to help design novel template-based materials from chiral liquid crystals. PMID:26412643

  9. Double Emulsion Templated Celloidosomes

    NASA Astrophysics Data System (ADS)

    Arriaga, Laura R.; Marquez, Samantha M.; Kim, Shin-Hyun; Chang, Connie; Wilking, Jim; Monroy, Francisco; Marquez, Manuel; Weitz, David A.

    2012-02-01

    We present a novel approach for fabricating celloidosomes, which represent a hollow and spherical three-dimensional self-assembly of living cells encapsulating an aqueous core. Glass- capillary microfluidics is used to generate monodisperse water-in-oil-in-water double emulsion templates using lipids as stabilizers. Such templates allow for obtaining single but also double concentric celloidosomes. In addition, after a solvent removal step the double emulsion templates turn into monodisperse lipid vesicles, whose membrane spontaneously phase separates when choosing the adequate lipid composition, providing the adequate scaffold for fabricating Janus-celloidosomes. These structures may find applications in the development of bioreactors in which the synergistic effects of two different types of cells selectively adsorbed on one of the vesicle hemispheres may be exploited.

  10. What is the best approach in a patient with a failed aortic bioprosthetic valve: transcatheter aortic valve replacement or redo aortic valve replacement?

    PubMed

    Tourmousoglou, Christos; Rao, Vivek; Lalos, Spiros; Dougenis, Dimitrios

    2015-06-01

    A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether transcatheter aortic valve-in-valve replacement (viv-TAVR) or redo aortic valve replacement (rAVR) is the best strategy in a patient with a degenerative bioprosthetic aortic valve. Altogether, 162 papers were found using the reported search, of which 12 represented the best evidence to answer the question. The authors, journal, date, country of publication, patient group, study type, outcomes and results of papers are tabulated. The results of the studies provided interesting results. All the studies are retrospective. Four papers reported the results of redo aortic valve replacement in patients with failed aortic bioprosthetic valve, six papers demonstrated their results with transcatheter aortic valve-in-valve replacement for the same indication and two papers reported their propensity-matched analysis of outcomes between viv-TAVR and rAVR in patients with previous cardiac surgery. Thirty-day mortality for rAVR was 2.3-15.5% and 0-17% for viv-TAVR. For rAVR, survival rate at 30 days was 83.6%, 76.1% at 1 year, 70.8% at 3 years, at 51.3-66% at 5 years, 61% at 8 years and 61.5% at 10 years. For viv-TAVR, the overall Kaplan-Meier survival rate at 1 year was 83.2%. After viv-TAVR at 1 year, 86.2% of surviving patients were at New York Heart Association (NYHA) class I/II. The complications after rAVR were stroke (4.6-5.8%), reoperation for bleeding (6.9-9.7%), low-cardiac output syndrome (9.9%) whereas complications after viv-TAVR at 30 days were major stroke (1.7%), aortic regurgitation of at least moderate degree (25%), new permanent pacemaker implantation rate (0-11%), ostial coronary obstruction (2%), need for implantation of a second device (5.7%) and major vascular complications (9.2%). It is noteworthy to mention that there is a valve-in-valve application that provides information to surgeons for choosing the correct size of the TAVR valve

  11. Active magnetic regenerator

    DOEpatents

    Barclay, John A.; Steyert, William A.

    1982-01-01

    The disclosure is directed to an active magnetic regenerator apparatus and method. Brayton, Stirling, Ericsson, and Carnot cycles and the like may be utilized in an active magnetic regenerator to provide efficient refrigeration over relatively large temperature ranges.

  12. Biometric template revocation

    NASA Astrophysics Data System (ADS)

    Arndt, Craig M.

    2004-08-01

    Biometric are a powerful technology for identifying humans both locally and at a distance. In order to perform identification or verification biometric systems capture an image of some biometric of a user or subject. The image is then converted mathematical to representation of the person call a template. Since we know that every human in the world is different each human will have different biometric images (different fingerprints, or faces, etc.). This is what makes biometrics useful for identification. However unlike a credit card number or a password to can be given to a person and later revoked if it is compromised and biometric is with the person for life. The problem then is to develop biometric templates witch can be easily revoked and reissued which are also unique to the user and can be easily used for identification and verification. In this paper we develop and present a method to generate a set of templates which are fully unique to the individual and also revocable. By using bases set compression algorithms in an n-dimensional orthogonal space we can represent a give biometric image in an infinite number of equally valued and unique ways. The verification and biometric matching system would be presented with a given template and revocation code. The code will then representing where in the sequence of n-dimensional vectors to start the recognition.

  13. Subsea well template levelling system

    SciTech Connect

    Regan, M.; Matsuda, E.S.

    1987-06-23

    A template levelling system is described for levelling a template on piles implanted in the floor of a body of water. The template has receptacles, comprising in combination: a pile receptacle carried in each template receptacle on a gimbal, the pile receptacle having a lower flange extending outwardly from and below the template receptacle; slip means located within each of the pile receptacles for gripping one of the piles to prevent downward movement of the template with respect to the piles; and hydraulic jack means for gripping the pile receptacle and pulling it and the slip means upwardly, causing the flange to contact the lower side of the template receptacle to lift the template to a level position.

  14. Cyclodextrin-Templated Porphyrin Nanorings**

    PubMed Central

    Liu, Pengpeng; Neuhaus, Patrik; Kondratuk, Dmitry V; Balaban, T Silviu; Anderson, Harry L

    2014-01-01

    α- and β-Cyclodextrins have been used as scaffolds for the synthesis of six- and seven-legged templates by functionalizing every primary CH2OH with a 4-pyridyl moiety. Although these templates are flexible, they are very effective for directing the synthesis of macrocyclic porphyrin oligomers consisting of six or seven porphyrin units. The transfer of chirality from the cyclodextrin templates to their nanoring hosts is evident from NMR and circular dichroism spectroscopy. Surprisingly, the mean effective molarity for binding the flexible α-cyclodextrin-based template within the six-porphyrin nanoring (74 m) is almost as high as for the previously studied rigid hexadentate template (180 m). The discovery that flexible templates are effective in this system, and the availability of a template with a prime number of binding sites, open up many possibilities for the template-directed synthesis of larger macrocycles. PMID:24916813

  15. Cyclodextrin-templated porphyrin nanorings.

    PubMed

    Liu, Pengpeng; Neuhaus, Patrik; Kondratuk, Dmitry V; Balaban, T Silviu; Anderson, Harry L

    2014-07-21

    α- and β-cyclodextrins have been used as scaffolds for the synthesis of six- and seven-legged templates by functionalizing every primary CH2OH with a 4-pyridyl moiety. Although these templates are flexible, they are very effective for directing the synthesis of macrocyclic porphyrin oligomers consisting of six or seven porphyrin units. The transfer of chirality from the cyclodextrin templates to their nanoring hosts is evident from NMR and circular dichroism spectroscopy. Surprisingly, the mean effective molarity for binding the flexible α-cyclodextrin-based template within the six-porphyrin nanoring (74 M) is almost as high as for the previously studied rigid hexadentate template (180 M). The discovery that flexible templates are effective in this system, and the availability of a template with a prime number of binding sites, open up many possibilities for the template-directed synthesis of larger macrocycles. PMID:24916813

  16. Protein-templated peptide ligation.

    PubMed

    Brauckhoff, Nicolas; Hahne, Gernot; Yeh, Johannes T-H; Grossmann, Tom N

    2014-04-22

    Molecular templates bind particular reactants, thereby increasing their effective concentrations and accelerating the corresponding reaction. This concept has been successfully applied to a number of chemical problems with a strong focus on nucleic acid templated reactions. We present the first protein-templated reaction that allows N-terminal linkage of two peptides. In the presence of a protein template, ligation reactions were accelerated by more than three orders of magnitude. The templated reaction is highly selective and proved its robustness in a protein-labeling reaction that was performed in crude cell lysate. PMID:24644125

  17. Bioactive and Biodegradable Nanocomposites and Hybrid Biomaterials for Bone Regeneration

    PubMed Central

    Allo, Bedilu A.; Costa, Daniel O.; Dixon, S. Jeffrey; Mequanint, Kibret; Rizkalla, Amin S.

    2012-01-01

    Strategies for bone tissue engineering and regeneration rely on bioactive scaffolds to mimic the natural extracellular matrix and act as templates onto which cells attach, multiply, migrate and function. Of particular interest are nanocomposites and organic-inorganic (O/I) hybrid biomaterials based on selective combinations of biodegradable polymers and bioactive inorganic materials. In this paper, we review the current state of bioactive and biodegradable nanocomposite and O/I hybrid biomaterials and their applications in bone regeneration. We focus specifically on nanocomposites based on nano-sized hydroxyapatite (HA) and bioactive glass (BG) fillers in combination with biodegradable polyesters and their hybrid counterparts. Topics include 3D scaffold design, materials that are widely used in bone regeneration, and recent trends in next generation biomaterials. We conclude with a perspective on the future application of nanocomposites and O/I hybrid biomaterials for regeneration of bone. PMID:24955542

  18. Desulfurization sorbent regeneration

    DOEpatents

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

    1982-07-07

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

  19. Regeneration Heat Exchange

    SciTech Connect

    J. Lin

    2003-07-30

    The original project goals were to establish the viability of the proposed gas turbine regenerator concept by performing the following tasks: (1) Perform detailed design of a working model of the regenerator concept. (2) Construct a ''bench-top'' model of the regenerator concept based upon the detail design. (3) Test the bench-top model and gather data to support the concept's viability. The project funding was used to acquire the tools and material to perform the aforementioned tasks.

  20. Cubic nitride templates

    DOEpatents

    Burrell, Anthony K; McCleskey, Thomas Mark; Jia, Quanxi; Mueller, Alexander H; Luo, Hongmei

    2013-04-30

    A polymer-assisted deposition process for deposition of epitaxial cubic metal nitride films and the like is presented. The process includes solutions of one or more metal precursor and soluble polymers having binding properties for the one or more metal precursor. After a coating operation, the resultant coating is heated at high temperatures under a suitable atmosphere to yield metal nitride films and the like. Such films can be used as templates for the development of high quality cubic GaN based electronic devices.

  1. Templated biomimetic multifunctional coatings

    NASA Astrophysics Data System (ADS)

    Sun, Chih-Hung; Gonzalez, Adriel; Linn, Nicholas C.; Jiang, Peng; Jiang, Bin

    2008-02-01

    We report a bioinspired templating technique for fabricating multifunctional optical coatings that mimic both unique functionalities of antireflective moth eyes and superhydrophobic cicada wings. Subwavelength-structured fluoropolymer nipple arrays are created by a soft-lithography-like process. The utilization of fluoropolymers simultaneously enhances the antireflective performance and the hydrophobicity of the replicated films. The specular reflectivity matches the optical simulation using a thin-film multilayer model. The dependence of the size and the crystalline ordering of the replicated nipples on the resulting antireflective properties have also been investigated by experiment and modeling. These biomimetic materials may find important technological application in self-cleaning antireflection coatings.

  2. Maintenance of regenerated bone beneath pontics: preliminary clinical report of 43 sites.

    PubMed

    Fugazzotto, P A; De Paoli, S

    1999-01-01

    Ridge augmentation was achieved through the use of guided bone regeneration procedures in pontic areas of 43 planned fixed prostheses. Measurements taken through templates, which fit over the final fixed prostheses, at the time of prosthetic placement and a mean of 123 weeks after prosthesis placement demonstrated a change of less than 0.1 mm in buccopalatal dimensions of the regenerated hard tissues. PMID:10379113

  3. Ceramic regenerator program

    NASA Technical Reports Server (NTRS)

    Franklin, Jerrold E.

    1991-01-01

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

  4. Specialized progenitors and regeneration

    PubMed Central

    Reddien, Peter W.

    2013-01-01

    Planarians are flatworms capable of regenerating all body parts. Planarian regeneration requires neoblasts, a population of dividing cells that has been studied for over a century. Neoblast progeny generate new cells of blastemas, which are the regenerative outgrowths at wounds. If the neoblasts comprise a uniform population of cells during regeneration (e.g. they are all uncommitted and pluripotent), then specialization of new cell types should occur in multipotent, non-dividing neoblast progeny cells. By contrast, recent data indicate that some neoblasts express lineage-specific transcription factors during regeneration and in uninjured animals. These observations raise the possibility that an important early step in planarian regeneration is the specialization of neoblasts to produce specified rather than naïve blastema cells. PMID:23404104

  5. A Template for Insect Cryopreservation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article is intended to update the reader on the progress made on insect embryo cryopreservation in the past 20 years and gives information for developing a protocol for cryopreserving insects by using a 2001 study as a template. The study used for the template is the cryopreservation of the Old...

  6. From scores to face templates: a model-based approach.

    PubMed

    Mohanty, Pranab; Sarkar, Sudeep; Kasturi, Rangachar

    2007-12-01

    Regeneration of templates from match scores has security and privacy implications related to any biometric authentication system. We propose a novel paradigm to reconstruct face templates from match scores using a linear approach. It proceeds by first modeling the behavior of the given face recognition algorithm by an affine transformation. The goal of the modeling is to approximate the distances computed by a face recognition algorithm between two faces by distances between points, representing these faces, in an affine space. Given this space, templates from an independent image set (break-in) are matched only once with the enrolled template of the targeted subject and match scores are recorded. These scores are then used to embed the targeted subject in the approximating affine (non-orthogonal) space. Given the coordinates of the targeted subject in the affine space, the original template of the targeted subject is reconstructed using the inverse of the affine transformation. We demonstrate our ideas using three, fundamentally different, face recognition algorithms: Principal Component Analysis (PCA) with Mahalanobis cosine distance measure, Bayesian intra-extrapersonal classifier (BIC), and a feature-based commercial algorithm. To demonstrate the independence of the break-in set with the gallery set, we select face templates from two different databases: Face Recognition Grand Challenge (FRGC) and Facial Recognition Technology (FERET) Database (FERET). With an operational point set at 1 percent False Acceptance Rate (FAR) and 99 percent True Acceptance Rate (TAR) for 1,196 enrollments (FERET gallery), we show that at most 600 attempts (score computations) are required to achieve a 73 percent chance of breaking in as a randomly chosen target subject for the commercial face recognition system. With similar operational set up, we achieve a 72 percent and 100 percent chance of breaking in for the Bayesian and PCA based face recognition systems, respectively. With

  7. Indentation hardness: A simple test that correlates with the dissipated-energy predictor for fatigue-life in bovine pericardium membranes for bioprosthetic heart valves.

    PubMed

    Tobaruela, Almudena; Rojo, Francisco Javier; García Paez, José María; Bourges, Jean Yves; Herrero, Eduardo Jorge; Millán, Isabel; Alvarez, Lourdes; Cordon, Ángeles; Guinea, Gustavo V

    2016-08-01

    The aim of this study was to evaluate the variation of hardness with fatigue in calf pericardium, a biomaterial commonly used in bioprosthetic heart valves, and its relationship with the energy dissipated during the first fatigue cycle that has been shown to be a predictor of fatigue-life (García Páez et al., 2006, 2007; Rojo et al., 2010). Fatigue tests were performed in vitro on 24 pericardium specimens cut in a root-to-apex direction. The specimens were subjected to a maximum stress of 1MPa in blocks of 10, 25, 50, 100, 250, 500, 1000 and 1500 cycles. By means of a modified Shore A hardness test procedure, the hardness of the specimen was measured before and after fatigue tests. Results showed a significant correlation of such hardness with fatigue performance and with the energy dissipated in the first cycle of fatigue, a predictor of pericardium durability. The study showed indentation hardness as a simple and reliable indicator of mechanical performance, one which could be easily implemented in improving tissue selection. PMID:26849027

  8. Neuronal Differentiation of Induced Pluripotent Stem Cells on Surfactant Templated Chitosan Hydrogels.

    PubMed

    Worthington, Kristan S; Green, Brian J; Rethwisch, Mary; Wiley, Luke A; Tucker, Budd A; Guymon, C Allan; Salem, Aliasger K

    2016-05-01

    The development of effective tissue engineering materials requires careful consideration of several properties beyond biocompatibility, including permeability and mechanical stiffness. While surfactant templating has been used for over a decade to control the physical properties of photopolymer materials, the potential benefit of this technique with regard to biomaterials has yet to be fully explored. Herein we demonstrate that surfactant templating can be used to tune the water uptake and compressive modulus of photo-cross-linked chitosan hydrogels. Interestingly, templating with quaternary ammonium surfactants also hedges against property fluctuations that occur with changing pH. Further, we demonstrate that, after adequate surfactant removal, these materials are nontoxic, support the attachment of induced pluripotent stem cells and facilitate stem cell differentiation to neuronal phenotypes. These results demonstrate the utility of surfactant templating for optimizing the properties of biomaterials intended for a variety of applications, including retinal regeneration. PMID:27008004

  9. Cloning nanocrystal morphology with soft templates

    NASA Astrophysics Data System (ADS)

    Thapa, Dev Kumar; Pandey, Anshu

    2016-08-01

    In most template directed preparative methods, while the template decides the nanostructure morphology, the structure of the template itself is a non-general outcome of its peculiar chemistry. Here we demonstrate a template mediated synthesis that overcomes this deficiency. This synthesis involves overgrowth of silica template onto a sacrificial nanocrystal. Such templates are used to copy the morphologies of gold nanorods. After template overgrowth, gold is removed and silver is regrown in the template cavity to produce a single crystal silver nanorod. This technique allows for duplicating existing nanocrystals, while also providing a quantifiable breakdown of the structure - shape interdependence.

  10. Characterization of a nanoscale S-layer protein based template for biomolecular patterning.

    PubMed

    Wong, Wing Sze; Yung, Pun To

    2014-01-01

    Well organized template for biomolecular conjugation is the foundation for biosensing. Most of the current devices are fabricated using lithographic patterning processes and self-assembly monolayer (SAM) methods. However, the research toward developing a sub-10 nm patterned, self-regenerated template on various types of substrates is limited, mainly due to the limited functional groups of the building material. Bacterial surface layer proteins (S-layer proteins) can self-assemble into ordered lattice with regular pore sizes of 2-8 nm on different material supports and interfaces. The ordered structure can regenerate after extreme variations of solvent conditions. In this work, we developed a nanoscale biomolecular template based on S-layer proteins on gold surface for fabrication of sensing layer in biosensors. S-layer proteins were isolated from Bacillus cereus, Lysinibacillus sphaericus and Geobacillus stearothermophilus. Protein concentrations were measured by Bradford assay. The protein purities were verified by SDS-PAGE, showing molecular weights ranging from 97-135 kDa. The hydrophilicity of the substrate surface was measured after surface treatments of protein recrystallization. Atomic force microscopic (AFM) measurement was performed on substrate surface, indicating a successful immobilization of a monolayer of S-layer protein with 8-9 nm height on gold surface. The template can be applied on various material supports and acts as a self-regenerated sensing layer of biosensors in the future. PMID:25570568

  11. Brain templates and atlases.

    PubMed

    Evans, Alan C; Janke, Andrew L; Collins, D Louis; Baillet, Sylvain

    2012-08-15

    The core concept within the field of brain mapping is the use of a standardized, or "stereotaxic", 3D coordinate frame for data analysis and reporting of findings from neuroimaging experiments. This simple construct allows brain researchers to combine data from many subjects such that group-averaged signals, be they structural or functional, can be detected above the background noise that would swamp subtle signals from any single subject. Where the signal is robust enough to be detected in individuals, it allows for the exploration of inter-individual variance in the location of that signal. From a larger perspective, it provides a powerful medium for comparison and/or combination of brain mapping findings from different imaging modalities and laboratories around the world. Finally, it provides a framework for the creation of large-scale neuroimaging databases or "atlases" that capture the population mean and variance in anatomical or physiological metrics as a function of age or disease. However, while the above benefits are not in question at first order, there are a number of conceptual and practical challenges that introduce second-order incompatibilities among experimental data. Stereotaxic mapping requires two basic components: (i) the specification of the 3D stereotaxic coordinate space, and (ii) a mapping function that transforms a 3D brain image from "native" space, i.e. the coordinate frame of the scanner at data acquisition, to that stereotaxic space. The first component is usually expressed by the choice of a representative 3D MR image that serves as target "template" or atlas. The native image is re-sampled from native to stereotaxic space under the mapping function that may have few or many degrees of freedom, depending upon the experimental design. The optimal choice of atlas template and mapping function depend upon considerations of age, gender, hemispheric asymmetry, anatomical correspondence, spatial normalization methodology and disease

  12. Nanomaterials and bone regeneration

    PubMed Central

    Gong, Tao; Xie, Jing; Liao, Jinfeng; Zhang, Tao; Lin, Shiyu; Lin, Yunfeng

    2015-01-01

    The worldwide incidence of bone disorders and conditions has been increasing. Bone is a nanomaterials composed of organic (mainly collagen) and inorganic (mainly nano-hydroxyapatite) components, with a hierarchical structure ranging from nanoscale to macroscale. In consideration of the serious limitation in traditional therapies, nanomaterials provide some new strategy in bone regeneration. Nanostructured scaffolds provide a closer structural support approximation to native bone architecture for the cells and regulate cell proliferation, differentiation, and migration, which results in the formation of functional tissues. In this article, we focused on reviewing the classification and design of nanostructured materials and nanocarrier materials for bone regeneration, their cell interaction properties, and their application in bone tissue engineering and regeneration. Furthermore, some new challenges about the future research on the application of nanomaterials for bone regeneration are described in the conclusion and perspectives part. PMID:26558141

  13. Templated Growth of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Siochik Emilie J. (Inventor)

    2007-01-01

    A method of growing carbon nanotubes uses a synthesized mesoporous si lica template with approximately cylindrical pores being formed there in. The surfaces of the pores are coated with a carbon nanotube precu rsor, and the template with the surfaces of the pores so-coated is th en heated until the carbon nanotube precursor in each pore is convert ed to a carbon nanotube.

  14. Motion detection using color templates

    NASA Astrophysics Data System (ADS)

    Chin, Kevin; Abbott, Derek

    1999-10-01

    The Horridge template model is an empirical motion detection model inspired by insect vision. This model has been successfully implemented on several micro-sensor VLSI chips using greyscale pixels. The template model is based on movement of detected edges rather than whole objects, which facilitate simple tracking techniques. Simple tracking algorithms developed by Nguyen have been successful in tracking coherent movement of objects in a simple environment. Due to the inherent edge detection nature of the template model, two closely spaced objects moving at the same speed relative to the template model sensor will appear to have a common edge and hence be interpreted as one object. Hence when the two objects separate, the tracking algorithm will be upset by the detection of two separate edges, resulting in a loss of tracking. This paper introduces a low-cost vision prototype, based on a color CMOS camera. Although this approach sacrifices auto gain control at each pixel, results are valid for controlled lighting conditions. We demonstrate working result, for indoor conditions, by extension of the template mole using the color CMOS sensor to form color templates. This enables the detection of color boundaries or edges of closely moving objects by exploiting the difference in color contrast between the objects. This paper also discusses the effectiveness of this technique in facilitating the independent tracking of multiple objects.

  15. Redo aortic valve surgery versus transcatheter valve-in-valve implantation for failing surgical bioprosthetic valves: consecutive patients in a single-center setting

    PubMed Central

    Wottke, Michael; Deutsch, Marcus-André; Krane, Markus; Piazza, Nicolo; Lange, Ruediger; Bleiziffer, Sabine

    2015-01-01

    Background Due to a considerable rise in bioprosthetic as opposed to mechanical valve implantations, an increase of patients presenting with failing bioprosthetic surgical valves in need of a reoperation is to be expected. Redo surgery may pose a high-risk procedure. Transcatheter aortic valve-in-valve implantation is an innovative, less-invasive treatment alternative for these patients. However, a comprehensive evaluation of the outcome of consecutive patients after a valve-in-valve TAVI [transcatheter aortic valve-in-surgical aortic valve (TAV-in-SAV)] as compared to a standard reoperation [surgical aortic valve redo-operation (SAV-in-SAV)] has not yet been performed. The goal of this study was to compare postoperative outcomes after TAV-in-SAV and SAV-in-SAV in a single center setting. Methods All SAV-in-SAV and TAV-in-SAV patients from January 2001 to October 2014 were retrospectively reviewed. Patients with previous mechanical or transcatheter valves, active endocarditis and concomitant cardiac procedures were excluded. Patient characteristics, preoperative data, post-procedural complications, and 30-day mortality were collected from a designated database. Mean values ± SD were calculated for all continuous variables. Counts and percentages were calculated for categorical variables. The Chi-square and Fisher exact tests were used to compare categorical variables. Continuous variables were compared using the t-test for independent samples. A 2-sided P value <0.05 was considered statistically significant. Results A total of 102 patients fulfilled the inclusion criteria, 50 patients (49%) underwent a transcatheter valve-in-valve procedure, while 52 patients (51%) underwent redo-surgery. Patients in the TAV-in-SAV group were significantly older, had a higher mean logistic EuroSCORE and exhibited a lower mean left ventricular ejection fraction than patients in the SAV-in-SAV group (78.1±6.7 vs. 66.2±13.1, P<0.001; 27.4±18.7 vs. 14.4±10, P<0.001; and 49.8±13

  16. Mid-term results of 17-mm St. Jude Medical Regent prosthetic valves in elder patients with small aortic annuli: comparison with 19-mm bioprosthetic valves.

    PubMed

    Teshima, Hideki; Ikebuchi, Masahiko; Sano, Toshikazu; Tai, Ryuta; Horio, Naohiro; Irie, Hiroyuki

    2014-09-01

    This study was designed to compare the mid-term outcomes after aortic valve replacement (AVR) between 17-mm mechanical heart valves (MV) and 19-mm bioprosthetic valves (BV) in elderly patients with small aortic annuli. Between 2000 and 2011, 127 consecutive patients (mean age 79 years; 87 % female) underwent AVR for aortic valve stenosis with a small aortic annulus. 19-mm BV (n = 67) was implanted. When the 19-mm BV did not fit the annulus, 17-mm St. Jude Medical Regent prosthetic mechanical valve (n = 60) was used instead of an aortic root-enlargement procedure. The follow-up rate was 94.0 % in the BV group, and 98.5 % in the MV group. No significant differences in survival rate and valve-related complications were found between the 2 groups. In-hospital mortality rates were 1.5 % (n = 1) in the BV group and 5.0 % (n = 3) in the MV group. Late mortality rates were 3.9 % per patient-years (p-y; n = 8) in the BV group, and 6.0 % per p-y (n = 10) in the MV group. Five-year Kaplan-Meier survival rates were 62 % in the BV group, and 72 % in the MV group (log-rank P = 0.280). Freedom from major adverse valve-related stroke and cerebral bleeding events was 92.5 and 98.5 % in the BV group, and 94.7 and 100 % in the MV group. AVR using 17-mm MV in elder patients with small aortic annuli provided equivalent mid-term clinical results to that with 19-mm BV. PMID:24878870

  17. Atlas Regeneration, Inc.

    PubMed

    Makarev, Eugene; Isayev, Olexandr; Atala, Anthony

    2016-03-01

    Atlas Regeneration is dedicated to the development of novel data-driven solutions for regenerative medicine, adapting proven technologies, and analysis strategies to take a multiomics-wide view of stem cell quality and cell fate design. Our core offering is a global comprehensive map of stem cell differentiation, Universal Signalome Atlas for Regenerative Medicine, reflecting the pathway activation states across all characterized stem cells and their differentiated products. Key applications of Universal Signalome Atlas for Regenerative Medicine will include quality assurance for engineered cell products, and directed regeneration pharmacology, where we will screen and identify compounds that can efficiently convert pluripotent cells into desired subtypes. Another marketable piece of IP is development of specialized signaling pathway analysis systems Regeneration Intelligence which supposed to target the unmet needs of determination and prediction of stem cell signaling pathway activation to govern cell differentiation in specific directions. PMID:26925598

  18. Nanostructured Biomaterials for Regeneration**

    PubMed Central

    Wei, Guobao; Ma, Peter X.

    2009-01-01

    Biomaterials play a pivotal role in regenerative medicine, which aims to regenerate and replace lost/dysfunctional tissues or organs. Biomaterials (scaffolds) serve as temporary 3D substrates to guide neo tissue formation and organization. It is often beneficial for a scaffolding material to mimic the characteristics of extracellular matrix (ECM) at the nanometer scale and to induce certain natural developmental or/and wound healing processes for tissue regeneration applications. This article reviews the fabrication and modification technologies for nanofibrous, nanocomposite, and nanostructured drug-delivering scaffolds. ECM-mimicking nanostructured biomaterials have been shown to actively regulate cellular responses including attachment, proliferation, differentiation and matrix deposition. Nano-scaled drug delivery systems can be successfully incorporated into a porous 3D scaffold to enhance the tissue regeneration capacity. In conclusion, nano-structured biomateials are a very exciting and rapidly expanding research area, and are providing new enabling technologies for regenerative medicine. PMID:19946357

  19. e-Stars Template Builder

    NASA Technical Reports Server (NTRS)

    Cox, Brian

    2003-01-01

    e-Stars Template Builder is a computer program that implements a concept of enabling users to rapidly gain access to information on projects of NASA's Jet Propulsion Laboratory. The information about a given project is not stored in a data base, but rather, in a network that follows the project as it develops. e-Stars Template Builder resides on a server computer, using Practical Extraction and Reporting Language (PERL) scripts to create what are called "e-STARS node templates," which are software constructs that allow for project-specific configurations. The software resides on the server and does not require specific software on the user machine except for an Internet browser. A user's computer need not be equipped with special software (other than an Internet-browser program). e-Stars Template Builder is compatible with Windows, Macintosh, and UNIX operating systems. A user invokes e-Stars Template Builder from a browser window. Operations that can be performed by the user include the creation of child processes and the addition of links and descriptions of documentation to existing pages or nodes. By means of this addition of "child processes" of nodes, a network that reflects the development of a project is generated.

  20. Biometric template transformation: a security analysis

    NASA Astrophysics Data System (ADS)

    Nagar, Abhishek; Nandakumar, Karthik; Jain, Anil K.

    2010-01-01

    One of the critical steps in designing a secure biometric system is protecting the templates of the users that are stored either in a central database or on smart cards. If a biometric template is compromised, it leads to serious security and privacy threats because unlike passwords, it is not possible for a legitimate user to revoke his biometric identifiers and switch to another set of uncompromised identifiers. One methodology for biometric template protection is the template transformation approach, where the template, consisting of the features extracted from the biometric trait, is transformed using parameters derived from a user specific password or key. Only the transformed template is stored and matching is performed directly in the transformed domain. In this paper, we formally investigate the security strength of template transformation techniques and define six metrics that facilitate a holistic security evaluation. Furthermore, we analyze the security of two wellknown template transformation techniques, namely, Biohashing and cancelable fingerprint templates based on the proposed metrics. Our analysis indicates that both these schemes are vulnerable to intrusion and linkage attacks because it is relatively easy to obtain either a close approximation of the original template (Biohashing) or a pre-image of the transformed template (cancelable fingerprints). We argue that the security strength of template transformation techniques must consider also consider the computational complexity of obtaining a complete pre-image of the transformed template in addition to the complexity of recovering the original biometric template.

  1. Electrochemically regenerable carbon dioxide absorber

    NASA Technical Reports Server (NTRS)

    Woods, R. R.; Marshall, R. D.; Schubert, F. H.; Heppner, D. B.

    1979-01-01

    Preliminary designs were generated for two electrochemically regenerable carbon dioxide absorber concepts. Initially, an electrochemically regenerable absorption bed concept was designed. This concept incorporated the required electrochemical regeneration components in the absorber design, permitting the absorbent to be regenerated within the absorption bed. This hardware was identified as the electrochemical absorber hardware. The second hardware concept separated the functional components of the regeneration and absorption process. This design approach minimized the extravehicular activity component volume by eliminating regeneration hardware components within the absorber. The electrochemical absorber hardware was extensively characterized for major operating parameters such as inlet carbon dioxide partial pressure, process air flow rate, operational pressure, inlet relative humidity, regeneration current density and absorption/regeneration cycle endurance testing.

  2. Template matching on parallel architectures

    SciTech Connect

    Sher

    1985-07-01

    Many important problems in computer vision can be characterized as template-matching problems on edge images. Some examples are circle detection and line detection. Two techniques for template matching are the Hough transform and correlation. There are two algorithms for correlation: a shift-and-add-based technique and a Fourier-transform-based technique. The most efficient algorithm of these three varies depending on the size of the template and the structure of the image. On different parallel architectures, the choice of algorithms for a specific problem is different. This paper describes two parallel architectures: the WARP and the Butterfly and describes why and how the criterion for making the choice of algorithms differs between the two machines.

  3. Cooperation of catalysts and templates

    NASA Technical Reports Server (NTRS)

    White, D. H.; Kanavarioti, A.; Nibley, C. W.; Macklin, J. W.

    1986-01-01

    In order to understand how self-reproducing molecules could have originated on the primitive Earth or extraterrestrial bodies, it would be useful to find laboratory models of simple molecules which are able to carry out processes of catalysis and templating. Furthermore, it may be anticipated that systems in which several components are acting cooperatively to catalyze each other's synthesis will have different behavior with respect to natural selection than those of purely replicating systems. As the major focus of this work, laboratory models are devised to study the influence of short peptide catalysts on template reactions which produce oligonucleotides or additional peptides. Such catalysts could have been the earliest protoenzymes of selective advantage produced by replicating oligonucleotides. Since this is a complex problem, simpler systems are also studied which embody only one aspect at a time, such as peptide formation with and without a template, peptide catalysis of nontemplated peptide synthesis, and model reactions for replication of the type pioneered by Orgel.

  4. Supercritical fluid regeneration of adsorbents

    NASA Astrophysics Data System (ADS)

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

    1983-05-01

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

  5. The cell biology of regeneration

    PubMed Central

    King, Ryan S.

    2012-01-01

    Regeneration of complex structures after injury requires dramatic changes in cellular behavior. Regenerating tissues initiate a program that includes diverse processes such as wound healing, cell death, dedifferentiation, and stem (or progenitor) cell proliferation; furthermore, newly regenerated tissues must integrate polarity and positional identity cues with preexisting body structures. Gene knockdown approaches and transgenesis-based lineage and functional analyses have been instrumental in deciphering various aspects of regenerative processes in diverse animal models for studying regeneration. PMID:22391035

  6. Wide band gap semiconductor templates

    SciTech Connect

    Arendt, Paul N.; Stan, Liliana; Jia, Quanxi; DePaula, Raymond F.; Usov, Igor O.

    2010-12-14

    The present invention relates to a thin film structure based on an epitaxial (111)-oriented rare earth-Group IVB oxide on the cubic (001) MgO terminated surface and the ion-beam-assisted deposition ("IBAD") techniques that are amendable to be over coated by semiconductors with hexagonal crystal structures. The IBAD magnesium oxide ("MgO") technology, in conjunction with certain template materials, is used to fabricate the desired thin film array. Similarly, IBAD MgO with appropriate template layers can be used for semiconductors with cubic type crystal structures.

  7. Regeneration: rewarding, but potentially risky.

    PubMed

    Egger, Bernhard

    2008-12-01

    Some bilaterally symmetric animals, such as flatworms, annelids, and nemerteans, are renowned for their outstanding regeneration capacity-even a fraction of the body can give rise to a complete new animal. However, not all species of these taxa can regenerate equally well-some cannot regenerate at all. If regeneration was purely beneficial, why cannot all of members of the flat, round, and ribbon worms regenerate? At that, why cannot all other bilaterians, including humans, regenerate as well? Regeneration capacity is an obvious advantage in accidental, predatory, and parasitic loss of body parts and is also closely intertwined with asexual reproduction strategies. Regeneration is suspected to play a role in life span extension or even rejuvenation. An answer for reduced or missing regeneration capacity in many species may be found in limitations of the body plan, high costs, and inherent dangers of regeneration. Defects in adults and juveniles are shown, and similarities between development and regeneration are pointed out. With a focus on some worms, but also highlighting comparisons with other animal taxa, putative reasons for a limited and an advanced regeneration capacity are discussed in this article. PMID:19067421

  8. Regenerator seal design

    DOEpatents

    Eckart, Francis H.

    1982-01-01

    A rotary regenerator disc matrix has a face seal with a cross arm and arcuate rim segments joined by prestress clamps to prestrain the arcuate rim seals so as to compensate seal rim twisting or coning and resultant disc face seal leakage as produced by operating thermal gradients across the seal.

  9. Regenerated Fe is tasty!

    NASA Astrophysics Data System (ADS)

    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

  10. Supply-Chain Optimization Template

    NASA Technical Reports Server (NTRS)

    Quiett, William F.; Sealing, Scott L.

    2009-01-01

    The Supply-Chain Optimization Template (SCOT) is an instructional guide for identifying, evaluating, and optimizing (including re-engineering) aerospace- oriented supply chains. The SCOT was derived from the Supply Chain Council s Supply-Chain Operations Reference (SCC SCOR) Model, which is more generic and more oriented toward achieving a competitive advantage in business.

  11. Spreadsheet Templates for Chemical Equilibrium Calculations.

    ERIC Educational Resources Information Center

    Joshi, Bhairav D.

    1993-01-01

    Describes two general spreadsheet templates to carry out all types of one-equation chemical equilibrium calculations encountered by students in undergraduate chemistry courses. Algorithms, templates, macros, and representative examples are presented to illustrate the approach. (PR)

  12. Viral-templated Palladium Nanocatalysts

    NASA Astrophysics Data System (ADS)

    Yang, Cuixian

    Despite recent progress on nanocatalysis, there exist several critical challenges in simple and readily controllable nanocatalyst synthesis including the unpredictable particle growth, deactivation of catalytic activity, cumbersome catalyst recovery and lack of in-situ reaction monitoring. In this dissertation, two novel approaches are presented for the fabrication of viral-templated palladium (Pd) nanocatalysts, and their catalytic activities for dichromate reduction reaction and Suzuki Coupling reaction were thoroughly studied. In the first approach, viral template based bottom-up assembly is employed for the Pd nanocatalyst synthesis in a chip-based format. Specifically, genetically displayed cysteine residues on each coat protein of Tobacco Mosaic Virus (TMV) templates provide precisely spaced thiol functionalities for readily controllable surface assembly and enhanced formation of catalytically active Pd nanoparticles. Catalysts with the chip-based format allow for simple separation and in-situ monitoring of the reaction extent. Thorough examination of synthesis-structure-activity relationship of Pd nanoparticles formed on surface-assembled viral templates shows that Pd nanoparticle size, catalyst loading density and catalytic activity of viral-templated Pd nanocatalysts can be readily controlled simply by tuning the synthesis conditions. The viral-templated Pd nanocatalysts with optimized synthesis conditions are shown to have higher catalytic activity per unit Pd mass than the commercial Pd/C catalysts. Furthermore, tunable and selective surface assembly of TMV biotemplates is exploited to control the loading density and location of Pd nanocatalysts on solid substrates via preferential electroless deposition. In addition, the catalytic activities of surface-assembled TMV-templated Pd nanocatalysts were also investigated for the ligand-free Suzuki Coupling reaction under mild reaction conditions. The chip-based format enables simple catalyst separation and

  13. Statistical templates for visual search.

    PubMed

    Ackermann, John F; Landy, Michael S

    2014-01-01

    How do we find a target embedded in a scene? Within the framework of signal detection theory, this task is carried out by comparing each region of the scene with a "template," i.e., an internal representation of the search target. Here we ask what form this representation takes when the search target is a complex image with uncertain orientation. We examine three possible representations. The first is the matched filter. Such a representation cannot account for the ease with which humans can find a complex search target that is rotated relative to the template. A second representation attempts to deal with this by estimating the relative orientation of target and match and rotating the intensity-based template. No intensity-based template, however, can account for the ability to easily locate targets that are defined categorically and not in terms of a specific arrangement of pixels. Thus, we define a third template that represents the target in terms of image statistics rather than pixel intensities. Subjects performed a two-alternative, forced-choice search task in which they had to localize an image that matched a previously viewed target. Target images were texture patches. In one condition, match images were the same image as the target and distractors were a different image of the same textured material. In the second condition, the match image was of the same texture as the target (but different pixels) and the distractor was an image of a different texture. Match and distractor stimuli were randomly rotated relative to the target. We compared human performance to pixel-based, pixel-based with rotation, and statistic-based search models. The statistic-based search model was most successful at matching human performance. We conclude that humans use summary statistics to search for complex visual targets. PMID:24627458

  14. Tissue regeneration with photobiomodulation

    NASA Astrophysics Data System (ADS)

    Tang, Elieza G.; Arany, Praveen R.

    2013-03-01

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

  15. Reprogramming for cardiac regeneration

    PubMed Central

    Raynaud, Christophe Michel; Ahmad, Faizzan Syed; Allouba, Mona; Abou-Saleh, Haissam; Lui, Kathy O.; Yacoub, Magdi

    2014-01-01

    Treatment of cardiovascular diseases remains challenging considering the limited regeneration capacity of the heart muscle. Developments of reprogramming strategies to create in vitro and in vivo cardiomyocytes have been the focus point of a considerable amount of research in the past decades. The choice of cells to employ, the state-of-the-art methods for different reprogramming strategies, and their promises and future challenges before clinical entry, are all discussed here. PMID:25763379

  16. Regenerable adsorption system

    NASA Technical Reports Server (NTRS)

    Roychoudhury, Subir (Inventor); Perry, Jay (Inventor); Walsh, Dennis (Inventor)

    2006-01-01

    A method for regenerable adsorption includes providing a substrate that defines at least one layer of ultra short channel length mesh capable of conducting an electrical current therethrough, coating at least a portion of the substrate with a desired sorbent for trace contaminant control or CO.sub.2 sorption, resistively heating the substrate, and passing a flowstream through the substrate and in contact with the sorbent.

  17. DNA Templating of Au Nanowires

    NASA Astrophysics Data System (ADS)

    Wood, David; Braun, Gary; Inagaki, Katsuhiko

    2005-03-01

    We have developed a process for fabricating nanoscale wires using DNA templates. The templates were subsequently decorated with gold nanoparticles to make metallic wires. We have successfully deposited linear, straight sections of random (λ-phage) and regular-repeat sequences of DNA, of various lengths, on oxidized silicon substrates. We have also successfully deposited thiolated DNA on gold electrodes, allowing the DNA to electrically bridge gaps between electrode pairs. Electrode gaps ranged from 50 nm to 300 nm, fabricated using electron beam lithography. We decorated the DNA with gold nanoparticles with diameters in the range of 1-13 nm, and have used the nanoparticles as nucleation sites for the growth of continuous gold wires. We have performed AFM characterization of all surfaces and structures. In addition, we have performed current-voltage measurements on the undecorated DNA, the nanoparticle-decorated DNA, and the gold nanowires.

  18. Random template banks and relaxed lattice coverings

    SciTech Connect

    Messenger, C.; Prix, R.; Papa, M. A.

    2009-05-15

    Template-based searches for gravitational waves are often limited by the computational cost associated with searching large parameter spaces. The study of efficient template banks, in the sense of using the smallest number of templates, is therefore of great practical interest. The traditional approach to template-bank construction requires every point in parameter space to be covered by at least one template, which rapidly becomes inefficient at higher dimensions. Here we study an alternative approach, where any point in parameter space is covered only with a given probability {eta}<1. We find that by giving up complete coverage in this way, large reductions in the number of templates are possible, especially at higher dimensions. The prime examples studied here are random template banks in which templates are placed randomly with uniform probability over the parameter space. In addition to its obvious simplicity, this method turns out to be surprisingly efficient. We analyze the statistical properties of such random template banks, and compare their efficiency to traditional lattice coverings. We further study relaxed lattice coverings (using Z{sub n} and A{sub n}* lattices), which similarly cover any signal location only with probability {eta}. The relaxed A{sub n}* lattice is found to yield the most efficient template banks at low dimensions (n < or approx. 10), while random template banks increasingly outperform any other method at higher dimensions.

  19. Distorted colloidal arrays as designed template

    NASA Astrophysics Data System (ADS)

    Yu, Ye; Zhou, Ziwei; Möhwald, Helmuth; Ai, Bin; Zhao, Zhiyuan; Ye, Shunsheng; Zhang, Gang

    2015-01-01

    In this paper, a novel type of colloidal template with broken symmetry was generated using commercial, inductively coupled plasma reactive ion etching (ICP-RIE). With proper but simple treatment, the traditional symmetric non-close-packed colloidal template evolves into an elliptical profile with high uniformity. This unique feature can add flexibility to colloidal lithography and/or other lithography techniques using colloidal particles as building blocks to fabricate nano-/micro-structures with broken symmetry. Beyond that the novel colloidal template we developed possesses on-site tunability, i.e. the transformability from a symmetric into an asymmetric template. Sandwich-type particles with eccentric features were fabricated utilizing this tunable template. This distinguishing feature will provide the possibility to fabricate structures with unique asymmetric features using one set of colloidal template, providing flexibility and broad tunability to enable nano-/micro-structure fabrication with colloidal templates.

  20. Metal nanodisks using bicellar templates

    DOEpatents

    Song, Yujiang; Shelnutt, John A

    2013-12-03

    Metallic nanodisks and a method of making them. The metallic nanodisks are wheel-shaped structures that that provide large surface areas for catalytic applications. The metallic nanodisks are grown within bicelles (disk-like micelles) that template the growth of the metal in the form of approximately circular dendritic sheets. The zero-valent metal forming the nanodisks is formed by reduction of a metal ion using a suitable electron donor species.

  1. Titanium template for scaphoid reconstruction.

    PubMed

    Haefeli, M; Schaefer, D J; Schumacher, R; Müller-Gerbl, M; Honigmann, P

    2015-06-01

    Reconstruction of a non-united scaphoid with a humpback deformity involves resection of the non-union followed by bone grafting and fixation of the fragments. Intraoperative control of the reconstruction is difficult owing to the complex three-dimensional shape of the scaphoid and the other carpal bones overlying the scaphoid on lateral radiographs. We developed a titanium template that fits exactly to the surfaces of the proximal and distal scaphoid poles to define their position relative to each other after resection of the non-union. The templates were designed on three-dimensional computed tomography reconstructions and manufactured using selective laser melting technology. Ten conserved human wrists were used to simulate the reconstruction. The achieved precision measured as the deviation of the surface of the reconstructed scaphoid from its virtual counterpart was good in five cases (maximal difference 1.5 mm), moderate in one case (maximal difference 3 mm) and inadequate in four cases (difference more than 3 mm). The main problems were attributed to the template design and can be avoided by improved pre-operative planning, as shown in a clinical case. PMID:25167978

  2. LTL - The Little Template Library

    NASA Astrophysics Data System (ADS)

    Gössl, C. A.; Drory, N.; Snigula, J.

    2004-07-01

    The Little Template Library is an expression templates based C++ library for array processing, image processing, FITS and ASCII I/O, and linear algebra. It is released under the GNU Public License (GPL). Although the library is developed with application to astronomical image and data processing in mind, it is by no means restricted to these fields of application. In fact, it qualifies as a fully general array processing package. Focus is laid on a high abstraction level regarding the handling of expressions involving arrays or parts thereof and linear algebra related operations without the usually involved negative impact on performance. The price to pay is dependence on a compiler implementing enough of the current ANSI C++ specification, as well as significantly higher demand on resources at compile time. The LTL provides dynamic arrays of up to 5 dimensions, sub-arrays and slicing, support for fixed size vectors and matrices including basic linear algebra operations, expression templates based evaluation, and I/O facilities for columnar ASCII and FITS format files. In addition it supplies utility classes for statistics, linear and non-linear least squares fitting, and command line and configuration file parsing. YODA (Drory 2002) and all elements of the WeCAPP reduction pipeline (Riffeser et al. 2001, Gössl & Riffeser 2002, 2003) were implemented using the LTL.

  3. FUZZY SUPERNOVA TEMPLATES. I. CLASSIFICATION

    SciTech Connect

    Rodney, Steven A.; Tonry, John L. E-mail: jt@ifa.hawaii.ed

    2009-12-20

    Modern supernova (SN) surveys are now uncovering stellar explosions at rates that far surpass what the world's spectroscopic resources can handle. In order to make full use of these SN data sets, it is necessary to use analysis methods that depend only on the survey photometry. This paper presents two methods for utilizing a set of SN light-curve templates to classify SN objects. In the first case, we present an updated version of the Bayesian Adaptive Template Matching program (BATM). To address some shortcomings of that strictly Bayesian approach, we introduce a method for Supernova Ontology with Fuzzy Templates (SOFT), which utilizes fuzzy set theory for the definition and combination of SN light-curve models. For well-sampled light curves with a modest signal-to-noise ratio (S/N >10), the SOFT method can correctly separate thermonuclear (Type Ia) SNe from core collapse SNe with >=98% accuracy. In addition, the SOFT method has the potential to classify SNe into sub-types, providing photometric identification of very rare or peculiar explosions. The accuracy and precision of the SOFT method are verified using Monte Carlo simulations as well as real SN light curves from the Sloan Digital Sky Survey and the SuperNova Legacy Survey. In a subsequent paper, the SOFT method is extended to address the problem of parameter estimation, providing estimates of redshift, distance, and host galaxy extinction without any spectroscopy.

  4. Regenerating Water-Sterilizing Resins

    NASA Technical Reports Server (NTRS)

    Colombo, G. V.; Putnam, D. F.

    1982-01-01

    Iodine-dispensing resin can be regenerated after iodine content has been depleted, without being removed from water system. Resin is used to make water potable by killing bacteria, fungi, and viruses. Regeneration technique may be come basis of water purifier for very long space missions. Enough crystalline iodine for multiple regenerations during mission can be stored in one small cartridge. Cartridge could be inserted in waterline as necessary on signal from iodine monitor or timer.

  5. Intrinsic Control of Axon Regeneration.

    PubMed

    He, Zhigang; Jin, Yishi

    2016-05-01

    A determinant of axon regeneration is the intrinsic growth ability of injured neurons, which dictates a battery of injury responses in axons and cell bodies. While some of these regulatory mechanisms are evolutionarily conserved, others are unique to the mammalian central nervous system (CNS) where spontaneous regeneration usually does not occur. Here we examine our current understanding of these mechanisms at cellular and molecular terms and discuss their potential implications for promoting axon regeneration and functional recovery after nerve injury. PMID:27151637

  6. Synthetic Phage for Tissue Regeneration

    PubMed Central

    Merzlyak, Anna; Lee, Seung-Wuk

    2014-01-01

    Controlling structural organization and signaling motif display is of great importance to design the functional tissue regenerating materials. Synthetic phage, genetically engineered M13 bacteriophage has been recently introduced as novel tissue regeneration materials to display a high density of cell-signaling peptides on their major coat proteins for tissue regeneration purposes. Structural advantages of their long-rod shape and monodispersity can be taken together to construct nanofibrous scaffolds which support cell proliferation and differentiation as well as direct orientation of their growth in two or three dimensions. This review demonstrated how functional synthetic phage is designed and subsequently utilized for tissue regeneration that offers potential cell therapy. PMID:24991085

  7. Understanding Urban Regeneration in Turkey

    NASA Astrophysics Data System (ADS)

    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.

  8. Closed end regeneration method

    DOEpatents

    Yang, Arthur Jing-Min; Zhang, Yuehua

    2006-06-27

    A nanoporous reactive adsorbent incorporates a relatively small number of relatively larger reactant, e.g. metal, enzyme, etc. particles (10) forming a discontinuous or continuous phase interspersed among and surrounded by a continuous phase of smaller adsorbent particles (12) and connected interstitial pores (14) therebetween. The reactive adsorbent can effectively remove inorganic or organic impurities in a liquid by causing the liquid to flow through the adsorbent. For example, silver ions may be adsorbed by the adsorbent particles (12) and reduced to metallic silver by reducing metal, such as irons, as the reactant particles (10). The column can be regenerated by backwashing with the liquid effluent containing, for example, acetic acid.

  9. Regenerable solid imine sorbents

    DOEpatents

    Gray, McMahan; Champagne, Kenneth J.; Fauth, Daniel; Beckman, Eric

    2013-09-10

    Two new classes of amine-based sorbents are disclosed. The first class comprises new polymer-immobilized tertiary amine sorbents; the second class new polymer-bound amine sorbents. Both classes are tailored to facilitate removal of acid anhydrides, especially carbon dioxide (CO.sub.2), from effluent gases. The amines adsorb acid anhydrides in a 1:1 molar ratio. Both classes of amine sorbents adsorb in the temperature range from about 20.degree. C. upwards to 90.degree. C. and can be regenerated by heating upwards to 100.degree. C.

  10. Novel ebullated bed catalyst regeneration technology improves regenerated catalyst quality

    SciTech Connect

    Neuman, D.J.

    1995-09-01

    Regeneration of spent hydroprocessing catalysts has long been practiced by the refining industry. With increased pressures on refiners to reduce catalyst expenditures and waste generation, refiners are more frequently reusing spent hydroprocessing catalysts after ex-situ regeneration to restore catalytic activity. By reusing regenerated catalyst for at least two cycles, the refiner reduces catalyst waste by at least one-half. As environmental laws become more restrictive, spent hydroprocessing catalyst is more likely to be classified as hazardous waste. Disposal of spent catalyst, which was previously accomplished by landfilling, now requires more expensive reclamation techniques. TRICAT has introduced the TRICAT Regeneration Process (TRP), a novel ebullated bed regeneration plant, to improve the catalyst regeneration process. The ebullated bed design allows for better control of heat release during the regeneration process. As a result, the regeneration can be accomplished in a single-pass, with improved catalyst activity retention. Catalyst losses are also minimized due to reduced catalyst handling. Commercial results from the TRP have demonstrated successful scale-up of the technology from pilot scale. The plant has achieved complete recovery of the available catalyst activity with little or no losses in catalyst yield or extrudate length. The flexibility of the TRP to process a variety of catalysts is also discussed.

  11. Calcifying tissue regeneration via biomimetic materials chemistry

    PubMed Central

    Green, David W.; Goto, Tazuko K.; Kim, Kye-Seong; Jung, Han-Sung

    2014-01-01

    Materials chemistry is making a fundamental impact in regenerative sciences providing many platforms for tissue development. However, there is a surprising paucity of replacements that accurately mimic the structure and function of the structural fabric of tissues or promote faithful tissue reconstruction. Methodologies in biomimetic materials chemistry have shown promise in replicating morphologies, architectures and functional building blocks of acellular mineralized tissues dentine, enamel and bone or that can be used to fully regenerate them with integrated cell populations. Biomimetic materials chemistry encompasses the two processes of crystal formation and mineralization of crystals into inorganic formations on organic templates. This review will revisit the successes of biomimetics materials chemistry in regenerative medicine, including coccolithophore simulants able to promote in vivo bone formation. In-depth knowledge of biomineralization throughout evolution informs the biomimetic materials chemist of the most effective techniques for regenerative framework construction exemplified via exploitation of liquid crystals (LCs) and complex self-organizing media. Therefore, a new innovative direction would be to create chemical environments that perform reaction–diffusion exchanges as the basis for building complex biomimetic inorganic structures. This has evolved widely in biology, as have LCs, serving as self-organizing templates in pattern formation of structural biomaterials. For instance, a study is highlighted in which artificially fabricated chiral LCs, made from bacteriophages are transformed into a faithful copy of enamel. While chemical-based strategies are highly promising at creating new biomimetic structures there are limits to the degree of complexity that can be generated. Thus, there may be good reason to implement living or artificial cells in ‘morphosynthesis’ of complex inorganic constructs. In the future, cellular construction is

  12. Regeneration of desiccants with solar energy

    SciTech Connect

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

    1985-01-01

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

  13. Polymer scaffolds with preferential parallel grooves enhance nerve regeneration.

    PubMed

    Mobasseri, Atefeh; Faroni, Alessandro; Minogue, Ben M; Downes, Sandra; Terenghi, Giorgio; Reid, Adam J

    2015-03-01

    We have modified the surface topography of poly ɛ-caprolactone (PCL) and polylactic acid (PLA) blended films to improve cell proliferation and to guide the regeneration of peripheral nerves. Films with differing shaped grooves were made using patterned silicon templates, sloped walls (SL), V-shaped (V), and square-shaped (SQ), and compared with nongrooved surfaces with micropits. The solvent cast films were tested in vitro using adult adipose-derived stem cells differentiated to Schwann cell-like cells. Cell attachment, proliferation, and cell orientation were all improved on the grooved surfaces, with SL grooves giving the best results. We present in vivo data on Sprague-Dawley rat sciatic nerve injury with a 10-mm gap, evaluating nerve regeneration at 3 weeks across a polymer nerve conduit modified with intraluminal grooves (SL, V, and SQ) and differing wall thicknesses (70, 100, 120, and 210 μm). The SL-grooved nerve conduit showed a significant improvement over the other topographical-shaped grooves, while increasing the conduit wall thickness saw no positive effect on the biological response of the regenerating nerve. Furthermore, the preferred SL-grooved conduit (C) with 70 μm wall thickness was compared with the current clinical gold standard of autologous nerve graft (Ag) in the rat 10-mm sciatic nerve gap model. At 3 weeks postsurgery, all nerve gaps across both groups were bridged with regenerated nerve fibers. At 16 weeks, features of regenerated axons were comparable between the autograft (Ag) and conduit (C) groups. End organ assessments of muscle weight, electromyography, and skin reinnervation were also similar between the groups. The comparable experimental outcome between conduit and autograft, suggests that the PCL/PLA conduit with inner lumen microstructured grooves could be used as a potential alternative treatment for peripheral nerve repair. PMID:25435096

  14. Polymer Scaffolds with Preferential Parallel Grooves Enhance Nerve Regeneration

    PubMed Central

    Mobasseri, Atefeh; Faroni, Alessandro; Minogue, Ben M.; Downes, Sandra; Reid, Adam J.

    2015-01-01

    We have modified the surface topography of poly ɛ-caprolactone (PCL) and polylactic acid (PLA) blended films to improve cell proliferation and to guide the regeneration of peripheral nerves. Films with differing shaped grooves were made using patterned silicon templates, sloped walls (SL), V-shaped (V), and square-shaped (SQ), and compared with nongrooved surfaces with micropits. The solvent cast films were tested in vitro using adult adipose-derived stem cells differentiated to Schwann cell-like cells. Cell attachment, proliferation, and cell orientation were all improved on the grooved surfaces, with SL grooves giving the best results. We present in vivo data on Sprague-Dawley rat sciatic nerve injury with a 10-mm gap, evaluating nerve regeneration at 3 weeks across a polymer nerve conduit modified with intraluminal grooves (SL, V, and SQ) and differing wall thicknesses (70, 100, 120, and 210 μm). The SL-grooved nerve conduit showed a significant improvement over the other topographical-shaped grooves, while increasing the conduit wall thickness saw no positive effect on the biological response of the regenerating nerve. Furthermore, the preferred SL-grooved conduit (C) with 70 μm wall thickness was compared with the current clinical gold standard of autologous nerve graft (Ag) in the rat 10-mm sciatic nerve gap model. At 3 weeks postsurgery, all nerve gaps across both groups were bridged with regenerated nerve fibers. At 16 weeks, features of regenerated axons were comparable between the autograft (Ag) and conduit (C) groups. End organ assessments of muscle weight, electromyography, and skin reinnervation were also similar between the groups. The comparable experimental outcome between conduit and autograft, suggests that the PCL/PLA conduit with inner lumen microstructured grooves could be used as a potential alternative treatment for peripheral nerve repair. PMID:25435096

  15. An on-line template improvement algorithm

    NASA Astrophysics Data System (ADS)

    Yin, Yilong; Zhao, Bo; Yang, Xiukun

    2005-03-01

    In automatic fingerprint identification system, incomplete or rigid template may lead to false rejection and false matching. So, how to improve quality of the template, which is called template improvement, is important to automatic fingerprint identify system. In this paper, we propose a template improve algorithm. Based on the case-based method of machine learning and probability theory, we improve the template by deleting pseudo minutia, restoring lost genuine minutia and updating the information of minutia such as positions and directions. And special fingerprint image database is built for this work. Experimental results on this database indicate that our method is effective and quality of fingerprint template is improved evidently. Accordingly, performance of fingerprint matching is also improved stably along with the increase of using time.

  16. Hard template synthesis of metal nanowires

    PubMed Central

    Kawamura, Go; Muto, Hiroyuki; Matsuda, Atsunori

    2014-01-01

    Metal nanowires (NWs) have attracted much attention because of their high electron conductivity, optical transmittance, and tunable magnetic properties. Metal NWs have been synthesized using soft templates such as surface stabilizing molecules and polymers, and hard templates such as anodic aluminum oxide, mesoporous oxide, carbon nanotubes. NWs prepared from hard templates are composites of metals and the oxide/carbon matrix. Thus, selecting appropriate elements can simplify the production of composite devices. The resulting NWs are immobilized and spatially arranged, as dictated by the ordered porous structure of the template. This avoids the NWs from aggregating, which is common for NWs prepared with soft templates in solution. Herein, the hard template synthesis of metal NWs is reviewed, and the resulting structures, properties and potential applications are discussed. PMID:25453031

  17. Hard template synthesis of metal nanowires.

    PubMed

    Kawamura, Go; Muto, Hiroyuki; Matsuda, Atsunori

    2014-01-01

    Metal nanowires (NWs) have attracted much attention because of their high electron conductivity, optical transmittance, and tunable magnetic properties. Metal NWs have been synthesized using soft templates such as surface stabilizing molecules and polymers, and hard templates such as anodic aluminum oxide, mesoporous oxide, carbon nanotubes. NWs prepared from hard templates are composites of metals and the oxide/carbon matrix. Thus, selecting appropriate elements can simplify the production of composite devices. The resulting NWs are immobilized and spatially arranged, as dictated by the ordered porous structure of the template. This avoids the NWs from aggregating, which is common for NWs prepared with soft templates in solution. Herein, the hard template synthesis of metal NWs is reviewed, and the resulting structures, properties and potential applications are discussed. PMID:25453031

  18. Hard template synthesis of metal nanowires

    NASA Astrophysics Data System (ADS)

    Kawamura, Go; Muto, Hiroyuki; Matsuda, Atsunori

    2014-11-01

    Metal nanowires (NWs) have attracted much attention because of their high electron conductivity, optical transmittance and tunable magnetic properties. Metal NWs have been synthesized using soft templates such as surface stabilizing molecules and polymers, and hard templates such as anodic aluminum oxide, mesoporous oxide, carbon nanotubes. NWs prepared from hard templates are composites of metals and the oxide/carbon matrix. Thus, selecting appropriate elements can simplify the production of composite devices. The resulting NWs are immobilized and spatially arranged, as dictated by the ordered porous structure of the template. This avoids the NWs from aggregating, which is common for NWs prepared with soft templates in solution. Herein, the hard template synthesis of metal NWs is reviewed, and the resulting structures, properties and potential applications are discussed.

  19. Regenerable Iodine Water-Disinfection System

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  20. Stereolithographic Surgical Template: A Review

    PubMed Central

    Dandekeri, Shilpa Sudesh; Sowmya, M.K.; Bhandary, Shruthi

    2013-01-01

    Implant placement has become a routine modality of dental care.Improvements in surgical reconstructive methods as well as increased prosthetic demands,require a highly accurate diagnosis, planning and placement. Recently,computer-aided design and manufacturing have made it possible to use data from computerised tomography to not only plan implant rehabilitation,but also transfer this information to the surgery.A review on one of this technique called Stereolithography is presented in this article.It permits graphic and complex 3D implant placement and fabrication of stereolithographic surgical templates. Also offers many significant benefits over traditional procedures. PMID:24179955

  1. Stereolithographic surgical template: a review.

    PubMed

    Dandekeri, Shilpa Sudesh; Sowmya, M K; Bhandary, Shruthi

    2013-09-01

    Implant placement has become a routine modality of dental care.Improvements in surgical reconstructive methods as well as increased prosthetic demands,require a highly accurate diagnosis, planning and placement. Recently,computer-aided design and manufacturing have made it possible to use data from computerised tomography to not only plan implant rehabilitation,but also transfer this information to the surgery.A review on one of this technique called Stereolithography is presented in this article.It permits graphic and complex 3D implant placement and fabrication of stereolithographic surgical templates. Also offers many significant benefits over traditional procedures. PMID:24179955

  2. Vertical Carbon Nanotube Device in Nanoporous Templates

    NASA Technical Reports Server (NTRS)

    Maschmann, Matthew Ralph (Inventor); Fisher, Timothy Scott (Inventor); Sands, Timothy (Inventor); Bashir, Rashid (Inventor)

    2014-01-01

    A modified porous anodic alumina template (PAA) containing a thin CNT catalyst layer directly embedded into the pore walls. CNT synthesis using the template selectively catalyzes SWNTs and DWNTs from the embedded catalyst layer to the top PAA surface, creating a vertical CNT channel within the pores. Subsequent processing allows for easy contact metallization and adaptable functionalization of the CNTs and template for a myriad of applications.

  3. Templated Dry Printing of Conductive Metal Nanoparticles

    NASA Astrophysics Data System (ADS)

    Rolfe, David Alexander

    Printed electronics can lower the cost and increase the ubiquity of electrical components such as batteries, sensors, and telemetry systems. Unfortunately, the advance of printed electronics has been held back by the limited minimum resolution, aspect ratio, and feature fidelity of present printing techniques such as gravure, screen printing and inkjet printing. Templated dry printing offers a solution to these problems by patterning nanoparticle inks into templates before drying. This dissertation shows advancements in two varieties of templated dry nanoprinting. The first, advective micromolding in vapor-permeable templates (AMPT) is a microfluidic approach that uses evaporation-driven mold filling to create submicron features with a 1:1 aspect ratio. We will discuss submicron surface acoustic wave (SAW) resonators made through this process, and the refinement process in the template manufacturing process necessary to make these devices. We also present modeling techniques that can be applied to future AMPT templates. We conclude with a modified templated dry printing that improves throughput and isolated feature patterning by transferring dry-templated features with laser ablation. This method utilizes surface energy-defined templates to pattern features via doctor blade coating. Patterned and dried features can be transferred to a polymer substrate with an Nd:YAG MOPA fiber laser, and printed features can be smaller than the laser beam width.

  4. Influence of template fill in graphoepitaxy DSA

    NASA Astrophysics Data System (ADS)

    Doise, Jan; Bekaert, Joost; Chan, Boon Teik; Hong, SungEun; Lin, Guanyang; Gronheid, Roel

    2016-03-01

    Directed self-assembly (DSA) of block copolymers (BCP) is considered a promising patterning approach for the 7 nm node and beyond. Specifically, a grapho-epitaxy process using a cylindrical phase BCP may offer an efficient solution for patterning randomly distributed contact holes with sub-resolution pitches, such as found in via and cut mask levels. In any grapho-epitaxy process, the pattern density impacts the template fill (local BCP thickness inside the template) and may cause defects due to respectively over- or underfilling of the template. In order to tackle this issue thoroughly, the parameters that determine template fill and the influence of template fill on the resulting pattern should be investigated. In this work, using three process flow variations (with different template surface energy), template fill is experimentally characterized as a function of pattern density and film thickness. The impact of these parameters on template fill is highly dependent on the process flow, and thus pre-pattern surface energy. Template fill has a considerable effect on the pattern transfer of the DSA contact holes into the underlying layer. Higher fill levels give rise to smaller contact holes and worse critical dimension uniformity. These results are important towards DSA-aware design and show that fill is a crucial parameter in grapho-epitaxy DSA.

  5. Method of installing sub-sea templates

    SciTech Connect

    Hampton, J.E.

    1984-03-06

    A subsea template is installed by a method which includes the steps of securing the template in a position beneath the deck of a semi-submersible drilling vessel, moving the semi-submersible drilling vessel to an appropriate offshore site and subsequently lowering the template from the semi-submersible to the sea bed. In addition, at least three anchorage templates may be loaded onto one or both of the pontoons of the semi-submersible drilling vessel at its original position and are subsequently lowered from the pontoons to their respective locations on the sea bed after the semi-submersible has moved to the offshore site.

  6. Colloidal assembly by ice templating.

    PubMed

    Kumaraswamy, Guruswamy; Biswas, Bipul; Choudhury, Chandan Kumar

    2016-04-12

    We investigate ice templating of aqueous dispersions of polymer coated colloids and crosslinkers, at particle concentrations far below that required to form percolated monoliths. Freezing the aqueous dispersions forces the particles into close proximity to form clusters, that are held together as the polymer chains coating the particles are crosslinked. We observe that, with an increase in the particle concentration from about 10(6) to 10(8) particles per ml, there is a transition from isolated single particles to increasingly larger clusters. In this concentration range, most of the colloidal clusters formed are linear or sheet like particle aggregates. Remarkably, the cluster size distribution for clusters smaller than about 30 particles, as well as the size distribution of linear clusters, is only weakly dependent on the dispersion concentration in the range that we investigate. We demonstrate that the main features of cluster formation are captured by kinetic simulations that do not consider hydrodynamics or instabilities at the growing ice front due to particle concentration gradients. Thus, clustering of colloidal particles by ice templating dilute dispersions appears to be governed only by particle exclusion by the growing ice crystals that leads to their accumulation at ice crystal boundaries. PMID:26780838

  7. Elucidation of differential mineralisation on native and regenerated silk matrices.

    PubMed

    Midha, Swati; Tripathi, Rohit; Geng, Hua; Lee, Peter D; Ghosh, Sourabh

    2016-11-01

    Bone mineralisation is a well-orchestrated procedure triggered by a protein-based template inducing the nucleation of hydroxyapatite (HA) nanocrystals on the matrix. In an attempt to fabricate superior nanocomposites from silk fibroin, textile braided structures made of natively spun fibres of Bombyx mori silkworm were compared against regenerated fibroin (lyophilized and films) underpinning the influence of intrinsic properties of fibroin matrices on HA nucleation. We found that native braids could bind Ca(2+) ions through electrostatic attraction, which initiated the nucleation and deposition of HA, as evidenced by discrete shift in amide peaks via ATR-FTIR. This phenomenon also suggests the involvement of amide linkages in promoting HA nucleation on fibroin. Moreover, CaCl2-SBF immersion of native braids resulted in preferential growth of HA along the c-axis, forming needle-like nanocrystals and possessing Ca/P ratio comparable to commercial HA. Though regenerated lyophilized matrix also witnessed prominent peak shift in amide linkages, HA growth was restricted to (211) plane only, albeit at a significantly lower intensity than braids. Regenerated films, on the other hand, provided no crystallographic evidence of HA deposition within 7days of SBF immersion. The present work sheds light on the primary fibroin structure of B. mori which probably plays a crucial role in regulating template-induced biomineralisation on the matrix. We also found that intrinsic material properties such as surface roughness, geometry, specific surface area, tortuosity and secondary conformation exert influence in modulating the extent of mineralisation. Thus our work generates useful insights and warrants future studies to further investigate the potential of bone mimetic, silk/mineral nanocomposite matrices for orthopaedic applications. PMID:27524066

  8. Neural tissue engineering options for peripheral nerve regeneration.

    PubMed

    Gu, Xiaosong; Ding, Fei; Williams, David F

    2014-08-01

    Tissue engineered nerve grafts (TENGs) have emerged as a potential alternative to autologous nerve grafts, the gold standard for peripheral nerve repair. Typically, TENGs are composed of a biomaterial-based template that incorporates biochemical cues. A number of TENGs have been used experimentally to bridge long peripheral nerve gaps in various animal models, where the desired outcome is nerve tissue regeneration and functional recovery. So far, the translation of TENGs to the clinic for use in humans has met with a certain degree of success. In order to optimize the TENG design and further approach the matching of TENGs with autologous nerve grafts, many new cues, beyond the traditional ones, will have to be integrated into TENGs. Furthermore, there is a strong requirement for monitoring the real-time dynamic information related to the construction of TENGs. The aim of this opinion paper is to specifically and critically describe the latest advances in the field of neural tissue engineering for peripheral nerve regeneration. Here we delineate new attempts in the design of template (or scaffold) materials, especially in the context of biocompatibility, the choice and handling of support cells, and growth factor release systems. We further discuss the significance of RNAi for peripheral nerve regeneration, anticipate the potential application of RNAi reagents for TENGs, and speculate on the possible contributions of additional elements, including angiogenesis, electrical stimulation, molecular inflammatory mediators, bioactive peptides, antioxidant reagents, and cultured biological constructs, to TENGs. Finally, we consider that a diverse array of physicochemical and biological cues must be orchestrated within a TENG to create a self-consistent coordinated system with a close proximity to the regenerative microenvironment of the peripheral nervous system. PMID:24818883

  9. Nanocomposites and bone regeneration

    NASA Astrophysics Data System (ADS)

    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.

  10. Injectable Silk Foams for Soft Tissue Regeneration

    PubMed Central

    Bellas, E.; Lo, T.J.; Fournier, E.P.; Brown, J.E.; Abbott, R.D.; Gil, E.S.; Marra, K.G.; Rubin, J.P.; Leisk, G.G.; Kaplan, D.L.

    2015-01-01

    Soft tissue fillers are needed for restoration of a defect or augmentation of existing tissues. Autografts and lipotransfer have been under study for soft tissue reconstruction but yield inconsistent results, often with considerable resorption of the grafted tissue. A minimally invasive procedure would reduce scarring and recovery time as well as allow for the implant and/or grafted tissue to be placed closer to existing vasculature. Here, we demonstrate the feasibility of an injectable silk foam for soft tissue regeneration. Adipose derived stem cells survive and migrate through the foam over a 10 day period in vitro. The silk foams are also successfully injected into the subcutaneous space in a rat and over a 3 month period integrating with the surrounding native tissue. The injected foams are palpable and soft to the touch through the skin and returning to their original dimensions after pressure was applied and then released. The foams readily absorb lipoaspirate making the foams useful as a scaffold or template for existing soft tissue filler technologies, useful either as a biomaterial alone or in combination with the lipoaspirate. PMID:25323438

  11. Biomaterial Selection for Tooth Regeneration

    PubMed Central

    Yuan, Zhenglin; Nie, Hemin; Wang, Shuang; Lee, Chang Hun; Li, Ang; Fu, Susan Y.; Zhou, Hong

    2011-01-01

    Biomaterials are native or synthetic polymers that act as carriers for drug delivery or scaffolds for tissue regeneration. When implanted in vivo, biomaterials should be nontoxic and exert intended functions. For tooth regeneration, biomaterials have primarily served as a scaffold for (1) transplanted stem cells and/or (2) recruitment of endogenous stem cells. This article critically synthesizes our knowledge of biomaterial use in tooth regeneration, including the selection of native and/or synthetic polymers, three-dimensional scaffold fabrication, stem cell transplantation, and stem cell homing. A tooth is a complex biological organ. Tooth loss represents the most common organ failure. Tooth regeneration encompasses not only regrowth of an entire tooth as an organ, but also biological restoration of individual components of the tooth including enamel, dentin, cementum, or dental pulp. Regeneration of tooth root represents perhaps more near-term opportunities than the regeneration of the whole tooth. In the adult, a tooth owes its biological vitality, arguably more, to the root than the crown. Biomaterials are indispensible for the regeneration of tooth root, tooth crown, dental pulp, or an entire tooth. PMID:21699433

  12. Cardiac Regeneration and Stem Cells.

    PubMed

    Zhang, Yiqiang; Mignone, John; MacLellan, W Robb

    2015-10-01

    After decades of believing the heart loses the ability to regenerate soon after birth, numerous studies are now reporting that the adult heart may indeed be capable of regeneration, although the magnitude of new cardiac myocyte formation varies greatly. While this debate has energized the field of cardiac regeneration and led to a dramatic increase in our understanding of cardiac growth and repair, it has left much confusion in the field as to the prospects of regenerating the heart. Studies applying modern techniques of genetic lineage tracing and carbon-14 dating have begun to establish limits on the amount of endogenous regeneration after cardiac injury, but the underlying cellular mechanisms of this regeneration remained unclear. These same studies have also revealed an astonishing capacity for cardiac repair early in life that is largely lost with adult differentiation and maturation. Regardless, this renewed focus on cardiac regeneration as a therapeutic goal holds great promise as a novel strategy to address the leading cause of death in the developed world. PMID:26269526

  13. Evaluation of advanced regenerator systems

    NASA Technical Reports Server (NTRS)

    Cook, J. A.; Fucinari, C. A.; Lingscheit, J. N.; Rahnke, C. J.

    1978-01-01

    The major considerations are discussed which will affect the selection of a ceramic regenerative heat exchanger for an improved 100 HP automotive gas turbine engine. The regenerator considered for this application is about 36cm in diameter. Regenerator comparisons are made on the basis of material, method of fabrication, cost, and performance. A regenerator inlet temperature of 1000 C is assumed for performance comparisons, and laboratory test results are discussed for material comparisons at 1100 and 1200 C. Engine test results using the Ford 707 industrial gas turbine engine are also discussed.

  14. Visual Templates in Pattern Generalization Activity

    ERIC Educational Resources Information Center

    Rivera, F. D.

    2010-01-01

    In this research article, I present evidence of the existence of visual templates in pattern generalization activity. Such templates initially emerged from a 3-week design-driven classroom teaching experiment on pattern generalization involving linear figural patterns and were assessed for existence in a clinical interview that was conducted four…

  15. Transforming surgery through biomaterial template technology.

    PubMed

    Hodde, Jason; Hiles, Michael

    2016-03-01

    Templates inserted into surgical wounds strongly influence the healing responses in humans. The science of these templates, in the form of extracellular matrix biomaterials, is rapidly evolving and improving as the natural interactions with the body become better understood. PMID:26961446

  16. Air Sampling System Evaluation Template

    Energy Science and Technology Software Center (ESTSC)

    2000-05-09

    The ASSET1.0 software provides a template with which a user can evaluate an Air Sampling System against the latest version of ANSI N13.1 "Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stacks and Ducts of Nuclear Facilities". The software uses the ANSI N13.1 PIC levels to establish basic design criteria for the existing or proposed sampling system. The software looks at such criteria as PIC level, type of radionuclide emissions, physical state ofmore » the radionuclide, nozzle entrance effects, particulate transmission effects, system and component accuracy and precision evaluations, and basic system operations to provide a detailed look at the subsystems of a monitoring and sampling system/program. A GAP evaluation can then be completed which leads to identification of design and operational flaws in the proposed systems. Corrective measures can then be limited to the GAPs.« less

  17. Solvable model for template coexistence in protocells

    NASA Astrophysics Data System (ADS)

    Fontanari, J. F.; Serva, M.

    2013-02-01

    Compartmentalization of self-replicating molecules (templates) in protocells is a necessary step towards the evolution of modern cells. However, coexistence between distinct template types inside a protocell can be achieved only if there is a selective pressure favoring protocells with a mixed template composition. Here we study analytically a group selection model for the coexistence between two template types using the diffusion approximation of population genetics. The model combines competition at the template and protocell levels as well as genetic drift inside protocells. At the steady state, we find a continuous phase transition separating the coexistence and segregation regimes, with the order parameter vanishing linearly with the distance to the critical point. In addition, we derive explicit analytical expressions for the critical steady-state probability density of protocell compositions.

  18. Rapid oligonucleotide-templated fluorogenic tetrazine ligations

    PubMed Central

    Šečkutė, Jolita; Yang, Jun; Devaraj, Neal K.

    2013-01-01

    Template driven chemical ligation of fluorogenic probes represents a powerful method for DNA and RNA detection and imaging. Unfortunately, previous techniques have been hampered by requiring chemistry with sluggish kinetics and background side reactions. We have developed fluorescent DNA probes containing quenched fluorophore-tetrazine and methyl-cyclopropene groups that rapidly react by bioorthogonal cycloaddition in the presence of complementary DNA or RNA templates. Ligation increases fluorescence with negligible background signal in the absence of hybridization template. Reaction kinetics depend heavily on template length and linker structure. Using this technique, we demonstrate rapid discrimination between single template mismatches both in buffer and cell media. Fluorogenic bioorthogonal ligations offer a promising route towards the fast and robust fluorescent detection of specific DNA or RNA sequences. PMID:23775794

  19. Nanoimprint lithography using disposable biomass template

    NASA Astrophysics Data System (ADS)

    Hanabata, Makoto; Takei, Satoshi; Sugahara, Kigen; Nakajima, Shinya; Sugino, Naoto; Kameda, Takao; Fukushima, Jiro; Matsumoto, Yoko; Sekiguchi, Atsushi

    2016-04-01

    A novel nanoimprint lithography process using disposable biomass template having gas permeability was investigated. It was found that a disposable biomass template derived from cellulose materials shows an excellent gas permeability and decreases transcriptional defects in conventional templates such as quartz, PMDS, DLC that have no gas permeability. We believe that outgasses from imprinted materials are easily removed through the template. The approach to use a cellulose for template material is suitable as the next generation of clean separation technology. It is expected to be one of the defect-less thermal nanoimprint lithographic technologies. It is also expected that volatile materials and solvent including materials become available that often create defects and peelings in conventional temples that have no gas permeability.

  20. Regenerable Iodine Water-Disinfection System

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  1. Endogenous Mechanisms of Cardiac Regeneration.

    PubMed

    Xiang, M S W; Kikuchi, K

    2016-01-01

    Zebrafish possess a remarkable capacity for cardiac regeneration throughout their lifetime, providing a model for investigating endogenous cellular and molecular mechanisms regulating myocardial regeneration. By contrast, adult mammals have an extremely limited capacity for cardiac regeneration, contributing to mortality and morbidity from cardiac diseases such as myocardial infarction and heart failure. However, the viewpoint of the mammalian heart as a postmitotic organ was recently revised based on findings that the mammalian heart contains multiple undifferentiated cell types with cardiogenic potential as well as a robust regenerative capacity during a short period early in life. Although it occurs at an extremely low level, continuous cardiomyocyte turnover has been detected in adult mouse and human hearts, which could potentially be enhanced to restore lost myocardium in damaged human hearts. This review summarizes and discusses recent advances in the understanding of endogenous mechanisms of cardiac regeneration. PMID:27572127

  2. Hairpin Vortex Regeneration Threshold

    NASA Astrophysics Data System (ADS)

    Sabatino, Daniel; Maharjan, Rijan

    2015-11-01

    A free surface water channel is used to study hairpin vortex formation created by fluid injection through a narrow slot into a laminar boundary layer. Particle image velocimetry is used to calculate the circulation of the primary hairpin vortex head which is found to monotonically decrease in strength with downstream distance. When a secondary hairpin vortex is formed upstream of the primary vortex, the circulation strength of the head is comparable to the strength of the primary head at the time of regeneration. However, the legs of the primary vortex strengthen up to the moment the secondary hairpin is generated. Although the peak circulation in the legs is not directly correlated to the strength of the original elongated ring vortex, when the circulation is scaled with the injection momentum ratio it is linearly related to scaled injection time. It is proposed that the injection momentum ratio and nondimensionalized injection time based on the wall normal penetration time can be used to identify threshold conditions which produce a secondary vortex. Supported by the National Science Foundation under Grant CBET- 1040236.

  3. Biomaterials for periodontal regeneration

    PubMed Central

    Shue, Li; Yufeng, Zhang; Mony, Ullas

    2012-01-01

    Periodontal disease is characterized by the destruction of periodontal tissues. Various methods of regenerative periodontal therapy, including the use of barrier membranes, bone replacement grafts, growth factors and the combination of these procedures have been investigated. The development of biomaterials for tissue engineering has considerably improved the available treatment options above. They fall into two broad classes: ceramics and polymers. The available ceramic-based materials include calcium phosphate (eg, tricalcium phosphate and hydroxyapatite), calcium sulfate and bioactive glass. The bioactive glass bonds to the bone with the formation of a layer of carbonated hydroxyapatite in situ. The natural polymers include modified polysaccharides (eg, chitosan,) and polypeptides (collagen and gelatin). Synthetic polymers [eg, poly(glycolic acid), poly(L-lactic acid)] provide a platform for exhibiting the biomechanical properties of scaffolds in tissue engineering. The materials usually work as osteogenic, osteoconductive and osteoinductive scaffolds. Polymers are more widely used as a barrier material in guided tissue regeneration (GTR). They are shown to exclude epithelial downgrowth and allow periodontal ligament and alveolar bone cells to repopulate the defect. An attempt to overcome the problems related to a collapse of the barrier membrane in GTR or epithelial downgrowth is the use of a combination of barrier membranes and grafting materials. This article reviews various biomaterials including scaffolds and membranes used for periodontal treatment and their impacts on the experimental or clinical management of periodontal defect. PMID:23507891

  4. Regenerable biocide delivery unit

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    A method and apparatus are disclosed for maintaining continuous, long-term microbial control in the water supply for potable, hygiene, and experimental water for space activities, as well as treatment of water supplies on Earth. The water purification is accomplished by introduction of molecular iodine into the water supply to impart a desired iodine residual. The water is passed through an iodinated anion exchange resin bed. The iodine is bound as I-(sub n) at the anion exchange sites and releases I(sub 2) into the water stream flowing through the bed. The concentration of I(sub 2) in the flowing water gradually decreases and, in the prior art, the ion-exchange bed has had to be replaced. In a preferred embodiment, a bed of iodine crystals is provided with connections for flowing water therethrough to produce a concentrated (substantially saturated) aqueous iodine solution which is passed through the iodinated resin bed to recharge the bed with bound iodine. The bed of iodine crystals is connected in parallel with the iodinated resin bed and is activated periodically (e.g., by timer, by measured flow of water, or by iodine residual level) to recharge the bed. Novelty resides in the capability of inexpensively and repeatedly regenerating the ion-exchange bed in situ.

  5. Enhancement of skeletal muscle regeneration.

    PubMed

    Bischoff, R; Heintz, C

    1994-09-01

    We have studied the effect of adding extra satellite cells or soluble factors from crushed muscle on regeneration of minced fragments from rat tibialis muscle. The muscle mince was wrapped in an artificial epimysium to prevent adhesions and cell immigration from adjacent muscles. Regeneration was quantitatively assessed by electrophoretic determination of the muscle-specific form of creatine kinase. Control minces exhibited three periods of change in creatine kinase activity during a 7-week regeneration period. Activity fell rapidly during the first week, then rose gradually from 1-3 weeks and increased more rapidly from 3-7 weeks. To augment the original complement of myogenic cells, satellite cells were isolated from the contralateral muscle, purified by density gradient centrifugation, and expanded in culture for 3 days before adding to the muscle mince. The added cells resulted in a 3-fold enhancement of creatine kinase activity throughout the regeneration period. Soluble muscle extract incorporated into a collagen matrix also stimulated regeneration when added to muscle mince. The extract accelerated the rate of creatine kinase increase during the 1-3 week period beyond that observed in the control or cell augmented mince, suggesting that factors in the extract may facilitate revascularization or reinnervation. The specific activity of creatine kinase was increased in regenerates augmented with both cells and extract, indicating that the effects enhance primarily myogenic processes. PMID:7803846

  6. Testing sensory evidence against mnemonic templates.

    PubMed

    Myers, Nicholas E; Rohenkohl, Gustavo; Wyart, Valentin; Woolrich, Mark W; Nobre, Anna C; Stokes, Mark G

    2015-01-01

    Most perceptual decisions require comparisons between current input and an internal template. Classic studies propose that templates are encoded in sustained activity of sensory neurons. However, stimulus encoding is itself dynamic, tracing a complex trajectory through activity space. Which part of this trajectory is pre-activated to reflect the template? Here we recorded magneto- and electroencephalography during a visual target-detection task, and used pattern analyses to decode template, stimulus, and decision-variable representation. Our findings ran counter to the dominant model of sustained pre-activation. Instead, template information emerged transiently around stimulus onset and quickly subsided. Cross-generalization between stimulus and template coding, indicating a shared neural representation, occurred only briefly. Our results are compatible with the proposal that template representation relies on a matched filter, transforming input into task-appropriate output. This proposal was consistent with a signed difference response at the perceptual decision stage, which can be explained by a simple neural model. PMID:26653854

  7. Testing sensory evidence against mnemonic templates

    PubMed Central

    Myers, Nicholas E; Rohenkohl, Gustavo; Wyart, Valentin; Woolrich, Mark W; Nobre, Anna C; Stokes, Mark G

    2015-01-01

    Most perceptual decisions require comparisons between current input and an internal template. Classic studies propose that templates are encoded in sustained activity of sensory neurons. However, stimulus encoding is itself dynamic, tracing a complex trajectory through activity space. Which part of this trajectory is pre-activated to reflect the template? Here we recorded magneto- and electroencephalography during a visual target-detection task, and used pattern analyses to decode template, stimulus, and decision-variable representation. Our findings ran counter to the dominant model of sustained pre-activation. Instead, template information emerged transiently around stimulus onset and quickly subsided. Cross-generalization between stimulus and template coding, indicating a shared neural representation, occurred only briefly. Our results are compatible with the proposal that template representation relies on a matched filter, transforming input into task-appropriate output. This proposal was consistent with a signed difference response at the perceptual decision stage, which can be explained by a simple neural model. DOI: http://dx.doi.org/10.7554/eLife.09000.001 PMID:26653854

  8. Template optimization and transfer in perceptual learning.

    PubMed

    Kurki, Ilmari; Hyvärinen, Aapo; Saarinen, Jussi

    2016-08-01

    We studied how learning changes the processing of a low-level Gabor stimulus, using a classification-image method (psychophysical reverse correlation) and a task where observers discriminated between slight differences in the phase (relative alignment) of a target Gabor in visual noise. The method estimates the internal "template" that describes how the visual system weights the input information for decisions. One popular idea has been that learning makes the template more like an ideal Bayesian weighting; however, the evidence has been indirect. We used a new regression technique to directly estimate the template weight change and to test whether the direction of reweighting is significantly different from an optimal learning strategy. The subjects trained the task for six daily sessions, and we tested the transfer of training to a target in an orthogonal orientation. Strong learning and partial transfer were observed. We tested whether task precision (difficulty) had an effect on template change and transfer: Observers trained in either a high-precision (small, 60° phase difference) or a low-precision task (180°). Task precision did not have an effect on the amount of template change or transfer, suggesting that task precision per se does not determine whether learning generalizes. Classification images show that training made observers use more task-relevant features and unlearn some irrelevant features. The transfer templates resembled partially optimized versions of templates in training sessions. The template change direction resembles ideal learning significantly but not completely. The amount of template change was highly correlated with the amount of learning. PMID:27559720

  9. Rate in template-directed polymer synthesis

    NASA Astrophysics Data System (ADS)

    Saito, Takuya

    2014-06-01

    We discuss the temporal efficiency of template-directed polymer synthesis, such as DNA replication and transcription, under a given template string. To weigh the synthesis speed and accuracy on the same scale, we propose a template-directed synthesis (TDS) rate, which contains an expression analogous to that for the Shannon entropy. Increasing the synthesis speed accelerates the TDS rate, but the TDS rate is lowered if the produced sequences are diversified. We apply the TDS rate to some production system models and investigate how the balance between the speed and the accuracy is affected by changes in the system conditions.

  10. Biomineralization Guided by Paper Templates.

    PubMed

    Camci-Unal, Gulden; Laromaine, Anna; Hong, Estrella; Derda, Ratmir; Whitesides, George M

    2016-01-01

    This work demonstrates the fabrication of partially mineralized scaffolds fabricated in 3D shapes using paper by folding, and by supporting deposition of calcium phosphate by osteoblasts cultured in these scaffolds. This process generates centimeter-scale free-standing structures composed of paper supporting regions of calcium phosphate deposited by osteoblasts. This work is the first demonstration that paper can be used as a scaffold to induce template-guided mineralization by osteoblasts. Because paper has a porous structure, it allows transport of O2 and nutrients across its entire thickness. Paper supports a uniform distribution of cells upon seeding in hydrogel matrices, and allows growth, remodelling, and proliferation of cells. Scaffolds made of paper make it possible to construct 3D tissue models easily by tuning material properties such as thickness, porosity, and density of chemical functional groups. Paper offers a new approach to study mechanisms of biomineralization, and perhaps ultimately new techniques to guide or accelerate the repair of bone. PMID:27277575

  11. Biomineralization Guided by Paper Templates

    PubMed Central

    Camci-Unal, Gulden; Laromaine, Anna; Hong, Estrella; Derda, Ratmir; Whitesides, George M.

    2016-01-01

    This work demonstrates the fabrication of partially mineralized scaffolds fabricated in 3D shapes using paper by folding, and by supporting deposition of calcium phosphate by osteoblasts cultured in these scaffolds. This process generates centimeter-scale free-standing structures composed of paper supporting regions of calcium phosphate deposited by osteoblasts. This work is the first demonstration that paper can be used as a scaffold to induce template-guided mineralization by osteoblasts. Because paper has a porous structure, it allows transport of O2 and nutrients across its entire thickness. Paper supports a uniform distribution of cells upon seeding in hydrogel matrices, and allows growth, remodelling, and proliferation of cells. Scaffolds made of paper make it possible to construct 3D tissue models easily by tuning material properties such as thickness, porosity, and density of chemical functional groups. Paper offers a new approach to study mechanisms of biomineralization, and perhaps ultimately new techniques to guide or accelerate the repair of bone. PMID:27277575

  12. Templated Native Silk Smectic Gels

    NASA Technical Reports Server (NTRS)

    Jin, Hyoung-Joon (Inventor); Park, Jae-Hyung (Inventor); Valluzzi, Regina (Inventor)

    2013-01-01

    One aspect of the present invention relates to a method of preparing a fibrous protein smectic hydrogel by way of a solvent templating process, comprising the steps of pouring an aqueous fibrous protein solution into a container comprising a solvent that is not miscible with water; sealing the container and allowing it to age at about room temperature; and collecting the resulting fibrous protein smectic hydrogel and allowing it to dry. Another aspect of the present invention relates to a method of obtaining predominantly one enantiomer from a racemic mixture, comprising the steps of pouring an aqueous fibrous protein solution into a container comprising a solvent that is not miscible with water; sealing the container and allowing it to age at about room temperature; allowing the enantiomers of racemic mixture to diffuse selectively into the smectic hydrogel in solution; removing the smectic hydrogel from the solution; rinsing predominantly one enantiomer from the surface of the smectic hydrogel; and extracting predominantly one enantiomer from the interior of the smectic hydrogel. The present invention also relates to a smectic hydrogel prepared according to an aforementioned method.

  13. Templated Native Silk Smectic Gels

    NASA Technical Reports Server (NTRS)

    Jin, Hyoung-Joon (Inventor); Park, Jae-Hyung (Inventor); Valluzzi, Regina (Inventor)

    2016-01-01

    One aspect of the present invention relates to a method of preparing a fibrous protein smectic hydrogel by way of a solvent templating process, comprising the steps of pouring an aqueous fibrous protein solution into a container comprising a solvent that is not miscible with water; sealing the container and allowing it to age at about room temperature; and collecting the resulting fibrous protein smectic hydrogel and allowing it to dry. Another aspect of the present invention relates to a method of obtaining predominantly one enantiomer from a racemic mixture, comprising the steps of pouring an aqueous fibrous protein solution into a container comprising a solvent that is not miscible with water; sealing the container and allowing it to age at about room temperature; allowing the enantiomers of racemic mixture to diffuse selectively into the smectic hydrogel in solution; removing the smectic hydrogel from the solution; rinsing predominantly one enantiomer from the surface of the smectic hydrogel; and extracting predominantly one enantiomer from the interior of the smectic hydrogel. The present invention also relates to a smectic hydrogel prepared according to an aforementioned method.

  14. Templated native silk smectic gels

    NASA Technical Reports Server (NTRS)

    Jin, Hyoung-Joon (Inventor); Park, Jae-Hyung (Inventor); Valluzzi, Regina (Inventor)

    2009-01-01

    One aspect of the present invention relates to a method of preparing a fibrous protein smectic hydrogel by way of a solvent templating process, comprising the steps of pouring an aqueous fibrous protein solution into a container comprising a solvent that is not miscible with water; sealing the container and allowing it to age at about room temperature; and collecting the resulting fibrous protein smectic hydrogel and allowing it to dry. Another aspect of the present invention relates to a method of obtaining predominantly one enantiomer from a racemic mixture, comprising the steps of pouring an aqueous fibrous protein solution into a container comprising a solvent that is not miscible with water; sealing the container and allowing it to age at about room temperature; allowing the enantiomers of racemic mixture to diffuse selectively into the smectic hydrogel in solution; removing the smectic hydrogel from the solution; rinsing predominantly one enantiomer from the surface of the smectic hydrogel; and extracting predominantly one enantiomer from the interior of the smectic hydrogel. The present invention also relates to a smectic hydrogel prepared according to an aforementioned method.

  15. Using wavelets to learn pattern templates

    NASA Astrophysics Data System (ADS)

    Scott, Clayton D.; Nowak, Robert D.

    2002-07-01

    Despite the success of wavelet decompositions in other areas of statistical signal and image processing, current wavelet-based image models are inadequate for modeling patterns in images, due to the presence of unknown transformations (e.g., translation, rotation, location of lighting source) inherent in most pattern observations. In this paper we introduce a hierarchical wavelet-based framework for modeling patterns in digital images. This framework takes advantage of the efficient image representations afforded by wavelets, while accounting for unknown translation and rotation. Given a trained model, we can use this framework to synthesize pattern observations. If the model parameters are unknown, we can infer them from labeled training data using TEMPLAR (Template Learning from Atomic Representations), a novel template learning algorithm with linear complexity. TEMPLAR employs minimum description length (MDL) complexity regularization to learn a template with a sparse representation in the wavelet domain. We discuss several applications, including template learning, pattern classification, and image registration.

  16. Amesos2 Templated Direct Sparse Solver Package

    Energy Science and Technology Software Center (ESTSC)

    2011-05-24

    Amesos2 is a templated direct sparse solver package. Amesos2 provides interfaces to direct sparse solvers, rather than providing native solver capabilities. Amesos2 is a derivative work of the Trilinos package Amesos.

  17. Cell Therapy for Cardiovascular Regeneration

    PubMed Central

    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 redevelop the evidence of cell-based cardiovascular regeneration therapy, focusing on targets (disease, patient’s status, cardiac function), materials (cells, cytokines, genes), and methodology (transplantation route, implantation technology, tissue engineering). Meanwhile, establishment of the induced pluripotent stem (iPS) cells is an extremely innovative technology which should be proposed as embryonic stem (ES) cellularization of post natal somatic cells, and this application have also showed the milestones of the direct conversion to reconstruct cardiomyocyte from the various somatic cells, which does not need the acquisition of the re-pluripotency. This review discusses the new advance in cardiovascular regeneration therapy from cardiac regeneration to cardiac re-organization, which is involved in recent progress of on-going clinical trials, basic research in cardiovascular regeneration, and the possibility of tissue engineering technology. PMID:23825492

  18. Hindlimb suspension reduces muscle regeneration

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

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

  19. Lipid bilayers on nano-templates

    DOEpatents

    Noy, Aleksandr; Artyukhin, Alexander B.; Bakajin, Olgica; Stoeve, Pieter

    2009-08-04

    A lipid bilayer on a nano-template comprising a nanotube or nanowire and a lipid bilayer around the nanotube or nanowire. One embodiment provides a method of fabricating a lipid bilayer on a nano-template comprising the steps of providing a nanotube or nanowire and forming a lipid bilayer around the polymer cushion. One embodiment provides a protein pore in the lipid bilayer. In one embodiment the protein pore is sensitive to specific agents

  20. Structural templates for comparative protein docking

    PubMed Central

    Anishchenko, Ivan; Kundrotas, Petras J.; Tuzikov, Alexander V.; Vakser, Ilya A.

    2014-01-01

    Structural characterization of protein-protein interactions is important for understanding life processes. Because of the inherent limitations of experimental techniques, such characterization requires computational approaches. Along with the traditional protein-protein docking (free search for a match between two proteins), comparative (template-based) modeling of protein-protein complexes has been gaining popularity. Its development puts an emphasis on full and partial structural similarity between the target protein monomers and the protein-protein complexes previously determined by experimental techniques (templates). The template-based docking relies on the quality and diversity of the template set. We present a carefully curated, non-redundant library of templates containing 4,950 full structures of binary complexes and 5,936 protein-protein interfaces extracted from the full structures at 12Å distance cut-off. Redundancy in the libraries was removed by clustering the PDB structures based on structural similarity. The value of the clustering threshold was determined from the analysis of the clusters and the docking performance on a benchmark set. High structural quality of the interfaces in the template and validation sets was achieved by automated procedures and manual curation. The library is included in the Dockground resource for molecular recognition studies at http://dockground.bioinformatics.ku.edu. PMID:25488330

  1. A metadata template for ocean acidification data

    NASA Astrophysics Data System (ADS)

    Jiang, L.-Q.; O'Connor, S. A.; Arzayus, K. M.; Parsons, A. R.

    2015-06-01

    This paper defines the best practices for documenting ocean acidification (OA) data and presents a framework for an OA metadata template. Metadata is structured information that describes and locates an information resource. It is the key to ensuring that a data set will be accessible into the future. With the rapid expansion of studies on biological responses to OA, the lack of a common metadata template to document the resulting data poses a significant hindrance to effective OA data management efforts. In this paper, we present a metadata template that can be applied to a broad spectrum of OA studies, including those studying the biological responses to OA. The "variable metadata section", which includes the variable name, observation type, whether the variable is a manipulation condition or response variable, and the biological subject on which the variable is studied, forms the core of this metadata template. Additional metadata elements, such as investigators, temporal and spatial coverage, and data citation, are essential components to complete the template. We explain the structure of the template, and define many metadata elements that may be unfamiliar to researchers.

  2. Template Matching Using a Fluid Flow Model

    NASA Astrophysics Data System (ADS)

    Newman, William Curtis

    Template matching is successfully used in machine recognition of isolated spoken words. In these systems a word is broken into frames (20 millisecond time slices) and the spectral characteristics of each frame are found. Thus, each word is represented as a 2-dimensional (2-D) function of spectral characteristic and frame number. An unknown word is recognized by matching its 2-D representation to previously stored example words, or templates, also in this 2-D form. A new model for this matching step will be introduced. The 2-D representations of the template and unknown are used to determine the shape of a volume of viscous fluid. This volume is broken up into many small elements. The unknown is changed into the template by allowing flows between the element boundaries. Finally the match between the template and unknown is determined by calculating a weighted squared sum of the flow values. The model also allows the relative flow resistance between the element boundaries to be changed. This is useful for characterizing the important features of a given template. The flow resistances are changed according to the gradient of a simple performance function. This performance function is evaluated using a set of training samples provided by the user. The model is applied to isolated word and single character recognition tasks. Results indicate the applications where this model works best.

  3. [From Chromosome Theory to the Template Principle].

    PubMed

    Inge-Vechtomov, S G

    2015-04-01

    The template principle has originated from the chromosome theory of inheritance and claims to be the universal paradigm of modern biology. It considers the mechanisms of inheritance and different types of variability from a unified standpoint. The type I template processes (TP I) operate with linear templates: DNA and RNA. TP II deal with spatial, or conformational, templates of protein nature. TP II are based on variation and reproduction of the spatial structure of proteins and do not affect their primary structure. They are involved in many pathological and adaptive processes in living systems. The universal properties of TP I, ambiguity and repair (correction), are common to all three stages of each template process-initiation, elongation, and termination. These properties are typical for TP II as well. Ambiguity and correction at stages of initiation and termination of TP are prerequisites for the regulation of template processes. The variation in this regulation underlies the complexity and progressive evolution of living-systems. PMID:26087617

  4. A metadata template for ocean acidification data

    NASA Astrophysics Data System (ADS)

    Jiang, L.

    2014-12-01

    Metadata is structured information that describes, explains, and locates an information resource (e.g., data). It is often coarsely described as data about data, and documents information such as what was measured, by whom, when, where, and how it was sampled, analyzed, with what instruments. Metadata is inherent to ensure the survivability and accessibility of the data into the future. With the rapid expansion of biological response ocean acidification (OA) studies, the lack of a common metadata template to document such type of data has become a significant gap for ocean acidification data management efforts. In this paper, we present a metadata template that can be applied to a broad spectrum of OA studies, including those studying the biological responses of organisms on ocean acidification. The "variable metadata section", which includes the variable name, observation type, whether the variable is a manipulation condition or response variable, and the biological subject on which the variable is studied, forms the core of this metadata template. Additional metadata elements, such as principal investigators, temporal and spatial coverage, platforms for the sampling, data citation are essential components to complete the template. We explain the structure of the template, and define many metadata elements that may be unfamiliar to researchers. For that reason, this paper can serve as a user's manual for the template.

  5. Molecular Sieve Regeneration System (MSRS)

    SciTech Connect

    Nasise, J.E.; Anderson, J.L. ); Naruse, Y. )

    1992-01-01

    A Molecular Sieve Regeneration System (MSRS) was added to the existing Tritium Waste Treatment system (TWT) within the Tritium Systems Test Assembly (TSTA) at Los Alamos National Laboratory. The Department of Energy (DOE) no longer allows inventory by difference'' for radioactive wastes that are to be buried. The MSRS was designed and built to comply with this requirement. Within the TWT, water is generated by the catalytic conversion of hydrogen isotopes and removed by molecular sieve trapping prior to release to the environment. Molecular sieve regeneration is required to remove the trapped water and to rejuvenate the beds. The MSRS permits the collection and direct tritium assay of regenerated tritiated water from molecular sieve beds. This paper describes the MSRS in detail and how it is interfaced with the TWT.

  6. Molecular Sieve Regeneration System (MSRS)

    SciTech Connect

    Nasise, J.E.; Anderson, J.L.; Naruse, Y.

    1992-03-01

    A Molecular Sieve Regeneration System (MSRS) was added to the existing Tritium Waste Treatment system (TWT) within the Tritium Systems Test Assembly (TSTA) at Los Alamos National Laboratory. The Department of Energy (DOE) no longer allows ``inventory by difference`` for radioactive wastes that are to be buried. The MSRS was designed and built to comply with this requirement. Within the TWT, water is generated by the catalytic conversion of hydrogen isotopes and removed by molecular sieve trapping prior to release to the environment. Molecular sieve regeneration is required to remove the trapped water and to rejuvenate the beds. The MSRS permits the collection and direct tritium assay of regenerated tritiated water from molecular sieve beds. This paper describes the MSRS in detail and how it is interfaced with the TWT.

  7. Regenerator cross arm seal assembly

    DOEpatents

    Jackman, Anthony V.

    1988-01-01

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

  8. Self-regenerating column chromatography

    SciTech Connect

    Park, Woo K.

    1994-12-31

    The present invention provides a process for treating both cations and anions by using a self-regenerating, multi-ionic exchange resin column system which requires no separate regeneration steps. The process involves alternation ion-exchange chromatography for cations and anions in a multi-ionic exchange column packed with a mixture of cation and anion exchange resins. The multi-ionic mixed-charge resin column works as a multifunction column, capable of independently processing either cationic or anionic exchange, or simultaneously processing both cationic and anionic exchanges. The major advantage offered by the alternating multifunction ion exchange process is the self-regeneration of the resins. Applications are to separation of nitrogen and sulfur isotopes.

  9. Ceramic regenerator systems development program

    NASA Technical Reports Server (NTRS)

    Fucinari, C. A.; Rahnke, C. J.; Rao, V. D. N.; Vallance, J. K.

    1980-01-01

    The DOE/NASA Ceramic Regenerator Design and Reliability Program aims to develop ceramic regenerator cores that can be used in passenger car and industrial/truck gas turbine engines. The major cause of failure of early gas turbine regenerators was found to be chemical attack of the ceramic material. Improved materials and design concepts aimed at reducing or eliminating chemical attack were placed on durability test in Ford 707 industrial gas turbine engines late in 1974. Results of 53,065 hours of turbine engine durability testing are described. Two materials, aluminum silicate and magnesium aluminum silicate, show promise. Five aluminum silicate cores attained the durability objective of 10,000 hours at 800 C (1472 F). Another aluminum silicate core shows minimal evidence of chemical attack after 8071 hours at 982 C (1800 F). Results obtained in ceramic material screening tests, aerothermodynamic performance tests, stress analysis, cost studies, and material specifications are included.

  10. Self-regenerating column chromatography

    DOEpatents

    Park, W.K.

    1995-05-30

    The present invention provides a process for treating both cations and anions by using a self-regenerating, multi-ionic exchange resin column system which requires no separate regeneration steps. The process involves alternating ion-exchange chromatography for cations and anions in a multi-ionic exchange column packed with a mixture of cation and anion exchange resins. The multi-ionic mixed-charge resin column works as a multi-function column, capable of independently processing either cationic or anionic exchange, or simultaneously processing both cationic and anionic exchanges. The major advantage offered by the alternating multi-function ion exchange process is the self-regeneration of the resins.

  11. Cardiac regeneration: epicardial mediated repair

    PubMed Central

    2015-01-01

    The hearts of lower vertebrates such as fish and salamanders display scarless regeneration following injury, although this feature is lost in adult mammals. The remarkable capacity of the neonatal mammalian heart to regenerate suggests that the underlying machinery required for the regenerative process is evolutionarily retained. Recent studies highlight the epicardial covering of the heart as an important source of the signalling factors required for the repair process. The developing epicardium is also a major source of cardiac fibroblasts, smooth muscle, endothelial cells and stem cells. Here, we examine animal models that are capable of scarless regeneration, the role of the epicardium as a source of cells, signalling mechanisms implicated in the regenerative process and how these mechanisms influence cardiomyocyte proliferation. We also discuss recent advances in cardiac stem cell research and potential therapeutic targets arising from these studies. PMID:26702046

  12. Ceramic regenerator systems development program

    NASA Technical Reports Server (NTRS)

    Cook, J. A.; Fucinari, C. A.; Lingscheit, J. N.; Rahnke, C. J.; Rao, V. D.

    1978-01-01

    Ceramic regenerator cores are considered that can be used in passenger car gas turbine engines, Stirling engines, and industrial/truck gas turbine engines. Improved materials and design concepts aimed at reducing or eliminating chemical attack were placed on durability tests/in industrial gas turbine engines. A regenerator core made from aluminum silicate shows minimal evidence of chemical attack damage after 7804 hours of engine test at 800 C and another showed little distress after 4983 hours at 982 C. The results obtained in ceramic material screening tests, aerothermodynamic performance tests, stress analysis, cost studies, and material specifications are also included.

  13. Osteoinductivity of engineered cartilaginous templates devitalized by inducible apoptosis

    PubMed Central

    Bourgine, Paul E.; Scotti, Celeste; Pigeot, Sebastien; Tchang, Laurent A.; Todorov, Atanas; Martin, Ivan

    2014-01-01

    The role of cell-free extracellular matrix (ECM) in triggering tissue and organ regeneration has gained increased recognition, yet current approaches are predominantly based on the use of ECM from fully developed native tissues at nonhomologous sites. We describe a strategy to generate customized ECM, designed to activate endogenous regenerative programs by recapitulating tissue-specific developmental processes. The paradigm was exemplified in the context of the skeletal system by testing the osteoinductive capacity of engineered and devitalized hypertrophic cartilage, which is the primordial template for the development of most bones. ECM was engineered by inducing chondrogenesis of human mesenchymal stromal cells and devitalized by the implementation of a death-inducible genetic device, leading to cell apoptosis on activation and matrix protein preservation. The resulting hypertrophic cartilage ECM, tested in a stringent ectopic implantation model, efficiently remodeled to form de novo bone tissue of host origin, including mature vasculature and a hematopoietic compartment. Importantly, cartilage ECM could not generate frank bone tissue if devitalized by standard “freeze & thaw” (F&T) cycles, associated with a significant loss of glycosaminoglycans, mineral content, and ECM-bound cytokines critically involved in inflammatory, vascularization, and remodeling processes. These results support the utility of engineered ECM-based devices as off-the-shelf regenerative niches capable of recruiting and instructing resident cells toward the formation of a specific tissue. PMID:25422415

  14. Osteoinductivity of engineered cartilaginous templates devitalized by inducible apoptosis.

    PubMed

    Bourgine, Paul E; Scotti, Celeste; Pigeot, Sebastien; Tchang, Laurent A; Todorov, Atanas; Martin, Ivan

    2014-12-01

    The role of cell-free extracellular matrix (ECM) in triggering tissue and organ regeneration has gained increased recognition, yet current approaches are predominantly based on the use of ECM from fully developed native tissues at nonhomologous sites. We describe a strategy to generate customized ECM, designed to activate endogenous regenerative programs by recapitulating tissue-specific developmental processes. The paradigm was exemplified in the context of the skeletal system by testing the osteoinductive capacity of engineered and devitalized hypertrophic cartilage, which is the primordial template for the development of most bones. ECM was engineered by inducing chondrogenesis of human mesenchymal stromal cells and devitalized by the implementation of a death-inducible genetic device, leading to cell apoptosis on activation and matrix protein preservation. The resulting hypertrophic cartilage ECM, tested in a stringent ectopic implantation model, efficiently remodeled to form de novo bone tissue of host origin, including mature vasculature and a hematopoietic compartment. Importantly, cartilage ECM could not generate frank bone tissue if devitalized by standard "freeze & thaw" (F&T) cycles, associated with a significant loss of glycosaminoglycans, mineral content, and ECM-bound cytokines critically involved in inflammatory, vascularization, and remodeling processes. These results support the utility of engineered ECM-based devices as off-the-shelf regenerative niches capable of recruiting and instructing resident cells toward the formation of a specific tissue. PMID:25422415

  15. A model regenerator for a Stirling cycle

    NASA Astrophysics Data System (ADS)

    Carolan, James

    2001-05-01

    An essential feature of the engine patented by Robert Stirling in 1817 was the careful description of the idea of regeneration. In the standard thermodynamic cycle representation of the engine, regeneration is the storing and the reusing of the thermal energy released in the constant volume cooling part of the cycle. Due to the difficulty in treating regeneration quantitatively, introductory physics texts generally either ignore the concept or assume the regeneration to be perfect. As a result students obtain little or no understanding of regeneration. In addition there seem to be differing views in various texts about the efficiency of Stirling engines. In this work a simple finite element model regenerator is presented with which one can do simple calculations. The model does not accurately represent actual regeneration in a practical engine. But the model might help students gain better insight into Stirling engine efficiency and the idea of regeneration.

  16. Regulation of crustacean molting and regeneration

    SciTech Connect

    Skinner, D.M.; Graham, D.E.; Holland, C.A.; Soumoff, C.; Mykles, D.L.

    1981-01-01

    The regulation of molting and regeneration by two antagonistic hormones is discussed. The time course of ecdysteroid titers in crustacean tissues has been followed during molt and regeneration cycles. (ACR)

  17. Conversion of Radiology Reporting Templates to the MRRT Standard.

    PubMed

    Kahn, Charles E; Genereaux, Brad; Langlotz, Curtis P

    2015-10-01

    In 2013, the Integrating the Healthcare Enterprise (IHE) Radiology workgroup developed the Management of Radiology Report Templates (MRRT) profile, which defines both the format of radiology reporting templates using an extension of Hypertext Markup Language version 5 (HTML5), and the transportation mechanism to query, retrieve, and store these templates. Of 200 English-language report templates published by the Radiological Society of North America (RSNA), initially encoded as text and in an XML schema language, 168 have been converted successfully into MRRT using a combination of automated processes and manual editing; conversion of the remaining 32 templates is in progress. The automated conversion process applied Extensible Stylesheet Language Transformation (XSLT) scripts, an XML parsing engine, and a Java servlet. The templates were validated for proper HTML5 and MRRT syntax using web-based services. The MRRT templates allow radiologists to share best-practice templates across organizations and have been uploaded to the template library to supersede the prior XML-format templates. By using MRRT transactions and MRRT-format templates, radiologists will be able to directly import and apply templates from the RSNA Report Template Library in their own MRRT-compatible vendor systems. The availability of MRRT-format reporting templates will stimulate adoption of the MRRT standard and is expected to advance the sharing and use of templates to improve the quality of radiology reports. PMID:25776768

  18. A metadata template for ocean acidification data

    NASA Astrophysics Data System (ADS)

    Jiang, L.-Q.; O'Connor, S. A.; Arzayus, K. M.; Kozyr, A.; Parsons, A. R.

    2015-01-01

    This paper defines the best practices for documenting ocean acidification (OA) metadata and presents a framework for an OA metadata template. Metadata is structured information that describes and locates an information resource. It is the key to ensuring that a data set will survive and continue to be accessible into the future. With the rapid expansion of studies on biological responses of organisms to OA, the lack of a common metadata template to document the resulting data poses a significant hindrance to effective OA data management efforts. In this paper, we present a metadata template that can be applied to a broad spectrum of OA studies, including those studying the biological responses of organisms to OA. The "variable metadata section", which includes the variable name, observation type, whether the variable is a manipulation condition or response variable, and the biological subject on which the variable is studied, forms the core of this metadata template. Additional metadata elements, such as investigators, temporal and spatial coverage, platforms for the sampling, data citation, are essential components to complete the template. We also explain the structure of the template, and define many metadata elements that may be unfamiliar to researchers. Template availability. - Available at: http://ezid.cdlib.org/id/doi:10.7289/V5C24TCK. - DOI: doi:10.7289/V5C24TCK. - NOAA Institutional Repository Accession number: ocn881471371.

  19. Cryogenic regenerator including sarancarbon heat conduction matrix

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor); Petrick, S. Walter (Inventor); Britcliffe, Michael J. (Inventor)

    1989-01-01

    A saran carbon matrix is employed to conduct heat through the heat storing volume of a cryogenic regenerator. When helium is adsorbed into the saran carbon matrix, the combination exhibits a volumetric specific heat much higher than previously used lead balls. A helium adsorbed saran regenerator should allow much lower refrigerator temperatures than those practically obtainable with lead based regenerators for regenerator type refrigeration systems.

  20. Patterned substrates and methods for nerve regeneration

    DOEpatents

    Mallapragada, Surya K.; Heath, Carole; Shanks, Howard; Miller, Cheryl A.; Jeftinija, Srdija

    2004-01-13

    Micropatterned substrates and methods for fabrication of artificial nerve regeneration conduits and methods for regenerating nerves are provided. Guidance compounds or cells are seeded in grooves formed on the patterned substrate. The substrates may also be provided with electrodes to provide electrical guidance cues to the regenerating nerve. The micropatterned substrates give physical, chemical, cellular and/or electrical guidance cues to promote nerve regeneration at the cellular level.

  1. Regeneration: New Neurons Wire Up.

    PubMed

    Raymond, Pamela A

    2016-09-12

    Functional repair of damage in the nervous system requires re-establishment of precise patterns of synaptic connectivity. A new study shows that after selective ablation, zebrafish retinal neurons regenerate and reconstruct some, although not all, of their stereotypic wiring. PMID:27623258

  2. Increasing FCC regenerator catalyst level

    SciTech Connect

    Wong, R.F. )

    1993-11-01

    A Peruvian FCC unit's operations were improved by increasing the regenerator's catalyst level. This increase resulted in lower stack losses, an improved temperature profile, increased catalyst activity and a lower catalyst consumption rate. A more stable operation saved this Peruvian refiner over $131,000 per year in catalyst alone. These concepts and data may be suitable for your FCC unit as well.

  3. Cytoskeletal regulation of dermal regeneration.

    PubMed

    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

  4. Cryopump regeneration method and apparatus

    SciTech Connect

    Andeen, B.R.; Pandorf, R.C.

    1988-01-12

    A vacuum system is described comprising: a cryopump for evacuating a chamber; an ejector pump in direct communication with the cryopump through a valve for removing gas from the cryopump during regeneration; and a source of pressurized, substantially inert gas in a communication with the ejector pump for use as the actuating fluid in the ejector pump.

  5. Cytoskeletal Regulation of Dermal Regeneration

    PubMed Central

    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

  6. Distinctive Capillary Action by Micro-channels in Bone-like Templates can Enhance Recruitment of Cells for Restoration of Large Bony Defect.

    PubMed

    Oh, Daniel S; Koch, Alia; Eisig, Sidney; Kim, Sahng Gyoon; Kim, Yoon Hyuk; Kim, Do-Gyoon; Shim, Jae Hyuck

    2015-01-01

    Without an active, thriving cell population that is well-distributed and stably anchored to the inserted template, exceptional bone regeneration does not occur. With conventional templates, the absence of internal micro-channels results in the lack of cell infiltration, distribution, and inhabitance deep inside the templates. Hence, a highly porous and uniformly interconnected trabecular-bone-like template with micro-channels (biogenic microenvironment template; BMT) has been developed to address these obstacles. The novel BMT was created by innovative concepts (capillary action) and fabricated with a sponge-template coating technique. The BMT consists of several structural components: inter-connected primary-pores (300-400 µm) that mimic pores in trabecular bone, micro-channels (25-70 µm) within each trabecula, and nanopores (100-400 nm) on the surface to allow cells to anchor. Moreover, the BMT has been documented by mechanical test study to have similar mechanical strength properties to those of human trabecular bone (~3.8 MPa)12. The BMT exhibited high absorption, retention, and habitation of cells throughout the bridge-shaped (Π) templates (3 cm height and 4 cm length). The cells that were initially seeded into one end of the templates immediately mobilized to the other end (10 cm distance) by capillary action of the BMT on the cell media. After 4 hr, the cells homogenously occupied the entire BMT and exhibited normal cellular behavior. The capillary action accounted for the infiltration of the cells suspended in the media and the distribution (active migration) throughout the BMT. Having observed these capabilities of the BMT, we project that BMTs will absorb bone marrow cells, growth factors, and nutrients from the periphery under physiological conditions. The BMT may resolve current limitations via rapid infiltration, homogenous distribution and inhabitance of cells in large, volumetric templates to repair massive skeletal defects. PMID:26380953

  7. Distinctive Capillary Action by Micro-channels in Bone-like Templates can Enhance Recruitment of Cells for Restoration of Large Bony Defect

    PubMed Central

    Oh, Daniel S.; Koch, Alia; Eisig, Sidney; Kim, Sahng Gyoon; Kim, Yoon Hyuk; Kim, Do-Gyoon; Shim, Jae Hyuck

    2015-01-01

    Without an active, thriving cell population that is well-distributed and stably anchored to the inserted template, exceptional bone regeneration does not occur. With conventional templates, the absence of internal micro-channels results in the lack of cell infiltration, distribution, and inhabitance deep inside the templates. Hence, a highly porous and uniformly interconnected trabecular-bone-like template with micro-channels (biogenic microenvironment template; BMT) has been developed to address these obstacles. The novel BMT was created by innovative concepts (capillary action) and fabricated with a sponge-template coating technique. The BMT consists of several structural components: inter-connected primary-pores (300-400 µm) that mimic pores in trabecular bone, micro-channels (25-70 µm) within each trabecula, and nanopores (100-400 nm) on the surface to allow cells to anchor. Moreover, the BMT has been documented by mechanical test study to have similar mechanical strength properties to those of human trabecular bone (~3.8 MPa)12. The BMT exhibited high absorption, retention, and habitation of cells throughout the bridge-shaped (Π) templates (3 cm height and 4 cm length). The cells that were initially seeded into one end of the templates immediately mobilized to the other end (10 cm distance) by capillary action of the BMT on the cell media. After 4 hr, the cells homogenously occupied the entire BMT and exhibited normal cellular behavior. The capillary action accounted for the infiltration of the cells suspended in the media and the distribution (active migration) throughout the BMT. Having observed these capabilities of the BMT, we project that BMTs will absorb bone marrow cells, growth factors, and nutrients from the periphery under physiological conditions. The BMT may resolve current limitations via rapid infiltration, homogenous distribution and inhabitance of cells in large, volumetric templates to repair massive skeletal defects. PMID:26380953

  8. Synthesis of RNA oligomers on heterogeneous templates

    NASA Technical Reports Server (NTRS)

    Ertem, G.; Ferris, J. P.

    1996-01-01

    The concept of an RNA world in the chemical origin of life is appealing, as nucleic acids are capable of both information storage and acting as templates that catalyse the synthesis of complementary molecules. Template-directed synthesis has been demonstrated for homogeneous oligonucleotides that, like natural nucleic acids, have 3',5' linkages between the nucleotide monomers. But it seems likely that prebiotic routes to RNA-like molecules would have produced heterogeneous molecules with various kinds of phosphodiester linkages and both linear and cyclic nucleotide chains. Here we show that such heterogeneity need be no obstacle to the templating of complementary molecules. Specifically, we show that heterogeneous oligocytidylates, formed by the montmorillonite clay-catalysed condensation of actuated monomers, can serve as templates for the synthesis of oligoguanylates. Furthermore, we show that oligocytidylates that are exclusively 2',5'-linked can also direct synthesis of oligoguanylates. Such heterogeneous templating reactions could have increased the diversity of the pool of protonucleic acids from which life ultimately emerged.

  9. Method And Apparatus For Regenerating Nox Adsorbers

    DOEpatents

    Driscoll, J. Joshua; Endicott, Dennis L.; Faulkner, Stephen A.; Verkiel, Maarten

    2006-03-28

    Methods and apparatuses for regenerating a NOx adsorber coupled with an exhaust of an engine. An actuator drives a throttle valve to a first position when regeneration of the NOx adsorber is desired. The first position is a position that causes the regeneration of the NOx adsorber. An actuator drives the throttle valve to a second position while regeneration of the NOx adsorber is still desired. The second position being a position that is more open than the first position and operable to regenerate a NOx adsorber.

  10. An efficient VLSI architecture for template matching

    SciTech Connect

    Ranganathan, N.; Venugopal, S.

    1994-12-31

    In this paper, we describe a new special purpose VLSI architecture for template matching, based on a technique known as moment preserving pattern matching (MPPM). This technique first converts the given gray scale image and template into binary form using the moment preserving quantization method and then uses a pairing function to compute the similarity measure. The technique yields accurate results comparable to other approaches but involves simpler computations. The proposed architecture is systolic in nature and achieves a high degree of parallelism and pipelining. It is shown that the proposed architecture is much simpler, achieves higher speed, has a lower hardware complexity and utilizes lesser memory than other special purpose architectures for template matching.

  11. Learning probabilistic document template models via interaction

    NASA Astrophysics Data System (ADS)

    Ahmadullin, Ildus; Damera-Venkata, Niranjan

    2013-03-01

    Document aesthetics measures are key to automated document composition. Recently we presented a probabilistic document model (PDM) which is a micro-model for document aesthetics based on a probabilistic modeling of designer choice in document design. The PDM model comes with efficient layout synthesis algorithms once the aesthetic model is defined. A key element of this approach is an aesthetic prior on the parameters of a template encoding aesthetic preferences for template parameters. Parameters of the prior were required to be chosen empirically by designers. In this work we show how probabilistic template models (and hence the PDM cost function) can be learnt directly by observing a designer making design choices in composing sample documents. From such training data our learning approach can learn a quality measure that can mimic some of the design tradeoffs a designer makes in practice.

  12. The preliminary investigation of template with C++

    NASA Astrophysics Data System (ADS)

    Sandal, Shruti; Singh, Raghuraj; Khilji, Abdul Jabbar; Ranga, Shashi Shekhar; Tejasvee, Sanjay; Gahlot, Devendra

    2010-11-01

    This paper describe the relationship between C++ templates and partial evaluation. In C++, templates were designed to support generic programming, but not deliberately provided the ability to perform compile-time computations and code generation. These features are completely deliberate, and as a result their syntax is ill at ease. After a review, these features in terms of partial evaluation, a much simpler syntax can be achieved. In C++, it may be regarded as a two-level language in which types are first-class values. Template instantiation resembles an offline partial assessor. In this paper, we explain groundwork in the direction of a single mechanism based on Partial Evaluation which unifies generic programming, compile-time computation and code generation. The language Catat is introduced to demonstrate these ideas.

  13. Polyaniline nanowire synthesis templated by DNA

    NASA Astrophysics Data System (ADS)

    Nickels, Patrick; Dittmer, Wendy U.; Beyer, Stefan; Kotthaus, Jörg P.; Simmel, Friedrich C.

    2004-11-01

    DNA-templated polyaniline nanowires and networks are synthesized using three different methods. The resulting DNA/polyaniline hybrids are fully characterized using atomic force microscopy, UV-vis spectroscopy and current-voltage measurements. Oxidative polymerization of polyaniline at moderate pH values is accomplished using ammonium persulfate as an oxidant, or alternatively in an enzymatic oxidation by hydrogen peroxide using horseradish peroxidase, or by photo-oxidation using a ruthenium complex as photo-oxidant. Atomic force microscopy shows that all three methods lead to the preferential growth of polyaniline along DNA templates. With ammonium persulfate, polyaniline can be grown on DNA templates already immobilized on a surface. Current-voltage measurements are successfully conducted on DNA/polyaniline networks synthesized by the enzymatic method and the photo-oxidation method. The conductance is found to be consistent with values measured for undoped polyaniline films.

  14. A Hybrid Approach to Protect Palmprint Templates

    PubMed Central

    Sun, Dongmei; Xiong, Ke; Qiu, Zhengding

    2014-01-01

    Biometric template protection is indispensable to protect personal privacy in large-scale deployment of biometric systems. Accuracy, changeability, and security are three critical requirements for template protection algorithms. However, existing template protection algorithms cannot satisfy all these requirements well. In this paper, we propose a hybrid approach that combines random projection and fuzzy vault to improve the performances at these three points. Heterogeneous space is designed for combining random projection and fuzzy vault properly in the hybrid scheme. New chaff point generation method is also proposed to enhance the security of the heterogeneous vault. Theoretical analyses of proposed hybrid approach in terms of accuracy, changeability, and security are given in this paper. Palmprint database based experimental results well support the theoretical analyses and demonstrate the effectiveness of proposed hybrid approach. PMID:24982977

  15. Regeneration: Thomas Hunt Morgan's window into development.

    PubMed

    Sunderland, Mary Evelyn

    2010-01-01

    Early in his career Thomas Hunt Morgan was interested in embryology and dedicated his research to studying organisms that could regenerate. Widely regarded as a regeneration expert, Morgan was invited to deliver a series of lectures on the topic that he developed into a book, Regeneration (1901). In addition to presenting experimental work that he had conducted and supervised, Morgan also synthesized and critiqued a great deal of work by his peers and predecessors. This essay probes into the history of regeneration studies by looking in depth at Regeneration and evaluating Morgan's contribution. Although famous for his work with fruit fly genetics, studying Regeneration illuminates Morgan's earlier scientific approach which emphasized the importance of studying a diversity of organisms. Surveying a broad range of regenerative phenomena allowed Morgan to institute a standard scientific terminology that continues to inform regeneration studies today. Most importantly, Morgan argued that regeneration was a fundamental aspect of the growth process and therefore should be accounted for within developmental theory. Establishing important similarities between regeneration and development allowed Morgan to make the case that regeneration could act as a model of development. The nature of the relationship between embryogenesis and regeneration remains an active area of research. PMID:20665231

  16. Stochastic template placement algorithm for gravitational wave data analysis

    SciTech Connect

    Harry, I. W.; Sathyaprakash, B. S.; Allen, B.

    2009-11-15

    This paper presents an algorithm for constructing matched-filter template banks in an arbitrary parameter space. The method places templates at random, then removes those which are 'too close' together. The properties and optimality of stochastic template banks generated in this manner are investigated for some simple models. The effectiveness of these template banks for gravitational wave searches for binary inspiral waveforms is also examined. The properties of a stochastic template bank are then compared to the deterministically placed template banks that are currently used in gravitational wave data analysis.

  17. Templates for Deposition of Microscopic Pointed Structures

    NASA Technical Reports Server (NTRS)

    Pugel, Diane E.

    2008-01-01

    Templates for fabricating sharply pointed microscopic peaks arranged in nearly regular planar arrays can be fabricated by a relatively inexpensive technique that has recently been demonstrated. Depending on the intended application, a semiconducting, insulating, or metallic film could be deposited on such a template by sputtering, thermal evaporation, pulsed laser deposition, or any other suitable conventional deposition technique. Pointed structures fabricated by use of these techniques may prove useful as photocathodes or field emitters in plasma television screens. Selected peaks could be removed from such structures and used individually as scanning tips in atomic force microscopy or mechanical surface profiling.

  18. Deformable template models for emission tomography

    SciTech Connect

    Amit, Y. . Dept. of Statistics); Manbeck, K.M. . Div. of Applied Mathematics)

    1993-06-01

    The reconstruction of emission tomography data is an ill-posed inverse problem and, as such, requires some form of regularization. Previous efforts to regularize the restoration process have incorporated rather general assumptions about the isotope distribution within a patient's body. Here, the authors present a theoretical and algorithmic framework in which the notion of a deformable template can be used to identify and quantify brain tumors in pediatric patients. Patient data and computer simulation experiments are presented which illustrate the performance of the deformable template approach to single photon emission computed tomography (SPECT).

  19. Affordance Templates for Shared Robot Control

    NASA Technical Reports Server (NTRS)

    Hart, Stephen; Dinh, Paul; Hambuchen, Kim

    2014-01-01

    This paper introduces the Affordance Template framework used to supervise task behaviors on the NASA-JSC Valkyrie robot at the 2013 DARPA Robotics Challenge (DRC) Trials. This framework provides graphical interfaces to human supervisors that are adjustable based on the run-time environmental context (e.g., size, location, and shape of objects that the robot must interact with, etc.). Additional improvements, described below, inject degrees of autonomy into instantiations of affordance templates at run-time in order to enable efficient human supervision of the robot for accomplishing tasks.

  20. Preparation of porous lanthanum phosphate with templates

    SciTech Connect

    Onoda, Hiroaki; Ishima, Yuya; Takenaka, Atsushi; Tanaka, Isao

    2009-08-05

    Malonic acid, propionic acid, glycine, n-butylamine, and urea were added to the preparation of lanthanum phosphate from lanthanum nitrate and phosphoric acid solutions. All additives were taken into lanthanum phosphate particles. The additives that have a basic site were easy to contain in precipitates. The addition of templates improved the specific surface area of lanthanum phosphate. The amount of pore, with radius smaller than 4 nm, increased with the addition of templates. The remained additives had influence on the acidic properties of lanthanum phosphate.

  1. Vertex finding with deformable templates at LHC

    NASA Astrophysics Data System (ADS)

    Stepanov, Nikita; Khanov, Alexandre

    1997-02-01

    We present a novel vertex finding technique. The task is formulated as a discrete-continuous optimisation problem in a way similar to the deformable templates approach for the track finding. Unlike the track finding problem, "elastic hedgehogs" rather than elastic arms are used as deformable templates. They are initialised by a set of procedures which provide zero level approximation for vertex positions and track parameters at the vertex point. The algorithm was evaluated using the simulated events for the LHC CMS detector and demonstrated good performance.

  2. Controlling Nanostructures by Templated Templates: Inheriting Molecular Orientation in Binary Heterostructures.

    PubMed

    Breuer, Tobias; Witte, Gregor

    2015-09-16

    Precise preparation strategies are required to fabricate molecular nanostructures of specific arrangement. In bottom-up approaches, where nanostructures are gradually formed by piecing together individual parts to the final structure, the self-ordering mechanisms of the involved structures are utilized. In order to achieve the desired structures regarding morphology, grain size, and orientation of the individual moieties, templates can be applied, which influence the formation process of subsequent structures. However, this strategy is of limited use for complex architectures because the templates only influence the structure formation at the interface between the template and the first compound. Here, we discuss the implementation of so-called templated templates and analyze to what extent orientations of the initial layers are inherited in the top layers of another compound to enable structural control in binary heterostructures. For that purpose, we prepared crystalline templates of the organic semiconductors pentacene and perfluoropentacene in different exclusive orientations. We observe that for templates of both individual materials the molecular orientation is inherited in the top layers of the respective counterpart. This behavior is also observed for various other molecules, indicating the robustness of this approach. PMID:26305339

  3. The regeneration capacity of the flatworm Macrostomum lignano—on repeated regeneration, rejuvenation, and the minimal size needed for regeneration

    PubMed Central

    Ladurner, P.; Nimeth, K.; Gschwentner, R.; Rieger, R.

    2006-01-01

    The lion’s share of studies on regeneration in Plathelminthes (flatworms) has been so far carried out on a derived taxon of rhabditophorans, the freshwater planarians (Tricladida), and has shown this group’s outstanding regeneration capabilities in detail. Sharing a likely totipotent stem cell system, many other flatworm taxa are capable of regeneration as well. In this paper, we present the regeneration capacity of Macrostomum lignano, a representative of the Macrostomorpha, the basal-most taxon of rhabditophoran flatworms and one of the most basal extant bilaterian protostomes. Amputated or incised transversally, obliquely, and longitudinally at various cutting levels, M. lignano is able to regenerate the anterior-most body part (the rostrum) and any part posterior of the pharynx, but cannot regenerate a head. Repeated regeneration was observed for 29 successive amputations over a period of almost 12 months. Besides adults, also first-day hatchlings and older juveniles were shown to regenerate after transversal cutting. The minimum number of cells required for regeneration in adults (with a total of 25,000 cells) is 4,000, including 160 neoblasts. In hatchlings only 1,500 cells, including 50 neoblasts, are needed for regeneration. The life span of untreated M. lignano was determined to be about 10 months. PMID:16604349

  4. The biogeochemical cycle of the adsorbed template. II - Selective adsorption of mononucleotides on adsorbed polynucleotide templates

    NASA Technical Reports Server (NTRS)

    Lazard, Daniel; Lahav, Noam; Orenberg, James B.

    1988-01-01

    Experimental results are presented for the verification of the specific interaction step of the 'adsorbed template' biogeochemical cycle, a simple model for a primitive prebiotic replication system. The experimental system consisted of gypsum as the mineral to which an oligonucleotide template attaches (Poly-C or Poly-U) and (5-prime)-AMP, (5-prime)-GMP, (5-prime)-CMP and (5-prime)-UMP as the interacting biomonomers. When Poly-C or Poly-U were used as adsorbed templates, (5-prime)-GMP and (5-prime)-AMP, respectively, were observed to be the most strongly adsorbed species.

  5. Textile-templated electrospun anisotropic scaffolds for regenerative cardiac tissue engineering.

    PubMed

    Şenel Ayaz, H Gözde; Perets, Anat; Ayaz, Hasan; Gilroy, Kyle D; Govindaraj, Muthu; Brookstein, David; Lelkes, Peter I

    2014-10-01

    For patients with end-stage heart disease, the access to heart transplantation is limited due to the shortage of donor organs and to the potential for rejection of the donated organ. Therefore, current studies focus on bioengineering approaches for creating biomimetic cardiac patches that will assist in restoring cardiac function, by repairing and/or regenerating the intrinsically anisotropic myocardium. In this paper we present a simplified, straightforward approach for creating bioactive anisotropic cardiac patches, based on a combination of bioengineering and textile-manufacturing techniques in concert with nano-biotechnology based tissue-engineering stratagems. Using knitted conventional textiles, made of cotton or polyester yarns as template targets, we successfully electrospun anisotropic three-dimensional scaffolds from poly(lactic-co-glycolic) acid (PLGA), and thermoplastic polycarbonate-urethane (PCU, Bionate(®)). The surface topography and mechanical properties of textile-templated anisotropic scaffolds significantly differed from those of scaffolds electrospun from the same materials onto conventional 2-D flat-target electrospun scaffolds. Anisotropic textile-templated scaffolds electrospun from both PLGA and PCU, supported the adhesion and proliferation of H9C2 cardiac myoblasts cell line, and guided the cardiac tissue-like anisotropic organization of these cells in vitro. All cell-seeded PCU scaffolds exhibited mechanical properties comparable to those of a human heart, but only the cells on the polyester-templated scaffolds exhibited prolonged spontaneous synchronous contractility on the entire engineered construct for 10 days in vitro at a near physiologic frequency of ∼120 bpm. Taken together, the methods described here take advantage of straightforward established textile manufacturing strategies as an efficient and cost-effective approach to engineering 3D anisotropic, elastomeric PCU scaffolds that can serve as a cardiac patch. PMID:25017096

  6. Islet cell plasticity and regeneration.

    PubMed

    Migliorini, Adriana; Bader, Erik; Lickert, Heiko

    2014-06-01

    Insulin-dependent diabetes is a complex multifactorial disorder characterized by loss or dysfunction of β-cells resulting in failure of metabolic control. Even though type 1 and 2 diabetes differ in their pathogenesis, restoring β-cell function is the overarching goal for improved therapy of both diseases. This could be achieved either by cell-replacement therapy or by triggering intrinsic regenerative mechanisms of the pancreas. For type 1 diabetes, a combination of β-cell replacement and immunosuppressive therapy could be a curative treatment, whereas for type 2 diabetes enhancing endogenous mechanisms of β-cell regeneration might optimize blood glucose control. This review will briefly summarize recent efforts to allow β-cell regeneration where the most promising approaches are currently (1) increasing β-cell self-replication or neogenesis from ductal progenitors and (2) conversion of α-cells into β-cells. PMID:24749056

  7. Diverse routes to liver regeneration.

    PubMed

    Alison, Malcolm R; Lin, Wey-Ran

    2016-02-01

    The liver's ability to regenerate is indisputable; for example, after a two-thirds partial hepatectomy in rats all residual hepatocytes can divide, questioning the need for a specific stem cell population. On the other hand, there is a potential stem cell compartment in the canals of Hering, giving rise to ductular reactions composed of hepatic progenitor cells (HPCs) when the liver's ability to regenerate is hindered by replicative senescence, but the functional relevance of this response has been questioned. Several papers have now clarified regenerative mechanisms operative in the mouse liver, suggesting that the liver is possibly unrivalled in its versatility to replace lost tissue. Under homeostatic conditions a perivenous population of clonogenic hepatocytes operates, whereas during chronic damage a minor population of periportal clonogenic hepatocytes come to the fore, while the ability of HPCs to completely replace the liver parenchyma has now been shown. PMID:26510495

  8. Silica-based mesoporous nanobiomaterials as promoter of bone regeneration process.

    PubMed

    Shadjou, Nasrin; Hasanzadeh, Mohammad

    2015-11-01

    Silica-based mesostructured nanomaterials have emerged as a full family of biomaterials with tremendous potential to address the requirements for the bone regeneration process. This review focuses on more recent advances in bone regeneration process based on silica-based mesoporous biomaterials during 2012 to January 2015. In this review, we describe application of silica-based mesoporous mesostructured nanomaterials (possessing pore sizes in the range 2-50 nm) for the bone regeneration process. We summarize the preparation methods, the effect of mesopore templates and composition on the mesopore-structure characteristics, and different forms of these materials, including particles, fibers, spheres, scaffolds, and composites. The effect of structural and textural properties of mesoporous materials on the development of new biomaterials for treatment of different bone pathologies such as infection, osteoporosis, cancer, and so forth is discussed. In addition, silica-based mesoporous bioactive glass, as a potential drug/growth factor carrier, is reviewed, which includes the composition-structure-drug delivery relationship and the functional effect on the antibacteria and tissue-stimulation properties. Also, application of different mesoporous materials on construction of 3D macroporous scaffolds for bone tissue engineering was disused. Finally, this review discusses the possibility of covalently grafting different osteoinductive agents to the silica-based mesoporous scaffold surface that act as attracting signals for bone cells to promote the bone regeneration process. PMID:26011776

  9. Recyclable Waste Paper Sorting Using Template Matching

    NASA Astrophysics Data System (ADS)

    Osiur Rahman, Mohammad; Hussain, Aini; Scavino, Edgar; Hannan, M. A.; Basri, Hassan

    This paper explores the application of image processing techniques in recyclable waste paper sorting. In recycling, waste papers are segregated into various grades as they are subjected to different recycling processes. Highly sorted paper streams will facilitate high quality end products, and save processing chemicals and energy. Since 1932 to 2009, different mechanical and optical paper sorting methods have been developed to fill the demand of paper sorting. Still, in many countries including Malaysia, waste papers are sorted into different grades using manual sorting system. Due to inadequate throughput and some major drawbacks of mechanical paper sorting systems, the popularity of optical paper sorting systems is increased. Automated paper sorting systems offer significant advantages over human inspection in terms of fatigue, throughput, speed, and accuracy. This research attempts to develop a smart vision sensing system that able to separate the different grades of paper using Template Matching. For constructing template database, the RGB components of the pixel values are used to construct RGBString for template images. Finally, paper object grade is identified based on the maximum occurrence of a specific template image in the search image. The outcomes from the experiment in classification for White Paper, Old Newsprint Paper and Old Corrugated Cardboard are 96%, 92% and 96%, respectively. The remarkable achievement obtained with the method is the accurate identification and dynamic sorting of all grades of papers using simple image processing techniques.

  10. Templates Aid Removal Of Defects From Castings

    NASA Technical Reports Server (NTRS)

    Hendrickson, Robert G.

    1992-01-01

    Templates used to correlate defects in castings with local wall thicknesses. Placed on part to be inspected after coated with penetrant dye. Positions of colored spots (indicative of defects) noted. Ultrasonic inspector measures thickness of wall at unacceptable defects only - overall inspection not necessary.

  11. Structured Hydrogels using Micelles as Templates

    NASA Astrophysics Data System (ADS)

    Lee, Wonjoo; Kofinas, Peter; Briber, Robert M.

    2008-03-01

    Molecularly imprinted polymers can be created by crosslinking polymers in the presence of molecular templates. If the pores generated after the removing of templates have almost the same size and shape as the template, the material has a potential to be used for separation, biosensor and drug delivery applications. In this work, micelles were used as the template as they can be easily removed from the hydrogel and a range of structures are accessible by combining a (linear) polyelectrolyte and an oppositely charged surfactant. Poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) was synthesized and quaternized using methyl iodide. We have performed small angle neutron scattering (SANS) on solutions and hydrogels of PDMAEMA with sodium dodecylsulfate (SDS) under different contrast matching conditions. A structured hydrogel was then formed by chemically crosslinking the semi-dilute PDMAEMA solution which contained SDS. It was confirmed that spherical micelle-like structures were associated along the polymer chain in a bead-and-necklace structure consistent with what has been observed in the (uncharged) poly(ethylene oxide)/SDS system. Furthermore, it was shown that the interaction between PDMAEMA and micelles is strong enough to maintain the nanoscale structure formed along the PDMAEMA chain, even after crosslinking, leading to a structured hydrogel.

  12. Organic or organometallic template mediated clay synthesis

    SciTech Connect

    Gregar, K.C.; Winans, R.E.; Botto, R.E.

    1992-12-31

    A method is given for incorporating diverse varieties of intercalants or templates directly during hydrothermal synthesis of clays such as hectorite or montmorillonite-type layer-silicate clays. For a hectorite layer-silicate clay, refluxing a gel of silica sol, magnesium hydroxide sol and LiF for 2 days with an organic or organometallic intercalant or template results in crystalline products containing either (a) organic dye molecules such as ethyl violet and methyl green, (b) dye molecules such as alcian blue based on a Cu(II)-phthalocyannine complex, or (c) transition metal complexes such as Ru(II)phenanthroline and Co(III)sepulchrate or (d) water-soluble porphyrins and metalloporphyrins. Montmorillonite-type clays are made by the method taught by US patent No. 3,887,454 issued to Hickson, June 13, 1975; however, a variety of intercalants or templates may be introduced. The intercalants or templates should have water-solubility, positive charge, and thermal stability under moderately basic (pH 9-10) aqueous reflux conditions or hydrothermal pressurized conditions for the montmorillonite-type clays.

  13. Organic or organometallic template mediated clay synthesis

    DOEpatents

    Gregar, K.C.; Winans, R.E.; Botto, R.E.

    1994-05-03

    A method is described for incorporating diverse varieties of intercalates or templates directly during hydrothermal synthesis of clays such as hectorite or montmorillonite-type layer-silicate clays. For a hectorite layer-silicate clay, refluxing a gel of silica sol, magnesium hydroxide sol and lithium fluoride for two days in the presence of an organic or organometallic intercalate or template results in crystalline products containing either (a) organic dye molecules such as ethyl violet and methyl green, (b) dye molecules such as alcian blue that are based on a Cu(II)-phthalocyannine complex, or (c) transition metal complexes such as Ru(II)phenanthroline and Co(III)sepulchrate or (d) water-soluble porphyrins and metalloporphyrins. Montmorillonite-type clays are made by the method taught by U.S. Pat. No. 3,887,454 issued to Hickson, Jun. 13, 1975; however, a variety of intercalates or templates may be introduced. The intercalates or templates should have (i) water-solubility, (ii) positive charge, and (iii) thermal stability under moderately basic (pH 9-10) aqueous reflux conditions or hydrothermal pressurized conditions for the montmorillonite-type clays. 22 figures.

  14. Organic or organometallic template mediated clay synthesis

    DOEpatents

    Gregar, Kathleen C.; Winans, Randall E.; Botto, Robert E.

    1994-01-01

    A method for incorporating diverse Varieties of intercalants or templates directly during hydrothermal synthesis of clays such as hectorite or montmorillonite-type layer-silicate clays. For a hectorite layer-silicate clay, refluxing a gel of silica sol, magnesium hydroxide sol and lithium fluoride for two days in the presence of an organic or organometallic intercalant or template results in crystalline products containing either (a) organic dye molecules such as ethyl violet and methyl green, (b) dye molecules such as alcian blue that are based on a Cu(II)-phthalocyannine complex, or (c) transition metal complexes such as Ru(II)phenanthroline and Co(III)sepulchrate or (d) water-soluble porphyrins and metalloporphyrins. Montmorillonite-type clays are made by the method taught by U.S. Pat. No. 3,887,454 issued to Hickson, Jun. 13, 1975; however, a variety of intercalants or templates may be introduced. The intercalants or templates should have (i) water-solubility, (ii) positive charge, and (iii) thermal stability under moderately basic (pH 9-10) aqueous reflux conditions or hydrothermal pressurized conditions for the montmorillonite-type clays.

  15. Photon signature analysis using template matching

    NASA Astrophysics Data System (ADS)

    Bradley, D. A.; Hashim, S.; Saripan, M. I.; Wells, K.; Dunn, W. L.

    2011-10-01

    We describe an approach to detect improvised explosive devices (IEDs) by using a template matching procedure. This approach relies on the signature due to backstreaming γ photons from various targets. In this work we have simulated cylindrical targets of aluminum, iron, copper, water and ammonium nitrate (nitrogen-rich fertilizer). We simulate 3.5 MeV source photons distributed on a plane inside a shielded area using Monte Carlo N-Particle (MCNP TM) code version 5 (V5). The 3.5 MeV source gamma rays yield 511 keV peaks due to pair production and scattered gamma rays. In this work, we simulate capture of those photons that backstream, after impinging on the target element, toward a NaI detector. The captured backstreamed photons are expected to produce a unique spectrum that will become part of a simple signal processing recognition system based on the template matching method. Different elements were simulated using different sets of random numbers in the Monte Carlo simulation. To date, the sum of absolute differences (SAD) method has been used to match the template. In the examples investigated, template matching was found to detect all elements correctly.

  16. A lightweight approach for biometric template protection

    NASA Astrophysics Data System (ADS)

    Al-Assam, Hisham; Sellahewa, Harin; Jassim, Sabah

    2009-05-01

    Privacy and security are vital concerns for practical biometric systems. The concept of cancelable or revocable biometrics has been proposed as a solution for biometric template security. Revocable biometric means that biometric templates are no longer fixed over time and could be revoked in the same way as lost or stolen credit cards are. In this paper, we describe a novel and an efficient approach to biometric template protection that meets the revocability property. This scheme can be incorporated into any biometric verification scheme while maintaining, if not improving, the accuracy of the original biometric system. However, we shall demonstrate the result of applying such transforms on face biometric templates and compare the efficiency of our approach with that of the well-known random projection techniques. We shall also present the results of experimental work on recognition accuracy before and after applying the proposed transform on feature vectors that are generated by wavelet transforms. These results are based on experiments conducted on a number of well-known face image databases, e.g. Yale and ORL databases.

  17. Cell migration during heart regeneration in zebrafish.

    PubMed

    Tahara, Naoyuki; Brush, Michael; Kawakami, Yasuhiko

    2016-07-01

    Zebrafish possess the remarkable ability to regenerate injured hearts as adults, which contrasts the very limited ability in mammals. Although very limited, mammalian hearts do in fact have measurable levels of cardiomyocyte regeneration. Therefore, elucidating mechanisms of zebrafish heart regeneration would provide information of naturally occurring regeneration to potentially apply to mammalian studies, in addition to addressing this biologically interesting phenomenon in itself. Studies over the past 13 years have identified processes and mechanisms of heart regeneration in zebrafish. After heart injury, pre-existing cardiomyocytes dedifferentiate, enter the cell cycle, and repair the injured myocardium. This process requires interaction with epicardial cells, endocardial cells, and vascular endothelial cells. Epicardial cells envelope the heart, while endocardial cells make up the inner lining of the heart. They provide paracrine signals to cardiomyocytes to regenerate the injured myocardium, which is vascularized during heart regeneration. In addition, accumulating results suggest that local migration of these major cardiac cell types have roles in heart regeneration. In this review, we summarize the characteristics of various heart injury methods used in the research community and regeneration of the major cardiac cell types. Then, we discuss local migration of these cardiac cell types and immune cells during heart regeneration. Developmental Dynamics 245:774-787, 2016. © 2016 Wiley Periodicals, Inc. PMID:27085002

  18. Computational templates for introductory nuclear science using mathcad

    NASA Astrophysics Data System (ADS)

    Sarantites, D. G.; Sobotka, L. G.

    2013-01-01

    Computational templates used to teach an introductory course in nuclear chemistry and physics at Washington University in St. Louis are presented in brief. The templates cover both basic and applied topics.

  19. Visual cluster analysis and pattern recognition template and methods

    DOEpatents

    Osbourn, G.C.; Martinez, R.F.

    1999-05-04

    A method of clustering using a novel template to define a region of influence is disclosed. Using neighboring approximation methods, computation times can be significantly reduced. The template and method are applicable and improve pattern recognition techniques. 30 figs.

  20. Visual cluster analysis and pattern recognition template and methods

    DOEpatents

    Osbourn, Gordon Cecil; Martinez, Rubel Francisco

    1999-01-01

    A method of clustering using a novel template to define a region of influence. Using neighboring approximation methods, computation times can be significantly reduced. The template and method are applicable and improve pattern recognition techniques.

  1. Visual cluster analysis and pattern recognition template and methods

    SciTech Connect

    Osbourn, G.C.; Martinez, R.F.

    1993-12-31

    This invention is comprised of a method of clustering using a novel template to define a region of influence. Using neighboring approximation methods, computation times can be significantly reduced. The template and method are applicable and improve pattern recognition techniques.

  2. Templated Self Assemble of Nano-Structures

    SciTech Connect

    Suo, Zhigang

    2013-04-29

    This project will identify and model mechanisms that template the self-assembly of nanostructures. We focus on a class of systems involving a two-phase monolayer of molecules adsorbed on a solid surface. At a suitably elevated temperature, the molecules diffuse on the surface to reduce the combined free energy of mixing, phase boundary, elastic field, and electrostatic field. With no template, the phases may form a pattern of stripes or disks. The feature size is on the order of 1-100 nm, selected to compromise the phase boundary energy and the long-range elastic or electrostatic interaction. Both experimental observations and our theoretical simulations have shown that the pattern resembles a periodic lattice, but has abundant imperfections. To form a perfect periodic pattern, or a designed aperiodic pattern, one must introduce a template to guide the assembly. For example, a coarse-scale pattern, lithographically defined on the substrate, will guide the assembly of the nanoscale pattern. As another example, if the molecules on the substrate surface carry strong electric dipoles, a charged object, placed in the space above the monolayer, will guide the assembly of the molecular dipoles. In particular, the charged object can be a mask with a designed nanoscale topographic pattern. A serial process (e.g., e-beam lithography) is necessary to make the mask, but the pattern transfer to the molecules on the substrate is a parallel process. The technique is potentially a high throughput, low cost process to pattern a monolayer. The monolayer pattern itself may serve as a template to fabricate a functional structure. This project will model fundamental aspects of these processes, including thermodynamics and kinetics of self-assembly, templated self-assembly, and self-assembly on unconventional substrates. It is envisioned that the theory will not only explain the available experimental observations, but also motivate new experiments.

  3. Template changes with perceptual learning are driven by feature informativeness

    PubMed Central

    Kurki, Ilmari; Eckstein, Miguel P.

    2014-01-01

    Perceptual learning changes the way the human visual system processes stimulus information. Previous studies have shown that the human brain's weightings of visual information (the perceptual template) become better matched to the optimal weightings. However, the dynamics of the template changes are not well understood. We used the classification image method to investigate whether visual field or stimulus properties govern the dynamics of the changes in the perceptual template. A line orientation discrimination task where highly informative parts were placed in the peripheral visual field was used to test three hypotheses: (1) The template changes are determined by the visual field structure, initially covering stimulus parts closer to the fovea and expanding toward the periphery with learning; (2) the template changes are object centered, starting from the center and expanding toward edges; and (3) the template changes are determined by stimulus information, starting from the most informative parts and expanding to less informative parts. Results show that, initially, the perceptual template contained only the more peripheral, highly informative parts. Learning expanded the template to include less informative parts, resulting in an increase in sampling efficiency. A second experiment interleaved parts with high and low signal-to-noise ratios and showed that template reweighting through learning was restricted to stimulus elements that are spatially contiguous to parts with initial high template weights. The results suggest that the informativeness of features determines how the perceptual template changes with learning. Further, the template expansion is constrained by spatial proximity. PMID:25194018

  4. Template Mining for Information Extraction from Digital Documents.

    ERIC Educational Resources Information Center

    Chowdhury, Gobinda G.

    1999-01-01

    Reviews template mining research and shows how templates are used in World Wide Web search engines and metasearch engines for helping end-users generate natural language search expressions. Potential areas of application of template mining for extraction of information from digital documents are highlighted, and how such applications are used is…

  5. 21 CFR 888.4800 - Template for clinical use.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Template for clinical use. 888.4800 Section 888...) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4800 Template for clinical use. (a) Identification. A template for clinical use is a device that consists of a pattern or guide intended for...

  6. A quantitative metabolomics peek into planarian regeneration.

    PubMed

    Natarajan, Nivedita; Ramakrishnan, Padma; Lakshmanan, Vairavan; Palakodeti, Dasaradhi; Rangiah, Kannan

    2015-05-21

    The fresh water planarian species Schmidtea mediterranea is an emerging stem cell model because of its capability to regenerate a whole animal from a small piece of tissue. It is one of the best model systems to address the basic mechanisms essential for regeneration. Here, we are interested in studying the roles of various amines, thiols and nucleotides in planarian regeneration, stem cell function and growth. We developed mass spectrometry based quantitative methods and validated the differential enrichment of 35 amines, 7 thiol metabolites and 4 nucleotides from both intact and regenerating planarians. Among the amines, alanine in sexual and asparagine in asexual are the highest (>1000 ng/mg) in the intact planarians. The levels of thiols such as cysteine and GSH are 651 and 1107 ng mg(-1) in planarians. Among the nucleotides, the level of cGMP is the lowest (0.03 ng mg(-1)) and the level of AMP is the highest (187 ng mg(-1)) in both of the planarian strains. We also noticed increasing levels of amines in both anterior and posterior regenerating planarians. The blastema from day 3 regenerating planarians also showed higher amounts of many amines. Interestingly, the thiol (cysteine and GSH) levels are well maintained during planarian regeneration. This suggests an inherent and effective mechanism to control induced oxidative stress because of the robust regeneration and stem cell proliferation. Like in intact planarians, the level of cGMP is also very low in regenerating planarians. Surprisingly, the levels of amines and thiols in head regenerating blastemas are ∼3 times higher compared to those for tail regenerating blastemas. Thus our results strongly indicate the potential roles of amines, thiols and nucleotides in planarian regeneration. PMID:25815385

  7. Assembly Methods for Etched Foil Regenerators

    NASA Astrophysics Data System (ADS)

    Mitchell, Matthew P.

    2004-06-01

    Etched foil appears to offer substantial advantages over other regenerator materials, especially for annular regenerators. However, assembly of etched foil regenerators has been difficult because etching regenerator patterns in foil is most satisfactorily accomplished using pieces too small for a complete, spiral-wrapped regenerator. Two techniques have been developed to deal with that problem: For spiral-wrapped regenerators, a new technique for joining pieces of foil using tabs has been successfully employed. The joints are no thicker than the parent material. The tabs substantially fill the holes into which they are locked, virtually eliminating any undesired leak path through the regenerator. The holes constitute breaks in the conductive path through the regenerator. A patent is pending. An alternate method is to insert pieces of foil in a cylindrical housing one at a time. An inflatable bladder presses each newly-inserted piece of foil against the previous layer until both edges slip past each other and contact the previously-installed piece. When the bladder is deflated, the natural springiness of the foil causes the cut edges to seek the wall and meet each other in a butt joint. A patent on the method has been issued; a patent on the resulting regenerator is pending.

  8. Unraveling tissue regeneration pathways using chemical genetics.

    PubMed

    Mathew, Lijoy K; Sengupta, Sumitra; Kawakami, Atsushi; Andreasen, Eric A; Löhr, Christiane V; Loynes, Catherine A; Renshaw, Stephen A; Peterson, Randall T; Tanguay, Robert L

    2007-11-30

    Identifying the molecular pathways that are required for regeneration remains one of the great challenges of regenerative medicine. Although genetic mutations have been useful for identifying some molecular pathways, small molecule probes of regenerative pathways might offer some advantages, including the ability to disrupt pathway function with precise temporal control. However, a vertebrate regeneration model amenable to rapid throughput small molecule screening is not currently available. We report here the development of a zebrafish early life stage fin regeneration model and its use in screening for small molecules that modulate tissue regeneration. By screening 2000 biologically active small molecules, we identified 17 that specifically inhibited regeneration. These compounds include a cluster of glucocorticoids, and we demonstrate that transient activation of the glucocorticoid receptor is sufficient to block regeneration, but only if activation occurs during wound healing/blastema formation. In addition, knockdown of the glucocorticoid receptor restores regenerative capability to nonregenerative, glucocorticoid-exposed zebrafish. To test whether the classical anti-inflammatory action of glucocorticoids is responsible for blocking regeneration, we prevented acute inflammation following amputation by antisense repression of the Pu.1 gene. Although loss of Pu.1 prevents the inflammatory response, regeneration is not affected. Collectively, these results indicate that signaling from exogenous glucocorticoids impairs blastema formation and limits regenerative capacity through an acute inflammation-independent mechanism. These studies also demonstrate the feasibility of exploiting chemical genetics to define the pathways that govern vertebrate regeneration. PMID:17848559

  9. Plant regeneration: cellular origins and molecular mechanisms.

    PubMed

    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

  10. Angiogenesis is inhibitory for mammalian digit regeneration

    PubMed Central

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

    2014-01-01

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

  11. The cellular basis for animal regeneration

    PubMed Central

    Tanaka, Elly; Reddien, Peter W.

    2011-01-01

    The ability of animals to regenerate missing parts is a dramatic and poorly understood aspect of biology. The sources of new cells for these regenerative phenomena have been sought for decades. Recent advances involving cell fate tracking in complex tissues have shed new light on the cellular underpinnings of regeneration in Hydra, planarians, zebrafish, Xenopus, and Axolotl. Planarians accomplish regeneration with use of adult pluripotent stem cells, whereas several vertebrates utilize a collection of lineage-restricted progenitors from different tissues. Together, an array of cellular strategies—from pluripotent stem cells to tissue-specific stem cells and dedifferentiation—are utilized for regeneration. PMID:21763617

  12. [Regeneration of planarians: experimental object].

    PubMed

    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

  13. Towards Regeneration of Articular Cartilage

    PubMed Central

    Iwamoto, Masahiro; Ohta, Yoichi; Larmour, Colleen; Enomoto-Iwamoto, Motomi

    2014-01-01

    Articular cartilage is classified into permanent hyaline cartilage and has significant differences in structure, extracelluar matrix components, gene expression profile, and mechanical property from transient hyaline cartilage found in growth plate. In the process of synovial joint development, articular cartilage is originated from the interzone, developing at the edge of the cartilaginous anlagen, it establishes zonal structure over time and supports smooth movement of the synovial joint through life. The cascade actions of key regulators such as Wnts, GDF5, Erg, and PTHLH coordinate sequential steps of articular cartilage formation. Articular chondrocytes are restrictedly controlled not to differentiate into a hypertrophic stage by autocrine and paracrine factors and extracerllular matrix microenvironment, but retain potential to undergo hypertrophy. The basal calcified zone of articular cartilage is connected with subchondral bone, but not invaded by blood vessels nor replaced by bone, which is highly contrasted with the growth plate. Articular cartilage has limited regenerative capacity, but likely possesses and potentially uses intrinsic stem cell source in the superficial layer, Ranvier’s groove, the intra-articular tissues such as synovium and fat pad, and marrow below the subchondral bone. Considering the biological views on articular cartilage, several important points are raised for regeneration of articular cartilage. We should evaluate the nature of regenerated cartilage as permanent hyaline cartilage and not just hyaline cartilage. We should study how a hypertrophic phenotype of transplanted cells can be lastingly suppressed in regenerating tissue. Further, we should develop the methods and reagents to activate recruitment of intrinsic stem/progenitor cells into the damaged site. PMID:24078496

  14. Optical imaging systems analyzed with a 2D template.

    PubMed

    Haim, Harel; Konforti, Naim; Marom, Emanuel

    2012-05-10

    Present determination of optical imaging systems specifications are based on performance values and modulation transfer function results carried with a 1D resolution template (such as the USAF resolution target or spoke templates). Such a template allows determining image quality, resolution limit, and contrast. Nevertheless, the conventional 1D template does not provide satisfactory results, since most optical imaging systems handle 2D objects for which imaging system response may be different by virtue of some not readily observable spatial frequencies. In this paper we derive and analyze contrast transfer function results obtained with 1D as well as 2D templates. PMID:22614498

  15. Bone regeneration and stem cells

    PubMed Central

    Arvidson, K; Abdallah, B M; Applegate, L A; Baldini, N; Cenni, E; Gomez-Barrena, E; Granchi, D; Kassem, M; Konttinen, Y T; Mustafa, K; Pioletti, D P; Sillat, T; Finne-Wistrand, A

    2011-01-01

    Abstract This invited review covers research areas of central importance for orthopaedic and maxillofacial bone tissue repair, including normal fracture healing and healing problems, biomaterial scaffolds for tissue engineering, mesenchymal and foetal 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. PMID:21129153

  16. Regenerator matrix physical property data

    NASA Technical Reports Server (NTRS)

    Fucinari, C. A.

    1980-01-01

    Among several cellular ceramic structures manufactured by various suppliers for regenerator application in a gas turbine engine, three have the best potential for achieving durability and performance objectives for use in gas turbines, Stirling engines, and waste heat recovery systems: (1) an aluminum-silicate sinusoidal flow passage made from a corrugated wate paper process; (2) an extruded isosceles triangle flow passage; and (3) a second generation matrix incorporating a square flow passage formed by an embossing process. Key physical and thermal property data for these configurations presented include: heat transfer and pressure drop characteristics, compressive strength, tensile strength and elasticity, thermal expansion characteristics, chanical attack, and thermal stability.

  17. Macroporous polymer foams by hydrocarbon templating.

    PubMed

    Shastri, V P; Martin, I; Langer, R

    2000-02-29

    Porous polymeric media (polymer foams) are utilized in a wide range of applications, such as thermal and mechanical insulators, solid supports for catalysis, and medical devices. A process for the production of polymer foams has been developed. This process, which is applicable to a wide range of polymers, uses a hydrocarbon particulate phase as a template for the precipitation of the polymer phase and subsequent pore formation. The use of a hydrocarbon template allows for enhanced control over pore structure, porosity, and other structural and bulk characteristics of the polymer foam. Polymer foams with densities as low as 120 mg/cc, porosity as high as 87%, and high surface areas (20 m(2)/g) have been produced. Foams of poly(l-lactic acid), a biodegradable polymer, produced by this process have been used to engineer a variety of different structures, including tissues with complex geometries such as in the likeness of a human nose. PMID:10696111

  18. LOTUS template for calculating well logs

    SciTech Connect

    Mitchell, R.J. ); Taylor, S.J. )

    1993-09-01

    Calculating well logs is a time-consuming process. This template uses input parameters consisting of well name, location county, state, formation name, starting depth, repeat interval, resistivity of shale, and irreducible bulk volume water, which provides heading information for print outs. Required information from basic well logs are porosity, conductivity (optional), formation resistivity, resistivity of the formation water for the zone being calculated, resistivity of the mud filtrate, the porosity cutoff for pay in the zone being calculated, and the saltwater saturation cutoff for the pay zone. These parameters are used to calculate apparent water resistivity, saltwater saturation, bulk volume water, ratio of apparent water resistivity to input water resistivity, irreducible saltwater saturation, resistivity volume of shale, permeability, and a derived porosity value. A print out of the results is available through the lotus print function. Using this template allows maximum control of the input parameters and reduces hand calculation time.

  19. Physical synthesis of quantum circuits using templates

    NASA Astrophysics Data System (ADS)

    Mirkhani, Zahra; Mohammadzadeh, Naser

    2016-06-01

    Similar to traditional CMOS circuits, quantum circuit design flow is divided into two main processes: logic synthesis and physical design. Addressing the limitations imposed on optimization of the quantum circuit metrics because of no information sharing between logic synthesis and physical design processes, the concept of "physical synthesis" was introduced for quantum circuit flow, and a few techniques were proposed for it. Following that concept, in this paper a new approach for physical synthesis inspired by template matching idea in quantum logic synthesis is proposed to improve the latency of quantum circuits. Experiments show that by using template matching as a physical synthesis approach, the latency of quantum circuits can be improved by more than 23.55 % on average.

  20. Assessing particle kinematics via template matching algorithms.

    PubMed

    Weber, M; Fink, M; Fortov, V; Lipaev, A; Molotkov, V; Morfill, G; Petrov, O; Pustylnik, M; Thoma, M; Thomas, H; Usachev, A; Raeth, C

    2016-04-18

    Template matching algorithms represent a viable tool to locate particles in optical images. A crucial factor of the performance of these methods is the choice of the similarity measure. Recently, it was shown in [Gao and Helgeson, Opt. Express 22 (2014)] that the correlation coefficient (CC) leads to good results. Here, we introduce the mutual information (MI) as a nonlinear similarity measure and compare the performance of the MI and the CC for different noise scenarios. It turns out that the mutual information leads to superior results in the case of signal dependent noise. We propose a novel approach to estimate the velocity of particles which is applicable in imaging scenarios where the particles appear elongated due to their movement. By designing a bank of anisotropic templates supposed to fit the elongation of the particles we are able to reliably estimate their velocity and direction of motion out of a single image. PMID:27137240

  1. Age-specific CT and MRI templates for spatial normalization

    PubMed Central

    Rorden, Christopher; Bonilha, Leonardo; Fridriksson, Julius; Bender, Benjamin; Karnath, Hans-Otto

    2012-01-01

    Spatial normalization reshapes an individual’s brain to match the shape and size of a template image. This is a crucial step required for group-level statistical analyses. The most popular standard templates are derived from MRI scans of young adults. We introduce specialized templates that allow normalization algorithms to be applied to stroke-aged populations. First, we developed a CT template: while this is the dominant modality for many clinical situations, there are no modern CT templates and popular algorithms fail to successfully normalize CT scans. Importantly, our template was based on healthy individuals with ages similar to what is commonly seen in stroke (mean 65 years old). This template allows studies where only CT scans are available. Second, we derived a MRI template that approximately matches the shape of our CT template as well as processing steps that aid the normalization of scans from older individuals (including lesion masking and the ability to generate high quality cortical renderings despite brain injury). The benefit of this strategy is that the resulting templates can be used in studies where mixed modalities are present. We have integrated these templates and processing algorithms into a simple SPM toolbox (http://www.mccauslandcenter.sc.edu/CRNL/tools/spm8-scripts). PMID:22440645

  2. A Template-Free, Ultra-Adsorbing, High Surface Area Carbonate Nanostructure

    PubMed Central

    Grandfield, Kathryn; Mihranyan, Albert; Strømme, Maria

    2013-01-01

    We report the template-free, low-temperature synthesis of a stable, amorphous, and anhydrous magnesium carbonate nanostructure with pore sizes below 6 nm and a specific surface area of ∼ 800 m2 g−1, substantially surpassing the surface area of all previously described alkali earth metal carbonates. The moisture sorption of the novel nanostructure is featured by a unique set of properties including an adsorption capacity ∼50% larger than that of the hygroscopic zeolite-Y at low relative humidities and with the ability to retain more than 75% of the adsorbed water when the humidity is decreased from 95% to 5% at room temperature. These properties can be regenerated by heat treatment at temperatures below 100°C.The structure is foreseen to become useful in applications such as humidity control, as industrial adsorbents and filters, in drug delivery and catalysis. PMID:23874640

  3. CLIPS template system for program understanding

    NASA Technical Reports Server (NTRS)

    Finkbine, Ronald B.

    1994-01-01

    Program understanding is a subfield of software reengineering and attempts to recognize the run-time behavior of source code. To this point, success in this area has been limited to very small code segments. An expert system, HLAR (High-Level Algorithm Recognizer), has been written in CLIPS and recognizes three sorting algorithms, selection sort, quicksort, and heapsort. This paper describes the HLAR system in general and, in depth, the CLIPS templates used for program representation and understanding.

  4. Deep Human Parsing with Active Template Regression.

    PubMed

    Liang, Xiaodan; Liu, Si; Shen, Xiaohui; Yang, Jianchao; Liu, Luoqi; Dong, Jian; Lin, Liang; Yan, Shuicheng

    2015-12-01

    In this work, the human parsing task, namely decomposing a human image into semantic fashion/body regions, is formulated as an active template regression (ATR) problem, where the normalized mask of each fashion/body item is expressed as the linear combination of the learned mask templates, and then morphed to a more precise mask with the active shape parameters, including position, scale and visibility of each semantic region. The mask template coefficients and the active shape parameters together can generate the human parsing results, and are thus called the structure outputs for human parsing. The deep Convolutional Neural Network (CNN) is utilized to build the end-to-end relation between the input human image and the structure outputs for human parsing. More specifically, the structure outputs are predicted by two separate networks. The first CNN network is with max-pooling, and designed to predict the template coefficients for each label mask, while the second CNN network is without max-pooling to preserve sensitivity to label mask position and accurately predict the active shape parameters. For a new image, the structure outputs of the two networks are fused to generate the probability of each label for each pixel, and super-pixel smoothing is finally used to refine the human parsing result. Comprehensive evaluations on a large dataset well demonstrate the significant superiority of the ATR framework over other state-of-the-arts for human parsing. In particular, the F1-score reaches 64.38 percent by our ATR framework, significantly higher than 44.76 percent based on the state-of-the-art algorithm [28]. PMID:26539846

  5. Partial CO combustion with staged regeneration of catalyst

    SciTech Connect

    Cabrera, C.A.; Myers, D.N.; Hammershaimb, H.V.

    1989-07-18

    This paper describes a process for the regeneration of spent hydrocarbon conversion catalyst withdrawn from a fluidized reaction zone. The process comprises the steps of: passing to a lower locus of a combustion zone of a riser-type fluidized regeneration zone; spent catalyst from the reaction zone, a stream comprising regenerated catalyst from a hereinafter described dense bed regeneration zone, and a first oxygen containing regeneration gas stream in an amount sufficient to maintain fast fluidized conditions; oxidizing coke and coke combustion by-products in the combustion zone while transporting the spent and regenerated catalyst upward in cocurrent flow with rising regeneration gas; passing catalyst and regeneration gas upward in cocurrent flow and therein oxidizing coke and coke combustion by-products to produce partially regenerated catalyst and a spent first generation gas; discharging partially regenerated and regenerated catalyst and the spent first regeneration gas from an upper locus of the riser regeneration zone into a catalyst disengagement zone through an outlet means that effects at least a partial separation of catalyst and regeneration gas. Thereby causing an initial separation of catalyst and the spend first regeneration gas; allowing partially regenerated and regenerated catalyst discharged through the outlet means to settle downward through a dilute phase above a dense fluidized bed and introducing into the dense fluidized bed a second oxygen containing regeneration gas stream in a quantity at least sufficient to produce regenerated catalyst having less than 0.1 wt% coke and to oxidize essentially all of the carbon monoxide produced.

  6. Porous graphitized carbon for adsorptive removal of benzene and the electrothermal regeneration.

    PubMed

    Li, Jinjun; Lu, Renjie; Dou, Baojuan; Ma, Chunyan; Hu, Qiuhong; Liang, Yan; Wu, Feng; Qiao, Shizhang; Hao, Zhengping

    2012-11-20

    Graphitized carbons with mesoporous and macroporous structures were synthesized by a facile template-catalysis procedure using resorcinol and formaldehyde as carbon precursors and particulate hydrated metal oxides as both template and catalyst precursors. The materials were used as novel adsorbents for low-concentration benzene vapor. Furthermore, on the basis of the good electrical conductivities associated with the graphitized structures, an electrothermal desorption technique, which involved passing electric currents through the adsorbents to generate Joule heat, was employed to regenerate the saturated adsorbents and produce enriched benzene vapors. In comparison to microporous activated carbon, the porous graphitized carbons could afford a much quicker and more efficient regeneration by electrothermal desorption technique due to their enhanced conductivity and larger pore sizes. In addition, the concentration of the desorbed organics could be controlled by adjusting the applied voltages, which might be interesting for practical secondary treatment. It is promising that the joint utilization of porous graphitized carbon adsorbents and electrothermal desorption technique might develop effective and energy-saving processes for VOCs removal. PMID:23092151

  7. Human action recognition using motion energy template

    NASA Astrophysics Data System (ADS)

    Shao, Yanhua; Guo, Yongcai; Gao, Chao

    2015-06-01

    Human action recognition is an active and interesting research topic in computer vision and pattern recognition field that is widely used in the real world. We proposed an approach for human activity analysis based on motion energy template (MET), a new high-level representation of video. The main idea for the MET model is that human actions could be expressed as the composition of motion energy acquired in a three-dimensional (3-D) space-time volume by using a filter bank. The motion energies were directly computed from raw video sequences, thus some problems, such as object location and segmentation, etc., are definitely avoided. Another important competitive merit of this MET method is its insensitivity to gender, hair, and clothing. We extract MET features by using the Bhattacharyya coefficient to measure the motion energy similarity between the action template video and the tested video, and then the 3-D max-pooling. Using these features as input to the support vector machine, extensive experiments on two benchmark datasets, Weizmann and KTH, were carried out. Compared with other state-of-the-art approaches, such as variation energy image, dynamic templates and local motion pattern descriptors, the experimental results demonstrate that our MET model is competitive and promising.

  8. Sacrificial template method of fabricating a nanotube

    DOEpatents

    Yang, Peidong; He, Rongrui; Goldberger, Joshua; Fan, Rong; Wu, Yi-Ying; Li, Deyu; Majumdar, Arun

    2007-05-01

    Methods of fabricating uniform nanotubes are described in which nanotubes were synthesized as sheaths over nanowire templates, such as using a chemical vapor deposition process. For example, single-crystalline zinc oxide (ZnO) nanowires are utilized as templates over which gallium nitride (GaN) is epitaxially grown. The ZnO templates are then removed, such as by thermal reduction and evaporation. The completed single-crystalline GaN nanotubes preferably have inner diameters ranging from 30 nm to 200 nm, and wall thicknesses between 5 and 50 nm. Transmission electron microscopy studies show that the resultant nanotubes are single-crystalline with a wurtzite structure, and are oriented along the <001> direction. The present invention exemplifies single-crystalline nanotubes of materials with a non-layered crystal structure. Similar "epitaxial-casting" approaches could be used to produce arrays and single-crystalline nanotubes of other solid materials and semiconductors. Furthermore, the fabrication of multi-sheath nanotubes are described as well as nanotubes having multiple longitudinal segments.

  9. Development of Total Knee Replacement Digital Templating Software

    NASA Astrophysics Data System (ADS)

    Yusof, Siti Fairuz; Sulaiman, Riza; Thian Seng, Lee; Mohd. Kassim, Abdul Yazid; Abdullah, Suhail; Yusof, Shahril; Omar, Masbah; Abdul Hamid, Hamzaini

    In this study, by taking full advantage of digital X-ray and computer technology, we have developed a semi-automated procedure to template knee implants, by making use of digital templating method. Using this approach, a software system called OrthoKneeTMhas been designed and developed. The system is to be utilities as a study in the Department of Orthopaedic and Traumatology in medical faculty, UKM (FPUKM). OrthoKneeTMtemplating process employs uses a technique similar to those used by many surgeons, using acetate templates over X-ray films. Using template technique makes it easy to template various implant from every Implant manufacturers who have with a comprehensive database of templates. The templating functionality includes, template (knee) and manufactures templates (Smith & Nephew; and Zimmer). From an image of patient x-ray OrthoKneeTMtemplates help in quickly and easily reads to the approximate template size needed. The visual templating features then allow us quickly review multiple template sizes against the X-ray and thus obtain the nearly precise view of the implant size required. The system can assist by templating on one patient image and will generate reports that can accompany patient notes. The software system was implemented in Visual basic 6.0 Pro using the object-oriented techniques to manage the graphics and objects. The approaches for image scaling will be discussed. Several of measurement in orthopedic diagnosis process have been studied and added in this software as measurement tools features using mathematic theorem and equations. The study compared the results of the semi-automated (using digital templating) method to the conventional method to demonstrate the accuracy of the system.

  10. [Stem cells and cardiac regeneration].

    PubMed

    Perez Millan, Maria Ines; Lorenti, Alicia

    2006-01-01

    Stem cells are defined by virtue of their functional attributes: absence of tissue specific differentitated markers, capable of proliferation, able to self-maintain the population, able to produce a large number of differentiated, functional progeny, able to regenerate the tissue after injury. Cell therapy is an alternative for the treatment of several diseases, like cardiac diseases (cell cardiomyoplasty). A variety of stem cells could be used for cardiac repair: from cardiac and extracardiac sources. Each cell type has its own profile of advantages, limitations, and practicability issues in specific clinical settings. Differentiation of bone marrow stem cells to cardiomyocyte-like cells have been observed under different culture conditions. The presence of resident cardiac stem cell population capable of differentiation into cardiomyocyte or vascular lineage suggests that these cells could be used for cardiac tissue repair, and represent a great promise for clinical application. Stem cells mobilization by cytokines may also offer a strategy for cardiac regeneration. The use of stem cells (embryonic and adult) may hold the key to replacing cells lost in many devastating diseases. This potential benefit is a major focus for stem cell research. PMID:17240634

  11. Microwave Regenerable Air Purification Device

    NASA Technical Reports Server (NTRS)

    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.

  12. Infection, Inflammation, and Bone Regeneration

    PubMed Central

    Thomas, M.V.; Puleo, D.A.

    2011-01-01

    Various strategies have been developed to promote bone regeneration in the craniofacial region. Most of these interventions utilize implantable materials or devices. Infections resulting from colonization of these implants may result in local tissue destruction in a manner analogous to periodontitis. This destruction is mediated via the expression of various inflammatory mediators and tissue-destructive enzymes. Given the well-documented association among microbial biofilms, inflammatory mediators, and tissue destruction, it seems reasonable to assume that inflammation may interfere with bone healing and regeneration. Paradoxically, recent evidence also suggests that the presence of certain pro-inflammatory mediators is actually required for bone healing. Bone injury (e.g., subsequent to a fracture or surgical intervention) is followed by a choreographed cascade of events, some of which are dependent upon the presence of pro-inflammatory mediators. If inflammation resolves promptly, then proper bone healing may occur. However, if inflammation persists (which might occur in the presence of an infected implant or graft material), then the continued inflammatory response may result in suboptimal bone formation. Thus, the effect of a given mediator is dependent upon the temporal context in which it is expressed. Better understanding of this temporal sequence may be used to optimize regenerative outcomes. PMID:21248364

  13. Extracellular Control of Limb Regeneration

    NASA Astrophysics Data System (ADS)

    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.

  14. Progenitor Cells and Podocyte Regeneration

    PubMed Central

    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

  15. Nonventing, Regenerable, Lightweight Heat Absorber

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo

    2008-01-01

    A lightweight, regenerable heat absorber (RHA), developed for rejecting metabolic heat from a space suit, may also be useful on Earth for short-term cooling of heavy protective garments. Unlike prior space-suit-cooling systems, a system that includes this RHA does not vent water. The closed system contains water reservoirs, tubes through which water is circulated to absorb heat, an evaporator, and an absorber/radiator. The radiator includes a solution of LiCl contained in a porous material in titanium tubes. The evaporator cools water that circulates through a liquid-cooled garment. Water vapor produced in the evaporator enters the radiator tubes where it is absorbed into the LiCl solution, releasing heat. Much of the heat of absorption is rejected to the environment via the radiator. After use, the RHA is regenerated by heating it to a temperature of 100 C for about 2 hours to drive the absorbed water back to the evaporator. A system including a prototype of the RHA was found to be capable of maintaining a temperature of 20 C while removing heat at a rate of 200 W for 6 hours.

  16. Scaffolds in vascular regeneration: current status

    PubMed Central

    Thottappillil, Neelima; Nair, Prabha D

    2015-01-01

    An ideal vascular substitute, especially in <6 mm diameter applications, is a major clinical essentiality in blood vessel replacement surgery. Blood vessels are structurally complex and functionally dynamic tissue, with minimal regeneration potential. These have composite extracellular matrix (ECM) and arrangement. The interplay between ECM components and tissue specific cells gives blood vessels their specialized functional attributes. The core of vascular tissue engineering and regeneration relies on the challenges in creating vascular conduits that match native vessels and adequately regenerate in vivo. Out of numerous vascular regeneration concerns, the relevance of ECM emphasizes much attention toward appropriate choice of scaffold material and further scaffold development strategies. The review is intended to be focused on the various approaches of scaffold materials currently in use in vascular regeneration and current state of the art. Scaffold of choice in vascular tissue engineering ranges from natural to synthetic, decellularized, and even scaffold free approach. The applicability of tubular scaffold for in vivo vascular regeneration is under active investigation. A patent conduit with an ample endothelial luminal layer that can regenerate in vivo remains an unanswered query in the field of small diameter vascular tissue engineering. Besides, scaffolds developed for vascular regeneration, should aim at providing functional substitutes for use in a regenerative approach from the laboratory bench to patient bedside. PMID:25632236

  17. Enzymatic regeneration of adenosine triphosphate cofactor

    NASA Technical Reports Server (NTRS)

    Marshall, D. L.

    1974-01-01

    Regenerating adenosine triphosphate (ATP) from adenosine diphosphate (ADP) by enzymatic process which utilizes carbamyl phosphate as phosphoryl donor is technique used to regenerate expensive cofactors. Process allows complex enzymatic reactions to be considered as candidates for large-scale continuous processes.

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

    PubMed Central

    Li, Guang-shuai; Li, Qing-feng; Dong, Ming-min; Zan, Tao; Ding, Shuang; Liu, Lin-bo

    2016-01-01

    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, C8β 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. PMID:27212935

  19. The effect of collagen-chitosan porous scaffold thickness on dermal regeneration in a one-stage grafting procedure.

    PubMed

    Haifei, Shi; Xingang, Wang; Shoucheng, Wu; Zhengwei, Mao; Chuangang, You; Chunmao, Han

    2014-01-01

    Dermal substitutes are used as dermal regeneration templates to reduce scar formation and improve wound healing. Unlike autografts, dermal substitutes lack normal vascular networks. The increased distance required for diffusion of oxygen and nutrients to the autograft following interpositioning of the substitute dramatically affects graft survival. To evaluate the effect of collagen-chitosan scaffold thickness on dermal regeneration, single-layer collagen-chitosan porous scaffolds of 0.5-, 1- and 2-mm thicknesses were fabricated and used to treat full-thickness wounds in a one-stage grafting procedure in a rat model. Skin-graft viability, wound contraction, histological changes, and wound tensile strength were evaluated. The results indicated that the distance for the diffusion of oxygen and nutrients to the autograft in the 2-mm-thick scaffold provided less support for graft take, which resulted in graft necrosis, extensive inflammatory reaction, marked foreign-body reaction (FBR), rapid scaffold degradation, and abnormal collagen deposition and remodeling. In contrast, the thinner scaffolds, especially of that 0.5-mm thickness, promoted earlier angiogenesis, ensuring skin-graft viability with a mild FBR, and ordered fibroblast infiltration and better collagen remodeling. It can be concluded that collagen-chitosan porous scaffolds with a thickness of <1mm are more suitable for dermal regeneration and can be used as dermal templates for treatment of dermal defects using a one-stage grafting procedure. PMID:24076783

  20. Tityus: a forgotten myth of liver regeneration.

    PubMed

    Tiniakos, Dina G; Kandilis, Apostolos; Geller, Stephen A

    2010-08-01

    The ancient Greek myth of Tityus is related to liver regeneration in the same way as the well known myth of Prometheus is. Depictions of the punishment of Prometheus are frequently used by lecturers on liver regeneration; however, Tityus remains unknown despite the fact that he received the same punishment and his myth could also be used as a paradigm for the organ's extraordinary ability to regenerate. Nevertheless, there is no convincing evidence that ancient Greeks had any specific knowledge about liver regeneration, a concept introduced in the early 19th century. We describe and analyze the myth of Tityus and compare it to the myth of Prometheus. We also explore artistic and literary links and summarize recent scientific data on the mechanisms of liver regeneration. Finally, we highlight links of the legend of Tityus with other sciences. PMID:20472318

  1. Protoplast formation and regeneration in Lactobacillus delbrueckii.

    PubMed

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

    2010-03-01

    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 mutanolysin (10 μg/ml). Maximum protoplast regeneration was obtained on MRS medium with sucrose (0.5 M) as an osmotic stabilizer. The regeneration medium was also applicable to other species of lactobacilli as well. This is, to our knowledge, the first report on protoplast formation and efficient regeneration in case of L. delbrueckii. PMID:23100814

  2. NOx adsorber and method of regenerating same

    SciTech Connect

    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.

  3. The Role of Nanoscale Architecture in Supramolecular Templating of Biomimetic Hydroxyapatite Mineralization

    PubMed Central

    Newcomb, Christina J.; Bitton, Ronit; Velichko, Yuri S.; Snead, Malcolm L.; Stupp, Samuel I.

    2012-01-01

    Understanding and mimicking the hierarchical structure of mineralized tissue is a challenge in the field of biomineralization and is important for the development of scaffolds to guide bone regeneration. Bone is a remarkable tissue with an organic matrix comprised of aligned collagen bundles embedded with nanometer-sized inorganic hydroxyapatite (HAP) crystals that exhibit orientation on the macroscale. Hybrid organic-inorganic structures mimic the composition of mineralized tissue for functional bone scaffolds, but the relationship between morphology of the organic matrix and orientation of mineral is poorly understood. We report here the mineralization of supramolecular peptide amphiphile templates that are designed to vary in nanoscale morphology by altering the amino acid sequence. We found that one-dimensional cylindrical nanostructures directed the growth of oriented HAP crystals, while flatter nanostructures failed to guide the orientation found in biological systems. The geometric constraints associated with the morphology of the nanostructures may effectively control HAP nucleation and growth. Additionally, we explored the mineralization of macroscopically aligned bundles of the nanoscale assemblies to create hierarchically ordered scaffolds. Again, we found that only aligned gel templates of cylindrical nanostructures led to hierarchical control over hydroxyapatite orientation across multiple length scales as found in bone. PMID:22570174

  4. Embryonic myogenesis pathways in muscle regeneration.

    PubMed

    Zhao, Po; Hoffman, Eric P

    2004-02-01

    Embryonic myogenesis involves the staged induction of myogenic regulatory factors and positional cues that dictate cell determination, proliferation, and differentiation into adult muscle. Muscle is able to regenerate after damage, and muscle regeneration is generally thought to recapitulate myogenesis during embryogenesis. There has been considerable progress in the delineation of myogenesis pathways during embryogenesis, but it is not known whether the same signaling pathways are relevant to muscle regeneration in adults. Here, we defined the subset of embryogenesis pathways induced in muscle regeneration using a 27 time-point in vivo muscle regeneration series. The embryonic Wnt (Wnt1, 3a, 7a, 11), Shh pathway, and the BMP (BMP2, 4, 7) pathway were not induced during muscle regeneration. Moreover, antagonists of Wnt signaling, sFRP1, sFRP2, and sFRP4 (secreted frizzled-related proteins) were significantly up-regulated, suggesting active inhibition of the Wnt pathway. The pro-differentiation FGFR4 pathway was transiently expressed at day 3, commensurate with expression of MyoD, Myogenin, Myf5, and Pax7. Protein verification studies showed fibroblast growth factor receptor 4 (FGFR4) protein to be strongly expressed in differentiating myoblasts and newly formed myotubes. We present evidence that FGF6 is likely the key ligand for FGFR4 during muscle regeneration, and further suggest that FGF6 is released from necrotic myofibers where it is then sequestered by basal laminae. We also confirmed activation of Notch1 in the regenerating muscle. Finally, known MyoD coactivators (MEF2A, p/CIP, TCF12) and repressors (Twist, Id2) were strongly induced at appropriate time points. Taken together, our results suggest that embryonic positional signals (Wnt, Shh, and BMP) are not induced in postnatal muscle regeneration, whereas cell-autonomous factors (Pax7, MRFs, FGFR4) involving muscle precursor proliferation and differentiation are recapitulated by muscle regeneration. PMID

  5. Building recognition based on big template in FLIR images

    NASA Astrophysics Data System (ADS)

    Zhang, Jiangwei; Niu, Zhaodong; Liu, Songlin; Liu, Fang; Chen, Zengping

    2014-10-01

    In order to enhance the robustness of building recognition in forward-looking infrared (FLIR) images, an effective method based on big template is proposed. Big template is a set of small templates which contains a great amount of information of surface features. Its information content cannot be matched by any small template and it has advantages in conquering noise interference or incompleteness and avoiding erroneous judgments. Firstly, digital surface model (DSM) was utilized to make big template, distance transformation was operated on the big template, and region of interest (ROI) was extracted by the way of template matching between the big template and contour of real-time image. Secondly, corners were detected from the big template, response function was defined by utilizing gradients and phases of corners and their neighborhoods, a kind of similarity measure was designed based on the response function and overlap ratio, then the template and real-time image were matched accurately. Finally, a large number of image data was used to test the performance of the algorithm, and optimal parameters selection criterion was designed. Test results indicate that the target matching ratio of the algorithm can reach 95%, it has effectively solved the problem of building recognition under the conditions of noise disturbance, incompleteness or the target is not in view.

  6. RABBIT: Rapid Alignment of Brains by Building Intermediate Templates

    PubMed Central

    Tang, Songyuan; Fan, Yong; Shen, Dinggang

    2009-01-01

    A brain image registration algorithm, referred to as RABBIT, is proposed to achieve fast and accurate image registration with the help of an intermediate template generated by a statistical deformation model. The statistical deformation model is built by principal component analysis (PCA) on a set of training samples of brain deformation fields that warp a selected template image to the individual brain samples. The statistical deformation model is capable of characterizing individual brain deformations by a small number of parameters, which is used to rapidly estimate the brain deformation between the template and a new individual brain image. The estimated deformation is then used to warp the template, thus generating an intermediate template close to the individual brain image. Finally, the shape difference between the intermediate template and the individual brain is estimated by an image registration algorithm, e.g., HAMMER. The overall registration between the template and the individual brain image can be achieved by directly combining the deformation fields that warp the template to the intermediate template, and the intermediate template to the individual brain image. The algorithm has been validated for spatial normalization of both simulated and real magnetic resonance imaging (MRI) brain images. Compared with HAMMER, the experimental results demonstrate that the proposed algorithm can achieve over five times speedup, with similar registration accuracy and statistical power in detecting brain atrophy. PMID:19285145

  7. DNA repair by RNA: Templated, or not templated, that is the question.

    PubMed

    Meers, Chance; Keskin, Havva; Storici, Francesca

    2016-08-01

    Cells are continuously exposed to both endogenous and exogenous sources of genomic stress. To maintain chromosome stability, a variety of mechanisms have evolved to cope with the multitude of genetic abnormalities that can arise over the life of a cell. Still, failures to repair these lesions are the driving force of cancers and other degenerative disorders. DNA double-strand breaks (DSBs) are among the most toxic genetic lesions, inhibiting cell ability to replicate, and are sites of mutations and chromosomal rearrangements. DSB repair is known to proceed via two major mechanisms: homologous recombination (HR) and non-homologous end joining (NHEJ). HR reliance on the exchange of genetic information between two identical or nearly identical DNA molecules offers increased accuracy. While the preferred substrate for HR in mitotic cells is the sister chromatid, this is limited to the S and G2 phases of the cell cycle. However, abundant amounts of homologous genetic substrate may exist throughout the cell cycle in the form of RNA. Considered an uncommon occurrence, the direct transfer of information from RNA to DNA is thought to be limited to special circumstances. Studies have shown that RNA molecules reverse transcribed into cDNA can be incorporated into DNA at DSB sites via a non-templated mechanism by NHEJ or a templated mechanism by HR. In addition, synthetic RNA molecules can directly template the repair of DSBs in yeast and human cells via an HR mechanism. New work suggests that even endogenous transcript RNA can serve as a homologous template to repair a DSB in chromosomal DNA. In this perspective, we will review and discuss the recent advancements in DSB repair by RNA via non-templated and templated mechanisms. We will provide current findings, models and future challenges investigating RNA and its role in DSB repair. PMID:27237587

  8. DNA repair by RNA: Templated, or not templated, that is the question

    PubMed Central

    Meers, Chance; Keskin, Havva; Storici, Francesca

    2016-01-01

    Cells are continuously exposed to both endogenous and exogenous sources of genomic stress. To maintain chromosome stability, a variety of mechanisms have evolved to cope with the multitude of genetic abnormalities that can arise over the life of a cell. Still, failures to repair these lesions are the driving force of cancers and other degenerative disorders. DNA double-strand breaks (DSBs) are among the most toxic genetic lesions, inhibiting cell ability to replicate, and are sites of mutations and chromosomal rearrangements. DSB repair is known to proceed via two major mechanisms: homologous recombination (HR) and non-homologous end joining (NHEJ). HR reliance on the exchange of genetic information between two identical or nearly identical DNA molecules offers increased accuracy. While the preferred substrate for HR in mitotic cells is the sister chromatid, this is limited to the S and G2 phases of the cell cycle. However, abundant amounts of homologous genetic substrate may exist throughout the cell cycle in the form of RNA. Considered an uncommon occurrence, the direct transfer of information from RNA to DNA is thought to be limited to special circumstances. Studies have shown that RNA molecules reverse transcribed into cDNA can be incorporated into DNA at DSB sites via a non-templated mechanism by NHEJ or a templated mechanism by HR. In addition, synthetic RNA molecules can directly template the repair of DSBs in yeast and human cells via an HR mechanism. New work suggests that even endogenous transcript RNA can serve as a homologous template to repair a DSB in chromosomal DNA. In this perspective, we will review and discuss the recent advancements in DSB repair by RNA via non-templated and templated mechanisms. We will provide current findings, models and future challenges investigating RNA and its role in DSB repair. PMID:27237587

  9. RTF glovebox stripper regeneration development

    SciTech Connect

    Birchenall, A.K.

    1992-10-31

    Currently, the Replacement Tritium Facility (RTF) glovebox stripper system consists of a catalytic oxidation front end where trace tritium which may escape from the primary tritium process into the glovebox nitrogen system is oxidized to tritiated water. The tritiated water, along with normal water which may leak into the glovebox from the surrounding atmosphere, is then captured on a zeolite bed. Eventually, the zeolite bed becomes saturated with water and must be regenerated to remain effective as a stripper. This is accomplished by heating the zeolite and evolving the trapped water which is then passed over an elevated temperature uranium bed. A waste minimization program was instituted to address this issue. The program has two parallel paths. One path investigates replacing the entire glovebox stripper system with a system of getters to scavenge trace tritium. This report concentrates on the second path, retaining the catalytic oxidation front end but replacing the uranium bed water cracking with alternative technologies.

  10. Solar-regenerated desiccant dehumidification

    NASA Astrophysics Data System (ADS)

    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.

  11. Regenerator for gas turbine engine

    DOEpatents

    Lewakowski, John J.

    1979-01-01

    A rotary disc-type counterflow regenerator for a gas turbine engine includes a disc-shaped ceramic core surrounded by a metal rim which carries a coaxial annular ring gear. Bonding of the metal rim to the ceramic core is accomplished by constructing the metal rim in three integral portions: a driving portion disposed adjacent the ceramic core which carries the ring gear, a bonding portion disposed further away from the ceramic core and which is bonded thereto by elastomeric pads, and a connecting portion connecting the bonding portion to the driving portion. The elastomeric pads are bonded to radially flexible mounts formed as part of the metal rim by circumferential slots in the transition portion and lateral slots extending from one end of the circumferential slots across the bonding portion of the rim.

  12. MHD seed recovery and regeneration

    NASA Astrophysics Data System (ADS)

    1988-10-01

    The TRW Econoseed MHD Seed Regeneration Process is based on the reaction of calcium formate with potassium sulfate spent seed from an MHD electric power generation plant. The process was tested at bench scale, design a proof of concept (POC) test plant, plan and cost a Phase 2 project for a POC plant evaluation and prepare a conceptual design of a 300 MW (t) commercial plant. The results of the project are as follows: (1) each of the unit operations is demonstrated, and (2) the data are incorporated into a POC plant design and project cost, as well as a 300 MW (t) commercial retrofit plant design and cost estimate. Specific results are as follows: (1) calcium formate can be produced at 100 percent yield in a total retention time of less than 5 minutes, (2) utilizing the calcium formate, spent seed can quantitatively be converted to potassium formate, potassium carbonate or mixtures of these with potassium sulfate as per the commercial design without measurable loss of potassium to insolubles at a total retention time under 20 minutes and ambient pressure, (3) the solid rejects form the process meet RCRA EP Toxicity requirements for safe disposal, and (4) filtration and evaporation data, as well as reaction data cited above, show that the Econoseed technology is ready for scale up to POC plant scale. Economics forecast studies show that the total cost per unit of potassium for seed regeneration by the Econoseed Process is in the range of $0.23 to $0.27/lb, a cost which is less than half the potassium cost of $0.63/lb for purchasing new potassium carbonate.

  13. Template for Systems Engineering Tools Trade Study

    NASA Technical Reports Server (NTRS)

    Bailey, Michelle D.

    2005-01-01

    A discussion of Systems Engineering tools brings out numerous preferences and reactions regarding tools of choice as well as the functions those tools are to perform. A recent study of Systems Engineering Tools for a new Program illustrated the need for a generic template for use by new Programs or Projects to determine the toolset appropriate for their use. This paper will provide the guidelines new initiatives can follow and tailor to their specific needs, to enable them to make their choice of tools in an efficient and informed manner. Clearly, those who perform purely technical functions will need different tools than those who perform purely systems engineering functions. And, everyone has tools they are comfortable with. That degree of comfort is frequently the deciding factor in tools choice rather than an objective study of all criteria and weighting factors. This paper strives to produce a comprehensive list of criteria for selection with suggestions for weighting factors based on a number of assumptions regarding the given Program or Project. In addition, any given Program will begin with assumptions for its toolset based on Program size, tool cost, user base and technical needs. In providing a template for tool selection, this paper will guide the reader through assumptions based on Program need; decision criteria; potential weighting factors; the need for a compilation of available tools; the importance of tool demonstrations; and finally a down selection of tools. While specific vendors cannot be mentioned in this work, it is expected that this template could serve other Programs in the formulation phase by alleviating the trade study process of some of its subjectivity.

  14. New organically templated photoluminescence iodocuprates(I)

    SciTech Connect

    Hou Qin; Zhao Jinjing; Zhao Tianqi; Jin Juan; Yu Jiehui; Xu Jiqing

    2011-07-15

    Two types of organic cyclic aliphatic diamine molecules piperazine (pip) and 1,3-bis(4-piperidyl)propane (bpp) were used, respectively, to react with an inorganic mixture of CuI and KI in the acidic CH{sub 3}OH solutions under the solvothermal conditions, generating finally three new organically templated iodocuprates as 2-D layered [(Hpip)Cu{sub 3}I{sub 4}] 1, 1-D chained [tmpip][Cu{sub 2}I{sub 4}] 2 (tmpip=N,N,N',N'-tetramethylpiperazinium) and dinuclear [H{sub 2}bpp]{sub 2}[Cu{sub 2}I{sub 5}] I.2H{sub 2}O 3. Note that the templating agent tmpip{sup 2+} in compound 2 originated from the in situ N-alkylation reaction between the pip molecule and the methanol solvent. The photoluminescence analysis indicates that the title compounds emit the different lights: yellow for 1, blue for 2 and yellow-green for 3, respectively. - Graphical abstract: The solvothermal self-assemblies of CuI, KI and pip/bpp in acidic CH{sub 3}OH solutions created three iodocuprates 2-D layered [(Hpip)Cu{sub 3}I{sub 4}] 1, 1-D chained [tmpip][Cu{sub 2}I{sub 4}] 2 and dinuclear [H{sub 2}bpp]{sub 2}[Cu{sub 2}I{sub 5}] I.2H{sub 2}O 3. Highlights: > A new layered iodocuprate(I) with 20-membered rings was hydrothermally prepared. > A simple approach to prepare the new organic templating agent was reported. > Photoluminescence analysis indicates the emission for iodocuprate(I) is associated with the Cu...Cu interactions.

  15. Fluorescent DNA-templated silver nanoclusters

    NASA Astrophysics Data System (ADS)

    Lin, Ruoqian

    Because of the ultra-small size and biocompatibility of silver nanoclusters, they have attracted much research interest for their applications in biolabeling. Among the many ways of synthesizing silver nanoclusters, DNA templated method is particularly attractive---the high tunability of DNA sequences provides another degree of freedom for controlling the chemical and photophysical properties. However, systematic studies about how DNA sequences and concentrations are controlling the photophysical properties are still lacking. The aim of this thesis is to investigate the binding mechanisms of silver clusters binding and single stranded DNAs. Here in this thesis, we report synthesis and characterization of DNA-templated silver nanoclusters and provide a systematic interrogation of the effects of DNA concentrations and sequences, including lengths and secondary structures. We performed a series of syntheses utilizing five different sequences to explore the optimal synthesis condition. By characterizing samples with UV-vis and fluorescence spectroscopy, we achieved the most proper reactants ratio and synthesis conditions. Two of them were chosen for further concentration dependence studies and sequence dependence studies. We found that cytosine-rich sequences are more likely to produce silver nanoclusters with stronger fluorescence signals; however, sequences with hairpin secondary structures are more capable in stabilizing silver nanoclusters. In addition, the fluorescence peak emission intensities and wavelengths of the DNA templated silver clusters have sequence dependent fingerprints. This potentially can be applied to sequence sensing in the future. However all the current conclusions are not warranted; there is still difficulty in formulating general rules in DNA strand design and silver nanocluster production. Further investigation of more sequences could solve these questions in the future.

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

    PubMed Central

    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

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

    PubMed

    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

  18. Reintegration of the regenerated and the remaining tissues during joint regeneration in the newt Cynops pyrrhogaster

    PubMed Central

    Inoue, Takeshi; Yamada, Shigehito

    2015-01-01

    Abstract Urodele amphibians, such as newts, can regenerate a functional limb, including joints, after amputation at any level along the proximal−distal axis of the limb. The blastema can regenerate the limb morphology largely independently of the stump after proximal−distal identity has been established, but the remaining and regenerated tissues must be structurally reintegrated (matched in size and shape). Here we used newt joint regeneration as a model to investigate reintegration, because a functionally interlocking joint requires structural integration between its opposing skeletal elements. After forelimbs were amputated at the elbow joint, the joint was regenerated between the remaining and regenerated skeletal elements. The regenerated cartilage was thick around the amputated joint to make a reciprocally interlocking joint structure with the remaining bone. Furthermore, during regeneration, the extracellular matrix of the remaining tissues was lost, suggesting that the remaining tissues might contribute to the morphogenesis of regenerating cartilage. Our results showed that the area of the regenerated cartilage matched the area of the apposed remaining cartilage, thus contributing to formation of a functional structure.

  19. Molecular engineering of porous silica using aryl templates

    DOEpatents

    Loy, Douglas A.; Shea, Kenneth J.

    1994-01-01

    A process for manipulating the porosity of silica using a series of organic template groups covalently incorporated into the silicate matrix. The templates in the bridged polysilsesquioxanes are selectively removed from the material by oxidation with oxygen plasma or other means, leaving engineered voids or pores. The size of these pores is dependent upon the length or size of the template or spacer. The size of the templates is measured in terms of Si-Si distances which range from about 0.67 nm to 1.08 nm. Changes introduced by the loss of the templates result in a narrow range of micropores (i.e. <2 nm). Both aryl and alkyl template groups are used as spacers. Novel microporous silica materials useful as molecular seives, dessicants, and catalyst supports are produced.

  20. Molecular engineering of porous silica using aryl templates

    DOEpatents

    Loy, D.A.; Shea, K.J.

    1994-06-14

    A process is described for manipulating the porosity of silica using a series of organic template groups covalently incorporated into the silicate matrix. The templates in the bridged polysilsesquioxanes are selectively removed from the material by oxidation with oxygen plasma or other means, leaving engineered voids or pores. The size of these pores is dependent upon the length or size of the template or spacer. The size of the templates is measured in terms of Si-Si distances which range from about 0.67 nm to 1.08 nm. Changes introduced by the loss of the templates result in a narrow range of micropores (i.e. <2 nm). Both aryl and alkyl template groups are used as spacers. Novel microporous silica materials useful as molecular sieves, desiccants, and catalyst supports are produced. 3 figs.

  1. Observers change their target template based on expected context.

    PubMed

    Bravo, Mary J; Farid, Hany

    2016-04-01

    Previous studies have shown that when observers search repeatedly for a target in a particular context, they may develop a target template that is biased for that context. Because the same target may appear in multiple contexts, we wondered whether observers are able to develop multiple templates for the same target, with each template biased for a particular context. In a series of behavioral experiments, we show that observers can learn multiple target templates for a single target and that they can voluntarily switch among these templates depending on the context they expect to see. Our results suggest that these biased templates may coexist with an unbiased representation of the target, provided they are learned first. PMID:26791232

  2. Assessing usage patterns of electronic clinical documentation templates.

    PubMed

    Vawdrey, David K

    2008-01-01

    Many vendors of electronic medical records support structured and free-text entry of clinical documents using configurable templates. At a healthcare institution comprising two large academic medical centers, a documentation management data mart and a custom, Web-accessible business intelligence application were developed to track the availability and usage of electronic documentation templates. For each medical center, template availability and usage trends were measured from November 2007 through February 2008. By February 2008, approximately 65,000 electronic notes were authored per week on the two campuses. One site had 934 available templates, with 313 being used to author at least one note. The other site had 765 templates, of which 480 were used. The most commonly used template at both campuses was a free text note called "Miscellaneous Nursing Note," which accounted for 33.3% of total documents generated at one campus and 15.2% at the other. PMID:18998863

  3. Human identification using temporal information preserving gait template.

    PubMed

    Wang, Chen; Zhang, Junping; Wang, Liang; Pu, Jian; Yuan, Xiaoru

    2012-11-01

    Gait Energy Image (GEI) is an efficient template for human identification by gait. However, such a template loses temporal information in a gait sequence, which is critical to the performance of gait recognition. To address this issue, we develop a novel temporal template, named Chrono-Gait Image (CGI), in this paper. The proposed CGI template first extracts the contour in each gait frame, followed by encoding each of the gait contour images in the same gait sequence with a multichannel mapping function and compositing them to a single CGI. To make the templates robust to a complex surrounding environment, we also propose CGI-based real and synthetic temporal information preserving templates by using different gait periods and contour distortion techniques. Extensive experiments on three benchmark gait databases indicate that, compared with the recently published gait recognition approaches, our CGI-based temporal information preserving approach achieves competitive performance in gait recognition with robustness and efficiency. PMID:22201053

  4. Micro-Nanostructured Polyaniline Assembled in Cellulose Matrix via Interfacial Polymerization for Applications in Nerve Regeneration.

    PubMed

    Xu, Dingfeng; Fan, Lin; Gao, Lingfeng; Xiong, Yan; Wang, Yanfeng; Ye, Qifa; Yu, Aixi; Dai, Honglian; Yin, Yixia; Cai, Jie; Zhang, Lina

    2016-07-13

    Conducting polymers have emerged as frontrunners to be alternatives for nerve regeneration, showing a possibility of the application of polyaniline (PANI) as the nerve guidance conduit. In the present work, the cellulose hydrogel was used as template to in situ synthesize PANI via the limited interfacial polymerization method, leading to one conductive side in the polymer. PANI sub-micrometer dendritic particles with mean diameter of ∼300 nm consisting of the PANI nanofibers and nanoparticles were uniformly assembled into the cellulose matrix. The hydrophobic PANI nanoparticles were immobilized in the hydrophilic cellulose via the phytic acid as "bridge" at presence of water through hydrogen bonding interaction. The PANI/cellulose composite hydrogels exhibited good mechanical properties and biocompatibility as well as excellent guiding capacity for the sciatic nerve regeneration of adult Sprague-Dawley rats without any extra treatment. On the basis of the fact that the pure cellulose hydrogel was an inert material for the neural repair, PANI played an indispensable role on the peripheral nerve regeneration. The hierarchical micro-nanostructure and electrical conductivity of PANI could remarkably induce the adhesion and guiding extension of neurons, showing its great potential in biomedical materials. PMID:27314673

  5. Multilayered Short Peptide-Alginate Blends as New Materials for Potential Applications in Cartilage Tissue Regeneration.

    PubMed

    Knoll, Grant A; Romanelli, Steven M; Brown, Alexandra M; Sortino, Rachel M; Banerjee, Ipsita A

    2016-03-01

    Peptide based nanomaterials have been gaining increased prominence due to their ability to form permeable scaffolds that promote growth and regeneration of new tissue. In this work for the first time a short hexapeptide motif VQIVYK, derived from the Tau protein family was conjugated with an organic polyamine linker, putrescine and utilized as a template for developing new materials for cartilage tissue regeneration. Our results showed that the conjugate formed extensive nanofibrous assemblies upon self-assembly under aqueous conditions. We then employed the layer-by-layer (LBL) approach to design the scaffold by first incorporating a short segment of the dentin sialophosphoprotein motif GDASYNSDESK followed by integration with the peptide sequence GSGAGAGSGAGAGSGAGA. This sequence mimics Ala, Gly, Ser repeats seen in the spider silk protein. We then incorporated the polysaccharide alginate which served as a hydrogel. To further enhance binding interactions with chondrocytes, and promote the formation of cartilage in vitro, the bionanocomposites were then attached to the chondrocyte binding peptide sequence HDSQLEALIKFM. The thermal properties as well as biodegradability of the scaffold was examined. To confirm biocompatibility, we examined cell viability, attachment and morphology in the presence of bovine chondrocytes. The cells were found to efficiently adhere to the scaffolds which formed an intricate mesh mimicking the extracellular matrix of cartilage tissue. To evaluate if differentiation occurred in the presence of the scaffolds, we examined in vitro deposition of proteoglycans. Thus, we have developed a new family of nanoscale scaffolds that may be utilized for cartilage tissue regeneration. PMID:27455656

  6. Production and characterization of chitosan/gelatin/β-TCP scaffolds for improved bone tissue regeneration.

    PubMed

    Serra, I R; Fradique, R; Vallejo, M C S; Correia, T R; Miguel, S P; Correia, I J

    2015-10-01

    Recently, bone tissue engineering emerged as a viable therapeutic alternative, comprising bone implants and new personalized scaffolds to be used in bone replacement and regeneration. In this study, biocompatible scaffolds were produced by freeze-drying, using different formulations (chitosan, chitosan/gelatin, chitosan/β-TCP and chitosan/gelatin/β-TCP) to be used as temporary templates during bone tissue regeneration. Sample characterization was performed through attenuated total reflectance-Fourier transform infrared spectroscopy, X-ray diffraction and energy dispersive spectroscopy analysis. Mechanical characterization and porosity analysis were performed through uniaxial compression test and liquid displacement method, respectively. In vitro studies were also done to evaluate the biomineralization activity and the cytotoxic profile of the scaffolds. Scanning electron and confocal microscopy analysis were used to study cell adhesion and proliferation at the scaffold surface and within their structure. Moreover, the antibacterial activity of the scaffolds was also evaluated through the agar diffusion method. Overall, the results obtained revealed that the produced scaffolds are bioactive and biocompatible, allow cell internalization and show antimicrobial activity against Staphylococcus aureus. Such, make these 3D structures as potential candidates for being used on the bone tissue regeneration, since they promote cell adhesion and proliferation and also prevent biofilm development at their surfaces, which is usually the main cause of implant failure. PMID:26117793

  7. Bioactive polymeric-ceramic hybrid 3D scaffold for application in bone tissue regeneration.

    PubMed

    Torres, A L; Gaspar, V M; Serra, I R; Diogo, G S; Fradique, R; Silva, A P; Correia, I J

    2013-10-01

    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. PMID:23910366

  8. [Tooth regeneration--dream to reality].

    PubMed

    Wang, Song-Ling; Wang, Xue-Jiu

    2008-04-01

    Tooth or dentition missing compromises human health physically and psychiatrically. Although several prosthesis methods are used to restore tooth loss, these restorations are still non-biological methods. It is a dream for human being to regenerate a real tooth for hundreds years. There are two ways to regenerate the tooth. One is application of conventional tissue engineering techniques including seed cells and scaffold. The other is regeneration tooth using dental epithelium and dental mesenchymal cells based on the knowledge of tooth initiation and development. Marked progress has been achieved in these two ways, while there is still a long way to go. Recently a new concept has been proposed for regeneration of a biological tooth root based on tooth-related stem cells and tissue engineering technique. A biological tooth root has been regenerated in swine. It may be a valuable method for restoration of tooth loss before successful whole tooth regeneration. A latest research showed that a subpopulation in bone marrow cells can give rise to ameloblast-like cells when mixed with embryonic epithelium and reassociation with integrated mesenchyme, which may provide a new seed cell source for tooth regeneration. PMID:18605442

  9. What makes a RAG regeneration associated?

    PubMed Central

    Ma, Thong C.; Willis, Dianna E.

    2015-01-01

    Regenerative failure remains a significant barrier for functional recovery after central nervous system (CNS) injury. As such, understanding the physiological processes that regulate axon regeneration is a central focus of regenerative medicine. Studying the gene transcription responses to axon injury of regeneration competent neurons, such as those of the peripheral nervous system (PNS), has provided insight into the genes associated with regeneration. Though several individual “regeneration-associated genes” (RAGs) have been identified from these studies, the response to injury likely regulates the expression of functionally coordinated and complementary gene groups. For instance, successful regeneration would require the induction of genes that drive the intrinsic growth capacity of neurons, while simultaneously downregulating the genes that convey environmental inhibitory cues. Thus, this view emphasizes the transcriptional regulation of gene “programs” that contribute to the overall goal of axonal regeneration. Here, we review the known RAGs, focusing on how their transcriptional regulation can reveal the underlying gene programs that drive a regenerative phenotype. Finally, we will discuss paradigms under which we can determine whether these genes are injury-associated, or indeed necessary for regeneration. PMID:26300725

  10. Muscle Cells Provide Instructions for Planarian Regeneration

    PubMed Central

    Witchley, Jessica N.; Mayer, Mirjam; Wagner, Daniel E.; Owen, Jared H.; Reddien, Peter W.

    2014-01-01

    Regeneration requires both potential and instructions for tissue replacement. In planarians, pluripotent stem cells have the potential to produce all new tissue. The identities of the cells that provide regeneration instructions are unknown. Here, we report that position control genes (PCGs) that control regeneration and tissue turnover are expressed in a subepidermal layer of nonneoblast cells. These subepidermal cells coexpress many PCGs. We propose that these subepidermal cells provide a system of body coordinates and positional information for regeneration, and identify them to be muscle cells of the planarian body wall. Almost all planarian muscle cells express PCGs, suggesting a dual function: contraction and control of patterning. PCG expression is dynamic in muscle cells after injury, even in the absence of neoblasts, suggesting that muscle is instructive for regeneration. We conclude that planarian regeneration involves two highly flexible systems: pluripotent neoblasts that can generate any new cell type and muscle cells that provide positional instructions for the regeneration of any body region. PMID:23954785

  11. Generating Test Templates via Automated Theorem Proving

    NASA Technical Reports Server (NTRS)

    Kancherla, Mani Prasad

    1997-01-01

    Testing can be used during the software development process to maintain fidelity between evolving specifications, program designs, and code implementations. We use a form of specification-based testing that employs the use of an automated theorem prover to generate test templates. A similar approach was developed using a model checker on state-intensive systems. This method applies to systems with functional rather than state-based behaviors. This approach allows for the use of incomplete specifications to aid in generation of tests for potential failure cases. We illustrate the technique on the cannonical triangle testing problem and discuss its use on analysis of a spacecraft scheduling system.

  12. Oriented Protein Nanoarrays on Block Copolymer Template.

    PubMed

    Shen, Lei; Zhu, Jintao

    2016-03-01

    Here, a simple yet robust method is developed to fabricate oriented protein nanoarrays by employing a block copolymer (BCP) template, which presents nano-scaled spot areas at high-density arrays. Unlike the conventional BCP nanolithography, the BCP platform described here resists nonspecific protein adsorption and prevents the denaturation of immobilized proteins in aqueous solution. The orderly arranged array areas are functionalized by linking chemistry which allows for the precise control of protein orientation. This approach allows us to generate potentially oriented protein nanoarrays at high-density array spots, which is useful for miniaturized nanoarrays within high-throughput proteomic applications. PMID:26785818

  13. Templated Synthesis of Uniform Perovskite Nanowire Arrays.

    PubMed

    Ashley, Michael J; O'Brien, Matthew N; Hedderick, Konrad R; Mason, Jarad A; Ross, Michael B; Mirkin, Chad A

    2016-08-17

    While the chemical composition of semiconducting metal halide perovskites can be precisely controlled in thin films for photovoltaic devices, the synthesis of perovskite nanostructures with tunable dimensions and composition has not been realized. Here, we describe the templated synthesis of uniform perovskite nanowires with controlled diameter (50-200 nm). Importantly, by providing three examples (CH3NH3PbI3, CH3NH3PbBr3, and Cs2SnI6), we show that this process is composition general and results in oriented nanowire arrays on transparent conductive substrates. PMID:27501464

  14. Surfactant-Templated Mesoporous Metal Oxide Nanowires

    DOE PAGESBeta

    Luo, Hongmei; Lin, Qianglu; Baber, Stacy; Naalla, Mahesh

    2010-01-01

    We demore » monstrate two approaches to prepare mesoporous metal oxide nanowires by surfactant assembly and nanoconfinement via sol-gel or electrochemical deposition. For example, mesoporous Ta 2 O 5 and zeolite nanowires are prepared by block copolymer Pluronic 123-templated sol-gel method, and mesoporous ZnO nanowires are prepared by electrodeposition in presence of anionic surfactant sodium dodecyl sulfate (SDS) surfactant, in porous membranes. The morphologies of porous nanowires are studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses.« less

  15. The Contextualization of Archetypes: Clinical Template Governance.

    PubMed

    Pedersen, Rune; Ulriksen, Gro-Hilde; Ellingsen, Gunnar

    2015-01-01

    This paper is a status report from a large-scale openEHR-based EPR project from the North Norway Regional Health Authority. It concerns the standardization of a regional ICT portfolio and the ongoing development of a new process oriented EPR systems encouraged by the unfolding of a national repository for openEHR archetypes. Subject of interest; the contextualization of clinical templates is governed over multiple national boundaries which is complex due to the dependency of clinical resources. From the outset of this, we are interested in how local, regional, and national organizers maneuver to standardize while applying OpenEHR technology. PMID:26262546

  16. Template-directed deposition of amyloid

    NASA Astrophysics Data System (ADS)

    Ha, Chanki

    The formation of amyloid plaques in tissue is a pathological feature of many neurodegenerative diseases. Amyloid deposition, the process of amyloid plaque growth by the association of individual soluble amyloid molecules with a pre-existing amyloid template (i.e. plaque), is known to be critical for amyloid formation in vivo. In order to characterize amyloid deposition, we developed novel, synthetic amyloid templates like amyloid plaques in the human Alzheimer's brain by attaching amyloid seeds covalently onto an N-hydroxysuccinimide-activated surface. Amyloid plaques with a characteristic beta-sheet structure formed through a conformational rearrangement of soluble insulin or Abeta monomers upon interaction with the template. The amyloid deposition rate followed saturation kinetics with respect to insulin concentration in the solution. According to visualization of temporal evolution of Abeta plaque deposition on a template, it was found that mature amyloid plaques serve as a sink of soluble Abeta in a solution as well as a reservoir of small aggregates such as oligomers and protofibrils. Quantitative analysis of seeding efficiencies of three different Abeta species revealed that oligomeric forms of Abeta act more efficiently as seeds than monomers or fibrils do. Furthermore, studies on the interaction between Abeta40 and 42 showed an important role of Abeta42 in amyloid deposition. A slightly acidic condition was found to be unfavorable for amyloid plaque formation. Effects of metal ions on amyloid deposition indicated that Fe3+, but not Cu3 and Zn2+, is important for the deposition of amyloid plaques. The binding of Fe3+ to Abeta42 peptide was confirmed by using SIMS analysis. Zn2+ induced nonfibrillar amorphous aggregates, but the release of Zn2+ from Abeta42 deposits by Fe3+ triggered the formation of amyloid fibers. Effects or metal ion chelators such as ethylenediamine tetraacetic acid, deferoxamine, and clioquinol on amyloid deposition were tested to

  17. Research of Search Template Based on Distributed Computing

    NASA Astrophysics Data System (ADS)

    Xiao, Yao; Huang, Long-Jun; Zuo, Yi

    Aiming at the problem of requirement identification in the field of search engine, we proposed a scheme that makes use of nature language template. In the help of map-reduce analyze of the user searching log, high frequency template can be obtained. Besides, based on tire tree we designed a algorithm that can make the search engine distinguish user requirements using the template. In that case, the search engine can offer different service according to the user requirements.

  18. Constructing binary black hole template banks using numerical relativity waveforms

    NASA Astrophysics Data System (ADS)

    Kumar, Prayush

    2013-04-01

    We present methods for constructing and validating template banks for gravitational waves from high mass binary black holes in advanced gravitational-wave detectors using waveforms from numerical relativity. We construct these template banks using numerical waveforms from the Simulating eXtreme Spacetimes (SXS) collaboration. We show how a template bank can be constructed using numerical waveforms for non-spinning black hole binaries and discuss how this can be extended into the aligned spin black hole binary space.

  19. Pulp Regeneration: Current Approaches and Future Challenges

    PubMed Central

    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

  20. Silicon template preparation for the fabrication of thin patterned gold films via template stripping

    NASA Astrophysics Data System (ADS)

    Schmidl, G.; Dellith, J.; Dellith, A.; Teller, N.; Zopf, D.; Li, G.; Dathe, A.; Mayer, G.; Hübner, U.; Zeisberger, M.; Stranik, O.; Fritzsche, W.

    2015-12-01

    Metallic nanostructures play an important role in the vast field of modern nanophotonics, which ranges from the life sciences to biomedicine and beyond. Gold is a commonly-used and attractive material for plasmonics in the visible wavelength range, most importantly due to its chemical stability. In the present work, we focused on the different methods of plasmonic nanostructure fabrication that possess the greatest potential for cost-efficient fabrication. Initially, reusable (1 0 0) silicon templates were prepared. For this purpose, three different lithography methods (i.e. e-beam, optical, and nanoparticle lithography) were used that correspond to the desired structural scales. The application of a subsequent anisotropic crystal orientation-dependent wet etching process produced well-defined pyramidal structures in a wide variety of sizes, ranging from several microns to less than 100 nm. Finally, a 200 nm-thick gold layer was deposited by means of confocal sputtering on the silicon templates and stripped in order to obtain gold films that feature a surface replica of the initial template structure. The surface roughness that was achieved on the stripped films corresponds well with the roughness of the template used. This makes it possible to prepare cost-efficient high-quality structured films in large quantities with little effort. The gold films produced were thoroughly characterized, particularly with respect to their plasmonic response.

  1. Two axles threaded using a single template site: active metal template macrobicyclic [3]rotaxanes.

    PubMed

    Goldup, Stephen M; Leigh, David A; McGonigal, Paul R; Ronaldson, Vicki E; Slawin, Alexandra M Z

    2010-01-13

    Template approaches to rotaxanes normally require at least n - 1 template sites to interlock n components. Here we describe the one-pot synthesis of [3]rotaxanes in which a single metal template site induces formation of axles through each cavity of a bicyclic macrocycle. Central to the approach is that a portion of the bicyclic molecule acts as a ligand for a transition metal ion that mediates covalent bond formation through one or other macrocyclic cavity, depending on the ligand's orientation, making a mechanical bond. The ligand can then rotate so that the transition metal can catalyze the formation of a second axle through the other macrocycle. Using this strategy with the Cu(I)-catalyzed azide-alkyne cycloaddition (the CuAAC reaction) generates a [3]rotaxane with two identical axles in up to 86% yield. [3]Rotaxanes with two different axles threaded through the macrobicyclic rings can also be created using a single template site, either by having copper(I) sequentially form both mechanical bonds (via the CuAAC reaction) using different sets of building blocks for each axle or by using two different reactions catalyzed by two different metal ions: a palladium(II)-mediated alkyne homocoupling to assemble the first thread through one cavity, followed by a copper(I)-mediated CuAAC reaction to form the second axle through the other ring. PMID:19968281

  2. A nanocluster beacon based on the template transformation of DNA-templated silver nanoclusters.

    PubMed

    Teng, Ye; Jia, Xiaofang; Zhang, Shan; Zhu, Jinbo; Wang, Erkang

    2016-01-28

    In this work, we developed a novel light-up nanocluster beacon (NCB) based on shuttling dark silver nanoclusters (NCs) to a bright scaffold through hybridization. The fluorescence enhancement was as high as 70-fold when the two templates were on the opposite sides of the duplexes, enabling sensitive and selective detection of DNA. PMID:26666564

  3. Nonenzymatic template-directed synthesis on hairpin oligonucleotides. 2. Templates containing cytidine and guanosine residues

    NASA Technical Reports Server (NTRS)

    Wu, T.; Orgel, L. E.

    1992-01-01

    We have prepared hairpin oligonucleotides in which a 5'-terminal single-stranded segment contains cytidylate (C) and guanylate (G) residues. When these hairpin substrates are incubated with a mixture of cytidine 5'-phosphoro(2-methly)imidazolide (2-MeImpC) and guanosine 5'-phosphoro(2-methyl)imidazolide (2-MeImpG), the 5'-terminal segment acts as a template to facilitate sequence-specific addition of G and C residues to the 3'-terminus of the hairpin. If an isolated G residue is present at the 3'-end of the template strand, it is copied regiospecifically in the presence of 2-MeImpC and 2-MeImpG to give a product containing an isolated C residue linked to its G neighbors by 3'-5'-internucleotide bonds. However, if only 2-MeImpC is present in the reaction mixture, very little reaction occurs. Thus, the presence of 2-MeImpG catalyzes the incorporation of C. If the template strand contains a short sequence of G residues, it is copied in the presence of a mixture of 2-MeImpC and 2-MeImpG. If only 2-MeImpC is present in the reaction mixture, efficient synthesis occurs to give a final product containing one fewer C residue than the number of G residues in the template.

  4. Resonantly-enhanced axion-photon regeneration

    SciTech Connect

    Mueller, Guido; Sikivie, Pierre; Tanner, David B.; Bibber, Karl van

    2010-08-30

    A resonantly-enhanced photon-regeneration experiment to search for the axion or axion-like particles is discussed. Photons enter a strong magnetic field and some are converted to axions; the axions can pass through an opaque wall and some may convert back to photons in a second high-field region. The photon regeneration is enhanced by employing matched Fabry-Perot optical cavities, with one cavity within the axion generation magnet and the second within the photon regeneration magnet. The optics for this experiment are discussed, with emphasis on the alignment of the two cavities.

  5. Reparative inflammation takes charge of tissue regeneration.

    PubMed

    Karin, Michael; Clevers, Hans

    2016-01-21

    Inflammation underlies many chronic and degenerative diseases, but it also mitigates infections, clears damaged cells and initiates tissue repair. Many of the mechanisms that link inflammation to damage repair and regeneration in mammals are conserved in lower organisms, indicating that it is an evolutionarily important process. Recent insights have shed light on the cellular and molecular processes through which conventional inflammatory cytokines and Wnt factors control mammalian tissue repair and regeneration. This is particularly important for regeneration in the gastrointestinal system, especially for intestine and liver tissues in which aberrant and deregulated repair results in severe pathologies. PMID:26791721

  6. Mechanisms of Guided Bone Regeneration: A Review

    PubMed Central

    Liu, Jie; Kerns, David G

    2014-01-01

    Post-extraction crestal bone resorption is common and unavoidable which can lead to significant ridge dimensional changes. To regenerate enough bone for successful implant placement, Guided Bone Regeneration (GBR) is often required. GBR is a surgical procedure that uses barrier membranes with or without particulate bone grafts or/and bone substitutes. There are two approaches of GBR in implant therapy: GBR at implant placement (simultaneous approach) and GBR before implant placement to increase the alveolar ridge or improve ridge morphology (staged approach). Angiogenesis and ample blood supply play a critical role in promoting bone regeneration. PMID:24894890

  7. Mechanisms of platelet-mediated liver regeneration.

    PubMed

    Lisman, Ton; Porte, Robert J

    2016-08-01

    Platelets have multiple functions beyond their roles in thrombosis and hemostasis. Platelets support liver regeneration, which is required after partial hepatectomy and acute or chronic liver injury. Although it is widely assumed that platelets stimulate liver regeneration by local excretion of mitogens stored within platelet granules, definitive evidence for this is lacking, and alternative mechanisms deserve consideration. In-depth knowledge of mechanisms of platelet-mediated liver regeneration may lead to new therapeutic strategies to treat patients with failing regenerative responses. PMID:27297793

  8. Theoretical Analysis of a Pulse Tube Regenerator

    NASA Technical Reports Server (NTRS)

    Roach, Pat R.; Kashani, Ali; Lee, J. M.; Cheng, Pearl L. (Technical Monitor)

    1995-01-01

    A theoretical analysis of the behavior of a typical pulse tube regenerator has been carried out. Assuming simple sinusoidal oscillations, the static and oscillatory pressures, velocities and temperatures have been determined for a model that includes a compressible gas and imperfect thermal contact between the gas and the regenerator matrix. For realistic material parameters, the analysis reveals that the pressure and, velocity oscillations are largely independent of details of the thermal contact between the gas and the solid matrix. Only the temperature oscillations depend on this contact. Suggestions for optimizing the design of a regenerator are given.

  9. An assessment template for introductory college biological laboratory manuals

    NASA Astrophysics Data System (ADS)

    Peters, Carolyn J.

    In this study, a template was designed in an effort to resolve an instructional problem defined as the absence of adequate biology laboratory exercises in introductory college biology laboratory manuals for use in the community college setting. The problem for study was a lack of an assessment template to analyze laboratory exercises for optimum delivery of problem resolution. Past templates were analyzed for deficiencies and objectives and research questions were developed. The literature search indicated a need for more problem resolution laboratory exercises in biology. Biology instructors agree that students should engage in laboratory practice in much the same way that scientists do in the real world. They should pose questions, solve problems, investigate phenomena, test hypotheses, reinvestigate if new hypotheses arise during testing, draw conclusions, and understand basic solutions. A new design template was formulated and reviewed by five experienced community college biology instructors in Illinois. Twelve introductory laboratory exercises containing problem resolution tasks were reviewed. These specialists offered suggestions and comments about the use of the template. Several templates had been developed since the 1960s. None of these templates were for individual instructor use and many were developed for secondary texts or laboratory manuals. In this study, the deficiencies of the templates were examined in an effort to design an optimum template for individual instructor use in analyzing laboratory exercises in community college introductory biology classes.

  10. Piled tool will level subsea well template for Heidrun TLP

    SciTech Connect

    Not Available

    1992-01-13

    This paper reports on piled leveling tools that were contracted for use during the installation of the subsea well template for Conoco Norway Inc.'s Heidrun tension leg platform (TLP) in the Norwegian sector of the North Sea. The leveling tools are employed after a template has been positioned on the seafloor and anchor pilings have been driven through the template sleeves. One or more tools are lowered and landed on anchor pilings at the low side of the template. No diver support or guidelines are required.

  11. Light Weight Biomorphous Cellular Ceramics from Cellulose Templates

    NASA Technical Reports Server (NTRS)

    Singh, Mrityunjay; Yee, Bo-Moon; Gray, Hugh R. (Technical Monitor)

    2003-01-01

    Bimorphous ceramics are a new class of materials that can be fabricated from the cellulose templates derived from natural biopolymers. These biopolymers are abundantly available in nature and are produced by the photosynthesis process. The wood cellulose derived carbon templates have three- dimensional interconnectivity. A wide variety of non-oxide and oxide based ceramics have been fabricated by template conversion using infiltration and reaction-based processes. The cellular anatomy of the cellulose templates plays a key role in determining the processing parameters (pyrolysis, infiltration conditions, etc.) and resulting ceramic materials. The processing approach, microstructure, and mechanical properties of the biomorphous cellular ceramics (silicon carbide and oxide based) have been discussed.

  12. Microporous silica prepared by organic templating: Relationship between the molecular template and pore structure

    SciTech Connect

    Lu, Y.; Brinker, C.J. |; Cao, G.; Kale, R.P.; Prabakar, S.; Lopez, G.P.

    1999-05-01

    Microporous silica materials with a controlled pore size and a narrow pore size distribution have been prepared by sol-gel processing using an organic-templating approach. Microporous networks were formed by pyrolytic removal of organic ligands (methacryloxypropyl groups) from organic/inorganic hybrid materials synthesized by copolymerization of 3-methacryloxypropylsilane (MPS) and tetraethoxysilane (TEOS). Molecular simulations and experimental measurements were conducted to examine the relationship between the microstructural characteristics of the porous silica (e.g., pore size, total pore volume, and pore connectivity) and the size and amount of organic template ligands added. Adsorption measurements suggest that the final porosity of the microporous silica is due to both primary pores (those present in the hybrid material prior to pyrolysis) and secondary pores (those created by pyrolytic removal of organic templates). Primary pores were inaccessible to N{sub 2} at 77 K but accessible to CO{sub 2} at 195 K; secondary pores were accessible to both N{sub 2} (at 77 K) and CO{sub 2} (at 195 K) in adsorption measurements. Primary porosity decreases with the amount of organic ligands added because of the enhanced densification of MPS/TEOS hybrid materials as the mole fraction of trifunctional MPS moieties increases. Pore volumes measured by nitrogen adsorption experiments at 77 K suggest that the secondary (template-derived) porosity exhibits a percolation behavior as the template concentration is increased. Gas permeation experiments indicate that the secondary pores are approximately 5 {angstrom} in diameter, consistent with predictions based on molecular simulations.

  13. Physical and Morphological Characterization of Templated Thermosets

    NASA Astrophysics Data System (ADS)

    Hermel-Davidock, Theresa J.

    2005-03-01

    It has been found that by the addition of low concentrations of an amphiphilic block copolymer to an epoxy resin, novel disordered morphologies can be formed and preserved through cure. It has also been found that the addition of small amounts of block copolymer can improve the fracture resistance significantly without sacrificing the high modulus and glass transition temperature of these thermoset materials. This report will focus on characterizing the influence of the block copolymer and casting solvent on the morphology achieved in the thermoset sample and the resulting physical properties. Templated thermoset samples exhibiting two different diblock copolymer morphologies, worm-like micelles and spherical micelles were investigated. The micro-deformation mechanisms of these templated thermosets were studied via an in-situ tensile deformation technique performed in a transmission electron microscope (TEM). The micro-deformation behaviors of these samples were found to correlate well with the macroscopic mechanical properties. The toughening effect obtained in the epoxy resin was attributed to the well-dispersed worm-like morphology and the weak interfacial adhesion between the micelles and the matrix.

  14. Kinetic theory of amyloid fibril templating

    NASA Astrophysics Data System (ADS)

    Schmit, Jeremy D.

    2013-05-01

    The growth of amyloid fibrils requires a disordered or partially unfolded protein to bind to the fibril and adapt the same conformation and alignment established by the fibril template. Since the H-bonds stabilizing the fibril are interchangeable, it is inevitable that H-bonds form between incorrect pairs of amino acids which are either incorporated into the fibril as defects or must be broken before the correct alignment can be found. This process is modeled by mapping the formation and breakage of H-bonds to a one-dimensional random walk. The resulting microscopic model of fibril growth is governed by two timescales: the diffusion time of the monomeric proteins, and the time required for incorrectly bound proteins to unbind from the fibril. The theory predicts that the Arrhenius behavior observed in experiments is due to off-pathway states rather than an on-pathway transition state. The predicted growth rates are in qualitative agreement with experiments on insulin fibril growth rates as a function of protein concentration, denaturant concentration, and temperature. These results suggest a templating mechanism where steric clashes due to a single mis-aligned molecule prevent the binding of additional molecules.

  15. Composite Matrix Regenerator for Stirling Engines

    NASA Technical Reports Server (NTRS)

    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.

  16. How-To-Do-It: Plant Regeneration.

    ERIC Educational Resources Information Center

    Pietraface, William J.

    1988-01-01

    Describes a procedure for the growth of tobacco plants in flasks. Demonstrates plant tissue culture manipulation, totipotency, and plant regeneration in approximately 12 weeks. Discusses methods, materials, and expected results. (CW)

  17. Organic solvent regeneration of granular activated carbon

    NASA Astrophysics Data System (ADS)

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

    1982-09-01

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

  18. De Novo Kidney Regeneration with Stem Cells

    PubMed Central

    Yokote, Shinya; Yamanaka, Shuichiro; Yokoo, Takashi

    2012-01-01

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

  19. Adult stem cells underlying lung regeneration

    PubMed Central

    2012-01-01

    Despite the massive toll in human suffering imparted by degenerative lung disease, including COPD, idiopathic pulmonary fibrosis and ARDS, the scientific community has been surprisingly agnostic regarding the potential of lung tissue and, in particular, the alveoli, to regenerate. However, there is circumstantial evidence in humans and direct evidence in mice that ARDS triggers robust regeneration of lung tissue rather than irreversible fibrosis. The stem cells responsible for this remarkable regenerative process has garnered tremendous attention, most recently yielding a defined set of cloned human airway stem cells marked by p63 expression but with distinct commitment to differentiated cell types typical of the upper or lower airways, the latter of which include alveoli-like structures in vitro and in vivo. These recent advances in lung regeneration and distal airway stem cells and the potential of associated soluble factors in regeneration must be harnessed for therapeutic options in chronic lung disease. PMID:22333577

  20. Degeneration and regeneration of ganglion cell axons.

    PubMed

    Weise, J; Ankerhold, R; Bähr, M

    2000-01-15

    The retino-tectal system has been used to study developmental aspects of axon growth, synapse formation and the establishment of a precise topographic order as well as degeneration and regeneration of adult retinal ganglion cell (RGC) axons after axonal lesion. This paper reviews some novel findings that provide new insights into the mechanisms of developmental RGC axon growth, pathfinding, and target formation. It also focuses on the cellular and molecular cascades that underlie RGC degeneration following an axonal lesion and on some therapeutic strategies to enhance survival of axotomized RGCs in vivo. In addition, this review deals with problems related to the induction of regeneration after axonal lesion in the adult CNS using the retino-tectal system as model. Different therapeutic approaches to promote RGC regeneration and requirements for specific target formation of regenerating RGCs in vitro and in vivo are discussed. PMID:10649506

  1. Homeobox genes expressed during echinoderm arm regeneration.

    PubMed

    Ben Khadra, Yousra; Said, Khaled; Thorndyke, Michael; Martinez, Pedro

    2014-04-01

    Regeneration in echinoderms has proved to be more amenable to study in the laboratory than the more classical vertebrate models, since the smaller genome size and the absence of multiple orthologs for different genes in echinoderms simplify the analysis of gene function during regeneration. In order to understand the role of homeobox-containing genes during arm regeneration in echinoderms, we isolated the complement of genes belonging to the Hox class that are expressed during this process in two major echinoderm groups: asteroids (Echinaster sepositus and Asterias rubens) and ophiuroids (Amphiura filiformis), both of which show an extraordinary capacity for regeneration. By exploiting the sequence conservation of the homeobox, putative orthologs of several Hox genes belonging to the anterior, medial, and posterior groups were isolated. We also report the isolation of a few Hox-like genes expressed in the same systems. PMID:24309817

  2. Regenerable hydrogen storage in lithium amidoborane.

    PubMed

    Tang, Ziwei; Tan, Yingbin; Chen, Xiaowei; Yu, Xuebin

    2012-09-25

    Regenerable hydrogen storage of lithium amidoborane is firstly achieved through the routes of direct thermal dehydrogenation and subsequent chemical hydrogenation of its dehydrogenated products by treatment with hydrazine in liquid ammonia. PMID:22875287

  3. Hyperbaric Oxygen Promotes Proximal Bone Regeneration and Organized Collagen Composition during Digit Regeneration

    PubMed Central

    Sammarco, Mimi C.; Simkin, Jennifer; Cammack, Alexander J.; Fassler, Danielle; Gossmann, Alexej; Marrero, Luis; Lacey, Michelle; Van Meter, Keith; Muneoka, Ken

    2015-01-01

    Oxygen is critical for optimal bone regeneration. While axolotls and salamanders have retained the ability to regenerate whole limbs, mammalian regeneration is restricted to the distal tip of the digit (P3) in mice, primates, and humans. Our previous study revealed the oxygen microenvironment during regeneration is dynamic and temporally influential in building and degrading bone. Given that regeneration is dependent on a dynamic and changing oxygen environment, a better understanding of the effects of oxygen during wounding, scarring, and regeneration, and better ways to artificially generate both hypoxic and oxygen replete microenvironments are essential to promote regeneration beyond wounding or scarring. To explore the influence of increased oxygen on digit regeneration in vivo daily treatments of hyperbaric oxygen were administered to mice during all phases of the entire regenerative process. Micro-Computed Tomography (μCT) and histological analysis showed that the daily application of hyperbaric oxygen elicited the same enhanced bone degradation response as two individual pulses of oxygen applied during the blastema phase. We expand past these findings to show histologically that the continuous application of hyperbaric oxygen during digit regeneration results in delayed blastema formation at a much more proximal location after amputation, and the deposition of better organized collagen fibers during bone formation. The application of sustained hyperbaric oxygen also delays wound closure and enhances bone degradation after digit amputation. Thus, hyperbaric oxygen shows the potential for positive influential control on the various phases of an epimorphic regenerative response. PMID:26452224

  4. Liver Regeneration Is an Angiogenesis- Associated Phenomenon

    PubMed Central

    Drixler, Tom A.; Vogten, Mathys J.; Ritchie, Ewan D.; van Vroonhoven, Theo J. M. V.; Gebbink, Martijn F. B. G.; Voest, Emile E.; Borel Rinkes, Inne H. M.

    2002-01-01

    Objective To investigate whether liver regeneration is an angiogenesis-associated phenomenon. Summary Background Data Angiogenesis is predominantly known for its pivotal role in tumor growth. However, angiogenesis could also play a role in physiologic processes involving tissue repair, such as liver regeneration. Methods Mice subjected to 70% partial hepatectomy were treated with human angiostatin (100 mg/kg body weight). Regeneration-induced hepatic angiogenesis was determined by assessing intrahepatic microvascular density using CD31 staining of frozen liver sections. Liver regeneration was evaluated by assessing wet liver weights and BrdU incorporation in DNA at regular intervals after partial hepatectomy. Possible direct effects of angiostatin on hepatocytes were studied by assessment of liver enzymes (ASAT, ALAT, bilirubin, lactate dehydrogenase), MTT assay (cytotoxicity), aminophenol production (metabolic function), and TUNEL (apoptosis). Results In a regenerating liver, microvascular density increased by 38%. Angiostatin significantly inhibited this response by 60%. In addition, angiostatin inhibited liver regeneration by 50.4% and 24.9% on postoperative days 7 and 14, respectively. In control mice liver weights regained normalcy in 8 days, whereas those in angiostatin-treated mice normalized after 21 days. In angiostatin-treated mice, the maximal BrdU incorporation was decreased and delayed. Direct adverse effects of angiostatin on cultured and in vivo hepatocytes were not observed. Angiostatin neither induced necrosis on hematoxylin and eosin staining nor affected serum levels of liver enzymes. Conclusions Liver regeneration is accompanied by intrahepatic angiogenesis. Antiangiogenic treatment using angiostatin inhibits both phenomena. The authors conclude that liver regeneration is, at least in part, an angiogenesis-dependent phenomenon. PMID:12454508

  5. Straight-Pore Microfilter with Efficient Regeneration

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  6. Continuous microwave regeneration apparatus for absorption media

    SciTech Connect

    Smith, D.D.

    1999-09-07

    A method and apparatus are disclosed for continuously drying and regenerating ceramic beads for use in process gas moisture drying operations such as glove boxes. A microwave energy source is coupled to a process chamber to internally heat the ceramic beads and vaporize moisture contained therein. In a preferred embodiment, the moisture laden ceramic beads are conveyed toward the microwave source by a screw mechanism. The regenerated beads flow down outside of the screw mechanism and are available to absorb additional moisture.

  7. Regenerable activated bauxite adsorbent alkali monitor probe

    DOEpatents

    Lee, Sheldon H. D.

    1992-01-01

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

  8. Cell healing: Calcium, repair and regeneration.

    PubMed

    Moe, Alison M; Golding, Adriana E; Bement, William M

    2015-09-01

    Cell repair is attracting increasing attention due to its conservation, its importance to health, and its utility as a model for cell signaling and cell polarization. However, some of the most fundamental questions concerning cell repair have yet to be answered. Here we consider three such questions: (1) How are wound holes stopped? (2) How is cell regeneration achieved after wounding? (3) How is calcium inrush linked to wound stoppage and cell regeneration? PMID:26514621

  9. General Electric hot gas cleanup and regeneration

    SciTech Connect

    Gal, E.; Furman, A.H.; Ayala, R.

    1993-06-01

    GE Environmental Services, Inc. (GEESI) and its major subcontractors GE Corporate Research and Development (GE-CRD) and GE Power Generation (GEPG) have completed significant further pilot plant scale test operation of an integrated fixed bed gasification, hot gas cleanup and gas turbine simulation facility located at GE-CRD in Schenectady, NY. Progress during the past year has included first desulfurization and regeneration testing with zinc titanate, significant regeneration hardware and process modifications, continued test exposure of a full scale gas turbine fuel control valve, first long term integrated operation of the MS6000 based gas turbine simulator and off-line operation of a subscale, staged combustor system designed to minimize NO{sub x} production from fuel bound nitrogen. Long Duration Tests 3, 3AR1, 3AR2 and 3A were conducted with zinc titanate sorbent and demonstrated the continued ability of the absorber to reduce inlet H{sub 2}S levels of 3500 ppmv to less than 30 ppmv provided properly regenerated sorbent was returned to the absorber. Tests 3AR1 and 3AR2 were limited duration, off line regeneration tests, utilizing residual sulfided material from Test 3, to evaluate continuing regeneration hardware, instrumentation and process modification. Test 3A was a fully integrated 100 hour test incorporating final regenerator modifications and resulted in first fully controlled regeneration. Anthracite coal was utilized for Test 3A as a means of partial elimination of halogens in the fuel gas prior to inclusion of a specific halogen removal process step envisioned for Long Duration Test 4. Further test operation will revert to use of Illinois bituminous coal with up to 3.4 percent sulfur and 0.1 to 0.28 percent chloride content in order to fully evaluate high sulfur regeneration operation as well as halogen removal.

  10. Cascaded phase-preserving multilevel amplitude regeneration.

    PubMed

    Roethlingshoefer, Tobias; Onishchukov, Georgy; Schmauss, Bernhard; Leuchs, Gerd

    2014-12-29

    The performance of cascaded in-line phase-preserving amplitude regeneration using nonlinear amplifying loop mirrors has been studied in numerical simulations. As an example of a spectrally efficient modulation format with two amplitude states and multiple phase states, the regeneration performance of a star-16QAM format, basically an 8PSK format with two amplitude levels, was evaluated. An increased robustness against amplified spontaneous emission and nonlinear phase noise was observed resulting in a significantly increased transmission distance. PMID:25607142

  11. Cofactor regeneration at the lab scale.

    PubMed

    Wichmann, R; Vasic-Racki, D

    2005-01-01

    Progress made in lab-scale applications of various coenzyme regeneration systems over the last two decades has mainly focused on the applications of NAD+/NADH- and NADP+/NADPH-dependent oxidoreductase reactions. In situ regeneration systems for these reactions, as well as whole cell, enzymatic, electro-enzymatic, chemical, and photochemical reactions are presented, including details about their efficiency and novelty. The progress of enzyme reaction engineering is also reported. PMID:15791939

  12. Continuous microwave regeneration apparatus for absorption media

    DOEpatents

    Smith, Douglas D.

    1999-01-01

    A method and apparatus for continuously drying and regenerating ceramic beads for use in process gas moisture drying operations such as glove boxes. A microwave energy source is coupled to a process chamber to internally heat the ceramic beads and vaporize moisture contained therein. In a preferred embodiment, the moisture laden ceramic beads are conveyed toward the microwave source by a screw mechanism. The regenerated beads flow down outside of the screw mechanism and are available to absorb additional moisture.

  13. Regenerable activated bauxite adsorbent alkali monitor probe

    DOEpatents

    Lee, S.H.D.

    1992-12-22

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

  14. Meniscal regeneration with copolymeric collagen scaffolds. In vitro and in vivo studies evaluated clinically, histologically, and biochemically.

    PubMed

    Stone, K R; Rodkey, W G; Webber, R; McKinney, L; Steadman, J R

    1992-01-01

    We sought to create a regeneration template for the meniscal cartilage of the knee to induce complete meniscal regeneration, and to develop the technique for implanting the prosthetic appliance in vivo. We designed a resorbable collagen-based scaffold and conducted in vitro and in vivo studies. In vivo, the scaffold was implanted in the knees of immature swine and mature canines and evaluated clinically, histologically, and biochemically. Because the canine stifle joint meniscus is more clinically relevant to the human meniscus, this paper emphasizes those results. We studied 24 mixed breed dogs (14 males and 10 females) with an average weight of 25.5 kg (range, 20 to 35) that were obtained from a USDA-licensed supplier. The dogs were deemed clinically and radiographically skeletally mature. None of the dogs had a preexisting knee joint abnormality. All dogs underwent an 80% subtotal resection of the medial meniscus bilaterally. A collagen template was implanted in one stifle (N = 24). The contralateral side served as a control: 12 dogs had a total resection alone and the other 12 dogs had an immediate replantation of the autologous meniscus. Results were tabulated at 3, 6, 9, and 12 months. At final evaluation, before the animals were euthanized, the results were submitted for statistical analysis as well as histologic and biochemical analyses. The results demonstrated that a copolymeric collagen-based scaffold can be constructed that is compatible with meniscal fibrochondrocyte growth in vitro and in vivo, that does not inhibit meniscal regeneration in an immature pig, and that may induce regeneration of the meniscus in the mature dog.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1558234

  15. Solid electrolyte oxygen regeneration system

    NASA Technical Reports Server (NTRS)

    Shumar, J. W.; See, G. G.; Schubert, F. H.; Powell, J. D.

    1976-01-01

    A program to design, develop, fabricate and assemble a one-man, self-contained, solid electrolyte oxygen regeneration system (SX-1) incorporating solid electrolyte electrolyzer drums was completed. The SX-1 is a preprototype engineering model designed to produce 0.952 kg (2.1 lb)/day of breathable oxygen (O2) from the electrolysis of metabolic carbon dioxide (CO2) and water vapor. The CO2 supply rate was established based on the metabolic CO2 generation rate for one man of 0.998 kg (2.2 lb)/day. The water supply rate (0.254 kg (0.56 lb)/day) was designed to be sufficient to make up the difference between the 0.952 kg (2.1 lb)/day O2 generation specification and the O2 available through CO2 electrolysis, 0.726 kg (1.6 lb)/day. The SX-1 was successfully designed, fabricated and assembled. Design verification tests (DVT) or the CO Disproportionators, H2 separators, control instrumentation, monitor instrumentation, water feed mechanism were successfully completed. The erratic occurrence of electrolyzer drum leakage prevented the completion of the CO2 electrolyzer module and water electrolyzer module DVT's and also prevented the performance of SX-1 integrated testing. Further development work is required to improve the solid electrolyte cell high temperature seals.

  16. Tissue Regeneration: A Silk Road.

    PubMed

    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

  17. Scaffold Design for Bone Regeneration

    PubMed Central

    Polo-Corrales, Liliana; Latorre-Esteves, Magda; Ramirez-Vick, Jaime E.

    2014-01-01

    The use of bone grafts is the standard to treat skeletal fractures, or to replace and regenerate lost bone, as demonstrated by the large number of bone graft procedures performed worldwide. The most common of these is the autograft, however, its use can lead to complications such as pain, infection, scarring, blood loss, and donor-site morbidity. The alternative is allografts, but they lack the osteoactive capacity of autografts and carry the risk of carrying infectious agents or immune rejection. Other approaches, such as the bone graft substitutes, have focused on improving the efficacy of bone grafts or other scaffolds by incorporating bone progenitor cells and growth factors to stimulate cells. An ideal bone graft or scaffold should be made of biomaterials that imitate the structure and properties of natural bone ECM, include osteoprogenitor cells and provide all the necessary environmental cues found in natural bone. However, creating living tissue constructs that are structurally, functionally and mechanically comparable to the natural bone has been a challenge so far. This focus of this review is on the evolution of these scaffolds as bone graft substitutes in the process of recreating the bone tissue microenvironment, including biochemical and biophysical cues. PMID:24730250

  18. Engineered matrices for bone regeneration

    NASA Astrophysics Data System (ADS)

    Winn, Shelley R.; Hu, Yunhua; Pugh, Amy; Brown, Leanna; Nguyen, Jesse T.; Hollinger, Jeffrey O.

    2000-06-01

    Traditional therapies of autografts and allogeneic banked bone can promote reasonable clinical outcome to repair damaged bone. However, under certain conditions the success of these traditional approaches plummets, providing the incentive for researchers to develop clinical alternatives. The evolving field of tissue engineering in the musculoskeletal system attempts to mimic many of the components from the intact, healthy subject. Those components consist of a biologic scaffold, cells, extracellular matrix, and signaling molecules. The bone biomimetic, i.e., an engineered matrix, provides a porous structural architecture for the regeneration and ingrowth of osseous tissue at the site of injury. To further enhance the regenerative cascade, our strategy has involved porous biodegradable scaffolds containing and releasing signaling molecules and providing a suitable environment for cell attachment, growth and differentiation. In addition, the inclusion of genetically modified osteogenic precursor cells has brought the technology closer to developing a tissue-engineered equivalent. The presentation will describe various formulations and the methods utilized to evaluate the clinical utility of these biomimetics.

  19. MHD seed recovery/regeneration

    NASA Astrophysics Data System (ADS)

    Task 1 calls for the design, procurement, construction, and installation of the Seed Regeneration Proof-of-Concept Facility (SRPF) that will produce tonnage quantities of recyclable potassium formate seed at a design rate of 250 lb/hr for testing in the channel at the CDIF while collecting data that will be used to upgrade the design of a 300 MW(sub t) system. Approximately 12 tons of KCOOH (dry basis) as 70-75 wt percent solution were produced. The front end of the plant (potassium sulfate reaction and solids separation/washing units) was operated for five days in March. Most of the operations were conducted at a spent seed feed rate of 250 pounds/hour. A total of 8,500 gallons of dilute KCOOH solution was generated containing approximately 2.6 tons of potassium formate (dry basis). The average KCOOH content of this solution was 7 wt percent. The design KCOOH solution concentration for the front end of the plant is 8.5 wt percent. The evaporation unit was operated for a total of six days during March. Approximately 2.5 tons of potassium formate (dry basis) were processed through the evaporator and concentrated to greater then 7 wt percent.

  20. The art of fin regeneration in zebrafish

    PubMed Central

    Pfefferli, Catherine

    2015-01-01

    Abstract The zebrafish fin provides a valuable model to study the epimorphic type of regeneration, whereby the amputated part of the appendage is nearly perfectly replaced. To accomplish fin regeneration, two reciprocally interacting domains need to be established at the injury site, namely a wound epithelium and a blastema. The wound epithelium provides a supporting niche for the blastema, which contains mesenchyme‐derived progenitor cells for the regenerate. The fate of blastemal daughter cells depends on their relative position with respect to the fin margin. The apical compartment of the outgrowth maintains its undifferentiated character, whereas the proximal descendants of the blastema progressively switch from the proliferation program to the morphogenesis program. A delicate balance between self‐renewal and differentiation has to be continuously adjusted during the course of regeneration. This review summarizes the current knowledge about the cellular and molecular mechanisms of blastema formation, and discusses several studies related to the regulation of growth and morphogenesis during fin regeneration. A wide range of canonical signaling pathways has been implicated during the establishment and maintenance of the blastema. Epigenetic mechanisms play a crucial role in the regulation of cellular plasticity during the transition between differentiation states. Ion fluxes, gap‐junctional communication and protein phosphatase activity have been shown to coordinate proliferation and tissue patterning in the caudal fin. The identification of the downstream targets of the fin regeneration signals and the discovery of mechanisms integrating the variety of input pathways represent exciting future aims in this fascinating field of research. PMID:27499869

  1. Silymarin Accelerates Liver Regeneration after Partial Hepatectomy

    PubMed Central

    Wu, Jia-Ping; Tsai, Chin-Chuan; Yeh, Yu-Lan; Lin, Yueh-Min; Lin, Chien-Chung; Day, Cecilia Hsuan; Shen, Chia-Yao; Padma, V. Vijaya; Pan, Lung-Fa; Huang, Chih-Yang

    2015-01-01

    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. PMID:26339266

  2. Hedgehog Signaling during Appendage Development and Regeneration

    PubMed Central

    Singh, Bhairab N.; Koyano-Nakagawa, Naoko; Donaldson, Andrew; Weaver, Cyprian V.; Garry, Mary G.; Garry, Daniel J.

    2015-01-01

    Regulatory networks that govern embryonic development have been well defined. While a common hypothesis supports the notion that the embryonic regulatory cascades are reexpressed following injury and tissue regeneration, the mechanistic regulatory pathways that mediate the regenerative response in higher organisms remain undefined. Relative to mammals, lower vertebrates, including zebrafish and newts, have a tremendous regenerative capacity to repair and regenerate a number of organs including: appendages, retina, heart, jaw and nervous system. Elucidation of the pathways that govern regeneration in these lower organisms may provide cues that will enhance the capacity for the regeneration of mammalian organs. Signaling pathways, such as the hedgehog pathway, have been shown to play critical functions during development and during regeneration in lower organisms. These signaling pathways have been shown to modulate multiple processes including cellular origin, positional identity and cellular maturation. The present review will focus on the cellular and molecular regulation of the hedgehog (HH) signaling pathway and its interaction with other signaling factors during appendage development and regeneration. PMID:26110318

  3. Cell-based strategies for vascular regeneration.

    PubMed

    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

  4. Hedgehog Signaling during Appendage Development and Regeneration.

    PubMed

    Singh, Bhairab N; Koyano-Nakagawa, Naoko; Donaldson, Andrew; Weaver, Cyprian V; Garry, Mary G; Garry, Daniel J

    2015-01-01

    Regulatory networks that govern embryonic development have been well defined. While a common hypothesis supports the notion that the embryonic regulatory cascades are reexpressed following injury and tissue regeneration, the mechanistic regulatory pathways that mediate the regenerative response in higher organisms remain undefined. Relative to mammals, lower vertebrates, including zebrafish and newts, have a tremendous regenerative capacity to repair and regenerate a number of organs including: appendages, retina, heart, jaw and nervous system. Elucidation of the pathways that govern regeneration in these lower organisms may provide cues that will enhance the capacity for the regeneration of mammalian organs. Signaling pathways, such as the hedgehog pathway, have been shown to play critical functions during development and during regeneration in lower organisms. These signaling pathways have been shown to modulate multiple processes including cellular origin, positional identity and cellular maturation. The present review will focus on the cellular and molecular regulation of the hedgehog (HH) signaling pathway and its interaction with other signaling factors during appendage development and regeneration. PMID:26110318

  5. Image Hashes as Templates for Verification

    SciTech Connect

    Janik, Tadeusz; Jarman, Kenneth D.; Robinson, Sean M.; Seifert, Allen; McDonald, Benjamin S.; White, Timothy A.

    2012-07-17

    Imaging systems can provide measurements that confidently assess characteristics of nuclear weapons and dismantled weapon components, and such assessment will be needed in future verification for arms control. Yet imaging is often viewed as too intrusive, raising concern about the ability to protect sensitive information. In particular, the prospect of using image-based templates for verifying the presence or absence of a warhead, or of the declared configuration of fissile material in storage, may be rejected out-of-hand as being too vulnerable to violation of information barrier (IB) principles. Development of a rigorous approach for generating and comparing reduced-information templates from images, and assessing the security, sensitivity, and robustness of verification using such templates, are needed to address these concerns. We discuss our efforts to develop such a rigorous approach based on a combination of image-feature extraction and encryption-utilizing hash functions to confirm proffered declarations, providing strong classified data security while maintaining high confidence for verification. The proposed work is focused on developing secure, robust, tamper-sensitive and automatic techniques that may enable the comparison of non-sensitive hashed image data outside an IB. It is rooted in research on so-called perceptual hash functions for image comparison, at the interface of signal/image processing, pattern recognition, cryptography, and information theory. Such perceptual or robust image hashing—which, strictly speaking, is not truly cryptographic hashing—has extensive application in content authentication and information retrieval, database search, and security assurance. Applying and extending the principles of perceptual hashing to imaging for arms control, we propose techniques that are sensitive to altering, forging and tampering of the imaged object yet robust and tolerant to content-preserving image distortions and noise. Ensuring that the

  6. Bio-templated bioactive glass particles with hierarchical macro-nano porous structure and drug delivery capability.

    PubMed

    Zheng, Kai; Bortuzzo, Judith A; Liu, Yufang; Li, Wei; Pischetsrieder, Monika; Roether, Judith; Lu, Miao; Boccaccini, Aldo R

    2015-11-01

    Hierarchically porous bioactive glass particles (BGPs) were synthesized by a facile sol-gel process using pollen grains as the templates. The synthesized pollen-templated bioactive glass particles (PBGPs) exhibited dual macro-nano porous structure. The macro pores (∼ 1 μm) were inherited from the template of pollen grains while the nano pores (∼ 9.5 nm) were induced by the intrinsic mechanism of the sol-gel process. PBGPs possessed a high specific surface area (111.4m(2)/g) and pore volume (0.35 cm(3)/g). Hydroxyapatite (HA) formation on PBGPs was detected within 3 days after immersion in simulated body fluid (SBF). Due to their larger specific surface area and pore volume, PBGPs could be loaded with more tetracycline hydrochloride (TCH) than non-templated BGPs and conventional melt-derived 45S5 BGPs. In addition, PBGPs exhibited a low initial burst release (within 10% of the loaded amount) within 18 h and a sustained release with a two-stage release pattern for up to 6 days in phosphate buffered saline (PBS). The antibacterial assay confirmed that the TCH-loaded PBGPs could release TCH within 5 days, and the released TCH could reach the minimum inhibitory concentration (MIC) against Escherichia coli. MTT assay indicated that PBGPs showed non-cytotoxic effects toward human hepatocellular carcinoma (Hep G2) cells after co-culture for up to 72 h in vitro. These results showed that the biocompatible hierarchically macro-nano porous PBGPs are potential for bone regeneration and local drug delivery applications. PMID:25858191

  7. Templated repair of long bone defects in rats with bioactive spiral-wrapped electrospun amphiphilic polymer/hydroxyapatite scaffolds.

    PubMed

    Kutikov, Artem B; Skelly, Jordan D; Ayers, David C; Song, Jie

    2015-03-01

    Effective repair of critical-size long bone defects presents a significant clinical challenge. Electrospun scaffolds can be exploited to deliver protein therapeutics and progenitor cells, but their standalone application for long bone repair has not been explored. We have previously shown that electrospun composites of amphiphilic poly(d,l-lactic acid)-co-poly(ethylene glycol)-co-poly(d,l-lactic acid) (PELA) and hydroxyapatite (HA) guide the osteogenic differentiation of bone marrow stromal cells (MSCs), making these scaffolds uniquely suited for evaluating cell-based bone regeneration approaches. Here we examine whether the in vitro bioactivity of these electrospun scaffolds can be exploited for long bone defect repair, either through the participation of exogenous MSCs or through the activation of endogenous cells by a low dose of recombinant human bone morphogenetic protein-2 (rhBMP-2). In critical-size rat femoral segmental defects, spiral-wrapped electrospun HA-PELA with preseeded MSCs resulted in laminated endochondral ossification templated by the scaffold across the longitudinal span of the defect. Using GFP labeling, we confirmed that the exogenous MSCs adhered to HA-PELA survived at least 7 days postimplantation, suggesting direct participation of these exogenous cells in templated bone formation. When loaded with 500 ng of rhBMP-2, HA-PELA spirals led to more robust but less clearly templated bone formation than MSC-bearing scaffolds. Both treatment groups resulted in new bone bridging over the majority of the defect by 12 weeks. This study is the first demonstration of a standalone bioactive electrospun scaffold for templated bone formation in critical-size long bone defects. PMID:25695310

  8. Transdisciplinary Pedagogical Templates and Their Potential for Adaptive Reuse

    ERIC Educational Resources Information Center

    Dobozy, Eva; Dalziel, James

    2016-01-01

    This article explores the use and usefulness of carefully designed transdisciplinary pedagogical templates (TPTs) aligned to different learning theories. The TPTs are based on the Learning Design Framework outlined in the Larnaca Declaration (Dalziel et al. in this collection). The generation of pedagogical plans or templates is not new. However,…

  9. The Applicability of Interactive Item Templates in Varied Knowledge Types

    ERIC Educational Resources Information Center

    Koong, Chorng-Shiuh; Wu, Chi-Ying

    2011-01-01

    A well-edited assessment can enhance student's learning motives. Applicability of items, which includes item content and template, plays a crucial role in authoring a good assessment. Templates in discussion contain not only conventional true & false, multiple choice, completion item and short answer but also of those interactive ones. Methods…

  10. 48 CFR 302.7100 - HHS standard templates and formats.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false HHS standard templates and formats. 302.7100 Section 302.7100 Federal Acquisition Regulations System HEALTH AND HUMAN SERVICES GENERAL DEFINITIONS OF WORDS AND TERMS HHS Standard Templates and Formats 302.7100 HHS standard...

  11. 48 CFR 302.7100 - HHS standard templates and formats.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 4 2012-10-01 2012-10-01 false HHS standard templates and formats. 302.7100 Section 302.7100 Federal Acquisition Regulations System HEALTH AND HUMAN SERVICES GENERAL DEFINITIONS OF WORDS AND TERMS HHS Standard Templates and Formats 302.7100 HHS standard...

  12. Template-based syntheses for shape controlled nanostructures.

    PubMed

    Pérez-Page, María; Yu, Erick; Li, Jun; Rahman, Masoud; Dryden, Daniel M; Vidu, Ruxandra; Stroeve, Pieter

    2016-08-01

    A variety of nanostructured materials are produced through template-based synthesis methods, including zero-dimensional, one-dimensional, and two-dimensional structures. These span different forms such as nanoparticles, nanowires, nanotubes, nanoflakes, and nanosheets. Many physical characteristics of these materials such as the shape and size can be finely controlled through template selection and as a result, their properties as well. Reviewed here are several examples of these nanomaterials, with emphasis specifically on the templates and synthesis routes used to produce the final nanostructures. In the first section, the templates have been discussed while in the second section, their corresponding synthesis methods have been briefly reviewed, and lastly in the third section, applications of the materials themselves are highlighted. Some examples of the templates frequently encountered are organic structure directing agents, surfactants, polymers, carbon frameworks, colloidal sol-gels, inorganic frameworks, and nanoporous membranes. Synthesis methods that adopt these templates include emulsion-based routes and template-filling approaches, such as self-assembly, electrodeposition, electroless deposition, vapor deposition, and other methods including layer-by-layer and lithography. Template-based synthesized nanomaterials are frequently encountered in select fields such as solar energy, thermoelectric materials, catalysis, biomedical applications, and magnetowetting of surfaces. PMID:27154387

  13. Graphene Emerges as a Versatile Template for Materials Preparation.

    PubMed

    Li, Zhengjie; Wu, Sida; Lv, Wei; Shao, Jiao-Jing; Kang, Feiyu; Yang, Quan-Hong

    2016-05-01

    Graphene and its derivatives are emerging as a class of novel but versatile templates for the controlled preparation and functionalization of materials. In this paper a conceptual review on graphene-based templates is given, highlighting their versatile roles in materials preparation. Graphene is capable of acting as a low-dimensional hard template, where its two-dimensional morphology directs the formation of novel nanostructures. Graphene oxide and other functionalized graphenes are amphiphilic and may be seen as soft templates for formatting the growth or inducing the controlled assembly of nanostructures. In addition, nanospaces in restacked graphene can be used for confining the growth of sheet-like nanostructures, and assemblies of interlinked graphenes can behave either as skeletons for the formation of composite materials or as sacrificial templates for novel materials with a controlled network structure. In summary, flexible graphene and its derivatives together with an increasing number of assembled structures show great potentials as templates for materials production. Many challenges remain, for example precise structural control of such novel templates and the removal of the non-functional remaining templates. PMID:27059262

  14. DEXTRON TEMPLATED MICROWAVE-ASSISTED SYNTHESIS OF POROUS TITANIUM DIOXIDE

    EPA Science Inventory

    An alternative route to the preparation and formation of porous titania powders and carbon coated titania using microwave radiation is described. Inexpensive dextrose was chosen as capping agent or template in view of its high water solubility when compared to other sugar templat...

  15. Component design bases - A template approach

    SciTech Connect

    Pabst, L.F. ); Strickland, K.M. )

    1991-01-01

    A well-documented nuclear plant design basis can enhance plant safety and availability. Older plants, however, often lack historical evidence of the original design intent, particularly for individual components. Most plant documentation describes the actual design (what is) rather than the bounding limits of the design. Without knowledge of these design limits, information from system descriptions and equipment specifications is often interpreted as inviolate design requirements. Such interpretations may lead to unnecessary design conservatism in plant modifications and unnecessary restrictions on plant operation. In 1986, Florida Power and Light Company's (FP and L's) Turkey Point plant embarked on one of the first design basis reconstitution programs in the United States to catalog the true design requirements. As the program developed, design basis users expressed a need for additional information at the component level. This paper outlines a structured (template) approach to develop useful component design basis information (including the WHYs behind the design).

  16. Time Series Analysis Using Geometric Template Matching.

    PubMed

    Frank, Jordan; Mannor, Shie; Pineau, Joelle; Precup, Doina

    2013-03-01

    We present a novel framework for analyzing univariate time series data. At the heart of the approach is a versatile algorithm for measuring the similarity of two segments of time series called geometric template matching (GeTeM). First, we use GeTeM to compute a similarity measure for clustering and nearest-neighbor classification. Next, we present a semi-supervised learning algorithm that uses the similarity measure with hierarchical clustering in order to improve classification performance when unlabeled training data are available. Finally, we present a boosting framework called TDEBOOST, which uses an ensemble of GeTeM classifiers. TDEBOOST augments the traditional boosting approach with an additional step in which the features used as inputs to the classifier are adapted at each step to improve the training error. We empirically evaluate the proposed approaches on several datasets, such as accelerometer data collected from wearable sensors and ECG data. PMID:22641699

  17. Controlling template erosion with advanced cleaning methods

    NASA Astrophysics Data System (ADS)

    Singh, SherJang; Yu, Zhaoning; Wähler, Tobias; Kurataka, Nobuo; Gauzner, Gene; Wang, Hongying; Yang, Henry; Hsu, Yautzong; Lee, Kim; Kuo, David; Dress, Peter

    2012-03-01

    We studied the erosion and feature stability of fused silica patterns under different template cleaning conditions. The conventional SPM cleaning is compared with an advanced non-acid process. Spectroscopic ellipsometry optical critical dimension (SE-OCD) measurements were used to characterize the changes in pattern profile with good sensitivity. This study confirmed the erosion of the silica patterns in the traditional acid-based SPM cleaning mixture (H2SO4+H2O2) at a rate of ~0.1nm per cleaning cycle. The advanced non-acid clean process however only showed CD shift of ~0.01nm per clean. Contamination removal & pattern integrity of sensitive 20nm features under MegaSonic assisted cleaning is also demonstrated.

  18. Conductive Nanowires Templated by Molecular Brushes.

    PubMed

    Raguzin, Ivan; Stamm, Manfred; Ionov, Leonid

    2015-10-21

    In this paper, we report the fabrication of conductive nanowires using polymer bottle brushes as templates. In our approach, we synthesized poly(2-dimethylamino)ethyl methacrylate methyl iodide quaternary salt brushes by two-step atom transfer radical polymerization, loaded them with palladium salt, and reduced them in order to form metallic nanowires with average lengths and widths of 300 and 20 nm, respectively. The obtained nanowires were deposited between conductive gold pads and were connected to them by sputtering of additional pads to form an electric circuit. We connected the nanowires in an electric circuit and demonstrated that the conductivity of these nanowires is around 100 S·m(-1). PMID:26418290

  19. Formylborane formation with frustrated Lewis pair templates.

    PubMed

    Sajid, Muhammad; Kehr, Gerald; Daniliuc, Constantin G; Erker, Gerhard

    2014-01-20

    Boranes R2 BH react with carbon monoxide by forming the respective borane carbonyl compounds R2 BH(CO). The formation of (C6 F5 )2 BH(CO) derived from the Piers borane, HB(C6 F5 )2 , is a typical example. Subsequent CO-hydroboration does not take place, since the formation of the formylborane is usually endothermic. However, an "η(2) -formylborane" was formed by CO-hydroboration with the Piers borane at vicinal phosphane/borane frustrated Lewis pair (FLP) templates. Subsequent treatment with pyridine liberated the intact formylborane from the FLP framework, and (pyridine)(C6 F5 )2 BCHO was then isolated as a stable compound. This product underwent typical reactions of carbonyl compounds, such as Wittig olefination. PMID:24338931

  20. Using archetypes for defining CDA templates.

    PubMed

    Moner, David; Moreno, Alberto; Maldonado, José A; Robles, Montserrat; Parra, Carlos

    2012-01-01

    While HL7 CDA is a widely adopted standard for the documentation of clinical information, the archetype approach proposed by CEN/ISO 13606 and openEHR is gaining recognition as a means of describing domain models and medical knowledge. This paper describes our efforts in combining both standards. Using archetypes as an alternative for defining CDA templates permit new possibilities all based on the formal nature of archetypes and their ability to merge into the same artifact medical knowledge and technical requirements for semantic interoperability of electronic health records. We describe the process followed for the normalization of existing legacy data in a hospital environment, from the importation of the HL7 CDA model into an archetype editor, the definition of CDA archetypes and the application of those archetypes to obtain normalized CDA data instances. PMID:22874151

  1. Template based low data rate speech encoder

    NASA Astrophysics Data System (ADS)

    Fransen, Lawrence

    1993-09-01

    The 2400-b/s linear predictive coder (LPC) is currently being widely deployed to support tactical voice communication over narrowband channels. However, there is a need for lower-data-rate voice encoders for special applications: improved performance in high bit-error conditions, low-probability-of-intercept (LPI) voice communication, and narrowband integrated voice/data systems. An 800-b/s voice encoding algorithm is presented which is an extension of the 2400-b/s LPC. To construct template tables, speech samples of 420 speakers uttering 8 sentences each were excerpted from the Texas Instrument - Massachusetts Institute of Technology (TIMIT) Acoustic-Phonetic Speech Data Base. Speech intelligibility of the 800-b/s voice encoding algorithm measured by the diagnostic rhyme test (DRT) is 91.5 for three male speakers. This score compares favorably with the 2400-b/s LPC of a few years ago.

  2. Virus Assemblies as Templates for Nanocircuits

    SciTech Connect

    James N Culver; Michael T Harris

    2011-08-31

    The goals of this project were directed at the identification and characterization of bio-mineralization processes and patterning methods for the development of nano scale materials and structures with novel energy and conductive traits. This project utilized a simple plant virus as a model template to investigate methods to attach and coat metals and other inorganic compounds onto biologically based nanotemplates. Accomplishments include: the development of robust biological nanotemplates with enhanced inorganic coating activities; novel coating strategies that allow for the deposition of a continuous inorganic layer onto a bio-nanotemplate even in the absence of a reducing agent; three-dimensional patterning methods for the assemble of nano-featured high aspect ratio surfaces and the demonstrated use of these surfaces in enhancing battery and energy storage applications. Combined results from this project have significantly advanced our understanding and ability to utilize the unique self-assembly properties of biologically based molecules to produce novel materials at the nanoscale level.

  3. A series of template plasmids for Escherichia coli genome engineering.

    PubMed

    Deb, Shalini S; Reshamwala, Shamlan M S; Lali, Arvind M

    2016-06-01

    Metabolic engineering strategies often employ multi-copy episomal vectors to overexpress genes. However, chromosome-based overexpression is preferred as it avoids the use of selective pressure and reduces metabolic burden on the cell. We have constructed a series of template plasmids for λ Red-mediated Escherichia coli genome engineering. The template plasmids allow construction of genome integrating cassettes that can be used to integrate single copies of DNA sequences at predetermined sites or replace promoter regions. The constructed cassettes provide flexibility in terms of expression levels achieved and antibiotics used for selection, as well as allowing construction of marker-free strains. The modular design of the template plasmids allows replacement of genetic parts to construct new templates. Gene integration and promoter replacement using the template plasmids are illustrated. PMID:27071533

  4. Structural Basis of Template Boundary Definition in Tetrahymena Telomerase

    PubMed Central

    Jansson, Linnea I.; Akiyama, Ben M.; Ooms, Alexandra; Lu, Cheng; Rubin, Seth M.; Stone, Michael D.

    2015-01-01

    Telomerase is required to maintain repetitive G-rich telomeric DNA sequences at chromosome ends. To do so, the telomerase reverse transcriptase (TERT) subunit reiteratively uses a small region of the integral telomerase RNA (TER) as a template. An essential feature of telomerase catalysis is the strict definition of the template boundary to determine the precise TER nucleotides to be reverse transcribed by TERT. We report the 3 Å crystal structure of the Tetrahymena TERT RNA binding domain (tTRBD) bound to the template boundary element (TBE) of TER. tTRBD is wedged into the base of the TBE RNA stem-loop and each of the flanking RNA strands wraps around opposite sides of the protein domain. The structure illustrates how the tTRBD establishes the template boundary by positioning the TBE the correct distance from the TERT active site to prohibit copying of non-template nucleotides. PMID:26436828

  5. Template-based structure modeling of protein-protein interactions

    PubMed Central

    Szilagyi, Andras; Zhang, Yang

    2014-01-01

    The structure of protein-protein complexes can be constructed by using the known structure of other protein complexes as a template. The complex structure templates are generally detected either by homology-based sequence alignments or, given the structure of monomer components, by structure-based comparisons. Critical improvements have been made in recent years by utilizing interface recognition and by recombining monomer and complex template libraries. Encouraging progress has also been witnessed in genome-wide applications of template-based modeling, with modeling accuracy comparable to high-throughput experimental data. Nevertheless, bottlenecks exist due to the incompleteness of the proteinprotein complex structure library and the lack of methods for distant homologous template identification and full-length complex structure refinement. PMID:24721449

  6. Nanostructure templating using low temperature atomic layer deposition

    DOEpatents

    Grubbs, Robert K.; Bogart, Gregory R.; Rogers, John A.

    2011-12-20

    Methods are described for making nanostructures that are mechanically, chemically and thermally stable at desired elevated temperatures, from nanostructure templates having a stability temperature that is less than the desired elevated temperature. The methods comprise depositing by atomic layer deposition (ALD) structural layers that are stable at the desired elevated temperatures, onto a template employing a graded temperature deposition scheme. At least one structural layer is deposited at an initial temperature that is less than or equal to the stability temperature of the template, and subsequent depositions made at incrementally increased deposition temperatures until the desired elevated temperature stability is achieved. Nanostructure templates include three dimensional (3D) polymeric templates having features on the order of 100 nm fabricated by proximity field nanopatterning (PnP) methods.

  7. Assembly of synthetic Aβ miniamyloids on polyol templates.

    PubMed

    Fischer, Sebastian Nils; Geyer, Armin

    2015-01-01

    Covalent dynamic chemistry is used to mimic the first steps of the highly cooperative fibril formation of Aβ peptides. For that purpose, Aβ peptide pentapeptide boronic acids 1 and 2 were synthesized by solid-phase peptide synthesis and studied in esterification experiments with polyhydroxylated templates. The bis-hydroxylated dipeptide Hot=Tap serves as a template of adjustable degree of oligomerization which spontaneously forms boronic esters with peptides of type 1 and 2. Nuclear magnetic resonance can differentiate between regioisomeric boronic esters and identifies preferred sites of esterification on the dimeric template 9. 2-Formylphenylboronic acid (14) is used to link the parent pentapeptide Leu-Val-Phe-Phe-Ala to the template 16 to obtain threefold boronic ester 17. The miniamyloid 17 assembles from seven components by imine and boronic ester bonds between the peptides and the template. The relative orientation and spacing of the peptides mimic the assembly of peptides in Alzheimer β-amyloids. PMID:26734110

  8. Assembly of synthetic Aβ miniamyloids on polyol templates

    PubMed Central

    Fischer, Sebastian Nils

    2015-01-01

    Summary Covalent dynamic chemistry is used to mimic the first steps of the highly cooperative fibril formation of Aβ peptides. For that purpose, Aβ peptide pentapeptide boronic acids 1 and 2 were synthesized by solid-phase peptide synthesis and studied in esterification experiments with polyhydroxylated templates. The bis-hydroxylated dipeptide Hot=Tap serves as a template of adjustable degree of oligomerization which spontaneously forms boronic esters with peptides of type 1 and 2. Nuclear magnetic resonance can differentiate between regioisomeric boronic esters and identifies preferred sites of esterification on the dimeric template 9. 2-Formylphenylboronic acid (14) is used to link the parent pentapeptide Leu-Val-Phe-Phe-Ala to the template 16 to obtain threefold boronic ester 17. The miniamyloid 17 assembles from seven components by imine and boronic ester bonds between the peptides and the template. The relative orientation and spacing of the peptides mimic the assembly of peptides in Alzheimer β-amyloids. PMID:26734110

  9. Biologically Inspired Flagella-Templated Silica Nanotubes

    NASA Astrophysics Data System (ADS)

    Jo, Wonjin

    The desire and need for various types of nanostructures have been met with challenges of feasibility, reproducibility, and long fabrication time. To work towards improved bottom-up methods of nanofabrication, bacterial flagella are particularly attractive bio-templates for nanotubes due to their tubular structures and small inner and outer diameters. In this work, flagella isolated from Salmonella typhimurium are used as bio-templates to fabricate silica mineralized nanotubes. The process involves as well-controlled hydrolysis and condensation reaction with aminopropyltriethoxysilane (APTES), followed by the addition of tetraethoxysilane (TEOS). By controlling the concentration of TEOS and the reaction time, a simple and precise method is developed for creating silica-mineralized flagella nanotubes (SMFNs) with various thicknesses of the silica layer. In addition, the SMFNs are further modified to multifunctional nanotubes by coating metal nanoparticles (NPs) or metal oxide NPs such as gold, palladium, and iron oxide. The metallized SMFNs are achieved through reactions including reductive metallization or oxidative hydrolysis. The results from these studies provide evidence for the complete coating of SMFNs with uniform metal NP sizes and high surface area coverage. The metallized SMFNs are found to be electrically conductive along their network structures. The current-voltage characteristics show remarkably improved electrical conductivities depending on the types of metal NPs loading and SMFN networks concentration. The biologically inspired SMFNs with metal loading will allow have controlled electrical properties that can lead to the potential of creating unique and precise nanoelectronic materials. Lastly, the randomly entangled SMFNs are characterized to demonstrate their capabilities for hydrophilic and hydrophobic surface applications.

  10. Fuzzy Supernova Templates. II. Parameter Estimation

    NASA Astrophysics Data System (ADS)

    Rodney, Steven A.; Tonry, John L.

    2010-05-01

    Wide-field surveys will soon be discovering Type Ia supernovae (SNe) at rates of several thousand per year. Spectroscopic follow-up can only scratch the surface for such enormous samples, so these extensive data sets will only be useful to the extent that they can be characterized by the survey photometry alone. In a companion paper we introduced the Supernova Ontology with Fuzzy Templates (SOFT) method for analyzing SNe using direct comparison to template light curves, and demonstrated its application for photometric SN classification. In this work we extend the SOFT method to derive estimates of redshift and luminosity distance for Type Ia SNe, using light curves from the Sloan Digital Sky Survey (SDSS) and Supernova Legacy Survey (SNLS) as a validation set. Redshifts determined by SOFT using light curves alone are consistent with spectroscopic redshifts, showing an rms scatter in the residuals of rms z = 0.051. SOFT can also derive simultaneous redshift and distance estimates, yielding results that are consistent with the currently favored ΛCDM cosmological model. When SOFT is given spectroscopic information for SN classification and redshift priors, the rms scatter in Hubble diagram residuals is 0.18 mag for the SDSS data and 0.28 mag for the SNLS objects. Without access to any spectroscopic information, and even without any redshift priors from host galaxy photometry, SOFT can still measure reliable redshifts and distances, with an increase in the Hubble residuals to 0.37 mag for the combined SDSS and SNLS data set. Using Monte Carlo simulations, we predict that SOFT will be able to improve constraints on time-variable dark energy models by a factor of 2-3 with each new generation of large-scale SN surveys.

  11. FUZZY SUPERNOVA TEMPLATES. II. PARAMETER ESTIMATION

    SciTech Connect

    Rodney, Steven A.; Tonry, John L. E-mail: jt@ifa.hawaii.ed

    2010-05-20

    Wide-field surveys will soon be discovering Type Ia supernovae (SNe) at rates of several thousand per year. Spectroscopic follow-up can only scratch the surface for such enormous samples, so these extensive data sets will only be useful to the extent that they can be characterized by the survey photometry alone. In a companion paper we introduced the Supernova Ontology with Fuzzy Templates (SOFT) method for analyzing SNe using direct comparison to template light curves, and demonstrated its application for photometric SN classification. In this work we extend the SOFT method to derive estimates of redshift and luminosity distance for Type Ia SNe, using light curves from the Sloan Digital Sky Survey (SDSS) and Supernova Legacy Survey (SNLS) as a validation set. Redshifts determined by SOFT using light curves alone are consistent with spectroscopic redshifts, showing an rms scatter in the residuals of rms{sub z} = 0.051. SOFT can also derive simultaneous redshift and distance estimates, yielding results that are consistent with the currently favored {Lambda}CDM cosmological model. When SOFT is given spectroscopic information for SN classification and redshift priors, the rms scatter in Hubble diagram residuals is 0.18 mag for the SDSS data and 0.28 mag for the SNLS objects. Without access to any spectroscopic information, and even without any redshift priors from host galaxy photometry, SOFT can still measure reliable redshifts and distances, with an increase in the Hubble residuals to 0.37 mag for the combined SDSS and SNLS data set. Using Monte Carlo simulations, we predict that SOFT will be able to improve constraints on time-variable dark energy models by a factor of 2-3 with each new generation of large-scale SN surveys.

  12. Non-enzymatic template-directed synthesis on RNA random copolymers - Poly(C, U) templates

    NASA Technical Reports Server (NTRS)

    Joyce, G. F.; Inoue, T.; Orgel, L. E.

    1984-01-01

    Random copolymer templates containing cytosine and uracil in ratios of 3:1 and 1:1 are used to explore the optimum conditions for efficient synthesis of guanine and adenine-containing oligonucleotides. The experimental procedure is described, including the preparation of mononucleoside 5'-phospho-2-methylimidazolides and random copolymers, the template-directed oligomerization, the removal and reintroduction of mononucleotides in interrupted reactions, the determination of oligomerization efficiency, the alkaline and enzymatic hydrolysis of reaction products, and the column chromatography. Results are presented and discussed for the dependence of adenine incorporation on the formation of short oligo(G)s, optimization of incorporation efficiencies by adjusting monomer concentrations, the characterization of oligomeric product distribution, and the regiospecificity of adenine incorporation. The prebiotic significance of the results is assessed.

  13. Automatic Offloading C++ Expression Templates to CUDA Enabled GPUs

    SciTech Connect

    Chen, Jie; Joo, Balint; Watson, William A.; Edwards, Robert G.

    2012-05-01

    In the last few years, many scientific applications have been developed for powerful graphics processing units (GPUs) and have achieved remarkable speedups. This success can be partially attributed to high performance host callable GPU library routines that are offloaded to GPUs at runtime. These library routines are based on C/C++-like programming toolkits such as CUDA from NVIDIA and have the same calling signatures as their CPU counterparts. Recently, with the sufficient support of C++ templates from CUDA, the emergence of template libraries have enabled further advancement in code reusability and rapid software development for GPUs. However, Expression Templates (ET), which have been very popular for implementing data parallel scientific software for host CPUs because of their intuitive and mathematics-like syntax, have been underutilized by GPU development libraries. The lack of ET usage is caused by the difficulty of offloading expression templates from hosts to GPUs due to the inability to pass instantiated expressions to GPU kernels as well as the absence of the exact form of the expressions for the templates at the time of coding. This paper presents a general approach that enables automatic offloading of C++ expression templates to CUDA enabled GPUs by using the C++ metaprogramming technique and Just-In-Time (JIT) compilation methodology to generate and compile CUDA kernels for corresponding expression templates followed by executing the kernels with appropriate arguments. This approach allows developers to port applications to run on GPUs with virtually no code modifications. More specifically, this paper uses a large ET based data parallel physics library called QDP++ as an example to illustrate many aspects of the approach to offload expression templates automatically and to demonstrate very good speedups for typical QDP++ applications running on GPUs against running on CPUs using this method of offloading. In addition, this approach of automatic offlo

  14. Regeneration of meniscal cartilage with use of a collagen scaffold. Analysis of preliminary data.

    PubMed

    Stone, K R; Steadman, J R; Rodkey, W G; Li, S T

    1997-12-01

    A collagen scaffold was designed for use as a template for the regeneration of meniscal cartilage and was tested in ten patients in an initial, Food and Drug Administration-approved, clinical feasibility trial. The goal of the study was to evaluate the implantability and safety of the scaffold as well as its ability to support tissue ingrowth. The study was based on the findings of in vitro and in vivo investigations in dogs that had demonstrated cellular ingrowth and tissue regeneration through the scaffold. Nine patients remained in the study for at least thirty-six months, and one patient voluntarily withdrew after three months for personal reasons. The collagen scaffold was found to be implantable and to be safe over the three-year period. Histologically, it supported regeneration of tissue in meniscal defects of various sizes. No adverse immunological reactions were noted on sequential serological testing. On second-look arthroscopy, performed either three or six months after implantation, gross and histological evaluation revealed newly formed tissue replacing the implant as it was resorbed. At thirty-six months, the nine patients reported a decrease in the symptoms. According to a scale that assigned 1 point for strenuous activity and 5 points for an inability to perform sports activity, the average score was 1.5 points before the injury, 3.0 points after the injury and before the operation, and 2.4 points at six months postoperatively, 2.2 points at twelve months, 2.0 points at twenty-four months, and 1.9 points at thirty-six months. According to a scale that assigned 0 points for no pain and 3 points for severe pain, the average pain score was 2.2 points preoperatively and 0.6 point thirty-six months postoperatively. One patient, who had had a repair of a bucket-handle tear of the medial meniscus and augmentation with the collagen scaffold, had retearing of the cartilage nineteen months after implantation. Another patient had debridement because of an

  15. Tetrahydrobiopterin biosynthesis, regeneration and functions.

    PubMed Central

    Thöny, B; Auerbach, G; Blau, N

    2000-01-01

    Tetrahydrobiopterin (BH(4)) cofactor is essential for various processes, and is present in probably every cell or tissue of higher organisms. BH(4) is required for various enzyme activities, and for less defined functions at the cellular level. The pathway for the de novo biosynthesis of BH(4) from GTP involves GTP cyclohydrolase I, 6-pyruvoyl-tetrahydropterin synthase and sepiapterin reductase. Cofactor regeneration requires pterin-4a-carbinolamine dehydratase and dihydropteridine reductase. Based on gene cloning, recombinant expression, mutagenesis studies, structural analysis of crystals and NMR studies, reaction mechanisms for the biosynthetic and recycling enzymes were proposed. With regard to the regulation of cofactor biosynthesis, the major controlling point is GTP cyclohydrolase I, the expression of which may be under the control of cytokine induction. In the liver at least, activity is inhibited by BH(4), but stimulated by phenylalanine through the GTP cyclohydrolase I feedback regulatory protein. The enzymes that depend on BH(4) are the phenylalanine, tyrosine and tryptophan hydroxylases, the latter two being the rate-limiting enzymes for catecholamine and 5-hydroxytryptamine (serotonin) biosynthesis, all NO synthase isoforms and the glyceryl-ether mono-oxygenase. On a cellular level, BH(4) has been found to be a growth or proliferation factor for Crithidia fasciculata, haemopoietic cells and various mammalian cell lines. In the nervous system, BH(4) is a self-protecting factor for NO, or a general neuroprotecting factor via the NO synthase pathway, and has neurotransmitter-releasing function. With regard to human disease, BH(4) deficiency due to autosomal recessive mutations in all enzymes (except sepiapterin reductase) have been described as a cause of hyperphenylalaninaemia. Furthermore, several neurological diseases, including Dopa-responsive dystonia, but also Alzheimer's disease, Parkinson's disease, autism and depression, have been suggested to be

  16. Regeneration in brass wind instruments

    NASA Astrophysics Data System (ADS)

    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.

  17. Gene Expression Profile of the Regeneration Epithelium during Axolotl Limb Regeneration

    PubMed Central

    Campbell, Leah J.; Suárez-Castillo, Edna C.; Ortiz-Zuazaga, Humberto; Knapp, Dunja; Tanaka, Elly M.; Crews, Craig M.

    2012-01-01

    Urodele amphibians are unique amongst adult vertebrates in their ability to regenerate missing limbs. The process of limb regeneration requires several key tissues including a regeneration-competent wound epidermis called the regeneration epithelium (RE). We used microarray analysis to profile gene expression of the RE in the axolotl, a Mexican salamander. A list of 125 genes and expressed sequence tags (ESTs) showed a ≥1.5 fold expression in the RE than in a wound epidermis covering a lateral cuff wound. A subset of the RE ESTs and genes were further characterized for expression level changes over the time-course of regeneration. This study provides the first large scale identification of specific gene expression in the RE. PMID:21648017

  18. A Study of Regenerator for a Personal Stirling Refrigerator

    NASA Astrophysics Data System (ADS)

    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.

  19. Animated pose templates for modeling and detecting human actions.

    PubMed

    Yao, Benjamin Z; Nie, Bruce X; Liu, Zicheng; Zhu, Song-Chun

    2014-03-01

    This paper presents animated pose templates (APTs) for detecting short-term, long-term, and contextual actions from cluttered scenes in videos. Each pose template consists of two components: 1) a shape template with deformable parts represented in an And-node whose appearances are represented by the Histogram of Oriented Gradient (HOG) features, and 2) a motion template specifying the motion of the parts by the Histogram of Optical-Flows (HOF) features. A shape template may have more than one motion template represented by an Or-node. Therefore, each action is defined as a mixture (Or-node) of pose templates in an And-Or tree structure. While this pose template is suitable for detecting short-term action snippets in two to five frames, we extend it in two ways: 1) For long-term actions, we animate the pose templates by adding temporal constraints in a Hidden Markov Model (HMM), and 2) for contextual actions, we treat contextual objects as additional parts of the pose templates and add constraints that encode spatial correlations between parts. To train the model, we manually annotate part locations on several keyframes of each video and cluster them into pose templates using EM. This leaves the unknown parameters for our learning algorithm in two groups: 1) latent variables for the unannotated frames including pose-IDs and part locations, 2) model parameters shared by all training samples such as weights for HOG and HOF features, canonical part locations of each pose, coefficients penalizing pose-transition and part-deformation. To learn these parameters, we introduce a semi-supervised structural SVM algorithm that iterates between two steps: 1) learning (updating) model parameters using labeled data by solving a structural SVM optimization, and 2) imputing missing variables (i.e., detecting actions on unlabeled frames) with parameters learned from the previous step and progressively accepting high-score frames as newly labeled examples. This algorithm belongs to a

  20. Differential expression of HDACs and KATs in high and low regeneration capacity neurons during spinal cord regeneration.

    PubMed

    Chen, Jie; Laramore, Cindy; Shifman, Michael I

    2016-06-01

    After spinal cord injury (SCI) in mammals, injured axons fail to regenerate. By contrast, lampreys recover from complete spinal transection and axons regenerate selectively in their correct paths. Yet the large, identified reticulospinal neurons in the lamprey brain vary greatly in their regenerative abilities - some have high regeneration capacity (probability of regeneration >50%) and others have low regeneration capacity (<30%) - even though they have similar projection paths. The presence of both regenerating and non-regenerating neurons located in the same brain region and projecting to the same axon tracts suggests that differences in their regenerating abilities depend upon factors intrinsic to the neurons. Previous work has suggested that axon regeneration, especially in PNS, could depend on epigenetic mechanisms of histone modifications, such as the acetylation of histone tails. Our data indicated that expression of the enzymes responsible for regulating the acetylation of histone (KATs and HDACs) - KAT2A, KAT5 and P300 and HDAC3 did not change after SCI in either high regeneration capacity or low regeneration capacity neurons. In the present report, we show a novel and unexpected relationship between neuron regeneration abilities and expression of HDAC1. While HDAC1 expression was downregulated in both high and low regeneration capacity neurons 2 and 4weeks after SCI, it was upregulated at 7weeks at almost all RS neurons. However, at 10weeks post-transection only high regeneration capacity neurons displayed elevated HDAC1 mRNA expression and HDAC1 expression was again downregulated in low regeneration capacity neurons. Moreover, we show that HDAC1 is preferentially expressed in regenerated neurons, but not in non-regenerating neurons. Together, these results suggest that SCI causes significant changes in HDAC1 expression and that HDAC1 expression in regenerating neurons may modulates a survival or regeneration programs. PMID:27059134

  1. Equine Model for Soft Tissue Regeneration

    PubMed Central

    Moreau, J.E.; Lo, T.; Quinn, K.P.; Fourligas, N.; Georgakoudi, I.; Leisk, G.G.; Mazan, M.; Thane, K.E.; Taeymans, O.; Hoffman, A.M.; Kaplan, D. L.; Kirker-Head, C.A.

    2016-01-01

    Soft tissue regeneration methods currently yield suboptimal clinical outcomes due to loss of tissue volume and a lack of functional tissue regeneration. Grafted tissues and natural biomaterials often degrade or resorb too quickly, while most synthetic materials do not degrade. In previous research we demonstrated that soft tissue regeneration can be supported using silk porous biomaterials for at least 18 months in vivo in a rodent model. In the present study, we scaled the system to a survival study using a large animal model and demonstrated the feasibility of these biomaterials for soft tissue regeneration in adult horses. Both slow and rapidly degrading silk matrices were evaluated in subcutaneous pocket and intramuscular defect depots. We showed that we can effectively employ an equine model over six months to simultaneously evaluate many different implants, reducing the number of animals needed. Furthermore, we were able to tailor matrix degradation by varying the initial format of the implanted silk. Finally, we demonstrate ultrasound imaging of implants to be an effective means for tracking tissue regeneration and implant degradation. PMID:25350377

  2. Microwave-assisted regeneration of activated carbon.

    PubMed

    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

  3. A conceptual model of morphogenesis and regeneration

    PubMed Central

    Tosenberger, A.; Bessonov, N.; Levin, M.; Reinberg, N.; Volpert, V.; Morozova, N.

    2016-01-01

    This paper is devoted to computer modelling of the development and regeneration of multicellular biological structures. Some species (e.g., planaria and salamanders) are able to regenerate parts of their body after amputation damage, but the global rules governing cooperative cell behaviour during morphogenesis are not known. Here, we consider a simplified model organism, which consists of tissues formed around special cells that can be interpreted as stem cells. We assume that stem cells communicate with each other by a set of signals, and that the values of these signals depend on the distance between cells. Thus the signal distribution characterizes location of stem cells. If the signal distribution is changed, then the difference between the initial and the current signal distribution affects the behaviour of stem cells – e.g. as a result of an amputation of a part of tissue the signal distribution changes which stimulates stem cells to migrate to new locations, appropriate for regeneration of the proper pattern. Moreover, as stem cells divide and form tissues around them, they control the form and the size of regenerating tissues. This two-level organization of the model organism, with global regulation of stem cells and local regulation of tissues, allows its reproducible development and regeneration. PMID:25822060

  4. Unexpected regeneration in middle-aged mice.

    PubMed

    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

  5. Hippo signaling impedes adult heart regeneration

    PubMed Central

    Heallen, Todd; Morikawa, Yuka; Leach, John; Tao, Ge; Willerson, James T.; Johnson, Randy L.; Martin, James F.

    2013-01-01

    Heart failure due to cardiomyocyte loss after ischemic heart disease is the leading cause of death in the United States in large part because heart muscle regenerates poorly. The endogenous mechanisms preventing mammalian cardiomyocyte regeneration are poorly understood. Hippo signaling, an ancient organ size control pathway, is a kinase cascade that inhibits developing cardiomyocyte proliferation but it has not been studied postnatally or in fully mature adult cardiomyocytes. Here, we investigated Hippo signaling in adult cardiomyocyte renewal and regeneration. We found that unstressed Hippo-deficient adult mouse cardiomyocytes re-enter the cell cycle and undergo cytokinesis. Moreover, Hippo deficiency enhances cardiomyocyte regeneration with functional recovery after adult myocardial infarction as well as after postnatal day eight (P8) cardiac apex resection and P8 myocardial infarction. In damaged hearts, Hippo mutant cardiomyocytes also have elevated proliferation. Our findings reveal that Hippo signaling is an endogenous repressor of adult cardiomyocyte renewal and regeneration. Targeting the Hippo pathway in human disease might be beneficial for the treatment of heart disease. PMID:24255096

  6. Contemporary perspective on endogenous myocardial regeneration

    PubMed Central

    Milasinovic, Dejan; Mohl, Werner

    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 short in myocardial jeopardy. In spite of these enchaining limitations, cardiac rejuvenation occurs as well as restricted regeneration. In this review, the background as well as potential mechanisms of endogenous myocardial regeneration are summarized. We present and analyze the available evidence in three subsequent steps. First, we examine the experimental research data that provide insights into the mechanisms and origins of the replicating cardiac myocytes, including cell populations referred to as cardiac progenitor cells (i.e., c-kit+ cells). Second, we describe the role of clinical settings such as acute or chronic myocardial ischemia, as initiators of pathways of endogenous myocardial regeneration. Third, the hitherto conducted clinical studies that examined different approaches of initiating endogenous myocardial regeneration in failing human hearts are analyzed. In conclusion, we present the evidence in support of the notion that regaining cardiac function beyond cellular replacement of dysfunctional myocardium via initiation of innate regenerative pathways could create a new perspective and a paradigm change in heart failure therapeutics. Reinitiating cardiac morphogenesis by reintroducing developmental pathways in the adult failing heart might provide a feasible way of tissue regeneration. Based on our hypothesis “embryonic recall”, we present first supporting evidence on regenerative impulses in the myocardium, as induced by developmental processes. PMID:26131310

  7. Multimodal biometric approach for cancelable face template generation

    NASA Astrophysics Data System (ADS)

    Paul, Padma Polash; Gavrilova, Marina

    2012-06-01

    Due to the rapid growth of biometric technology, template protection becomes crucial to secure integrity of the biometric security system and prevent unauthorized access. Cancelable biometrics is emerging as one of the best solutions to secure the biometric identification and verification system. We present a novel technique for robust cancelable template generation algorithm that takes advantage of the multimodal biometric using feature level fusion. Feature level fusion of different facial features is applied to generate the cancelable template. A proposed algorithm based on the multi-fold random projection and fuzzy communication scheme is used for this purpose. In cancelable template generation, one of the main difficulties is keeping interclass variance of the feature. We have found that interclass variations of the features that are lost during multi fold random projection can be recovered using fusion of different feature subsets and projecting in a new feature domain. Applying the multimodal technique in feature level, we enhance the interclass variability hence improving the performance of the system. We have tested the system for classifier fusion for different feature subset and different cancelable template fusion. Experiments have shown that cancelable template improves the performance of the biometric system compared with the original template.

  8. The Molecular and Cellular Choreography of Appendage Regeneration.

    PubMed

    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

  9. Durable diamond-like carbon templates for UV nanoimprint lithography.

    PubMed

    Tao, L; Ramachandran, S; Nelson, C T; Lin, M; Overzet, L J; Goeckner, M; Lee, G; Willson, C G; Wu, W; Hu, W

    2008-03-12

    The interaction between resist and template during the separation process after nanoimprint lithography (NIL) can cause the formation of defects and damage to the templates and resist patterns. To alleviate these problems, fluorinated self-assembled monolayers (F-SAMs, i.e. tridecafluoro-1,1,2,2,tetrahydrooctyl trichlorosilane or FDTS) have been employed as template release coatings. However, we find that the FDTS coating undergoes irreversible degradation after only 10 cycles of UV nanoimprint processes with SU-8 resist. The degradation includes a 28% reduction in surface F atoms and significant increases in the surface roughness. In this paper, diamond-like carbon (DLC) films were investigated as an alternative material not only for coating but also for direct fabrication of nanoimprint templates. DLC films deposited on quartz templates in a plasma enhanced chemical vapor deposition system are shown to have better chemical and physical stability than FDTS. After the same 10 cycles of UV nanoimprints, the surface composition as well as the roughness of DLC films were found to be unchanged. The adhesion energy between the DLC surface and SU-8 is found to be smaller than that of FDTS despite the slightly higher total surface energy of DLC. DLC templates with 40 nm features were fabricated using e-beam lithography followed by Cr lift-off and reactive ion etching. UV nanoimprinting using the directly patterned DLC templates in SU-8 resist demonstrates good pattern transfer fidelity and easy template-resist separation. These results indicate that DLC is a promising material for fabricating durable templates for UV nanoimprint lithography. PMID:21817695

  10. Iris-based authentication system with template protection and renewability

    NASA Astrophysics Data System (ADS)

    Ercole, Chiara; Campisi, Patrizio; Neri, Alessandro

    2007-10-01

    Biometrics is the most emerging technology for automatic people authentication, nevertheless severe concerns raised about security of such systems and users' privacy. In case of malicious attacks toward one or more components of the authentication system, stolen biometric features cannot be replaced. This paper focuses on securing the enrollment database and the communication channel between such database and the matcher. In particular, a method is developed to protect the stored biometric templates, adapting the fuzzy commitment scheme to iris biometrics by exploiting error correction codes tailored on template discriminability. The aforementioned method allows template renewability applied to iris based authentication and guarantees high security performing the match in the encrypted domain.

  11. Translational Research Design Templates, Grid Computing, and HPC

    PubMed Central

    Saltz, Joel; Oster, Scott; Hastings, Shannon; Langella, Stephen; Ferreira, Renato; Permar, Justin; Sharma, Ashish; Ervin, David; Pan, Tony; Catalyurek, Umit; Kurc, Tahsin

    2011-01-01

    Design templates that involve discovery, analysis, and integration of information resources commonly occur in many scientific research projects. In this paper we present examples of design templates from the biomedical translational research domain and discuss the requirements imposed on Grid middleware infrastructures by them. Using caGrid, which is a Grid middleware system based on the model driven architecture (MDA) and the service oriented architecture (SOA) paradigms, as a starting point, we discuss architecture directions for MDA and SOA based systems like caGrid to support common design templates. PMID:21311740

  12. Template For Aiming An X-Ray Machine

    NASA Technical Reports Server (NTRS)

    Morphet, W. J.

    1994-01-01

    Relatively inexpensive template helps in aligning x-ray machine with phenolic ring to be inspected for flaws. Phenolic ring in original application part of rocket nozzle. Concept also applicable to x-ray inspection of other rings. Template contains alignment holes for adjusting orientation, plus target spot for adjusting lateral position, of laser spotting beam. (Laser spotting beam coincides with the x-ray beam, turned on later, after alignment completed.) Use of template decreases positioning time and error, providing consistent sensitivity for detection of flaws.

  13. Direct Interfacial Modification of Nanocellulose Films for Thermoresponsive Membrane Templates.

    PubMed

    Hakalahti, Minna; Mautner, Andreas; Johansson, Leena-Sisko; Hänninen, Tuomas; Setälä, Harri; Kontturi, Eero; Bismarck, Alexander; Tammelin, Tekla

    2016-02-10

    This letter proposes a strategy to construct tunable films combining the physical characteristics of cellulose nanofibrils and smart polymers for membrane applications. A functional membrane template was obtained by first fabricating a water stable film from cellulose nanofibrils and subsequently surface grafting it with a thermoresponsive polymer, poly(N-isopropylacrylamide). The behavior of the membrane template was dependent on temperature. The increment in slope of relative water permeance around the lower critical solution temperature of poly(N-isopropylacrylamide) increased from 18 to 100% upon polymer attachment. Although the membrane template essentially consisted of wood-based materials, the benefits of smart synthetic polymers were achieved. PMID:26812620

  14. Future perspectives in nerve repair and regeneration.

    PubMed

    Tos, Pierluigi; Ronchi, Giulia; Geuna, Stefano; Battiston, Bruno

    2013-01-01

    After peripheral nerve injuries, the process of nerve regeneration and target reinnervation is very complex and depends on many different events occurring not only at the lesion site but also proximally and distally to it. In spite of the recent scientific and technological advancements, the need to find out new strategies to improve clinical nerve repair and regeneration remains. To reach this goal, the therapeutic strategy should thus exert its effects at different levels in order to simultaneously potentiate axonal regeneration, increase neuronal survival, modulate central reorganization, and inhibit or reduce target organ atrophy. It is expected that this multilevel approach might lead to significant improvement in the functional outcome and thus the quality of life of the patients suffering from peripheral nerve injury. PMID:24093612

  15. Platelet Rich Fibrin in Periodontal Regeneration

    PubMed Central

    Arunachalam, Muthukumaraswamy; Pulikkotil, Shaju J.; Sonia, Nath

    2016-01-01

    Periodontitis is a chronic bacterial infection resulting in destruction of the supporting structures of the teeth. Regeneration of the lost tissues has faced difficulties primarily due to the lack of support during the intricate healing processes. A surgical additive which can ‘jump start’ the healing process to a more predictable regenerative process is always on the wish list of any periodontist. Platelet-rich fibrin (PRF) is a second generation platelet concentrate that has been considered to be an important, easy to obtain, predictable surgical additive for periodontal regeneration. This autologous scaffold provides the much needed bio-chemical mediators which has the potential for enhancing reconstruction of the periodontium. This review article tries to understand as to why PRF would be an important link to reach predictable periodontal regeneration. PMID:27386002

  16. Biodegradable synthetic scaffolds for tendon regeneration

    PubMed Central

    Reverchon, Ernesto; Baldino, Lucia; Cardea, Stefano; De Marco, Iolanda

    2012-01-01

    Summary Tissue regeneration is aimed at producing biological or synthetic scaffolds to be implanted in the body for regenerate functional tissues. Several techniques and materials have been used to obtain biodegradable synthetic scaffolds, on which adhesion, growth, migration and differentiation of human cells has been attempted. Scaffolds for tendon regeneration have been less frequently proposed, because they have a complex hierarchical structure and it is very difficult to mimic their peculiar mechanical properties. In this review, we critically analyzed the proposed materials and fabrication techniques for tendon tissue engineering and we indicated new preparation processes, based on the use of supercritical fluids, to produce scaffolds with characteristics very similar to the native tendon structure. PMID:23738295

  17. Heat engine regenerators: Research status and needs

    SciTech Connect

    Hutchinson, R.A.

    1987-08-01

    The rapidly oscillating, variable density flows of regenerative heat engines provide a class of poorly understood unsteady flow and heat transfer problems. These problems are not currently amenable to direct experimental resolution. Experiences in engine development and test programs and efforts to develop analysis tools point to the regenerator as a key area of insufficient understanding. Focusing on flow and heat transfer in regenerators, this report discusses similarity parameters for the flows and reviews the experimental data currently available for Stirling analysis. Then a number of experimental results are presented from recent fundamental fluid mechanical and thermal investigations that shed additional light on the functioning of heat engine regenerators. Suggestions are made for approaches for further measurement and analysis efforts.

  18. Analysis of magnetic refrigeration with external regeneration

    NASA Astrophysics Data System (ADS)

    Jaeger, Steven R.; Barclay, John A.; Overton, William C., Jr.

    A simplified computer model of a typical magnetic refrigerator using external regeneration is used to investigate different magnetic materials and refrigerator designs. It was found that nonideal temperature-entropy properties of the magnetic material and nonideal regeneration both contribute significantly to reducing the useful range and efficiency of these refrigerators. While the model cannot be used to predict the performance of actual refrigerators, it provides a quick means of evaluating whether inherent limitations, as a result of the choice of the magnetic material or the regenerator design, will make it impossible for a specific design to satisfy the requirements for a given application. Preliminary results from using this model with an approximate model for GdNi as the magnetic material are presented.

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

    PubMed Central

    Lin, Gufa; Chen, Ying; Slack, Jonathan MW

    2007-01-01

    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. PMID:17521450

  20. Microwave-Regenerated Diesel Exhaust Particulate Filter

    SciTech Connect

    Nixdorf, Richard D.; Green, Johney Boyd; Story, John M.; Wagner, Robert M.

    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.)

  1. Cooling exothermic regenerator with endothermic reactions

    SciTech Connect

    Sapre, A.V.

    1993-06-01

    A fluidized catalytic cracking (FCC) process is described wherein a heavy hydrocarbon feed having a boiling point above about 650 F is catalytically cracked in an FCC unit by direct contact with an inventory of hot regenerated cracking catalyst to lighter products and spent catalyst which is regenerated to produce hot regenerated catalyst, by: a. catalytically cracking the feed in a catalytic cracking reactor operating at conditions to produce a cracking reactor effluent mixture comprising cracked products and spent catalyst containing coke and strippable hydrocarbons; b. separating the cracking reactor effluent mixture into a cracked product rich vapor phase and a solids rich spent catalyst phase comprising strippable hydrocarbons and coked catalyst; c. stripping at least a portion of the spent catalyst phase to produce stripped coked catalyst; d. regenerating at least a portion of the stripped coked catalyst in a catalyst regeneration means to produce hot regenerated catalyst which is recycled to the catalytic cracking reactor; the process characterized by cooling at least a portion of the FCC catalyst inventory by indirect heat exchange against an endothermic chemical reaction in an endothermic cooler having two isolated sections, an FCC catalyst side section and an endothermic cooler reactant side section by: e. removing at least a portion of the FCC catalyst from the FCC unit and charging same to an inlet of the endothermic cooler; f. charging an endothermically reactive reactant selected from the group of ethane, propane, butane, light naphtha, and heavy naphtha to an inlet of the endothermic cooler reactant side of the heat exchange means; g. heating the endothermically reactive reactant, by indirect heat exchange with the FCC catalyst, to a temperature sufficient to drive the endothermic reaction and produce endothermic reaction products which are removed as a product and simultaneously remove heat from the FCC catalyst and produce cooled FCC catalyst.

  2. Injectable PolyMIPE Scaffolds for Soft Tissue Regeneration

    PubMed Central

    Moglia, Robert S.; Robinson, Jennifer L.; Muschenborn, Andrea D.; Touchet, Tyler J.; Maitland, Duncan J.; Cosgriff-Hernandez, Elizabeth

    2013-01-01

    Injury caused by trauma, burns, surgery, or disease often results in soft tissue loss leading to impaired function and permanent disfiguration. Tissue engineering aims to overcome the lack of viable donor tissue by fabricating synthetic scaffolds with the requisite properties and bioactive cues to regenerate these tissues. Biomaterial scaffolds designed to match soft tissue modulus and strength should also retain the elastomeric and fatigue-resistant properties of the tissue. Of particular design importance is the interconnected porous structure of the scaffold needed to support tissue growth by facilitating mass transport. Adequate mass transport is especially true for newly implanted scaffolds that lack vasculature to provide nutrient flux. Common scaffold fabrication strategies often utilize toxic solvents and high temperatures or pressures to achieve the desired porosity. In this study, a polymerized medium internal phase emulsion (polyMIPE) is used to generate an injectable graft that cures to a porous foam at body temperature without toxic solvents. These poly(ester urethane urea) scaffolds possess elastomeric properties with tunable compressive moduli (20–200 kPa) and strengths (4–60 kPa) as well as high recovery after the first conditioning cycle (97–99%). The resultant pore architecture was highly interconnected with large voids (0.5–2 mm) from carbon dioxide generation surrounded by water-templated pores (50–300 μm). The ability to modulate both scaffold pore architecture and mechanical properties by altering emulsion chemistry was demonstrated. Permeability and form factor were experimentally measured to determine the effects of polyMIPE composition on pore interconnectivity. Finally, initial human mesenchymal stem cell (hMSC) cytocompatibility testing supported the use of these candidate scaffolds in regenerative applications. Overall, these injectable polyMIPE foams show strong promise as a biomaterial scaffold for soft tissue repair. PMID

  3. Hydride heat pump with heat regenerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor)

    1991-01-01

    A regenerative hydride heat pump process and system is provided which can regenerate a high percentage of the sensible heat of the system. A series of at least four canisters containing a lower temperature performing hydride and a series of at least four canisters containing a higher temperature performing hydride is provided. Each canister contains a heat conductive passageway through which a heat transfer fluid is circulated so that sensible heat is regenerated. The process and system are useful for air conditioning rooms, providing room heat in the winter or for hot water heating throughout the year, and, in general, for pumping heat from a lower temperature to a higher temperature.

  4. The mammalian blastema: regeneration at our fingertips

    PubMed Central

    Simkin, Jennifer; Sammarco, Mimi C.; Dawson, Lindsay A.; Schanes, Paula P.; Yu, Ling

    2015-01-01

    Abstract In the mouse, digit tip regeneration progresses through a series of discrete stages that include inflammation, histolysis, epidermal closure, blastema formation, and redifferentiation. Recent studies reveal how each regenerative stage influences subsequent stages to establish a blastema that directs the successful regeneration of a complex mammalian structure. The focus of this review is on early events of healing and how an amputation wound transitions into a functional blastema. The stepwise formation of a mammalian blastema is proposed to provide a model for how specific targeted treatments can enhance regenerative performance in humans.

  5. [Own Chemiluminescence of Planarian Neoblasts during Regeneration].

    PubMed

    Tiras, H P; Gudkov, S V; Emelyanenko, V I; Aslanidi, K B

    2015-01-01

    We investigated the kinetics of the luminescence induced by reactive oxygen species in planarians during regeneration process. It was found that regeneration is accompanied with changes in the concentration of reactive oxygen species correlating with energy-intensive processes such as oxidative stress, caused by damage to cell membranes in the dissection of the planarian, phagocytosis of dying cells and mitosis of neoblasts. We showed for the first time that there is an opportunity of registering the physiological state of pluripotent stem cells at the level of the organism in vivo. PMID:26591608

  6. Fluidized bed regenerators for Brayton cycles

    NASA Technical Reports Server (NTRS)

    Nichols, L. D.

    1975-01-01

    A recuperator consisting of two fluidized bed regenerators with circulating solid particles is considered for use in a Brayton cycle. These fluidized beds offer the possibility of high temperature operation if ceramic particles are used. Calculations of the efficiency and size of fluidized bed regenerators for typical values of operating parameters were made and compared to a shell and tube recuperator. The calculations indicate that the fluidized beds will be more compact than the shell and tube as well as offering a high temperature operating capability.

  7. Fluidized bed regenerators for Brayton cycles

    NASA Technical Reports Server (NTRS)

    Nichols, L. D.

    1975-01-01

    A recuperator consisting of two fluidized bed regenerators with circulating solid particles is considered for use in a Brayton cycle. These fluidized beds offer the possibility of high temperature operation if ceramic particles are used. Calculations of the efficiency and size of fluidized bed regenerators for typical values of operating parameters have been made and compared to a shell and tube recuperator. The calculations indicate that the fluidized beds will be more compact than the shell and tube as well as offering a high temperature operating capability.

  8. Regeneration of sulfated metal oxides and carbonates

    DOEpatents

    Hubble, Bill R.; Siegel, Stanley; Cunningham, Paul T.

    1978-03-28

    Alkali metal or alkaline earth metal carbonates such as calcium carbonate and magnesium carbonate found in dolomite or limestone are employed for removal of sulfur dioxide from combustion exhaust gases. The sulfated carbonates are regenerated to oxides through use of a solid-solid reaction, particularly calcium sulfide with calcium sulfate to form calcium oxide and sulfur dioxide gas. The regeneration is performed by contacting the sulfated material with a reductant gas such as hydrogen within an inert diluent to produce calcium sulfide in mixture with the sulfate under process conditions selected to permit the sulfide-sulfate, solid-state reaction to occur.

  9. High temperature regenerable hydrogen sulfide removal agents

    DOEpatents

    Copeland, Robert J.

    1993-01-01

    A system for high temperature desulfurization of coal-derived gases using regenerable sorbents. One sorbent is stannic oxide (tin oxide, SnO.sub.2), the other sorbent is a metal oxide or mixed metal oxide such as zinc ferrite (ZnFe.sub.2 O.sub.4). Certain otherwise undesirable by-products, including hydrogen sulfide (H.sub.2 S) and sulfur dioxide (SO.sub.2) are reused by the system, and elemental sulfur is produced in the regeneration reaction. A system for refabricating the sorbent pellets is also described.

  10. Effects of pesticides on crab cheliped regeneration

    SciTech Connect

    Costlow, J.D. Jr.

    1993-01-01

    The mud crab cheliped regeneration bioassay has proven to be a sensitive and reliable bioassay in studies of the potential sublethal effects of pesticides, including teratogenesis, spontaneous autotomy, and duration of the various stages of development. The assay has also been demonstated to be a useful indication of mortality associated with the impact of these chemicals of anthropogenic origin during the megalopal and early postlarval stages of development. Four pesticides were tested here using the cheliped regeneration bioassay technique. Although carbofuran is approximately 5--6 times more toxic than methomyl, both compounds yield very similar results in terms of sublethal effects.

  11. Membrane reactors for continuous coenzyme regeneration

    NASA Astrophysics Data System (ADS)

    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.

  12. Holladay halftoning using super resolution encoded templates

    NASA Astrophysics Data System (ADS)

    McElvain, Jon S.; Hains, Charles M.

    2007-01-01

    A new method for halftoning using high resolution pattern templates is described, that expands the low level rendering capabilities for engines that support this feature. This approach, denoted super resolution encoded halftoning (SREH) is an extension of the Holladay concept, and provides a compact way to specify high resolution dot growth patterns using a lower resolution Holladay brick. Fundamentally, this new halftoning method involves using the SRE patterns as building blocks for constructing clustered dot growth assemblies. Like the traditional Holladay dot description, the SRE halftone is characterized by a size, height, and shift, all of which are specified at the lower resolution. Each low resolution pixel position in the SRE halftone brick contains a pair of lists. The first of these is a list of digital thresholds at which a transition in SRE patterns occurs for that pixel position, and the second is the corresponding list of SRE codes. For normal cluster dot growth sequences, this provides a simple and compact mechanism for specifying higher resolution halftones. Techniques for emulating traditional high resolution Holladay dots using SREH are discussed, including mechanisms for choosing substitutions for patterns that do not exist among the available SRE patterns.

  13. Biosilicification templated by amphiphilic block copolypeptide assemblies.

    PubMed

    Xia, Lin; Liu, Yu; Li, Zhibo

    2010-12-01

    An amphiphilic poly(L-lysine·HBr)-block-poly(L-leucine) (KL) diblock copolypeptide and its supramolecular assembly are used as a template to direct silica formation, which proceeds by a cooperative process involving biomimetic mineralization and copolypeptide reassembly under ambient conditions. Various silica structures can be obtained by using different counterions, changing the chain length of the KL diblocks, and applying a sol-gel mineralization method. We find that the chain length of the KL diblock is an important factor in terms of controlling biosilica morphologies. We also find that the nature of the counterions strongly affects the resulting silica structures. For the same KL diblock, variation of anions from phosphate to sulfate and to carbonate can produce hexagonal silica platelets, silica rods, and fused silica platelets, respectively. In contrast, application of a sol-gel method can replicate the copolypeptide fibril network morphology in water, while employment of ultrasonication to the sol-gel medium transforms the silica fibrils to rigid silica rods. The resulting silica morphology has been systematically characterized using SEM and TEM, and the polypeptide conformation is explored using FT-IR and CD spectroscopy. PMID:20872854

  14. Robust structural identification via polyhedral template matching

    NASA Astrophysics Data System (ADS)

    Mahler Larsen, Peter; Schmidt, Søren; Schiøtz, Jakob

    2016-06-01

    Successful scientific applications of large-scale molecular dynamics often rely on automated methods for identifying the local crystalline structure of condensed phases. Many existing methods for structural identification, such as common neighbour analysis, rely on interatomic distances (or thresholds thereof) to classify atomic structure. As a consequence they are sensitive to strain and thermal displacements, and preprocessing such as quenching or temporal averaging of the atomic positions is necessary to provide reliable identifications. We propose a new method, polyhedral template matching (PTM), which classifies structures according to the topology of the local atomic environment, without any ambiguity in the classification, and with greater reliability than e.g. common neighbour analysis in the presence of thermal fluctuations. We demonstrate that the method can reliably be used to identify structures even in simulations near the melting point, and that it can identify the most common ordered alloy structures as well. In addition, the method makes it easy to identify the local lattice orientation in polycrystalline samples, and to calculate the local strain tensor. An implementation is made available under a Free and Open Source Software license.

  15. Software Template for Instruction in Mathematics

    NASA Technical Reports Server (NTRS)

    Shelton, Robert O.; Moebes, Travis A.; Beall, Anna

    2005-01-01

    Intelligent Math Tutor (IMT) is a software system that serves as a template for creating software for teaching mathematics. IMT can be easily connected to artificial-intelligence software and other analysis software through input and output of files. IMT provides an easy-to-use interface for generating courses that include tests that contain both multiple-choice and fill-in-the-blank questions, and enables tracking of test scores. IMT makes it easy to generate software for Web-based courses or to manufacture compact disks containing executable course software. IMT also can function as a Web-based application program, with features that run quickly on the Web, while retaining the intelligence of a high-level language application program with many graphics. IMT can be used to write application programs in text, graphics, and/or sound, so that the programs can be tailored to the needs of most handicapped persons. The course software generated by IMT follows a "back to basics" approach of teaching mathematics by inducing the student to apply creative mathematical techniques in the process of learning. Students are thereby made to discover mathematical fundamentals and thereby come to understand mathematics more deeply than they could through simple memorization.

  16. The pediatric template of brain perfusion

    PubMed Central

    Avants, Brian B; Duda, Jeffrey T; Kilroy, Emily; Krasileva, Kate; Jann, Kay; Kandel, Benjamin T; Tustison, Nicholas J; Yan, Lirong; Jog, Mayank; Smith, Robert; Wang, Yi; Dapretto, Mirella; Wang, Danny J J

    2015-01-01

    Magnetic resonance imaging (MRI) captures the dynamics of brain development with multiple modalities that quantify both structure and function. These measurements may yield valuable insights into the neural patterns that mark healthy maturation or that identify early risk for psychiatric disorder. The Pediatric Template of Brain Perfusion (PTBP) is a free and public neuroimaging resource that will help accelerate the understanding of childhood brain development as seen through the lens of multiple modality neuroimaging and in relation to cognitive and environmental factors. The PTBP uses cross-sectional and longitudinal MRI to quantify cortex, white matter, resting state functional connectivity and brain perfusion, as measured by Arterial Spin Labeling (ASL), in 120 children 7–18 years of age. We describe the PTBP and show, as a demonstration of validity, that global summary measurements capture the trajectories that demarcate critical turning points in brain maturation. This novel resource will allow a more detailed understanding of the network-level, structural and functional landmarks that are obtained during normal adolescent brain development. PMID:25977810

  17. Convex lens-induced nanoscale templating

    PubMed Central

    Berard, Daniel J.; Michaud, François; Mahshid, Sara; Ahamed, Mohammed Jalal; McFaul, Christopher M. J.; Leith, Jason S.; Bérubé, Pierre; Sladek, Rob; Reisner, Walter; Leslie, Sabrina R.

    2014-01-01

    We demonstrate a new platform, convex lens-induced nanoscale templating (CLINT), for dynamic manipulation and trapping of single DNA molecules. In the CLINT technique, the curved surface of a convex lens is used to deform a flexible coverslip above a substrate containing embedded nanotopography, creating a nanoscale gap that can be adjusted during an experiment to confine molecules within the embedded nanostructures. Critically, CLINT has the capability of transforming a macroscale flow cell into a nanofluidic device without the need for permanent direct bonding, thus simplifying sample loading, providing greater accessibility of the surface for functionalization, and enabling dynamic manipulation of confinement during device operation. Moreover, as DNA molecules present in the gap are driven into the embedded topography from above, CLINT eliminates the need for the high pressures or electric fields required to load DNA into direct-bonded nanofluidic devices. To demonstrate the versatility of CLINT, we confine DNA to nanogroove and nanopit structures, demonstrating DNA nanochannel-based stretching, denaturation mapping, and partitioning/trapping of single molecules in multiple embedded cavities. In particular, using ionic strengths that are in line with typical biological buffers, we have successfully extended DNA in sub–30-nm nanochannels, achieving high stretching (90%) that is in good agreement with Odijk deflection theory, and we have mapped genomic features using denaturation analysis. PMID:25092333

  18. Convex Lens-Induced Nanoscale Templating

    NASA Astrophysics Data System (ADS)

    Berard, Daniel; Michaud, Francois; McFaul, Christopher; Mahsid, Sara; Reisner, Walter; Leslie, Sabrina

    2014-03-01

    We demonstrate a new platform, ``Convex Lens-Induced Nanoscale Templating'' (CLINT), for dynamic manipulation and trapping of single DNA molecules. In the CLINT technique, the curved surface of a convex lens is used to deform a flexible coverslip above a substrate containing embedded nanotopography, creating a nanoscale gap that can be adjusted during an experiment to confine molecules within the embedded nanostructures. Critically, CLINT has the capability of actively transforming a macroscale flow-cell into a nanofluidic device without need for high-temperature direct bonding, leading to ease of sample loading and greater accessibility of the surface. Moreover, as DNA molecules present in the gap will be driven into the embedded topography from above, CLINT eliminates the need for the high pressures or electric fields necessitated by direct bonded nanofluidic devices for loading DNA in the confined structures. To demonstrate the versatility of CLINT, we confine DNA to nanogroove structures, demonstrating DNA nanochannel-based stretching. Using ionic strengths that are in line with typical biological buffers, we have successfully extended DNA in sub 30nm nanochannels, achieving high stretching (90%) that is in good agreement with Odijk deflection theory.

  19. Template switching between PNA and RNA oligonucleotides

    NASA Technical Reports Server (NTRS)

    Bohler, C.; Nielsen, P. E.; Orgel, L. E.; Miller, S. L. (Principal Investigator)

    1995-01-01

    The origin of the RNA world is not easily understood, as effective prebiotic syntheses of the components of RNA, the beta-ribofuranoside-5'-phosphates, are hard to envisage. Recognition of this difficulty has led to the proposal that other genetic systems, the components of which are more easily formed, may have preceded RNA. This raises the question of how transitions between one genetic system and another could occur. Peptide nucleic acid (PNA) resembles RNA in its ability to form double-helical complexes stabilized by Watson-Crick hydrogen bonding between adenine and thymine and between cytosine and guanine, but has a backbone that is held together by amide rather than by phosphodiester bonds. Oligonucleotides bases on RNA are known to act as templates that catalyse the non-enzymatic synthesis of their complements from activated mononucleotides, we now show that RNA oligonucleotides facilitate the synthesis of complementary PNA strands and vice versa. This suggests that a transition between different genetic systems can occur without loss of information.

  20. DNA-Templated Molecular Silver Fluorophores

    PubMed Central

    Petty, Jeffrey T.; Story, Sandra P.; Hsiang, Jung-Cheng; Dickson, Robert M.

    2013-01-01

    Conductive and plasmon-supporting noble metals exhibit an especially wide range of size-dependent properties, with discrete electronic levels, strong optical absorption, and efficient radiative relaxation dominating optical behavior at the ~10-atom cluster scale. In this Perspective, we describe the formation and stabilization of silver clusters using DNA templates and highlight the distinct spectroscopic and photophysical properties of the resulting hybrid fluorophores. Strong visible to near-IR emission from DNA-encapsulated silver clusters ranging in size from 5–11 atoms has been produced and characterized. Importantly, this strong Ag cluster fluorescence can be directly modulated and selectively recovered by optically controlling the dark state residence, even when faced with an overwhelming background. The strength and sequence sensitivity of the oligonucleotide-Ag interaction suggests strategies for fine tuning and stabilizing cluster-based emitters in a host of sensing and biolabeling applications that would benefit from brighter, more photostable, and quantifiable emitters in high background environments. PMID:23745165

  1. Carbon Nanotube Synthesis Using Mesoporous Silica Templates

    SciTech Connect

    Zheng, Feng; Liang, Liang; Gao, Yufei; Sukamto, Johanes H.; Aardahl, Chris L.

    2002-07-01

    Well-aligned carbon nanotubes (CNTs) were grown on mesoporous silica films by chemical vapor deposition (CVD). Ethylene was used as the carbon source and CVD was performed at 1023 K and atmospheric pressure. The films were doped with Fe during gelation, and three different structure directing agents were used for mesoporous silica synthesis: polyoxyethylene (10) cetyl ether (C16EO10), Pluronic tri-block copolymer (P123), and cetyltriethylammonium chloride (CTAC). A high degree of CNT alignment on C16EO10-mesoporous silica films was produced at Fe:Si molar ratio of 1.80. Similar alignment of CNTs was achieved on the other two types of films but on CTAC-mesoporous silica films, CNTs only grew parallel to the substrate surface from the cracks in the films because of the in-plane arrangement of the mesopores in such films. Considerable progress has been made in producing multi-walled carbon nanotubes (CNTs) by catalytic CVD techniques. If CNTs are to be integrated into certain useful devices, it is critical to be able to grow highly aligned arrays of CNTs with narrow size distribution and at specific locations on a substrate. Long-range alignment normal to the substrate results from steric crowding if the initial catalyst sites are sufficiently dense. Alignment may be improved with better control of the density of catalytic sites by means of a template of appropriate pore structure. The confinement of CNTs by the pores during the initial growth may also help align CNTs.

  2. The biogeochemical cycle of the adsorbed template. I - formation of the template

    NASA Technical Reports Server (NTRS)

    Lazard, Daniel; Lahav, Noam; Orenberg, J. B.

    1987-01-01

    Experimental results are presented for the verification of the first adsorption step of the 'adsorbed template' biogeochemical cycle, a simple model for a primitive prebiotic replication system. The adsorption of Poly-C, Poly-U, Poly-A, Poly-G, and 5'-AMP, 5'-GMP, 5'-CMP and 5'-UMP onto gypsum was studied. It was found that under the conditions of the experiment, the polymers have a very high affinity for the mineral surface, while the monomers adsorb much less efficiently.

  3. Analysis of characteristic of microwave regeneration for diesel particulate filter

    SciTech Connect

    Ning Zhi; Zhang Guanglong; Lu Yong; Liu Junmin; Gao Xiyan; Liang Iunhui; Chen Jiahua

    1995-12-31

    The mathematical model for the microwave regeneration of diesel particulate filter is proposed according to the characteristic of microwave regeneration process. The model is used to calculate the temperature field, distribution of particulate and density field of oxygen in the filter during the process of regeneration with typical ceramic foam particulate filter data. The parametric study demonstrates how some of the main parameters, such as microwave attenuation constant of the filter, filter particulate loading, the power and distribution of microwave energy and so on, affect the efficiency of regeneration, the maximum filter temperature and regeneration duration. The results show that it is possible to regenerate the diesel particulate filters in certain conditions by using microwave energy. This paper can give one a whole understanding to several main factors that have effects on the process of microwave regeneration and provide a theoretical basis for the optimal design of the microwave regeneration system.

  4. FENTON-DRIVEN CHEMICAL REGENERATION OF MTBE-SPENT GAC

    EPA Science Inventory

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

  5. Regeneration in spiralians: evolutionary patterns and developmental processes.

    PubMed

    Bely, Alexandra E; Zattara, Eduardo E; Sikes, James M

    2014-01-01

    Animals differ markedly in their ability to regenerate, yet still little is known about how regeneration evolves. In recent years, important advances have been made in our understanding of animal phylogeny and these provide new insights into the phylogenetic distribution of regeneration. The developmental basis of regeneration is also being investigated in an increasing number of groups, allowing commonalities and differences across groups to become evident. Here, we focus on regeneration in the Spiralia, a group that includes several champions of animal regeneration, as well as many groups with more limited abilities. We review the phylogenetic distribution and developmental processes of regeneration in four major spiralian groups: annelids, nemerteans, platyhelminths, and molluscs. Although comparative data are still limited, this review highlights phylogenetic and developmental patterns that are emerging regarding regeneration in spiralians and identifies important avenues for future research. PMID:25690976

  6. Sustainable Regeneration of Nanoparticle Enhanced Activated Carbon in Water

    EPA Science Inventory

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

  7. SOCS3 deletion promotes optic nerve regeneration in vivo

    PubMed Central

    Smith, Patrice D.; Sun, Fang; Park, Kevin Kyungsuk; Cai, Bin; Wang, Chen; Kuwako, Kenichiro; Martinez-Carrasco, Irene; Connolly, Lauren; He, Zhigang

    2009-01-01

    SUMMARY Axon regeneration failure accounts for permanent functional deficits following CNS injury in adult mammals. However, the underlying mechanisms remain elusive. In analyzing axon regeneration in different mutant mouse lines, we discovered that deletion of suppressor of cytokine signaling 3 (SOCS3), in adult retinal ganglion cells (RGCs), promotes robust regeneration of injured optic nerve axons. This regeneration-promoting effect is efficiently blocked in SOCS3-gp130 double knockout mice, suggesting that SOCS3 deletion promotes axon regeneration via a gp130-dependent pathway. Consistently, a transient up-regulation of ciliary neurotrophic factor (CNTF) was observed within the retina following optic nerve injury. Intravitreal application of CNTF further enhances axon regeneration from SOCS3-deleted RGCs. Together, our results suggest that compromised responsiveness to injury-induced growth factors in mature neurons contributes significantly to regeneration failure. Thus, developing strategies to modulate negative signaling regulators may be an efficient strategy of promoting axon regeneration after CNS injury. PMID:20005819

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

    PubMed

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

    2016-06-01

    Hair cells regenerate throughout the lifetime of non-mammalian vertebrates, allowing these animals to recover from hearing and balance deficits. Such regeneration does not occur efficiently in humans and other mammals. Thus, balance deficits become permanent and is a common sensory disorder all over the world. Since Forge and Warchol discovered the limited spontaneous regeneration of vestibular hair cells after gentamicininduced damage in mature mammals, significant efforts have been exerted to trace the origin of the limited vestibular regeneration in mammals after hair cell loss. Moreover, recently many strategies have been developed to promote the hair cell regeneration and subsequent functional recovery of the vestibular system, including manipulating the Wnt, Notch and Atoh1. This article provides an overview of the recent advances in hair cell regeneration in mammalian vestibular epithelia. Furthermore, this review highlights the current limitations of hair cell regeneration and provides the possible solutions to regenerate functional hair cells and to partially restore vestibular function. PMID:27189205

  9. OXYGEN UPTAKE AND NUTRIENT REGENERATION IN THE PECONIC ESTUARY

    EPA Science Inventory

    EXECUTIVE SUMMARY: OXYGEN UPTAKE AND NUTRIENT REGENERATION IN THE PECONIC ESTUARY Rates of oxygen consumption and nutrient regeneration were measured annually throughout the Peconic Estuarine System. Sediment and water column oxygen uptake were measured to determine the potential...

  10. Ordered Nanomaterials Thin Films via Supported Anodized Alumina Templates

    NASA Astrophysics Data System (ADS)

    Es-Souni, Mohammed; Habouti, Salah

    2014-10-01

    Supported anodized alumina template films with highly ordered porosity are best suited for fabricating large area ordered nanostructures with tunable dimensions and aspect ratios. In this paper we first discuss important issues for the generation of such templates, including required properties of the Al/Ti/Au/Ti thin film heterostructure on a substrate for high quality templates. We then show examples of anisotropic nanostructure films consisting of noble metals using these templates, discuss briefly their optical properties and their applications to molecular detection using surface enhanced Raman spectroscopy. Finally we briefly address the possibility to make nanocomposite films, exemplary shown on a plasmonic-thermochromic nanocomposite of VO2-capped Au-nanorods.

  11. Finger multibiometric cryptosystems: fusion strategy and template security

    NASA Astrophysics Data System (ADS)

    Peng, Jialiang; Li, Qiong; Abd El-Latif, Ahmed A.; Niu, Xiamu

    2014-03-01

    We address two critical issues in the design of a finger multibiometric system, i.e., fusion strategy and template security. First, three fusion strategies (feature-level, score-level, and decision-level fusions) with the corresponding template protection technique are proposed as the finger multibiometric cryptosystems to protect multiple finger biometric templates of fingerprint, finger vein, finger knuckle print, and finger shape modalities. Second, we theoretically analyze different fusion strategies for finger multibiometric cryptosystems with respect to their impact on security and recognition accuracy. Finally, the performance of finger multibiometric cryptosystems at different fusion levels is investigated on a merged finger multimodal biometric database. The comparative results suggest that the proposed finger multibiometric cryptosystem at feature-level fusion outperforms other approaches in terms of verification performance and template security.

  12. Object recognition based on spatial active basis template

    NASA Astrophysics Data System (ADS)

    Peng, Shaowu; Xu, Jingcheng

    2011-11-01

    This article presents a method for the object classification that combines a generative template and a discriminative classifier. The method is a variant of the support vector machine (SVM), which uses Multiple Kernel Learning (MKL). The features are extracted from a generative template so called Active Basis template. Before using them for object classification, we construct a visual vocabulary by clustering a set of training features according to their orientations. To keep the spatial information, a "spatial pyramid" is used. The strength of this approach is that it combines the rich information encoded in the generative template, the Active Basis, with the discriminative power of the SVM algorithm. We show promising results of experiments for images from the LHI dataset.

  13. Template based illumination compensation algorithm for multiview video coding

    NASA Astrophysics Data System (ADS)

    Li, Xiaoming; Jiang, Lianlian; Ma, Siwei; Zhao, Debin; Gao, Wen

    2010-07-01

    Recently multiview video coding (MVC) standard has been finalized as an extension of H.264/AVC by Joint Video Team (JVT). In the project Joint Multiview Video Model (JMVM) for the standardization, illumination compensation (IC) is adopted as a useful tool. In this paper, a novel illumination compensation algorithm based on template is proposed. The basic idea of the algorithm is that the illumination of the current block has a strong correlation with its adjacent template. Based on this idea, firstly a template based illumination compensation method is presented, and then a template models selection strategy is devised to improve the illumination compensation performance. The experimental results show that the proposed algorithm can improve the coding efficiency significantly.

  14. Template-Guided Recombination: From Theory to Laboratory

    NASA Astrophysics Data System (ADS)

    Daley, Mark; Domaratzki, Michael

    Template-guided recombination (TGR) is a model for the rearrangement of genomic DNA that takes place in some ciliated protozoa. Originally proposed as a formal model, TGR has been investigated both as a realistic model for genome rearrangement in ciliates and, due to interest in the potential of ciliates as “in vivo computers”, in terms of its computational power. TGR was put forward as a biological hypothesis that certain types of DNA rearrangements in ciliates are primarily controlled by a process of template-matching, where new genes are generated by using old genes as templates. Most significantly, it has recently been experimentally established that gene rearrangement in the stichotrichous ciliate Oxytricha trifallax (Sterkiella histriomuscorum) proceeds in a template-guided fashion. This survey describes recent work on TGR as a biological process and the computational properties of the formal model of TGR.

  15. 21 CFR 888.4800 - Template for clinical use.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) Identification. A template for clinical use is a device that consists of a pattern or guide intended for medical... notification procedures in subpart E of part 807 of this chapter, subject to the limitations in § 888.9....

  16. Method for modifying trigger level for adsorber regeneration

    DOEpatents

    Ruth, Michael J.; Cunningham, Michael J.

    2010-05-25

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

  17. Effect of liver regeneration on malignant hepatic tumors

    PubMed Central

    Shi, Ji-Hua; Line, Pål-Dag

    2014-01-01

    Liver regeneration after major surgery may activate occult micrometastases and facilitate tumor growth, leading to liver tumor recurrence. Molecular changes during liver regeneration can provide a microenvironment that stimulates intrahepatic tumor propagation through alterations in cellular signaling pathways, where activation and proliferation of mature hepatocytes, hepatic progenitor cells, non-parenchymal liver cells might favor both liver regeneration and tumor growth. This review highlights recent advances of tumor growth and development in the regenerating liver, possible mechanisms and clinical implications. PMID:25473170

  18. Advanced regenerator testing in the Raytheon dual-use cryocoolerr

    SciTech Connect

    Schaefer, B. R.; Bellis, L.; Ellis, M. J.; Conrad, T. J.

    2014-01-29

    Significant progress has been made on the Raytheon low cost space cryocooler called the Dual-Use Cryocooler (DUC). Most notably, the DUC has been integrated and tested with an advanced regenerator. The advanced regenerator is a drop-in replacement for stainless steel screens and has shown significant thermodynamic performance improvements. This paper will compare the performance of two different regenerators and explain the benefits of the advanced regenerator.

  19. Advanced regenerator testing in the Raytheon dual-use cryocoolerr

    NASA Astrophysics Data System (ADS)

    Schaefer, B. R.; Bellis, L.; Ellis, M. J.; Conrad, T. J.

    2014-01-01

    Significant progress has been made on the Raytheon low cost space cryocooler called the Dual-Use Cryocooler (DUC). Most notably, the DUC has been integrated and tested with an advanced regenerator. The advanced regenerator is a drop-in replacement for stainless steel screens and has shown significant thermodynamic performance improvements. This paper will compare the performance of two different regenerators and explain the benefits of the advanced regenerator.

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

    NASA Astrophysics Data System (ADS)

    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.

  1. A Template Engine for Parsing Objects from Textual Representations

    NASA Astrophysics Data System (ADS)

    Rajković, Milan; Stanković, Milena; Marković, Ivica

    2011-09-01

    Template engines are widely used for separation of business and presentation logic. They are commonly used in web applications for clean rendering of HTML pages. Another area of usage is message formatting in distributed applications where they transform objects to appropriate representations. This paper explores the possibility of using templates for a reverse process—for creating objects starting from their representations. We present the prototype of engine that we have developed, and describe benefits and drawbacks of this approach.

  2. Studies of Template-based Photometric Classification of Supernovae

    NASA Astrophysics Data System (ADS)

    Asimacopoulos, Leia; Londo, Stephen; Macaluso, Joseph; Cunningham, John; Kuhlmann, Steve; Kovacs, Eve

    2016-01-01

    We study photometric classification of Type Ia (SNIa) and core collapse (SNcc) supernovae using a combination of simulated data from DES and real data from SDSS. We increase the number of core collapse templates from the eight commonly used to type SDSS supernovae (PSNID) to forty-five currently available in SNANA. These are implemented in the SNCosmo analysis package. Our goal is to study the accuracy in identifying all types of supernovae as a function of numbers and types of templates.

  3. Epitaxial Templating of C60 with a Molecular Monolayer.

    PubMed

    Rochford, L A; Jones, T S; Nielsen, C B

    2016-09-01

    Commensurate epitaxial monolayers of truxenone on Cu (111) were employed to template the growth of monolayer and bilayer C60. Through the combination of STM imaging and LEED analysis we have demonstrated that C60 forms a commensurate 8 × 8 overlayer on truxenone/Cu (111). Bilayers of C60 retain the 8 × 8 periodicity of templated monolayers and although Kagome lattice arrangements are observed these are explained with combinations of 8 × 8 symmetry. PMID:27540868

  4. Templating as a Chain of Custody Tool for Arms Control

    SciTech Connect

    Benz, Jacob M.; Tanner, Jennifer E.; Duckworth, Leesa L.

    2013-06-01

    Historically, templates have been considered for use as a treaty accountable item (TAI) authentication tool, alongside item attributes. Because of this, the use of templates has fallen by the wayside due to the perceived intrusiveness of and handling/storage of template data; especially when compared to the negotiability of unclassified attribute threshold values. However, as a chain of custody tool, templates potentially have a large and important role to play in maintaining confidence in the authenticity of the treaty accountable items as they progress through an arms control regime. In general terms, templating is the process of creating a unique, measurable, and repeatable signature which is representative of the TAI. At any point in time, the signature can be re-measured or re-inspected to verify the signature has not changed. Chain of custody is the process by which a controlled boundary is established and maintained around a TAI to both deter and detect unauthorized access to the item. Typically, this is accomplished by putting a tamper indicating device (TID) on the item or container. The TID now acts as a surrogate for the item itself, and is continually checked to ensure the unique identifier and tamper indicating mechanisms have not changed since last inspection. This in and of itself is a form of templating. A stronger template is one that utilizes a signature of the combined item and container. There are many potential signatures which may be exploited, including radiation-, electromagnetic-, and acoustic-based signatures. This paper/presentation will explore the technology and mechanisms in which templating can be applied to create a more robust chain of custody over treaty accountable items as part of a future arms control regime.

  5. Template synthesis of bismuth telluride nanowires. Interim report

    SciTech Connect

    Sapp, S.A.; Lakshmi, B.B.; Martin, C.R.

    1998-12-01

    The authors report the fabrication of thermoelectric bismuth telluride nanowires using the template synthesis method. A simple electrodeposition procedure was used to produce the nanowires within the pores of an alumina filtration membrane. The resulting bismuth telluride/alumina composite membranes constitute an array of thermoelectric nanowires surrounded by a thermally and electrically insulating matrix. The individual bismuth telluride nanowires can be isolated by removal of the template membrane. These nanowires were characterized and found to be composed of stoichiometric bismuth telluride.

  6. Stem Cells for Bone Regeneration: From Cell-Based Therapies to Decellularised Engineered Extracellular Matrices

    PubMed Central

    Fisher, James N.; Peretti, Giuseppe M.; Scotti, Celeste

    2016-01-01

    Currently, autologous bone grafting represents the clinical gold standard in orthopaedic surgery. In certain cases, however, alternative techniques are required. The clinical utility of stem and stromal cells has been demonstrated for the repair and regeneration of craniomaxillofacial and long bone defects although clinical adoption of bone tissue engineering protocols has been very limited. Initial tissue engineering studies focused on the bone marrow as a source of cells for bone regeneration, and while a number of promising results continue to emerge, limitations to this technique have prompted the exploration of alternative cell sources, including adipose and muscle tissue. In this review paper we discuss the advantages and disadvantages of cell sources with a focus on adipose tissue and the bone marrow. Additionally, we highlight the relatively recent paradigm of developmental engineering, which promotes the recapitulation of naturally occurring developmental processes to allow the implant to optimally respond to endogenous cues. Finally we examine efforts to apply lessons from studies into different cell sources and developmental approaches to stimulate bone growth by use of decellularised hypertrophic cartilage templates. PMID:26997959

  7. Hybrid Matrix Grafts to Favor Tissue Regeneration in Rabbit Femur Bone Lesions

    PubMed Central

    Goy, Dante Pascual; Gorosito, Emmanuel; Costa, Hermes S; Mortarino, Pablo; Pedemonte, Noelia Acosta; Toledo, Javier; Mansur, Herman S; Pereira, Marivalda M; Battaglino, Ricardo; Feldman, Sara

    2012-01-01

    At present, typical approaches employed to repair fractures and other bone lesions tend to use matrix grafts to promote tissue regeneration. These grafts act as templates, which promote cellular adhesion, growth and proliferation, osteoconduction, and even osteoinduction, which commonly results in de novo osteogenesis. The present work aimed to study the bone-repairing ability of hybrid matrixes (HM) prepared with polyvinyl alcohol (PVA) and bioactive glass in an experimental rabbit model. The HM were prepared by combining 30% bioactive glass (nominal composition of 58% SiO2 -33 % CaO - 9% P2O5) and 70% PVA. New Zealand rabbits were randomly divided into the control group (C group) and two groups with bone lesions, in which one received a matrix implant HM (Implant group), while the other did not (no Implant group). Clinical monitoring showed no altered parameters from either the Implant or the no Implant groups as compared to the control group, for the variables of diet grades, day and night temperatures and hemograms. In the Implant group, radiologic and tomographic studies showed implanted areas with clean edges in femoral non-articular direction, and radio-dense images that suggest incipient integration. Minimum signs of phlogosis could be observed, whereas no signs of rejection at this imaging level could be identified. Histological analysis showed evidence of osteo-integration, with the formation of a trabecular bone within the implant. Together, these results show that implants of hybrid matrixes of bioactive glass are capable of promoting bone regeneration. PMID:22848334

  8. Stem Cells for Bone Regeneration: From Cell-Based Therapies to Decellularised Engineered Extracellular Matrices.

    PubMed

    Fisher, James N; Peretti, Giuseppe M; Scotti, Celeste

    2016-01-01

    Currently, autologous bone grafting represents the clinical gold standard in orthopaedic surgery. In certain cases, however, alternative techniques are required. The clinical utility of stem and stromal cells has been demonstrated for the repair and regeneration of craniomaxillofacial and long bone defects although clinical adoption of bone tissue engineering protocols has been very limited. Initial tissue engineering studies focused on the bone marrow as a source of cells for bone regeneration, and while a number of promising results continue to emerge, limitations to this technique have prompted the exploration of alternative cell sources, including adipose and muscle tissue. In this review paper we discuss the advantages and disadvantages of cell sources with a focus on adipose tissue and the bone marrow. Additionally, we highlight the relatively recent paradigm of developmental engineering, which promotes the recapitulation of naturally occurring developmental processes to allow the implant to optimally respond to endogenous cues. Finally we examine efforts to apply lessons from studies into different cell sources and developmental approaches to stimulate bone growth by use of decellularised hypertrophic cartilage templates. PMID:26997959

  9. The Affordance Template ROS Package for Robot Task Programming

    NASA Technical Reports Server (NTRS)

    Hart, Stephen; Dinh, Paul; Hambuchen, Kimberly

    2015-01-01

    This paper introduces the Affordance Template ROS package for quickly programming, adjusting, and executing robot applications in the ROS RViz environment. This package extends the capabilities of RViz interactive markers by allowing an operator to specify multiple end-effector waypoint locations and grasp poses in object-centric coordinate frames and to adjust these waypoints in order to meet the run-time demands of the task (specifically, object scale and location). The Affordance Template package stores task specifications in a robot-agnostic XML description format such that it is trivial to apply a template to a new robot. As such, the Affordance Template package provides a robot-generic ROS tool appropriate for building semi-autonomous, manipulation-based applications. Affordance Templates were developed by the NASA-JSC DARPA Robotics Challenge (DRC) team and have since successfully been deployed on multiple platforms including the NASA Valkyrie and Robonaut 2 humanoids, the University of Texas Dreamer robot and the Willow Garage PR2. In this paper, the specification and implementation of the affordance template package is introduced and demonstrated through examples for wheel (valve) turning, pick-and-place, and drill grasping, evincing its utility and flexibility for a wide variety of robot applications.

  10. Template-directed synthesis of oligonucleotides under eutectic conditions

    NASA Technical Reports Server (NTRS)

    Stribling, R.; Miller, S. L.

    1991-01-01

    One of the most important sets of model prebiotic experiments consists of reactions that synthesize complementary oligonucleotides from preformed templates under nonenzymatic conditions. Most of these experiments are conducted at 4 degrees C using 0.01-0.1 M concentrations of activated nucleotide monomer and template (monomer equivalent). In an attempt to extend the conditions under which this type of reaction can occur, we have concentrated the reactants by freezing at -18 degrees C, which is close to the NaCl-H2O eutectic at -21 degrees C. The results from this set of experiments suggest that successful syntheses can occur with poly(C) concentrations as low at 5 x 10(-4) M and 2MeImpG concentrations at 10(-3) M. It was also anticipated that this mechanism might allow the previously unsuccessful poly(A)-directed synthesis of oligo(U)s to occur. However, no template effect was seen with the poly(A) and ImpU system. The failure of these conditions to allow template-directed synthesis of oligo(U)s supports the previously proposed idea that pyrimidines may not have been part of the earliest genetic material. Because of the low concentrations of monomer and template that would be expected from prebiotic syntheses, this lower temperature could be considered a more plausible geologic setting for template-directed synthesis than the standard reaction conditions.

  11. Biomimetic radical polymerization via cooperative assembly of segregating templates

    NASA Astrophysics Data System (ADS)

    McHale, Ronan; Patterson, Joseph P.; Zetterlund, Per B.; O'Reilly, Rachel K.

    2012-06-01

    Segregation and templating approaches have been honed by billions of years of evolution to direct many complex biological processes. Nature uses segregation to improve biochemical control by organizing reactants into defined, well-regulated environments, and the transfer of genetic information is a primary function of templating. The ribosome, wherein messenger RNA is translated into polypeptides, combines both techniques to allow for ideal biopolymer syntheses. Herein is presented a biomimetic segregation/templating approach to synthetic radical polymerization. Polymerization of a nucleobase-containing vinyl monomer in the presence of a complementary block copolymer template of low molecular weight yields high molecular weight (Mw up to ~400,000 g mol-1), extremely low polydispersity (≤1.08) daughter polymers. Control is attained by segregation of propagating radicals in discrete micelle cores (via cooperative assembly of dynamic template polymers). Significantly reduced bimolecular termination, combined with controlled propagation along a defined number of templates, ensures unprecedented control to afford well-defined high molecular weight polymers.

  12. Formation of novel morphologies of aragonite induced by inorganic template

    SciTech Connect

    Wang, Xiaoming; Nan, Zhaodong

    2011-07-15

    Graphical abstract: Glass-slices were used as a template to induce formation and assembly of aragonite. Different morphologies, such as hemisphere, twinborn hemisphere and flower-shaped particles, were produced by direction of the glass-slices. Highlights: {yields} Glass-slices were used as a template to induce formation and assembly of aragonite. {yields} Hemisphere, twinborn hemisphere and flower-shaped particles were produced by direction of the glass-slices. {yields} Planes were always appeared in these as-synthesized samples. {yields} Thermodynamic theory was applied to explain the production of the aragonite. -- Abstract: A glass-slice was used as a template to induce formation and assembly of aragonite. Thermodynamic theory was applied to explain the production of the aragonite. Transformation of three-dimensional nucleation to template-based two-dimensional surface nucleation caused the production of aragonite. Hemisphere, twinborn hemisphere and flower-shaped particles were produced by direction of the glass-slices. Planes were always appeared in these as-synthesized samples because the nucleation and the growth of these samples were adsorbed at the surfaces of the glass-slices. The formation mechanism of the as-formed sample was proposed. Compared with organic template, the present study provides a facile method to apply inorganic template to prepare functional materials.

  13. Silver nanowires-templated metal oxide for broadband Schottky photodetector

    NASA Astrophysics Data System (ADS)

    Patel, Malkeshkumar; Kim, Hong-Sik; Park, Hyeong-Ho; Kim, Joondong

    2016-04-01

    Silver nanowires (AgNWs)-templated transparent metal oxide layer was applied for Si Schottky junction device, which remarked the record fastest photoresponse of 3.4 μs. Self-operating AgNWs-templated Schottky photodetector showed broad wavelength photodetection with high responsivity (42.4 A W-1) and detectivity (2.75 × 1015 Jones). AgNWs-templated indium-tin-oxide (ITO) showed band-to-band excitation due to the internal photoemission, resulting in significant carrier collection performances. Functional metal oxide layer was formed by AgNWs-templated from ITO structure. The grown ITO above AgNWs has a cylindrical shape and acts as a thermal protector of AgNWs for high temperature environment without any deformation. We developed thermal stable AgNWs-templated transparent oxide devices and demonstrated the working mechanism of AgNWs-templated Schottky devices. We may propose the high potential of hybrid transparent layer design for various photoelectric applications, including solar cells.

  14. EYTHYLENE INFLUENCES GREEN PLANT REGENERATION FROM BARLEY CALLUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The plant hormone ethylene is involved in numerous plant processes including in vitro growth and regeneration. Manipulating ethylene in vitro may be useful for increasing plant regeneration from cultured cells. As part of ongoing efforts to improve plant regeneration from barley (Hordeum vulgare L...

  15. Thymus: the next (re)generation.

    PubMed

    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

  16. Organ repair and regeneration: an overview.

    PubMed

    Baddour, Joëlle A; Sousounis, Konstantinos; Tsonis, Panagiotis A

    2012-03-01

    A number of organs have the intrinsic ability to regenerate, a distinctive feature that varies among organisms. Organ regeneration is a process not fully yet understood. However, when its underlying mechanisms are unraveled, it holds tremendous therapeutic potential for humans. In this review, we chose to summarize the repair and regenerative potential of the following organs and organ systems: thymus, adrenal gland, thyroid gland, intestine, lungs, heart, liver, blood vessels, germ cells, nervous system, eye tissues, hair cells, kidney and bladder, skin, hair follicles, pancreas, bone, and cartilage. For each organ, a review of the following is presented: (a) factors, pathways, and cells that are involved in the organ's intrinsic regenerative ability, (b) contribution of exogenous cells - such as progenitor cells, embryonic stem cells, induced pluripotent stem cells, and bone marrow-, adipose- and umbilical cord blood-derived stem cells - in repairing and regenerating organs in the absence of an innate intrinsic regenerative capability, (c) and the progress made in engineering bio-artificial scaffolds, tissues, and organs. Organ regeneration is a promising therapy that can alleviate humans from diseases that have not been yet cured. It is also superior to already existing treatments that utilize exogenous sources to substitute for the organ's lost structure and/or function(s). PMID:22457174

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

    ERIC Educational Resources Information Center

    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…

  18. Regeneration of zinc chloride hydrocracking catalyst

    DOEpatents

    Zielke, Clyde W.

    1979-01-01

    Improved rate of recovery of zinc values from the solids which are carried over by the effluent vapors from the oxidative vapor phase regeneration of spent zinc chloride catalyst is achieved by treatment of the solids with both hydrogen chloride and calcium chloride to selectively and rapidly recover the zinc values as zinc chloride.

  19. Regenerating America: Opportunities To Build On.

    ERIC Educational Resources Information Center

    Rodale Press, Inc., Emmaus, PA.

    Many communities are unaware of the power they have and are therefore unfamiliar with how to use it. This document, by the Regeneration Project in Emmaus, Pennsylvania, is directed toward helping community leaders identify and develop opportunities that will help them expand their businesses, employment, and tax base, and improve their overall…

  20. The microbial challenge to pulp regeneration.

    PubMed

    Fouad, A F

    2011-07-01

    Pulp regeneration is considered in cases where the dental pulp has been destroyed because of microbial irritation. Diverse oral and food-borne micro-organisms are able to invade the pulp space, form biofilm on canal walls, and infiltrate dentinal tubules. Prior to pulp regeneration procedures, the pulp space and dentinal walls need to be sufficiently disinfected to allow for and promote regeneration. The necessary level of disinfection is likely higher than that accepted for traditional endodontic therapy, because in traditional techniques the mere lowering of bacterial loads and prevention of bacterial access to periapical tissues is conducive to healing. Moreover, several of the non-specific antimicrobials used in traditional endodontic therapy may cause significant changes in remaining dentin that interfere with its inherent potential to mediate regeneration. Non-specific antimicrobials also suppress all microbial taxa, which may allow residual virulent micro-organisms to preferentially repopulate the pulp space. Therefore, it is important for endodontic pathogens to be studied by molecular methods that allow for a broad depth of coverage. It is then essential to determine the most effective protocols to disinfect the pulp space, with minimal disruption of remaining dentin. These protocols include the topical use of effective antibiotics, including newer agents that have demonstrated efficacy against endodontic pathogens. PMID:21677080

  1. The Role of Schools in Area Regeneration

    ERIC Educational Resources Information Center

    Cummings, Colleen; Dyson, Alan

    2007-01-01

    There is evidence in recent Government policy in England of the emergence of a wider role for schools in relation to the neighbourhoods they serve. In particular, the National Strategy for Neighbourhood Renewal in England sets the work of schools within the context of an overarching regeneration strategy. The study reported here, sponsored by the…

  2. Gene therapy approaches to regenerating bone

    PubMed Central

    Bleich, Nadav Kimelman; Kallai, Ilan; Lieberman, Jay R.; Schwarz, Edward M.; Pelled, Gadi; Gazit, Dan

    2013-01-01

    Bone formation and regeneration therapies continue to require optimization and improvement because many skeletal disorders remain undertreated. Clinical solutions to nonunion fractures and osteoporotic vertebral compression fractures, for example, remain suboptimal and better therapeutic approaches must be created. The widespread use of recombinant human bone morphogenetic proteins (rhBMPs) for spine fusion was recently questioned by a series of reports in a special issue of The Spine Journal, which elucidated the side effects and complications of direct rhBMP treatments. Gene therapy—both direct (in vivo) and cell-mediated (ex vivo)—has long been studied extensively to provide much needed improvements in bone regeneration. In this article, we review recent advances in gene therapy research whose aims are in vivo or ex vivo bone regeneration or formation. We examine appropriate vectors, safety issues, and rates of bone formation. The use of animal models and their relevance for translation of research results to the clinical setting are also discussed in order to provide the reader with a critical view. Finally, we elucidate the main challenges and hurdles faced by gene therapy aimed at bone regeneration as well as expected future trends in this field. PMID:22429662

  3. Periodontal regeneration in gingival recession defects.

    PubMed

    Trombelli, L

    1999-02-01

    Surgical treatment of gingival recession defects aims at obtaining soft tissue coverage of exposed root surfaces and/or augmentation of gingival tissue dimensions. A variety of protocols have been developed to manage these clinical problems. Since one goal of periodontal therapy is the regeneration of the lost attachment apparatus of the tooth, full restoration of defect should be accomplished following mucogingival procedures. This implies regeneration of all periodontal structures, including formation of new cementum with inserting connective tissue fibers, alveolar bone regeneration and recreation of a functional and aesthetic morphology of the mucogingival complex. Animal and human histological studies have shown that healing at gingiva-root interface following pedicle flaps or free soft tissue grafts generally includes a long junctional epithelium with varying amounts of a new connective tissue attachment in the most apical aspect of the covered root surface. Limited bone regeneration has been observed. Adjunctive use of root conditioning agents and cell excluding, wound-stabilizing devices may amplify regenerative outcomes. Changes in the amount of keratinized tissue, which can significantly affect the aesthetic outcome of treatment, have been shown to depend on the interactions among various tissues involved in the healing process and the selected surgical procedure. PMID:10321221

  4. Feasibility study of silicon nitride regenerators

    NASA Technical Reports Server (NTRS)

    Fucinari, C. A.; Rao, V. D. N.

    1979-01-01

    The feasibility of silicon nitride as a regenerator matrix material for applications requiring inlet temperatures above 1000 C is examined. The present generation oxide ceramics are used as a reference to examine silicon nitride from a material characteristics, manufacturing, thermal stress and aerothermodynamic viewpoint.

  5. Conduction in regenerating dorsal root fibres.

    PubMed

    Feasby, T E; Bostock, H; Sears, T A

    1981-03-01

    Rat dorsal roots were crushed and recordings of compound action potentials and single fibre longitudinal currents were made 12-85 days later from the regenerating portions. Maximum conduction velocities rose from 1.3 m/s at day 10 to 25.7 m/s by day 41 and single fibre velocities varied from 1.2 m/s at 12 days postcrush to 23.8 m/s at 85 days. Many fibres appeared to conduct continuously in the early stages, although the resolution of the technique was insufficient to exclude saltatory conduction over short internodes. Two fibres showed internodes of about 200 microns at 9 and 13 days of regeneration, suggesting that "nodal" regions may be formed before significant myelination. At 27 days post-crush and later, internodes were 300-425 microns in length. Many regenerating fibres had branches, both retrograde and orthograde. Reduced conduction velocities in rostral portions of regenerating fibres suggested tapering. PMID:6260903

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

    SciTech Connect

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

    2009-03-13

    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.

  7. Template Matching Approach to Signal Prediction

    NASA Technical Reports Server (NTRS)

    Mackey, Ryan; Kulikov, Igor

    2010-01-01

    A new approach to signal prediction and prognostic assessment of spacecraft health resolves an inherent difficulty in fusing sensor data with simulated data. This technique builds upon previous work that demonstrated the importance of physics-based transient models to accurate prediction of signal dynamics and system performance. While models can greatly improve predictive accuracy, they are difficult to apply in general because of variations in model type, accuracy, or intended purpose. However, virtually any flight project will have at least some modeling capability at its disposal, whether a full-blown simulation, partial physics models, dynamic look-up tables, a brassboard analogue system, or simple hand-driven calculation by a team of experts. Many models can be used to develop a predict, or an estimate of the next day s or next cycle s behavior, which is typically used for planning purposes. The fidelity of a predict varies from one project to another, depending on the complexity of the simulation (i.e. linearized or full differential equations) and the level of detail in anticipated system operation, but typically any predict cannot be adapted to changing conditions or adjusted spacecraft command execution. Applying a predict blindly, without adapting the predict to current conditions, produces mixed results at best, primarily due to mismatches between assumed execution of spacecraft activities and actual times of execution. This results in the predict becoming useless during periods of complicated behavior, exactly when the predict would be most valuable. Each spacecraft operation tends to show up as a transient in the data, and if the transients are misaligned, using the predict can actually harm forecasting performance. To address this problem, the approach here expresses the predict in terms of a baseline function superposed with one or more transient functions. These transients serve as signal templates, which can be relocated in time and space against

  8. Virus Assemblies as Templates for Nanocircuits

    SciTech Connect

    James N. Culver; Michael T. Harris

    2002-09-25

    Advances in nanotechnology offer significant improvements in a wide range of applications that include, light weight materials with greater strength, increased energy efficiency from electronic devices, and better sensors for a range of environmental and manufacturing uses. Furthermore, since size constraints often produce qualitative changes in the characteristics of matter, it is anticipated that the exploitation of nanotechnology will result in the identification of new phenomena and functionalities derived from the physics, chemistry, and biology of matter at the nanoscale level. However, these advances will require the development of systems for the design, modeling, and synthesis of nanoscale materials. Interestingly, many biological molecules function on this scale and possess unique properties that impart the ability to assume defined conformations and assembles, as well as interact with specific chemical or biological substrates. These traits are ideally suited for developing new models and methods for the production of novel materials at the nanoscale level. The goal of this proposal is to combine expertise in biology/protein engineering (Dr. Culver, University of Maryland Biotechnology Institute) and chemical engineering/nanophase structures (Dr. Harris, Purdue University) to develop biological macromolecules suitable for use in a variety of nanotechnologies. Specifically, this work will focus on using the well-defined assembly process of Tobacco mosaic virus (TMV) as a model system for the production of template-dependent nanoparticles and nanowires. Plant viruses, such as TMV, produce remarkably stable virions that consist of identical protein subunits arranged to form larger macromolecules such as rods and spheres. The internal and external surfaces of these macromolecules contain repeating patterns of charged amino acids that can be used for the ordered nucleation of inorganic solids such as copper or gold. In addition, using molecular method s it is

  9. Inhibition of non-templated nucleotide addition by DNA polymerases in primer extension using twisted intercalating nucleic acid modified templates.

    PubMed

    Güixens-Gallardo, Pedro; Hocek, Michal; Perlíková, Pavla

    2016-01-15

    A simple and elegant method for inhibition of non-templated nucleotide addition by DNA polymerases and for following DNA 3'-heterogeneity in enzymatic DNA synthesis by primer extension (PEX) is described. When template bearing ortho-twisted intercalating nucleic acid (ortho-TINA) at the 5'-end is used, non-templated nucleotide addition is reduced in both the A- and B-family DNA polymerases (KOD XL, KOD (exo-), Bst 2.0, Therminator, Deep Vent (exo-) and Taq). Formation of a single oligonucleotide product was observed with ortho-TINA modified template and KOD XL, KOD (exo-), Bst 2.0, Deep Vent (exo-) and Taq DNA polymerases. This approach can be applied to the synthesis of both unmodified and base-modified oligonucleotides. PMID:26707394

  10. Circulating Extracellular RNA Markers of Liver Regeneration

    PubMed Central

    Yan, Irene K.; Wang, Xue; Asmann, Yan W.; Haga, Hiroaki; Patel, Tushar

    2016-01-01

    Background and Aims Although a key determinant of hepatic recovery after injury is active liver regeneration, the ability to detect ongoing regeneration is lacking. The restoration of liver mass after hepatectomy involves systemic changes with coordinated changes in gene expression guiding regenerative responses, activation of progenitor cells, and proliferation of quiescent hepatocytes. We postulated that these responses involve intercellular communication involving extracellular RNA and that these could represent biomarkers of active regenerative responses. Methods RNA sequencing was performed to identify temporal changes in serum extracellular non-coding RNA after partial hepatectomy in C57BL/6 male mice. Tissue expression of selected RNA was performed by microarray analysis and validated using qRT-PCR. Digital PCR was used to detect and quantify serum expression of selected RNA. Results A peak increase in extracellular RNA content occurred six hours after hepatectomy. RNA sequencing identified alterations in several small non-coding RNA including known and novel microRNAs, snoRNAs, tRNA, antisense and repeat elements after partial hepatectomy. Combinatorial effects and network analyses identified signal regulation, protein complex assembly, and signal transduction as the most common biological processes targeted by miRNA that altered. miR-1A and miR-181 were most significantly altered microRNA in both serum and in hepatic tissues, and their presence in serum was quantitated using digital PCR. Conclusions Extracellular RNA selectively enriched during acute regeneration can be detected within serum and represent biomarkers of ongoing liver regeneration in mice. The ability to detect ongoing active regeneration would improve the assessment of hepatic recovery from liver injury. PMID:27415797

  11. Polydopamine-Templated Hydroxyapatite Reinforced Polycaprolactone Composite Nanofibers with Enhanced Cytocompatibility and Osteogenesis for Bone Tissue Engineering.

    PubMed

    Gao, Xiang; Song, Jinlin; Ji, Ping; Zhang, Xiaohong; Li, Xiaoman; Xu, Xiao; Wang, Mengke; Zhang, Siqi; Deng, Yi; Deng, Feng; Wei, Shicheng

    2016-02-10

    Nanohydroxyapatite (HA) synthesized by biomimetic strategy is a promising nanomaterial as bone substitute due to its physicochemical features similar to those of natural nanocrystal in bone tissue. Inspired by mussel adhesive chemistry, a novel nano-HA was synthesized in our work by employing polydopamine (pDA) as template under weak alkaline condition. Subsequently, the as-prepared pDA-templated HA (tHA) was introduced into polycaprolactone (PCL) matrix via coelectrospinning, and a bioactive tHA/PCL composite nanofiber scaffold was developed targeted at bone regeneration application. Our research showed that tHA reinforced PCL composite nanofibers exhibited favorable cytocompatibility at given concentration of tHA (0-10 w.t%). Compared to pure PCL and traditional nano-HA enriched PCL (HA/PCL) composite nanofibers, enhanced cell adhesion, spreading and proliferation of human mesenchymal stem cells (hMSCs) were observed on tHA/PCL composite nanofibers on account of the contribution of pDA present in tHA. More importantly, tHA nanoparticles exposed on the surface of composite nanofibers could further promote osteogenesis of hMSCs in vitro even in the absence of osteogenesis soluble inducing factors when compared to traditional HA/PCL scaffolds, which was supported by in vivo test as well according to the histological analysis. Overall, our study demonstrated that the developed tHA/PCL composite nanofibers with enhanced cytocompatibility and osteogenic capacity hold great potential as scaffolds for bone tissue engineering. PMID:26756224

  12. Lizard tail skeletal regeneration combines aspects of fracture healing and blastema-based regeneration.

    PubMed

    Lozito, Thomas P; Tuan, Rocky S

    2016-08-15

    Lizards are amniotes with the remarkable ability to regenerate amputated tails. The early regenerated lizard tail forms a blastema, and the regenerated skeleton consists of a cartilage tube (CT) surrounding the regenerated spinal cord. The proximal, but not distal, CT undergoes hypertrophy and ossifies. We hypothesized that differences in cell sources and signaling account for divergent cartilage development between proximal and distal CT regions. Exogenous spinal cord implants induced ectopic CT formation in lizard (Anolis carolinensis) blastemas. Regenerated spinal cords expressed Shh, and cyclopamine inhibited CT induction. Blastemas containing vertebrae with intact spinal cords formed CTs with proximal hypertrophic regions and distal non-hypertrophic regions, whereas removal of spinal cords resulted in formation of proximal CT areas only. In fate-mapping studies, FITC-labeled vertebra periosteal cells were detected in proximal, but not distal, CT areas. Conversely, FITC-labeled blastema cells were restricted to distal CT regions. Proximal cartilage formation was inhibited by removal of periosteum and could be recapitulated in vitro by periosteal cells treated with Ihh and BMP-2. These findings suggest that proximal CTs are directly derived from vertebra periosteal cells in response to BMP and Ihh signaling, whereas distal CTs form from blastema cells in response to Shh signals from regenerated spinal cords. PMID:27387871

  13. Nonenzymatic template-directed synthesis on hairpin oligonucleotides. III - Incorporation of adenosine and uridine residues

    NASA Technical Reports Server (NTRS)

    Wu, Taifeng; Orgel, Leslie E.

    1992-01-01

    Nonenzymatic template-directed incorporation of adenosine and uridine residues into template sequences was obtained using nucleoside-5-prime phosphoro (2-methyl)imidazolides as substrates and hairpin oligonucleotides as templates. The reactions are regiospecific, producing mainly 3-prime-5-prime phosphodiester bonds. Limited synthesis of CA and AC sequences was observed along with some synthesis of the AA sequences on templates containing TG and GT sequences, along wilth some synthesis of the AA sequences on templates containing TT sequences.

  14. Molecular template-directed synthesis of microporous polymer networks for highly selective CO2 capture.

    PubMed

    Shi, Yao-Qi; Zhu, Jing; Liu, Xiao-Qin; Geng, Jian-Cheng; Sun, Lin-Bing

    2014-11-26

    Porous polymer networks have great potential in various applications including carbon capture. However, complex monomers and/or expensive catalysts are commonly used for their synthesis, which makes the process complicated, costly, and hard to scale up. Herein, we develop a molecular template strategy to fabricate new porous polymer networks by a simple nucleophilic substitution reaction of two low-cost monomers (i.e., chloromethylbenzene and ethylene diamine). The polymerization reactions can take place under mild conditions in the absence of any catalysts. The resultant materials are interconnected with secondary amines and show well-defined micropores due to the structure-directing role of solvent molecules. These properties make our materials highly efficient for selective CO2 capture, and unusually high CO2/N2 and CO2/CH4 selectivities are obtained. Furthermore, the adsorbents can be completely regenerated under mild conditions. Our materials may provide promising candidates for selective capture of CO2 from mixtures such as flue gas and natural gas. PMID:25401996

  15. The zebrafish as a model of heart regeneration.

    PubMed

    Raya, Angel; Consiglio, Antonella; Kawakami, Yasuhiko; Rodriguez-Esteban, Concepcion; Izpisúa-Belmonte, Juan Carlos

    2004-01-01

    Regeneration is a complex biological process by which animals can restore the shape, structure and function of body parts lost after injury, or after experimental amputation. Only a few species of vertebrates display the capacity to regenerate body parts during adulthood. In the case of the heart, newts display a remarkable ability to regenerate large portions of myocardium after amputation, although the mechanisms underlying this process have not been addressed. Recently, it has been shown that adult zebrafish can also regenerate their hearts, thus offering new possibilities for experimentally approaching this fascinating biological phenomenon. The first insights into heart regeneration gained by studying this model organism are reviewed here. PMID:15671662

  16. Electrocardiographic textbooks based on template hearts warped using ultrasonic images.

    PubMed

    Arthur, R Martin; Trobaugh, Jason W

    2012-09-01

    Advances in technology make the application of sophisticated approaches to assessing electrical condition of the heart practical. Estimates of cardiac electrical features inferred from body-surface electrocardiographic (ECG) maps are now routinely found in a clinical setting, but errors in those inverse solutions are especially sensitive to the accuracy of heart model geometry and placement within the torso. The use of a template heart model allows for accurate generation of individualized heart models and also permits effective comparison of inferred electrical features among multiple subjects. A collection of features mapped onto a common template forms a textbook of anatomically specific ECG variability. Our template warping process to individualize heart models based on a template heart uses ultrasonic images of the heart from a conventional, phased-array system. We chose ultrasound because it is nonionizing, less expensive, and more convenient than MR or CT imaging. To find the orientation and position in the torso model of each image, we calibrated the ultrasound probe by imaging a custom phantom consisting of multiple N-fiducials and computing a transformation between ultrasound coordinates and measurements of the torso surface. The template heart was warped using a mapping of corresponding landmarks identified on both the template and the ultrasonic images. Accuracy of the method is limited by patient movement, tracking error, and image analysis. We tested our approach on one normal control and one obese diabetic patient using the mixed-boundary-value inverse method and compared results from both on the template heart. We believe that our novel textbook approach using anatomically specific heart and torso models will facilitate the identification of electrophysiological biomarkers of cardiac dysfunction. Because the necessary data can be acquired and analyzed within about 30 min, this framework has the potential for becoming a routine clinical procedure

  17. Nanoparticle Array Assembly Using Chemical Templates

    NASA Astrophysics Data System (ADS)

    Adams, Sarah Marie

    This dissertation demonstrates chemically-driven self-assembly techniques to produce assemblies of closely-spaced metal nanoparticles from colloidal nanoparticle solution in order to engineer enhanced optical fields. Planar nanoparticle assemblies provide a platform for a multitude of applications and material architectures. With nanoscale inter-particle spacing, metallic nanoparticles enable increased efficiency of photovoltaic devices due to light focusing and enhancement of electromagnetic fields useful for optical sensing of molecules due to coupling of the plasmon resonance in nanoparticle gaps. For molecular sensors, development of self-assembled two-dimensional assemblies of closely-spaced nanoparticles is useful for producing surface plasmon resonance sensors and surface-enhanced Raman spectroscopy (SERS) based sensing. Using chemical self-assembly, monodisperse, colloidal gold nanoparticles were attached on self-organized polymer templates in order to pattern assemblies of nanoparticle clusters with sub-10 nanometer inter-particle spacing. First citrate-stabilized Au nanoparticles were functionalized with thioctic acid ligands in solution. Then poly(methyl methacrylate) domains in phase-separated poly(styrene-block-methyl methacrylate) (PS-b-PMMA) thin films were chemically modified with surface amine functional groups. Au nanoparticles were preferentially attached to the functionalized PMMA surface domains using cross-linking chemistry. This method allows for versatility of size, shape, and composition. In this dissertation, we demonstrated attachment of 5, 10, and 20 nm Au and 20 nm Ag nanoparticles. PS-b-PMMA thin films also exhibit versatility of domain size and morphology by varying polymer molecular weights. The nanoparticle diameter to PMMA domain size ratio influenced the cluster size. As the ratio decreased, larger clusters were observed on PMMA domains with increased frequency. SERS measurement of nanoparticle assemblies showed uniform signal

  18. Inhomogeneity of fluid flow in Stirling engine regenerators

    SciTech Connect

    Jones, J.D. )

    1989-10-01

    The literature relating to inhomogeneity of flow regenerators is briefly reviewed. It is noted that, in contrast to other applications of regenerators, relatively little attention has been paid to the consequences of flow inhomogeneity for thermal regeneration in Stirling cycle machines. The construction of regenerator capsules for a large stationary Stirling engine is described. A test rig is developed to measure the gas velocity profile across the face of the packed regenerator capsules under steady flow conditions. Measured flow profiles for a number of different matrix materials and construction techniques are presented, and it is noted that stacked-mesh regenerator matrices tend to display marked inhomogeneities of flow. The consequences of flow inhomogeneity for flow friction and regenerator effectiveness are analyzed theoretically, and approximate formulae deduced. One method for reducing flow inhomogeneity in stacked-screen matrice

  19. Vertebrate-like regeneration in the invertebrate chordate amphioxus

    PubMed Central

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

    2012-01-01

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

  20. Modulation of tissue repair by regeneration enhancer elements.

    PubMed

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

    2016-04-14

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