Traffic Management for Satellite-ATM Networks

NASA Technical Reports Server (NTRS)

Goyal, Rohit; Jain, Raj; Fahmy, Sonia; Vandalore, Bobby; Goyal, Mukul

1998-01-01

Various issues associated with "Traffic Management for Satellite-ATM Networks" are presented in viewgraph form. Specific topics include: 1) Traffic management issues for TCP/IP based data services over satellite-ATM networks; 2) Design issues for TCP/IP over ATM; 3) Optimization of the performance of TCP/IP over ATM for long delay networks; and 4) Evaluation of ATM service categories for TCP/IP traffic.

Flow-oriented dynamic assembly algorithm in TCP over OBS networks

NASA Astrophysics Data System (ADS)

Peng, Shuping; Li, Zhengbin; He, Yongqi; Xu, Anshi

2008-11-01

OBS is envisioned as a promising infrastructure for the next generation optical network, and TCP is likely to be the dominant transport protocol in the next generation network. Therefore, it is necessary to evaluate the performance of TCP over OBS networks. The assembly at the ingress edge nodes will impact the network performance. There have been several Fixed Assembly Period (FAP) algorithms proposed. However, the assembly period in FAP is fixed, and it can not be adjusted according to the network condition. Moreover, in FAP, the packets from different TCP sources are assembled into one burst. In that case, if such a burst is dropped, the TCP windows of the corresponding sources will shrink and the throughput will be reduced. In this paper, we introduced a flow-oriented Dynamic Assembly Period (DAP) algorithm for TCP over OBS networks. Through comparing the previous and current burst lengths, DAP can track the variation of TCP window, and update the assembly period dynamically for the next assembly. The performance of DAP is evaluated over a single TCP connection and multiple connections, respectively. The simulation results show that DAP performs better than FAP at almost the whole range of burst dropping probability.

Mg- and Zn-modified calcium phosphates prepared by biomimetic precipitation and subsequent treatment at high temperature.

PubMed

Rabadjieva, D; Tepavitcharova, S; Gergulova, R; Sezanova, K; Titorenkova, R; Petrov, O; Dyulgerova, E

2011-10-01

Powders of magnesium-modified as well as zinc-modified calcium phosphates (Me-β-TCP and HA) with a (Ca(2+)+Mg(2+)+Zn(2+)+Na(+)+K(+))/P ratio of 1.3-1.4 and various Me(2+)/(Me(2+)+Ca(2+)) ratios (from 0.005 to 0.16) were prepared in biomimetic electrolyte systems at pH 8, mother liquid maturation and further syntering at 600-1000°C. Some differences in zinc and magnesium modifications have been prognosed on the basis of thermodynamic modeling of the studied systems and explained by the Mg(2+) and Zn(2+) ion chemical behaviour. The temperature as well as the degree of Zn(2+) and Mg(2+) ions substitutions were found to stabilize the β-TCP structure and this effect was more prononced for zinc. Thus, zinc-modified β-TCP powders consisting of idiomorphic crystals were obtained through sintering of Zn(2+) ion substituted calcium phosphates precursors at 800-1000°C. The Mg(2+) ion substitution leads to obtaining magnesium-modified β-TCP with spherical grains.

The use of TCP based EUD to rank and compare lung radiotherapy plans: in-silico study to evaluate the correlation between TCP with physical quality indices.

PubMed

Chaikh, Abdulhamid; Balosso, Jacques

2017-06-01

To apply the equivalent uniform dose (EUD) radiobiological model to estimate the tumor control probability (TCP) scores for treatment plans using different radiobiological parameter settings, and to evaluate the correlation between TCP and physical quality indices of the treatment plans. Ten radiotherapy treatment plans for lung cancer were generated. The dose distributions were calculated using anisotropic analytical algorithm (AAA). Dose parameters and quality indices derived from dose volume histograms (DVH) for target volumes were evaluated. The predicted TCP was computed using EUD model with tissue-specific parameter (a=-10). The assumed radiobiological parameter setting for adjuvant therapy [tumor dose to control 50% of the tumor (TCD 50 ) =36.5 Gy and γ 50 =0.72] and curative intent (TCD 50 =51.24 Gy and γ 50 =0.83) were used. The bootstrap method was used to estimate the 95% confidence interval (95% CI). The coefficients (ρ) from Spearman's rank test were calculated to assess the correlation between quality indices with TCP. Wilcoxon paired test was used to calculate P value. The 95% CI of TCP were 70.6-81.5 and 46.6-64.7, respectively, for adjuvant radiotherapy and curative intent. The TCP outcome showed a positive and good correlation with calculated dose to 95% of the target volume (D95%) and minimum dose (Dmin). Consistently, TCP correlate negatively with heterogeneity indices. This study confirms that more relevant and robust radiobiological parameters setting should be integrated according to cancer type. The positive correlation with quality indices gives chance to improve the clinical out-come by optimizing the treatment plans to maximize the Dmin and D95%. This attempt to increase the TCP should be carried out with the respect of dose constraints for organs at risks. However, the negative correlation with heterogeneity indices shows that the optimization of beam arrangements could be also useful. Attention should be paid to obtain an appropriate optimization of initial plans, when comparing and ranking radiotherapy plans using TCP models, to avoid over or underestimated for TCP outcome.

Redox modulation of plant developmental regulators from the class I TCP transcription factor family.

PubMed

Viola, Ivana L; Güttlein, Leandro N; Gonzalez, Daniel H

2013-07-01

TEOSINTE BRANCHED1-CYCLOIDEA-PROLIFERATING CELL FACTOR1 (TCP) transcription factors participate in plant developmental processes associated with cell proliferation and growth. Most members of class I, one of the two classes that compose the family, have a conserved cysteine at position 20 (Cys-20) of the TCP DNA-binding and dimerization domain. We show that Arabidopsis (Arabidopsis thaliana) class I proteins with Cys-20 are sensitive to redox conditions, since their DNA-binding activity is inhibited after incubation with the oxidants diamide, oxidized glutathione, or hydrogen peroxide or with nitric oxide-producing agents. Inhibition can be reversed by treatment with the reductants dithiothreitol or reduced glutathione or by incubation with the thioredoxin/thioredoxin reductase system. Mutation of Cys-20 in the class I protein TCP15 abolished its redox sensitivity. Under oxidizing conditions, covalently linked dimers were formed, suggesting that inactivation is associated with the formation of intermolecular disulfide bonds. Inhibition of class I TCP protein activity was also observed in vivo, in yeast (Saccharomyces cerevisiae) cells expressing TCP proteins and in plants after treatment with redox agents. This inhibition was correlated with modifications in the expression of the downstream CUC1 gene in plants. Modeling studies indicated that Cys-20 is located at the dimer interface near the DNA-binding surface. This places this residue in the correct orientation for intermolecular disulfide bond formation and explains the sensitivity of DNA binding to the oxidation of Cys-20. The redox properties of Cys-20 and the observed effects of cellular redox agents both in vitro and in vivo suggest that class I TCP protein action is under redox control in plants.

Redox Modulation of Plant Developmental Regulators from the Class I TCP Transcription Factor Family1[W][OA

PubMed Central

Viola, Ivana L.; Güttlein, Leandro N.; Gonzalez, Daniel H.

2013-01-01

TEOSINTE BRANCHED1-CYCLOIDEA-PROLIFERATING CELL FACTOR1 (TCP) transcription factors participate in plant developmental processes associated with cell proliferation and growth. Most members of class I, one of the two classes that compose the family, have a conserved cysteine at position 20 (Cys-20) of the TCP DNA-binding and dimerization domain. We show that Arabidopsis (Arabidopsis thaliana) class I proteins with Cys-20 are sensitive to redox conditions, since their DNA-binding activity is inhibited after incubation with the oxidants diamide, oxidized glutathione, or hydrogen peroxide or with nitric oxide-producing agents. Inhibition can be reversed by treatment with the reductants dithiothreitol or reduced glutathione or by incubation with the thioredoxin/thioredoxin reductase system. Mutation of Cys-20 in the class I protein TCP15 abolished its redox sensitivity. Under oxidizing conditions, covalently linked dimers were formed, suggesting that inactivation is associated with the formation of intermolecular disulfide bonds. Inhibition of class I TCP protein activity was also observed in vivo, in yeast (Saccharomyces cerevisiae) cells expressing TCP proteins and in plants after treatment with redox agents. This inhibition was correlated with modifications in the expression of the downstream CUC1 gene in plants. Modeling studies indicated that Cys-20 is located at the dimer interface near the DNA-binding surface. This places this residue in the correct orientation for intermolecular disulfide bond formation and explains the sensitivity of DNA binding to the oxidation of Cys-20. The redox properties of Cys-20 and the observed effects of cellular redox agents both in vitro and in vivo suggest that class I TCP protein action is under redox control in plants. PMID:23686421

Osteoimmunomodulatory properties of magnesium scaffolds coated with β-tricalcium phosphate.

PubMed

Chen, Zetao; Mao, Xueli; Tan, Lili; Friis, Thor; Wu, Chengtie; Crawford, Ross; Xiao, Yin

2014-10-01

The osteoimmunomodulatory property of bone biomaterials is a vital property determining the in vivo fate of the implants. Endowing bone biomaterials with favorable osteoimmunomodulatory properties is of great importance in triggering desired immune response and thus supports the bone healing process. Magnesium (Mg) has been recognized as a revolutionary metal for applications in orthopedics due to it being biodegradable, biocompatible, and having osteoconductive properties. However, Mg's high rate of degradation leads to an excessive inflammatory response and this has restricted its application in bone tissue engineering. In this study, β-tricalcium phosphate (β-TCP) was used to coat Mg scaffolds in an effort to modulate the detrimental osteoimmunomodulatory properties of Mg scaffolds, due to the reported favorable osteoimmunomodulatory properties of β-TCP. It was noted that macrophages switched to the M2 extreme phenotype in response to the Mg-β-TCP scaffolds, which could be due to the inhibition of the toll like receptor (TLR) signaling pathway. VEGF and BMP2 were significantly upregulated in the macrophages exposed to Mg-β-TCP scaffolds, indicating pro-osteogenic properties of macrophages in β-TCP modified Mg scaffolds. This was further demonstrated by the macrophage-mediated osteogenic differentiation of bone marrow stromal cells (BMSCs). When BMSCs were stimulated by conditioned medium from macrophages cultured on Mg-β-TCP scaffolds, osteogenic differentiation of BMSCs was significantly enhanced; whereas osteoclastogenesis was inhibited, as indicated by the downregualtion of MCSF, TRAP and inhibition of the RANKL/RANK system. These findings suggest that β-TCP coating of Mg scaffolds can modulate the scaffold's osteoimmunomodulatory properties, shift the immune microenvironment towards one that favors osteogenesis over osteoclastogenesis. Endowing bone biomaterials with favorable osteoimmunomodulatory properties can be a highly valuable strategy for the development or modification of advanced bone biomaterials. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biofabrication of a PLGA-TCP-based porous bioactive bone substitute with sustained release of icaritin.

PubMed

Xie, Xin-Hui; Wang, Xin-Luan; Zhang, Ge; He, Yi-Xin; Leng, Yang; Tang, Ting-Ting; Pan, Xiaohua; Qin, Ling

2015-08-01

A phytomolecule, icaritin, has been identified and shown to be osteopromotive for the prevention of osteoporosis and osteonecrosis. This study aimed to produce a bioactive poly (l-lactide-co-glycolide)-tricalcium phosphate (PLGA-TCP)-based porous scaffold incorporating the osteopromotive phytomolecule icaritin, using a fine spinning technology. Both the structure and the composition of icaritin-releasing PLGA-TCP-based scaffolds were evaluated by scanning electron microscopy (SEM). The porosity was quantified by both water absorption and micro-computed tomography (micro-CT). The mechanical properties were evaluated using a compression test. In vitro release of icaritin from the PLGA-TCP scaffold was quantified by high-performance liquid chromatography (HPLC). The attachment, proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) on the composite scaffold were evaluated. Both an in vitro cytotoxicity test and an in vivo test via muscular implantation were conducted to confirm the scaffold's biocompatibility. The results showed that the PLGA-TCP-icaritin composite scaffold was porous, with interconnected macro- (about 480 µm) and micropores (2-15 µm). The mechanical properties of the PLGA-TCP-icaritin scaffold were comparable with those of the pure PLGA-TCP scaffold, yet was spinning direction-dependent. Icaritin content was detected in the medium and increased with time. The PLGA-TCP-icaritin scaffold facilitated the attachment, proliferation and osteogenic differentiation of BMSCs. In vitro cytotoxicity test and in vivo intramuscular implantation showed that the composite scaffold had no toxicity with good biocompatibility. In conclusion, an osteopromotive phytomolecule, icaritin, was successfully incorporated into PLGA-TCP to form an innovative porous composite scaffold with sustained release of osteopromotive icaritin, and this scaffold had good biocompatibility and osteopromotion, suggesting its potential for orthopaedic applications. Copyright © 2012 John Wiley & Sons, Ltd.

Performance of TCP variants over LTE network

NASA Astrophysics Data System (ADS)

Nor, Shahrudin Awang; Maulana, Ade Novia

2016-08-01

One of the implementation of a wireless network is based on mobile broadband technology Long Term Evolution (LTE). LTE offers a variety of advantages, especially in terms of access speed, capacity, architectural simplicity and ease of implementation, as well as the breadth of choice of the type of user equipment (UE) that can establish the access. The majority of the Internet connections in the world happen using the TCP (Transmission Control Protocol) due to the TCP's reliability in transmitting packets in the network. TCP reliability lies in the ability to control the congestion. TCP was originally designed for wired media, but LTE connected through a wireless medium that is not stable in comparison to wired media. A wide variety of TCP has been made to produce a better performance than its predecessor. In this study, we simulate the performance provided by the TCP NewReno and TCP Vegas based on simulation using network simulator version 2 (ns2). The TCP performance is analyzed in terms of throughput, packet loss and end-to-end delay. In comparing the performance of TCP NewReno and TCP Vegas, the simulation result shows that the throughput of TCP NewReno is slightly higher than TCP Vegas, while TCP Vegas gives significantly better end-to-end delay and packet loss. The analysis of throughput, packet loss and end-to-end delay are made to evaluate the simulation.

The prevalence and impact of thrombocytopenia, anaemia and leucopenia on sustained virological response in patients receiving hepatitis C therapy: evidence from a large 'real world' cohort.

PubMed

Wang, Huan; Innes, Hamish; Hutchinson, Sharon J; Goldberg, David J; Allen, Samuel; Barclay, Stephen T; Bramley, Peter; Fox, Raymond; Fraser, Andrew; Hayes, Peter C; Kennedy, Nicholas; Mills, Peter R; Dillon, John F

2016-04-01

The aim of the study was to explore the extent of thrombocytopenia (TCP), anaemia and leucopenia in patients with hepatitis C and evaluate how they impact the management of antiviral therapy, the attainment of sustained virological response (SVR), and some therapy-related adverse events. The Scottish Hepatitis C Clinical Database was used in this retrospective study. The prevalence of TCP, anaemia and leucopenia was evaluated. The impact of the three deficiencies on antiviral therapy management, serious adverse events and SVR attainment was assessed in patients who received therapy. The prevalence of TCP, anaemia and leucopenia was 18.5, 0.9 and 0.2% among 4907 treated patients at baseline, increasing to 72, 25.8 and 5.4% during treatment, respectively. Dose reduction occurred in 29.3% of the patients without TCP; this percentage was higher in those with baseline TCP (53%) and in those who acquired it during treatment (35%). Similar results were found for anaemia and leucopenia. Baseline TCP (odds ratio=0.67, P<0.001) and baseline anaemia (odds ratio=0.43, P=0.03) were identified as risk factors associated with lower SVR rate; acquired TCP and anaemia were not associated with reduced SVR. Baseline TCP or anaemia increased the risk of dose cessation. Patients who acquired TCP, anaemia or leucopenia during treatment did not exhibit compromised SVR rates, whereas patients with TCP or anaemia at baseline did. The potential benefit of growth factors in maintaining SVR rate is likely to be confined to those with baseline TCP or anaemia rather than to those who acquire it during therapy, where dose reduction does not appear to reduce the chance of SVR.

Fabrication of dicalcium phosphate dihydrate-coated β-TCP granules and evaluation of their osteoconductivity using experimental rats.

PubMed

Shariff, Khairul Anuar; Tsuru, Kanji; Ishikawa, Kunio

2017-06-01

β-Tricalcium phosphate (β-TCP) has attracted much attention as an artificial bone substitute owing to its biocompatibility and osteoconductivity. In this study, osteoconductivity of β-TCP bone substitute was enhanced without using growth factors or cells. Dicalcium phosphate dihydrate (DCPD), which is known to possess the highest solubility among calcium phosphates, was coated on β-TCP granules by exposing their surface with acidic calcium phosphate solution. The amount of coated DCPD was regulated by changing the reaction time between β-TCP granules and acidic calcium phosphate solution. Histomorphometry analysis obtained from histological results revealed that the approximately 10mol% DCPD-coated β-TCP granules showed the largest new bone formation compared to DCPD-free β-TCP granules, approximately 2.5mol% DCPD-coated β-TCP granules, or approximately 27mol% DCPD-coated β-TCP granules after 2 and 4weeks of implantation. Based on this finding, we demonstrate that the osteoconductivity of β-TCP granules could be improved by coating their surface with an appropriate amount of DCPD. Copyright © 2017 Elsevier B.V. All rights reserved.

Biphasic β-TCP mixed with silicon increases bone formation in critical site defects in rabbit calvaria.

PubMed

Calvo-Guirado, José Luis; Garces, Miguel; Delgado-Ruiz, Rafael Arcesio; Ramirez Fernandez, Maria P; Ferres-Amat, Eduard; Romanos, Georgios E

2015-08-01

The aim of this study was to assess the bone regeneration of critical size defects in rabbit calvarias filled with β-TCP doped with silicon. Twenty-one New Zealand rabbits were used in this study. Two critical size defects were created in the parietal bones. Three experimental groups were evaluated: Test A (HA/β-TCP granules alone), Test B (HA/β-TCP granules plus 3% silicon), Control (empty defect). The animals were sacrificed at 8 and 12 weeks. Evaluation was performed by μCT analysis and histomorphometry. μCT evaluation showed higher volume reduction in Test A group compared with Test B (P < 0.05). The Test B group showed the highest values for cortical closure and bone formation around the particles, followed by Test A and controls (P < 0.05). Within the limitations of this animal study, it can be concluded that HA/β-TCP plus 3% silicon increases bone formation in critical size defects in rabbit calvarias, and the incorporation of 3% silicon reduces the resorption rate of the HA/β-TCP granules. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

An Evaluation of TCP with Larger Initial Windows

NASA Technical Reports Server (NTRS)

Allman, Mark; Hayes, Christopher; Ostermann, Shawn

1998-01-01

Transmission Control Protocol (TCP's) slow start algorithm gradually increases the amount of data a sender injects into the network, which prevents the sender from overwhelming the network with an inappropriately large burst of traffic. However, the slow start algorithm can make poor use of the available band-width for transfers which are small compared to the bandwidth-delay product of the link, such as file transfers up to few thousand characters over satellite links or even transfers of several hundred bytes over local area networks. This paper evaluates a proposed performance enhancement that raises the initial window used by TCP from 1 MSS-sized segment to roughly 4 KB. The paper evaluates the impact of using larger initial windows on TCP transfers over both the shared Internet and dialup modem links.

Soft Tissue Augmentation with Autologous Platelet Gel and β-TCP: A Histologic and Histometric Study in Mice

PubMed Central

Ceccarelli, Maurizio; Marchetti, Massimiliano; Piattelli, Adriano; Mortellaro, Carmen

2016-01-01

Background. Facial aging is a dynamic process involving both soft tissue and bony structures. Skin atrophy, with loss of tone, elasticity, and distribution of facial fat, coupled with gravity and muscle activity, leads to wrinkling and folds. Purpose. The aim of the study was to evaluate microporous tricalcium phosphate (β-TCP) and autologous platelet gel (APG) mix in mice for oral and maxillofacial soft tissue augmentation. The hypothesis was that β-TCP added with APG was able to increase the biostimulating effect on fibroblasts and quicken resorption. Materials and Methods. Ten female, 6–8-week-old black-haired mice were selected. β-TCP/APG gel was injected into one cheek; the other was used as control. The animals were sacrificed at 8 weeks and histologically evaluated. Results. The new fibroblast was intensively stained with acid fuchsin and presented in contact with β-TCP. At higher magnification, actively secreting fibroblasts were observed at the periphery of β-TCP with a well differentiated fibroblast cell line and blood vessels. Acid fuchsin stained cutaneous structures in pink: no epidermal/dermal alterations or pathological inflammatory infiltrates were detected. The margins of β-TCP granules were clear and not diffused near tissues. Conclusion. APG with β-TCP preserves skin morphology, without immune response, with an excellent tolerability and is a promising scaffold for cells and biomaterial for soft tissue augmentation. PMID:27478828

Soft Tissue Augmentation with Autologous Platelet Gel and β-TCP: A Histologic and Histometric Study in Mice.

PubMed

Scarano, Antonio; Ceccarelli, Maurizio; Marchetti, Massimiliano; Piattelli, Adriano; Mortellaro, Carmen

2016-01-01

Background. Facial aging is a dynamic process involving both soft tissue and bony structures. Skin atrophy, with loss of tone, elasticity, and distribution of facial fat, coupled with gravity and muscle activity, leads to wrinkling and folds. Purpose. The aim of the study was to evaluate microporous tricalcium phosphate (β-TCP) and autologous platelet gel (APG) mix in mice for oral and maxillofacial soft tissue augmentation. The hypothesis was that β-TCP added with APG was able to increase the biostimulating effect on fibroblasts and quicken resorption. Materials and Methods. Ten female, 6-8-week-old black-haired mice were selected. β-TCP/APG gel was injected into one cheek; the other was used as control. The animals were sacrificed at 8 weeks and histologically evaluated. Results. The new fibroblast was intensively stained with acid fuchsin and presented in contact with β-TCP. At higher magnification, actively secreting fibroblasts were observed at the periphery of β-TCP with a well differentiated fibroblast cell line and blood vessels. Acid fuchsin stained cutaneous structures in pink: no epidermal/dermal alterations or pathological inflammatory infiltrates were detected. The margins of β-TCP granules were clear and not diffused near tissues. Conclusion. APG with β-TCP preserves skin morphology, without immune response, with an excellent tolerability and is a promising scaffold for cells and biomaterial for soft tissue augmentation.

Influence of Si substitution on the reactivity of α-tricalcium phosphate.

PubMed

Motisuke, Mariana; Mestres, Gemma; Renó, Caroline O; Carrodeguas, Raúl G; Zavaglia, Cecília A C; Ginebra, Maria-Pau

2017-06-01

Silicon substituted calcium phosphates have been widely studied over the last ten years due to their enhanced osteogenic properties. Notwithstanding, the role of silicon on α-TCP reactivity is not clear yet. Therefore, the aim of this work was to evaluate the reactivity and the properties of Si-α-TCP in comparison to α-TCP. Precursor powders have similar properties regarding purity, particle size distribution and specific surface area, which allowed a better comparison of the Si effects on their reactivity and cements properties. Both Si-α-TCP and α-TCP hydrolyzed to a calcium-deficient hydroxyapatite when mixed with water but their conversion rates were different. Si-α-TCP exhibited a slower setting rate than α-TCP, i.e. k SSA for Si-TCP (0.021g·m -2 ·h -1 ) was almost four times lower than for α-TCP (0.072g·m -2 ·h -1 ). On the other hand, the compressive strength of the CPC resulting from fully reacted Si-α-TCP was significantly higher (12.80±0.38MPa) than that of α-TCP (11.44±0.54MPa), due to the smaller size of the entangled precipitated apatite crystals. Copyright © 2017. Published by Elsevier B.V.

Improving TCP Network Performance by Detecting and Reacting to Packet Reordering

NASA Technical Reports Server (NTRS)

Kruse, Hans; Ostermann, Shawn; Allman, Mark

2003-01-01

There are many factors governing the performance of TCP-basec applications traversing satellite channels. The end-to-end performance of TCP is known to be degraded by the reordering, delay, noise and asymmetry inherent in geosynchronous systems. This result has been largely based on experiments that evaluate the performance of TCP in single flow tests. While single flow tests are useful for deriving information on the theoretical behavior of TCP and allow for easy diagnosis of problems they do not represent a broad range of realistic situations and therefore cannot be used to authoritatively comment on performance issues. The experiments discussed in this report test TCP s performance in a more dynamic environment with competing traffic flows from hundreds of TCP connections running simultaneously across the satellite channel. Another aspect we investigate is TCP's reaction to bit errors on satellite channels. TCP interprets loss as a sign of network congestion. This causes TCP to reduce its transmission rate leading to reduced performance when loss is due to corruption. We allowed the bit error rate on our satellite channel to vary widely and tested the performance of TCP as a function of these bit error rates. Our results show that the average performance of TCP on satellite channels is good even under conditions of loss as high as bit error rates of 10(exp -5)

[Biocompatibility of HA/TCP biphasic ceramics with co-cultured human osteoblasts in vitro].

PubMed

Lu, X; Li, S; Zhang, J; Zhang, Z; Lu, B; Bu, H; Li, Y; Cheng, J

2001-12-01

The biocompatibility of HA/TCP ceramic was evaluated by investigation of attachment and growth of osteoblasts on biomaterial, as well as monitoring the effects of biomaterial on expression of functional phenotypes of co-cultured osteoblasts in vitro. When co-cultured with HA/TCP ceramics, osteoblasts firstly attached to the surface of HA/TCP disk, then attached to notches and grew into the micropores of biomaterial during further culture period. At last, the ceramics were almost packed with osteoblasts. Additionally, osteoblasts co-cultured with HA/TCP were similar to osteoblasts cultured under normal condition in osteoblastic phenotypes; the secreted lots of collagen type I, possess strong activity of Alkaline Phosphatase and mineralized extracellular matrix. The fact that osteoblasts could grow well on HA/TCP ceramics and the biomaterial did not affect their physiological function suggest that HA/TCP ceramic is biocompatible with human osteoblasts.

Biocompatibility evaluation of HDPE-UHMWPE reinforced β-TCP nanocomposites using highly purified human osteoblast cells.

PubMed

Shokrgozar, M A; Farokhi, M; Rajaei, F; Bagheri, M H A; Azari, Sh; Ghasemi, I; Mottaghitalab, F; Azadmanesh, K; Radfar, J

2010-12-15

Biocompatibility of β-TCP/HDPE-UHMWPE nanocomposite as a new bone substitute material was evaluated by using highly purified human osteoblast cells. Human osteoblast cells were isolated from bone tissue and characterized by immunofluorescence Staining before and after purification using magnetic bead system. Moreover, proliferation, alkaline phosphatase production, cell attachment, calcium deposition, gene expression, and morphology of osteoblast cells on β-TCP/HDPE-UHMWPE nanocomposites were evaluated. The results have shown that the human osteoblast cells were successfully purified and were suitable for subsequent cell culturing process. The high proliferation rate of osteoblast cells on β-TCP/HDPE-UHMWPE nanocomposite confirmed the great biocompatibility of the scaffold. Expression of bone-specific genes was taken place after the cells were incubated in composite extract solutions. Furthermore, osteoblast cells were able to mineralize the matrix next to composite samples. Scanning electron microscopy demonstrated that cells had normal morphology on the scaffold. Thus, these results indicated that the nanosized β-TCP/HDPE-UHMWPE blend composites could be potential scaffold, which is used in bone tissue engineering. Copyright © 2010 Wiley Periodicals, Inc.

Immunizing Adult Female Mice with a TcpA-A2-CTB Chimera Provides a High Level of Protection for Their Pups in the Infant Mouse Model of Cholera

PubMed Central

Price, Gregory A.; Holmes, Randall K.

2014-01-01

Vibrio cholerae expresses two primary virulence factors, cholera toxin (CT) and the toxin-coregulated pilus (TCP). CT causes profuse watery diarrhea, and TCP (composed of repeating copies of the major pilin TcpA) is required for intestinal colonization by V. cholerae. Antibodies to CT or TcpA can protect against cholera in animal models. We developed a TcpA holotoxin-like chimera (TcpA-A2-CTB) to elicit both anti-TcpA and anti-CTB antibodies and evaluated its immunogenicity and protective efficacy in the infant mouse model of cholera. Adult female CD-1 mice were immunized intraperitoneally three times with the TcpA-A2-CTB chimera and compared with similar groups immunized with a TcpA+CTB mixture, TcpA alone, TcpA with Salmonella typhimurium flagellin subunit FliC as adjuvant, or CTB alone. Blood and fecal samples were analyzed for antigen-specific IgG or IgA, respectively, using quantitative ELISA. Immunized females were mated; their reared offspring were challenged orogastrically with 10 or 20 LD50 of V. cholerae El Tor N16961; and vaccine efficacy was assessed by survival of the challenged pups at 48 hrs. All pups from dams immunized with the TcpA-A2-CTB chimera or the TcpA+CTB mixture survived at both challenge doses. In contrast, no pups from dams immunized with TcpA+FliC or CTB alone survived at the 20 LD50 challenge dose, although the anti-TcpA or anti-CTB antibody level elicited by these immunizations was comparable to the corresponding antibody level achieved by immunization with TcpA-A2-CTB or TcpA+CTB. Taken together, these findings comprise strong preliminary evidence for synergistic action between anti-TcpA and anti-CTB antibodies in protecting mice against cholera. Weight loss analysis showed that only immunization of dams with TcpA-A2-CTB chimera or TcpA+CTB mixture protected their pups against excess weight loss from severe diarrhea. These data support the concept of including both TcpA and CTB as immunogens in development of an effective multivalent subunit vaccine against V. cholerae. PMID:25474636

Misato Controls Mitotic Microtubule Generation by Stabilizing the TCP-1 Tubulin Chaperone Complex [corrected].

PubMed

Palumbo, Valeria; Pellacani, Claudia; Heesom, Kate J; Rogala, Kacper B; Deane, Charlotte M; Mottier-Pavie, Violaine; Gatti, Maurizio; Bonaccorsi, Silvia; Wakefield, James G

2015-06-29

Mitotic spindles are primarily composed of microtubules (MTs), generated by polymerization of α- and β-Tubulin hetero-dimers. Tubulins undergo a series of protein folding and post-translational modifications in order to fulfill their functions. Defects in Tubulin polymerization dramatically affect spindle formation and disrupt chromosome segregation. We recently described a role for the product of the conserved misato (mst) gene in regulating mitotic MT generation in flies, but the molecular function of Mst remains unknown. Here, we use affinity purification mass spectrometry (AP-MS) to identify interacting partners of Mst in the Drosophila embryo. We demonstrate that Mst associates stoichiometrically with the hetero-octameric Tubulin Chaperone Protein-1 (TCP-1) complex, with the hetero-hexameric Tubulin Prefoldin complex, and with proteins having conserved roles in generating MT-competent Tubulin. We show that RNAi-mediated in vivo depletion of any TCP-1 subunit phenocopies the effects of mutations in mst or the Prefoldin-encoding gene merry-go-round (mgr), leading to monopolar and disorganized mitotic spindles containing few MTs. Crucially, we demonstrate that Mst, but not Mgr, is required for TCP-1 complex stability and that both the efficiency of Tubulin polymerization and Tubulin stability are drastically compromised in mst mutants. Moreover, our structural bioinformatic analyses indicate that Mst resembles the three-dimensional structure of Tubulin monomers and might therefore occupy the TCP-1 complex central cavity. Collectively, our results suggest that Mst acts as a co-factor of the TCP-1 complex, playing an essential role in the Tubulin-folding processes required for proper assembly of spindle MTs. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Vancomycin containing PLLA/β-TCP controls experimental osteomyelitis in vivo.

PubMed

Kankilic, Berna; Bilgic, Elif; Korkusuz, Petek; Korkusuz, Feza

2014-11-19

Implant-related osteomyelitis (IRO) is recently controlled with local antibiotic delivery systems to overcome conventional therapy disadvantages. In vivo evaluation of such systems is however too little. We asked whether vancomycin (V)-containing poly-l-lactic acid/β-tricalcium phosphate (PLLA/β-TCP) composites control experimental IRO and promote bone healing in vivo. Fifty-six rats were distributed to five groups in this longitudinal controlled study. Experimental IRO was established at tibiae by injecting methicillin-resistant Staphylococcus aureus (MRSA) suspensions with titanium particles in 32 rats. Vancomycin-free PLLA/β-TCP composites were implanted into the normal and infected tibiae, whereas V-PLLA/β-TCP composites and coated (C)-V-PLLA/β-TCP composites were implanted into IRO sites. Sham-operated tibiae established the control group. Radiological and histological scores were quantified with microbiological findings on weeks 1 and 6. IRO is resolved in the CV- and the V-PLLA/β-TCP groups but not in the PLLA/β-TCP group. MRSA was not isolated in the CV- and the V-PLLA/β-TCP groups at all times whereas the bacteria were present in the PLLA/β-TCP group. Radiological signs secondary to infection are improved from 10.9 ± 0.9 to 3.0 ± 0.3 in the V-PLLA/β-TCP group but remained constant in the PLLA/β-TCP group. Histology scores are improved from 24.7 ± 6.5 to 17.6 ± 4.8 and from 27.6 ± 7.9 to 32.4 ± 8.9 in the CV-PLLA/β-TCP and the V-PLLA/β-TCP groups, respectively. New bone was formed in all the PLLA/β-TCP group at weeks 1 and 6. CV- and V-PLLA/β-TCP composites controlled experimental IRO and promoted bone healing. CV- and V-PLLA/β-TCP composites have the potential of controlling experimental IRO and promoting bone healing.

Performance Evaluation of FAST TCP Traffic-Flows in Multihomed MANETs

NASA Astrophysics Data System (ADS)

Mudassir, Mumajjed Ul; Akram, Adeel

In Mobile Ad hoc Networks (MANETs) an efficient communication protocol is required at the transport layer. Mobile nodes moving around will have temporary and rather short-lived connectivity with each other and the Internet, thus requiring efficient utilization of network resources. Moreover the problems arising due to high mobility, collision and congestion must also be considered. Multihoming allows higher reliability and enhancement of network throughput. FAST TCP is a new promising transport layer protocol developed for high-speed high-latency networks. In this paper, we have analyzed the performance of FAST TCP traffic flows in multihomed MANETs and compared it with standard TCP (TCP Reno) traffic flows in non-multihomed MANETs.

Bone repair by cell-seeded 3D-bioplotted composite scaffolds made of collagen treated tricalciumphosphate or tricalciumphosphate-chitosan-collagen hydrogel or PLGA in ovine critical-sized calvarial defects.

PubMed

Haberstroh, Kathrin; Ritter, Kathrin; Kuschnierz, Jens; Bormann, Kai-Hendrik; Kaps, Christian; Carvalho, Carlos; Mülhaupt, Rolf; Sittinger, Michael; Gellrich, Nils-Claudius

2010-05-01

The aim of this study was to investigate the osteogenic effect of three different cell-seeded 3D-bioplotted scaffolds in a ovine calvarial critical-size defect model. The choice of scaffold-materials was based on their applicability for 3D-bioplotting and respective possibility to produce tailor-made scaffolds for the use in cranio-facial surgery for the replacement of complex shaped boneparts. Scaffold raw-materials are known to be osteoinductive when being cell-seeded [poly(L-lactide-co-glycolide) (PLGA)] or having components with osteoinductive properties as tricalciumphosphate (TCP) or collagen (Col) or chitosan. The scaffold-materials PLGA, TCP/Col, and HYDR (TCP/Col/chitosan) were cell-seeded with osteoblast-like cells whether gained from bone (OLB) or from periost (OLP). In a prospective and randomized design nine sheep underwent osteotomy to create four critical-sized calvarial defects. Three animals each were assigned to the HYDR-, the TCP/Col-, or the PLGA-group. In each animal, one defect was treated with a cell-free, an OLB- or OLP-seeded group-specific scaffold, respectively. The fourth defect remained untreated as control (UD). Fourteen weeks later, animals were euthanized for histo-morphometrical analysis of the defect healing. OLB- and OLP-seeded HYDR and OLB-seeded TCP/Col scaffolds significantly increased the amount of newly formed bone (NFB) at the defect bottom and OLP-seeded HYDR also within the scaffold area, whereas PLGA-scaffolds showed lower rates. The relative density of NFB was markedly higher in the HYDR/OLB group compared to the corresponding PLGA group. TCP/Col had good stiffness to prepare complex structures by bioplotting but HYDR and PLGA were very soft. HYDR showed appropriate biodegradation, TCP/Col and PLGA seemed to be nearly undegraded after 14 weeks. 3D-bioplotted, cell-seeded HYDR and TCP/Col scaffolds increased the amount of NFB within ovine critical-size calvarial defects, but stiffness, respectively, biodegradation of materials is not appropriate for the application in cranio-facial surgery and have to be improved further by modifications of the manufacturing process or their material composition. (c) 2010 Wiley Periodicals, Inc.

Research into alternative network approaches for space operations

NASA Technical Reports Server (NTRS)

Kusmanoff, Antone L.; Barton, Timothy J.

1990-01-01

The main goal is to resolve the interoperability problem of applications employing DOD TCP/IP (Department of Defence Transmission Control Protocol/Internet Protocol) family of protocols on a CCITT/ISO based network. The objective is to allow them to communicate over the CCITT/ISO protocol GPLAN (General Purpose Local Area Network) network without modification to the user's application programs. There were two primary assumptions associated with the solution that was actually realized. The first is that the solution had to allow for future movement to the exclusive use of the CCITT/ISO standards. The second is that the solution had to be software transparent to the currently installed TCP/IP and CCITT/ISO user application programs.

Coding and transmission of subband coded images on the Internet

NASA Astrophysics Data System (ADS)

Wah, Benjamin W.; Su, Xiao

2001-09-01

Subband-coded images can be transmitted in the Internet using either the TCP or the UDP protocol. Delivery by TCP gives superior decoding quality but with very long delays when the network is unreliable, whereas delivery by UDP has negligible delays but with degraded quality when packets are lost. Although images are delivered currently over the Internet by TCP, we study in this paper the use of UDP to deliver multi-description reconstruction-based subband-coded images. First, in order to facilitate recovery from UDP packet losses, we propose a joint sender-receiver approach for designing optimized reconstruction-based subband transform (ORB-ST) in multi-description coding (MDC). Second, we carefully evaluate the delay-quality trade-offs between the TCP delivery of SDC images and the UDP and combined TCP/UDP delivery of MDC images. Experimental results show that our proposed ORB-ST performs well in real Internet tests, and UDP and combined TCP/UDP delivery of MDC images provide a range of attractive alternatives to TCP delivery.

Can macrocirculation changes predict nonhealing diabetic foot ulcers?

PubMed

Lee, Ye-Na; Kim, Hyon-Surk; Kang, Jeong-A; Han, Seung-Kyu

2014-01-01

Transcutaneous partial oxygen tension (TcpO2) is considered the gold standard for assessment of tissue oxygenation, which is an essential factor for wound healing. The purpose of this study was to evaluate the association between macrocirculation and TcpO2 in persons with diabetes mellitus. Ninety-eight patients with diabetic foot ulcers participated in the study (61 men and 37 women). The subjects had a mean age of 66.6 years (range, 30-83 years) and were treated at the Diabetic Wound Center of Korea University Guro Hospital, Seoul, Republic of Korea. Macrocirculation was evaluated using 2 techniques: computed tomographic angiography and Doppler ultrasound. Macrocirculation scores were based on the patency of the two tibial arteries in 98 patients. Computed tomographic angiography and Doppler ultrasound scores (0-4 points) were given according to intraluminal filling defects and arterial pulse waveform of each vessel, respectively. Tissue oxygenation was measured by TcpO2. Macrocirculation scores were statistically analyzed as a function of the TcpO2. Statistical analysis revealed no significant linear trend between the macrocirculation status and TcpO2. Biavariate analysis using the Fisher exact test, Mantel-Haenszel tests, and McNemar-Bowker tests also found no significant relationship between macrocirculation and TcpO2. Computed tomographic angiography and Doppler ultrasound are not sufficiently reliable substitutes for TcpO2 measurements in regard to determining the optimal treatment for diabetic patients.

Scalable parallel communications

NASA Technical Reports Server (NTRS)

Maly, K.; Khanna, S.; Overstreet, C. M.; Mukkamala, R.; Zubair, M.; Sekhar, Y. S.; Foudriat, E. C.

1992-01-01

Coarse-grain parallelism in networking (that is, the use of multiple protocol processors running replicated software sending over several physical channels) can be used to provide gigabit communications for a single application. Since parallel network performance is highly dependent on real issues such as hardware properties (e.g., memory speeds and cache hit rates), operating system overhead (e.g., interrupt handling), and protocol performance (e.g., effect of timeouts), we have performed detailed simulations studies of both a bus-based multiprocessor workstation node (based on the Sun Galaxy MP multiprocessor) and a distributed-memory parallel computer node (based on the Touchstone DELTA) to evaluate the behavior of coarse-grain parallelism. Our results indicate: (1) coarse-grain parallelism can deliver multiple 100 Mbps with currently available hardware platforms and existing networking protocols (such as Transmission Control Protocol/Internet Protocol (TCP/IP) and parallel Fiber Distributed Data Interface (FDDI) rings); (2) scale-up is near linear in n, the number of protocol processors, and channels (for small n and up to a few hundred Mbps); and (3) since these results are based on existing hardware without specialized devices (except perhaps for some simple modifications of the FDDI boards), this is a low cost solution to providing multiple 100 Mbps on current machines. In addition, from both the performance analysis and the properties of these architectures, we conclude: (1) multiple processors providing identical services and the use of space division multiplexing for the physical channels can provide better reliability than monolithic approaches (it also provides graceful degradation and low-cost load balancing); (2) coarse-grain parallelism supports running several transport protocols in parallel to provide different types of service (for example, one TCP handles small messages for many users, other TCP's running in parallel provide high bandwidth service to a single application); and (3) coarse grain parallelism will be able to incorporate many future improvements from related work (e.g., reduced data movement, fast TCP, fine-grain parallelism) also with near linear speed-ups.

Evaluation of the effect of prostate volume change on tumor control probability in LDR brachytherapy.

PubMed

Knaup, Courtney; Mavroidis, Panayiotis; Stathakis, Sotirios; Smith, Mark; Swanson, Gregory; Papanikolaou, Niko

2011-09-01

This study evaluates low dose-rate brachytherapy (LDR) prostate plans to determine the biological effect of dose degradation due to prostate volume changes. In this study, 39 patients were evaluated. Pre-implant prostate volume was determined using ultrasound. These images were used with the treatment planning system (Nucletron Spot Pro 3.1(®)) to create treatment plans using (103)Pd seeds. Following the implant, patients were imaged using CT for post-implant dosimetry. From the pre and post-implant DVHs, the biologically equivalent dose and the tumor control probability (TCP) were determined using the biologically effective uniform dose. The model used RBE = 1.75 and α/β = 2 Gy. The prostate volume changed between pre and post implant image sets ranged from -8% to 110%. TCP and the mean dose were reduced up to 21% and 56%, respectively. TCP is observed to decrease as the mean dose decreases to the prostate. The post-implant tumor dose was generally observed to decrease, compared to the planned dose. A critical uniform dose of 130 Gy was established. Below this dose, TCP begins to fall-off. It was also determined that patients with a small prostates were more likely to suffer TCP decrease. The biological effect of post operative prostate growth due to operative trauma in LDR was evaluated using the concept. The post-implant dose was lower than the planned dose due to an increase of prostate volume post-implant. A critical uniform dose of 130 Gy was determined, below which TCP begun to decline.

Impact of window decrement rate on TCP performance in an adhoc network

NASA Astrophysics Data System (ADS)

Suherman; Hutasuhut, Arief T. W.; Badra, Khaldun; Al-Akaidi, Marwan

2017-09-01

Transmission control protocol (TCP) is a reliable transport protocol handling end to end connection in TCP/IP stack. It works well in copper or optical fibre link, but experiences increasing delay in wireless network. Further, TCP experiences multiple retransmissions due to higher collision probability within wireless network. The situation may get worsen in an ad hoc network. This paper examines the impact half window or window reduction rate to the overall TCP performances. The evaluation using NS-2 simulator shows that the smaller the window decrement rate results the smaller end to end delay. Delay is reduced to 17.05% in average when window decrement rate decreases. Average jitter also decreases 4.15%, while packet loss is not affected.

Performance analysis of TCP traffic and its influence on ONU's energy saving in energy efficient TDM-PON

NASA Astrophysics Data System (ADS)

Alaelddin, Fuad Yousif Mohammed; Newaz, S. H. Shah; Lee, Joohyung; Uddin, Mohammad Rakib; Lee, Gyu Myoung; Choi, Jun Kyun

2015-12-01

The majority of the traffic over the Internet is TCP based, which is very sensitive to packet loss and delay. Existing research efforts in TDM-Passive Optical Networks (TDM-PONs) mostly evaluate energy saving and traffic delay performances under different energy saving solutions. However, to the best of our knowledge, how energy saving mechanisms could affect TCP traffic performance in TDM-PONs has hardly been studied. In this paper, by means of our state-of-art OPNET Modular based TDM-PON simulator, we evaluate TCP traffic delay, throughput, and Optical Network Unit (ONU) energy consumption performances in a TDM-PON where energy saving mechanisms are employed in ONUs. Here, we study the performances under commonly used energy saving mechanisms defined in standards for TDM-PONs: cyclic sleep and doze mode. In cyclic sleep mode, we evaluate the performances under two well-known sleep interval length deciding algorithms (i.e. fixed sleep interval (FSI) and exponential sleep interval deciding (ESID)) that an OLT uses to decide sleep interval lengths for an ONU. Findings in this paper put forward the strong relationship among TCP traffic delay, throughput and ONU energy consumption under different sleep interval lengths. Moreover, we reveal that under high TCP traffic, both FSI and ESID will end up showing similar delay, energy and throughput performance. Our findings also show that doze mode can offer better TCP throughput and delay performance at the price of consuming more energy than cyclic sleep mode. In addition, our results provide a glimpse on understanding at what point doze mode becomes futile in improving energy saving of an ONU under TCP traffic. Furthermore, in this paper, we highlight important research issues that should be studied in future research to maximize energy saving in TDM-PONs while meeting traffic Quality of Service requirements.

Periodontal wound healing/regeneration following implantation of recombinant human growth/differentiation factor-5 in a beta-tricalcium phosphate carrier into one-wall intrabony defects in dogs.

PubMed

Lee, Jung-Seok; Wikesjö, Ulf M E; Jung, Ui-Won; Choi, Seong-Ho; Pippig, Susanne; Siedler, Michael; Kim, Chong-Kwan

2010-04-01

Recombinant human growth/differentiation factor-5 (rhGDF-5) is being evaluated as a candidate therapy in support of periodontal regeneration. The objective of this study was to evaluate periodontal wound healing/regeneration following the application of rhGDF-5 on a particulate beta-tricalcium phosphate (beta-TCP) carrier using an established defect model. Bilateral 4 x 5 mm (width x depth), one-wall, critical-size, intrabony periodontal defects were surgically created at the mandibular second and fourth pre-molar teeth in 15 Beagle dogs. Unilateral defects in five animals received rhGDF-5/beta-TCP (Scil Technology GmbH); five animals received beta-TCP solo; and five animals served as sham-surgery controls. Contralateral sites received treatments reported elsewhere. The animals were sacrificed following an 8-week healing interval for histological examination. Clinical healing was generally uneventful. Sites implanted with rhGDF-5/beta-TCP exhibited greater enhanced cementum and bone formation compared with beta-TCP and sham-surgery controls; cementum regeneration averaged (+/- SD) 3.83 +/- 0.73 versus 1.65 +/- 0.82 and 2.48 +/- 1.28 mm for the controls (p<0.05). Corresponding values for bone regeneration height averaged 3.26 +/- 0.30 versus 1.70 +/- 0.66 and 1.68 +/- 0.49 mm (p<0.05), and bone area 10.45 +/- 2.26 versus 6.31 +/- 2.41 and 3.00 +/- 1.97 mm(2) (p<0.05). Cementum regeneration included cellular/acellular cementum with or without a functionally oriented periodontal ligament. A non-specific connective tissue attachment was evident in the sham-surgery control. Controls exhibited mostly woven bone with primary osteons, whereas rhGDF-5/beta-TCP sites showed a noticeable extent of lamellar bone. Sites receiving rhGDF-5/beta-TCP or beta-TCP showed some residual beta-TCP granules apparently undergoing biodegradation without obvious differences between the sites. Sites receiving beta-TCP alone commonly showed residual beta-TCP granules sequestered in the connective tissue or fibrovascular marrow. rhGDF-5/beta-TCP has a greater potential to support the regeneration of the periodontal attachment. Long-term studies are necessary to confirm the uneventful maturation of the regenerated tissues.

Differential osteogenic activity of osteoprogenitor cells on HA and TCP/HA scaffold of tissue engineered bone.

PubMed

Ng, Angela M H; Tan, K K; Phang, M Y; Aziyati, O; Tan, G H; Isa, M R; Aminuddin, B S; Naseem, M; Fauziah, O; Ruszymah, B H I

2008-05-01

Biomaterial, an essential component of tissue engineering, serves as a scaffold for cell attachment, proliferation, and differentiation; provides the three dimensional (3D) structure and, in some applications, the mechanical strength required for the engineered tissue. Both synthetic and naturally occurring calcium phosphate based biomaterial have been used as bone fillers or bone extenders in orthopedic and reconstructive surgeries. This study aims to evaluate two popular calcium phosphate based biomaterial i.e., hydroxyapatite (HA) and tricalcium phosphate/hydroxyapatite (TCP/HA) granules as scaffold materials in bone tissue engineering. In our strategy for constructing tissue engineered bone, human osteoprogenitor cells derived from periosteum were incorporated with human plasma-derived fibrin and seeded onto HA or TCP/HA forming 3D tissue constructs and further maintained in osteogenic medium for 4 weeks to induce osteogenic differentiation. Constructs were subsequently implanted intramuscularly in nude mice for 8 weeks after which mice were euthanized and constructs harvested for evaluation. The differential cell response to the biomaterial (HA or TCP/HA) adopted as scaffold was illustrated by the histology of undecalcified constructs and evaluation using SEM and TEM. Both HA and TCP/HA constructs showed evidence of cell proliferation, calcium deposition, and collagen bundle formation albeit lesser in the former. Our findings demonstrated that TCP/HA is superior between the two in early bone formation and hence is the scaffold material of choice in bone tissue engineering. Copyright 2007 Wiley Periodicals, Inc.

Single-dose local administration of parathyroid hormone (1-34, PTH) with β-tricalcium phosphate/collagen (β-TCP/COL) enhances bone defect healing in ovariectomized rats.

PubMed

Tao, Zhou-Shan; Zhou, Wan-Shu; Wu, Xin-Jing; Wang, Lin; Yang, Min; Xie, Jia-Bing; Xu, Zhu-Jun; Ding, Guo-Zheng

2018-02-01

Parathyroid hormone (1-34, PTH) combined β-tricalcium phosphate (β-TCP) achieves stable bone regeneration without cell transplantation in previous studies. Recently, with the development of tissue engineering slow release technology, PTH used locally to promote bone defect healing become possible. This study by virtue of collagen with a combination of drugs and has a slow release properties, and investigated bone regeneration by β-TCP/collagen (β-TCP/COL) with the single local administration of PTH. After the creation of a rodent critical-sized femoral metaphyseal bone defect, β-TCP/COL was prepared by mixing sieved granules of β-TCP and atelocollagen for medical use, then β-TCP/COL with dripped PTH solution (1.0 µg) was implanted into the defect of OVX rats until death at 4 and 8 weeks. The defected area in distal femurs of rats was harvested for evaluation by histology, micro-CT, and biomechanics. The results of our study show that single-dose local administration of PTH combined local usage of β-TCP/COL can increase the healing of defects in OVX rats. Furthermore, treatments with single-dose local administration of PTH and β-TCP/COL showed a stronger effect on accelerating the local bone formation than β-TCP/COL used alone. The results from our study demonstrate that combination of single-dose local administration of PTH and β-TCP/COL had an additive effect on local bone formation in osteoporosis rats.

Effects of SiO2 and ZnO doping on mechanical and biological properties of 3D printed TCP scaffolds

PubMed Central

Fielding, Gary A.; Bandyopadhyay, Amit; Bose, Susmita

2011-01-01

Objectives To evaluate the effects of SiO2 (0.5 wt %) and ZnO (0.25 wt %) dopants on the mechanical and biological properties of tricalcium phosphate (TCP) scaffolds with three dimensionally (3D) interconnected pores. Methods Scaffolds were created with a commercial 3D printer. Post sintering phase analysis was determined by x-ray diffraction. Surface morphology of the scaffolds was examined by field emission electron microscopy. Mechanical strength was evaluated with a screw driven universal testing machine. MTT assay was used for cellular proliferation characteristics and cellular morphology was examined by field emission electron microscopy. Results Addition of dopants into TCP increased the average density of pure TCP from 90.8 ± 0.8% to 94.1 ± 1.6% and retarded the β to α phase transformation at high sintering temperatures, which resulted in up to 2.5 fold increase in compressive strength. In vitro cell-materials interaction studies, carried out using hFOB cells, confirmed that the addition of SiO2 and ZnO to the scaffolds facilitates faster cell proliferation when compared to pure TCP scaffolds. Significance Addition of SiO2 and ZnO dopants to the TCP scaffolds showed increased mechanical strength as well as increased cellular proliferation. PMID:22047943

Treatment of periodontal intrabony defects using β-TCP alone or in combination with rhPDGF-BB: a randomized controlled clinical and radiographic study.

PubMed

Maroo, Sneha; Murthy, K Raja V

2014-01-01

The need to increase the predictability of periodontal regeneration has encouraged clinicians and researchers to employ cell-stimulating proteins in combination with osteoconductive scaffolds, based on the principles of tissue engineering. The purpose of this clinical and radiographic study was to compare the regenerative potential of the combination of β-tricalcium phosphate (β-TCP) and recombinant human platelet-derived growth factor BB (rhPDGF-BB) in the grafting of intraosseous defects with the established technique of bone grafting with (β-TCP alone. A total of 30 sites from 15 patients with infrabony defects in two different quadrants were selected, and the sites were randomly divided into test sites (rhPDGF + β-TCP) and control sites (β-TCP alone) using a split-mouth design. Clinical parameters, including probing pocket depth, clinical attachment level, and gingival recession, were recorded at baseline, 6 months, and 9 months. Radiographic evaluation was carried out to evaluate defect fill, change in alveolar crest height, and percentage of defect fill at baseline, 6 months, and 9 months. Both the experimental groups showed statistically significant reduction in probing pocket depth and gain in clinical attachment level. On intergroup comparison, sites treated with rhPDGF + β-TCP demonstrated a significantly greater pocket depth reduction (P < .05) and greater gain in clinical attachment level (P < .01). Mean percentage defect fill was significantly greater in test sites as compared with control sites at 6 and 9 months (P < .01). rhPDGF + β-TCP-treated sites demonstrated a significant gain in mean alveolar crest height at 6 and 9 months (P < .05), while β-TCP-treated sites demonstrated crestal resorption. Both groups demonstrated potential in enhancing periodontal regeneration; however, on comparison between the two groups, the results obtained by rhPDGF + β-TCP were significantly better with respect to both clinical and radiographic parameters.

Biotin-avidin mediates the binding of adipose-derived stem cells to a porous β-tricalcium phosphate scaffold: Mandibular regeneration

PubMed Central

FENG, ZIHAO; LIU, JIAQI; SHEN, CONGCONG; LU, NANHANG; ZHANG, YONG; YANG, YANWEN; QI, FAZHI

2016-01-01

The present study aimed to investigate the properties of a promising bone scaffold for bone repair, which consisted of a novel composite of adipose-derived stem cells (ADSCs) attached to a porous β-tricalcium phosphate (β-TCP) scaffold with platelet-rich plasma (PRP). The β-TCP powder was synthesized and its composition was determined using X-ray diffraction and Fourier transform infrared spectroscopy. The surface morphology and microstructure of the fabricated porous β-TCP scaffold samples were analyzed using light and scanning electron microscopy, and their porosity and compressive strength were also evaluated. In addition, the viability of rabbit ADSCs incubated with various concentrations of the β-TCP extraction fluid was analyzed. The rate of attachment and the morphology of biotinylated ADSCs (Bio-ADSCs) on avidin-coated β-TCP (Avi-β-TCP), and untreated ADSCs on β-TCP, were compared. Furthermore, in vivo bone-forming abilities were determined following the implantation of group 1 (Bio-ADSCs/Avi-β-TCP) and group 2 (Bio-ADSCs/Avi-β-TCP/PRP) constructs using computed tomography, and histological osteocalcin (OCN) and alkaline phosphatase (ALP) expression analyses in a rabbit model of mandibulofacial defects. The β-TCP scaffold exhibited a high porosity (71.26±0.28%), suitable pore size, and good mechanical strength (7.93±0.06 MPa). Following incubation with β-TCP for 72 h, 100% of viable ADSCs remained. The avidin-biotin binding system significantly increased the initial attachment rate of Bio-ADSCs to Avi-β-TCP in the first hour (P<0.01). Following the addition of PRP, group 2 exhibited a bony-union and mandibular body shape, newly formed bone and increased expression levels of OCN and ALP in the mandibulofacial defect area, as compared with group 1 (P<0.05). The results of the present study suggested that the novel Bio-ADSCs/Avi-β-TCP/PRP composite may have potential application in bone repair and bone tissue engineering. PMID:26997987

ATM QoS Experiments Using TCP Applications: Performance of TCP/IP Over ATM in a Variety of Errored Links

NASA Technical Reports Server (NTRS)

Frantz, Brian D.; Ivancic, William D.

2001-01-01

Asynchronous Transfer Mode (ATM) Quality of Service (QoS) experiments using the Transmission Control Protocol/Internet Protocol (TCP/IP) were performed for various link delays. The link delay was set to emulate a Wide Area Network (WAN) and a Satellite Link. The purpose of these experiments was to evaluate the ATM QoS requirements for applications that utilize advance TCP/IP protocols implemented with large windows and Selective ACKnowledgements (SACK). The effects of cell error, cell loss, and random bit errors on throughput were reported. The detailed test plan and test results are presented herein.

TCP is hardly resorbed and not osteoconductive in a non-loading calvarial model.

PubMed

Handschel, Jörg; Wiesmann, Hans Peter; Stratmann, Udo; Kleinheinz, Johannes; Meyer, Ulrich; Joos, Ulrich

2002-04-01

Tricalciumphosphate (TCP) has been used as a ceramic bone substitute material in the orthopedic field as well as in craniofacial surgery. Some controversies exist concerning the osteoconductive potential of this material in different implantation sites. This study was designed to evaluate the biological response of calvarial bone towards TCP granules under non-loading conditions to assess the potential of TCP as a biodegredable and osteoconductive bone substitue material for the cranial vault. Full-thickness non-critical size defects were made bilaterally in the calvaria of 21 adult Wistar rats. One side was filled by TCP granules, the contralateral side was left empty and used as a control. Animals were sacrified in defined time intervals up to 6 months. Bone regeneration was analyzed with special respect toward the micromorphological and microanalytical features of the material-bone interaction by electron microscopy and electron diffraction analysis. Histologic examination revealed no TCP degradation even after 6 months of implantation. In contrast, a nearly complete bone regeneration of control defects was found after 6 months. At all times TCP was surrounded by a thin fibrous layer without presence of osteoblasts and features of regular mineralization. As far as degradation and substitution are concerned, TCP is a less favourable material tinder conditions of non-loading.

When Should We Give Up Filtration Surgery: Indications, Techniques and Results of Cyclodestruction.

PubMed

Masis Solano, Marisse; Huang, Guofu; Lin, Shan C

2017-01-01

Cyclodestructive procedures are traditionally used in cases of glaucoma that are refractory to medical and surgical therapy. The goal of this chapter is to describe the indications, contraindications, techniques, and pitfalls of cyclodestructive procedures, including transscleral cyclophotocoagulation (TCP), micropulse TCP (MP-TCP), endoscopic cyclophotocoagulation (ECP), and ultrasound cilioplasty. A literature search for cyclodestructive techniques was performed, and relevant studies were included for evaluation and review. It is encouraging that TCP seems relatively efficacious even for patients who have been refractory to other treatments, depending on the energy setting, follow-up period, and definition of success. Repeated TCP is often required. TCP was more often used in eyes with limited visual potential caused by severe forms of glaucoma than in eyes with good visual potential. Serious complications were significant vision loss, inflammation, hypotony, and phthisis. ECP came later into clinical use for the treatment of refractory glaucoma. ECP is able to specifically target the ciliary epithelium under direct viewing as compared to TCP, which is an indirect cyclodestructive procedure. In the literature, it has been demonstrated that ECP has overall good success with relatively low complication rates when used for adult forms of glaucoma. A new technology using MP-TCP is a promising alternative to conventional cyclophotocoagulation. Early evidence shows that MP-TCP has clinical utility and a good safety profile. Ultrasound cilioplasty is a possible alternative to laser cyclodestruction that is already being commercialized and is currently under investigation. Both TCP and ECP are effective cyclodestructive procedures and alternatives for the treatment of glaucoma refractory to medical and surgical therapy, though potential for serious complications exists. TCP, ECP, and ultrasound cilioplasty are being used increasingly as the primary surgery for various kinds and stages of glaucoma. © 2017 S. Karger AG, Basel.

Hierarchical structures of β-TCP/45S5 bioglass hybrid scaffolds prepared by gelcasting.

PubMed

Lopes, João Henrique; Magalhães, Jéssica Aparecida; Gouveia, Rubia Figueredo; Bertran, Celso Aparecido; Motisuke, Mariana; Camargo, Samira E A; Trichês, Eliandra de Sousa

2016-09-01

This paper investigates the microstructure and the mechanical properties of β-tricalcium phosphate (β-TCP) three-dimensional (3D) porous materials reinforced with 45S5 bioactive glass (BG). β-TCP and β-TCP/x%-BG scaffolds with interconnected pores networks, suitable for bone regeneration, were fabricated by gel-casting method. Mechanical properties, porosity, and morphological characteristics were evaluated by compressive strength test, scanning electron microscopy (SEM) and X-ray microtomography analysis, whereas the structures were fully explored by XRD, and Raman spectroscopy. To the best of our knowledge, this is the first time where the mechanism for understanding the effect of bioglass on the mechanical properties and microstruture of β-TCP/45S5-BG scaffolds has been systematically studied. The findings showed that ionic product lixiviated from 45S5 bioactive glass, rich in silicon species and sodium ion, catalyzes a phase transition from β-TCP to Si-TCP by replacement of phosphorus for silicon and contributes to the improvement of scaffolds mechanical properties. The compressive strength of β-TCP/5%-BG and β-TCP/7.5%-BG was improved around 200% in comparison to pure β-TCP. Osteoblast-like cells (MG 63) were exposed to the materials for 24h through the use of medium conditioned by β-tricalcium phosphate/bioactive glass. Cell viability was measured by MTT assay in the cells and the data obtained were submitted to ANOVA, Tukey׳s multiple comparison (p<0.05). The β-TCP/7.5-BG promoted an increase of cell proliferation. The results suggest that compositions and processing method studied may provide appropriate materials for tissue engineering. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enhancement of periodontal tissue regeneration by transplantation of osteoprotegerin-engineered periodontal ligament stem cells.

PubMed

Su, Fang; Liu, Shi-Sen; Ma, Jun-Li; Wang, Dong-Sheng; E, Ling-Ling; Liu, Hong-Chen

2015-03-12

The objective of the present study was to evaluate the capacity of a tissue-engineered complex of human osteoprotegerin (hOPG)-transfected periodontal ligament stem cells (PDLSCs) seeding on beta-tricalcium phosphate (β-TCP) to regenerate alveolar bone defects in New Zealand rabbits. PDLSCs were isolated from rabbit periodontal ligament tissues and expanded in vitro to enrich PDLSC numbers, and their proliferative activities and differentiation capability were evaluated under specific induction conditions. Lentiviral vector containing hOPG and enhanced green fluorescent protein (EGFP) was constructed by using Gateway technology and transfected into rabbit PDLSCs. The expression of hOPG was determined with quantitative real-time reverse transcription-polymerase chain reaction and Western blot. The PDLSCs with or without engineered hOPG were seeded on β-TCP scaffolds prior to transplantation. Morphological characterization of cells and materials was done by scanning electron microscope. Twenty rabbits with alveolar bone defects were randomly allocated into four groups and transplanted with β-TCP, PDLSCs/β-TCP, and hOPG-transfected PDLSCs/β-TCP or were left untreated as a control. Animals were sacrificed 12 weeks after operation for histological observation and histomorphometric analysis. PDLSCs expressed STRO-1 and vementin and favored osteogenesis and adipogenesis in conditioned media. Expressions of hOPG were significantly upregulated after transfection of the lentiviral vector into PDLSCs. PDLSCs attached and spread well on β-TCP, and there was no significant difference in growth of PDLSCs on β-TCP between the hOPG transfection group and the non-transfection group. The histological observation and histomorphometric analysis showed that the hOPG-transfected PDLSCs/β-TCP complex exhibited an earlier mineralization and more bone formation inside the scaffold than control, β-TCP, and PDLSCs/β-TCP complexes. Implantation of hOPG-transfected PDLSCs contributed to new bone formation as determined by EGFP gene expression under circularly polarized light microscopy. The present study demonstrated the feasibility of β-TCP scaffolds for primary PDLSC culture and expression of hOPG gene in vitro and in vivo, and hOPG-transfected PDLSCs could serve as a potential cell source for periodontal bone regeneration, which may shed light on the potential of systemic hOPG gene therapy in combination with PDLSC tissue engineering as a good candidate in periodontal tissue engineering for alveolar bone regeneration.

Evaluation of autogenous PRGF+β-TCP with or without a collagen membrane on bone formation and implant osseointegration in large size bone defects. A preclinical in vivo study.

PubMed

Batas, Leonidas; Stavropoulos, Andreas; Papadimitriou, Serafim; Nyengaard, Jens R; Konstantinidis, Antonios

2016-08-01

The aim of this study was to evaluate whether the adjunctive use of a collagen membrane enhances bone formation and implant osseointegration in non-contained defects grafted with chair-side prepared autologous platelet-rich growth factor (PRGF) adsorbed on a β-TCP particulate carrier. Large box-type defects (10 × 6 mm; W × D) were prepared in the edentulated and completely healed mandibles of six Beagles dogs. An implant with moderately rough surface was placed in the center of each defect leaving the coronal 6 mm of the implant not covered with bone. The remaining defect space was then filled out with chair-side prepared autologous PRGF adsorbed on β-TCP particles and either covered with a collagen membrane (PRGF/β-TCP+CM) (6 defects) or left without a membrane (PRGF/β-TCP) (5 defects). Histology 4 months post-op showed new lamellar and woven bone formation encompassing almost entirely the defect and limited residual β-TCP particles. Extent of osseointegration of the previously exposed portion of the implants varied, but in general was limited. Within the defect, new mineralized bone (%) averaged 43.2 ± 9.86 vs. 39.9 ± 13.7 in the PRGF/β-TCP+CM and PRGF/β-TCP group (P = 0.22) and relative mineralized bone-to-implant contact (%) averaged 26.2 ± 16.45 vs. 35.91 ± 24.45, respectively (P = 0.5). First, bone-to-implant contact from the implant top was 4.1 ± 1.5 and 3.2 ± 2.3 (P = 0.9), in the PRGF/β-TCP+CM and PRGF/β-TCP group, respectively. Implantation of chair-side prepared autologous PRGF adsorbed on a β-TCP carrier in non-contained peri-implant defects resulted in large amounts of bone regeneration, but osseointegration was limited. Provisions for GBR with a collagen membrane did not significantly enhance bone regeneration or implant osseointegration. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Bone engineering by phosphorylated-pullulan and β-TCP composite.

PubMed

Takahata, Tomohiro; Okihara, Takumi; Yoshida, Yasuhiro; Yoshihara, Kumiko; Shiozaki, Yasuyuki; Yoshida, Aki; Yamane, Kentaro; Watanabe, Noriyuki; Yoshimura, Masahide; Nakamura, Mariko; Irie, Masao; Van Meerbeek, Bart; Tanaka, Masato; Ozaki, Toshifumi; Matsukawa, Akihiro

2015-11-20

A multifunctional biomaterial with the capacity bond to hard tissues, such as bones and teeth, is a real need for medical and dental applications in tissue engineering and regenerative medicine. Recently, we created phosphorylated-pullulan (PPL), capable of binding to hydroxyapatite in bones and teeth. In the present study, we employed PPL as a novel biocompatible material for bone engineering. First, an in vitro evaluation of the mechanical properties of PPL demonstrated both PPL and PPL/β-TCP composites have higher shear bond strength than materials in current clinical use, including polymethylmethacrylate (PMMA) cement and α-tricalcium phosphate (TCP) cement, Biopex-R. Further, the compressive strength of PPL/β-TCP composite was significantly higher than Biopex-R. Next, in vivo osteoconductivity of PPL/β-TCP composite was investigated in a murine intramedular injection model. Bone formation was observed 5 weeks after injection of PPL/β-TCP composite, which was even more evident at 8 weeks; whereas, no bone formation was detected after injection of PPL alone. We then applied PPL/β-TCP composite to a rabbit ulnar bone defect model and observed bone formation comparable to that induced by Biopex-R. Implantation of PPL/β-TCP composite induced new bone formation at 4 weeks, which was remarkably evident at 8 weeks. In contrast, Biopex-R remained isolated from the surrounding bone at 8 weeks. In a pig vertebral bone defect model, defects treated with PPL/β-TCP composite were almost completely replaced by new bone; whereas, PPL alone failed to induce bone formation. Collectively, our results suggest PPL/β-TCP composite may be useful for bone engineering.

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

Lee, E; Yuan, F; Templeton, A

Purpose: The ultimate goal of radiotherapy treatment planning is to find a treatment that will yield a high tumor-control-probability(TCP) with an acceptable normal-tissue-complication probability(NTCP). Yet most treatment planning today is not based upon optimization of TCPs and NTCPs, but rather upon meeting physical dose and volume constraints defined by the planner. We design treatment plans that optimize TCP directly and contrast them with the clinical dose-based plans. PET image is incorporated to evaluate gain in TCP for dose escalation. Methods: We build a nonlinear mixed integer programming optimization model that maximizes TCP directly while satisfying the dose requirements on themore » targeted organ and healthy tissues. The solution strategy first fits the TCP function with a piecewise-linear approximation, then solves the problem that maximizes the piecewise linear approximation of TCP, and finally performs a local neighborhood search to improve the TCP value. To gauge the feasibility, characteristics, and potential benefit of PET-image guided dose escalation, initial validation consists of fifteen cervical cancer HDR patient cases. These patients have all received prior 45Gy of external radiation dose. For both escalated strategies, we consider 35Gy PTV-dose, and two variations (37Gy-boost to BTV vs 40Gy-boost) to PET-image-pockets. Results: TCP for standard clinical plans range from 59.4% - 63.6%. TCP for dose-based PET-guided escalated-dose-plan ranges from 63.8%–98.6% for all patients; whereas TCP-optimized plans achieves over 91% for all patients. There is marginal difference in TCP among those with 37Gy-boosted vs 40Gy-boosted. There is no increase in rectum and bladder dose among all plans. Conclusion: Optimizing TCP directly results in highly conformed treatment plans. The TCP-optimized plan is individualized based on the biological PET-image of the patients. The TCP-optimization framework is generalizable and has been applied successfully to other external-beam delivery modalities. A clinical trial is on-going to gauge the clinical significance. Partially supported by the National Science Foundation.« less

Biomimetic evaluation of β tricalcium phosphate prepared by hot isostatic pressing

PubMed Central

Mateescu, Mihaela; Rguitti, Emmanuelle; Ponche, Arnaud; Descamps, Michel; Anselme, Karine

2012-01-01

Two types of completely densified β-TCP tablets were synthesized from a stoichiometric β-TCP powder. The first ones (TCP) were conventionally sintered, while the second ones (TCP-T) were sintered and treated by hot isostatic process (HIP). The HIP produced completely densified materials with relative densities greater than 99.9% and a transparent appearance of tablets. Samples were immersed in culture medium with (CM) or without serum (NCM) in static and dynamic conditions for a biomimetic evaluation. Similarly, SaOs-2 cells were cultured on samples in a static or dynamic flow perfusion system. The results of surface transformation in absence of cells showed that the dynamic condition increased the speed of calcium phosphate precipitations compared with the static condition. The morphology of precipitates was different with nature of tablets. The immersion in CM did impede this precipitation. XPS analysis of TCP-T tablets showed the presence of hydroxyapatite (HA) precipitates after incubation in NCM while octacalcium phosphate (OCP) precipitates were formed after incubation in CM. The analysis of the response of SaOs-2 cells on surfaces showed that the two types of materials are biocompatible. However, the dynamic mode of culture stimulated the differentiation of cells. Finally, it appears that the HIP treatment of TCP produces highly densified and transparent samples that display a good in vitro biocompatibility in static and dynamic culture conditions. Moreover, an interesting result of this work is the relationship between the presence of proteins in the immersion medium and the quality of precipitates formed on hipped TCP surface. PMID:23507861

Alternatives to Autograft Evaluated in a Rabbit Segmental Bone Defect

DTIC Science & Technology

2015-07-09

available scaffolds containing either demineralised bone matrix (DBM) or a collagen /beta-tricalcium phosphate composite (Col:β-TCP); each scaffold was...also sub- jected to cell analyses and used to load scaffolds. Each batch of BMA or cBMA was used to load both a DBM and collagen -β-TCP (Col:β-TCP...with previously published work where rabbits [24], pigs [15] or humans [8] were used. Since the DBM grafts performed well regardless of whether BMA

Combination of BMP-2-releasing gelatin/β-TCP sponges with autologous bone marrow for bone regeneration of X-ray-irradiated rabbit ulnar defects.

PubMed

Yamamoto, Masaya; Hokugo, Akishige; Takahashi, Yoshitake; Nakano, Takayoshi; Hiraoka, Masahiro; Tabata, Yasuhiko

2015-07-01

The objective of this study is to evaluate the feasibility of gelatin sponges incorporating β-tricalcium phosphate (β-TCP) granules (gelatin/β-TCP sponges) to enhance bone regeneration at a segmental ulnar defect of rabbits with X-ray irradiation. After X-ray irradiation of the ulnar bone, segmental critical-sized defects of 20-mm length were created, and bone morphogenetic protein-2 (BMP-2)-releasing gelatin/β-TCP sponges with or without autologous bone marrow were applied to the defects to evaluate bone regeneration. Both gelatin/β-TCP sponges containing autologous bone marrow and BMP-2-releasing sponges enhanced bone regeneration at the ulna defect to a significantly greater extent than the empty sponges (control). However, in the X-ray-irradiated bone, the bone regeneration either by autologous bone marrow or BMP-2 was inhibited. When combined with autologous bone marrow, the BMP-2 exhibited significantly high osteoinductivity, irrespective of the X-ray irradiation. The bone mineral content at the ulna defect was similar to that of the intact bone. It is concluded that the combination of bone marrow with the BMP-2-releasing gelatin/β-TCP sponge is a promising technique to induce bone regeneration at segmental bone defects after X-ray irradiation. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Human Clinical, Histological, Histomorphometrical, and Radiographical Study on Biphasic HA-Beta-TCP 30/70 in Maxillary Sinus Augmentation.

PubMed

Mangano, Carlo; Sinjari, Bruna; Shibli, Jamil A; Mangano, Francesco; Hamisch, Sabine; Piattelli, Adriano; Perrotti, Vittoria; Iezzi, Giovanna

2015-06-01

By mixing hydroxyapatite (HA) and tricalcium phosphate (TCP), biphasic calcium phosphate ceramics can be obtained, and by varying their ratio it is possible to tailor the characteristics of the biomaterial. The aim of the present human study was to evaluate the histological and radiographical aspects of bone formation in maxillary sinus augmentation using a 30/70 HA-beta-TCP with a reticular structure. A total of 12 patients, undergoing two-stage sinus augmentation procedure using HA-beta-TCP at a ratio of 30/70, were included in the present study. After a 6-month healing period, during implant insertion, radiographical analysis was performed, and then the bone core biopsies were harvested and processed for histology. At radiographic evaluation, the bone gain was on average 6.85 ± 0.60 mm. HA-beta-TCP 30/70 appeared to be lined by newly formed bone, with no gaps at the interface. The histomorphometric analysis revealed 26 ± 2% of residual grafted biomaterial, 29 ± 3% of newly formed bone, and 45 ± 2% of marrow spaces. The present results indicate histologically the high biocompatibility and osteoconductivity of HA-beta-TCP 30/70, and clinically its successful use for sinus augmentation procedures. © 2013 Wiley Periodicals, Inc.

Systematic evaluation of a tissue-engineered bone for maxillary sinus augmentation in large animal canine model.

PubMed

Wang, Shaoyi; Zhang, Zhiyuan; Xia, Lunguo; Zhao, Jun; Sun, Xiaojuan; Zhang, Xiuli; Ye, Dongxia; Uludağ, Hasan; Jiang, Xinquan

2010-01-01

The objective of this study is to systematically evaluate the effects of a tissue-engineered bone complex for maxillary sinus augmentation in a canine model. Twelve sinus floor augmentation surgeries in 6 animals were performed bilaterally and randomly repaired with the following 3 groups of grafts: group A consisted of tissue-engineered osteoblasts/beta-TCP complex (n=4); group B consisted of beta-TCP alone (n=4); group C consisted of autogenous bone obtained from iliac crest as a positive control (n=4). All dogs had uneventful healings following the surgery. Sequential polychrome fluorescent labeling, maxillofacial CT, microhardness tests, as well as histological and histomorphometric analyses indicated that the tissue-engineered osteoblasts/beta-TCP complex dramatically promoted bone formation and mineralization and maximally maintained the height and volume of elevated maxillary sinus. By comparison, both control groups of beta-TCP or autologous iliac bone showed considerable resorption and replacement by fibrous or fatty tissue. We thus conclude that beta-TCP alone could barely maintain the height and volume of the elevated sinus floor, and that the transplantation of autogenous osteoblasts on beta-TCP could promote earlier bone formation and mineralization, maximally maintain height, volume and increase the compressive strength of augmented maxillary sinus. This tissue engineered bone complex might be a better alternative to autologous bone for the clinical edentulous maxillary sinus augmentation. Copyright (c) 2009 Elsevier Inc. All rights reserved.

Efficacy of rhBMP-2 Loaded PCL/β-TCP/bdECM Scaffold Fabricated by 3D Printing Technology on Bone Regeneration.

PubMed

Bae, Eun-Bin; Park, Keun-Ho; Shim, Jin-Hyung; Chung, Ho-Yun; Choi, Jae-Won; Lee, Jin-Ju; Kim, Chang-Hwan; Jeon, Ho-Jun; Kang, Seong-Soo; Huh, Jung-Bo

2018-01-01

This study was undertaken to evaluate the effect of 3D printed polycaprolactone (PCL)/ β -tricalcium phosphate ( β -TCP) scaffold containing bone demineralized and decellularized extracellular matrix (bdECM) and human recombinant bone morphogenetic protein-2 (rhBMP-2) on bone regeneration. Scaffolds were divided into PCL/ β -TCP, PCL/ β -TCP/bdECM, and PCL/ β -TCP/bdECM/BMP groups. In vitro release kinetics of rhBMP-2 were determined with respect to cell proliferation and osteogenic differentiation. These three reconstructive materials were implanted into 8 mm diameter calvarial bone defect in male Sprague-Dawley rats. Animals were sacrificed four weeks after implantation for micro-CT, histologic, and histomorphometric analyses. The findings obtained were used to calculate new bone volumes (mm 3 ) and new bone areas (%). Excellent cell bioactivity was observed in the PCL/ β -TCP/bdECM and PCL/ β -TCP/bdECM/BMP groups, and new bone volume and area were significantly higher in the PCL/ β -TCP/bdECM/BMP group than in the other groups ( p < .05). Within the limitations of this study, bdECM printed PCL/ β -TCP scaffolds can reproduce microenvironment for cells and promote adhering and proliferating the cells onto scaffolds. Furthermore, in the rat calvarial defect model, the scaffold which printed rhBMP-2 loaded bdECM stably carries rhBMP-2 and enhances bone regeneration confirming the possibility of bdECM as rhBMP-2 carrier.

Measuring and Evaluating TCP Splitting for Cloud Services

NASA Astrophysics Data System (ADS)

Pathak, Abhinav; Wang, Y. Angela; Huang, Cheng; Greenberg, Albert; Hu, Y. Charlie; Kern, Randy; Li, Jin; Ross, Keith W.

In this paper, we examine the benefits of split-TCP proxies, deployed in an operational world-wide network, for accelerating cloud services. We consider a fraction of a network consisting of a large number of satellite datacenters, which host split-TCP proxies, and a smaller number of mega datacenters, which ultimately perform computation or provide storage. Using web search as an exemplary case study, our detailed measurements reveal that a vanilla TCP splitting solution deployed at the satellite DCs reduces the 95 th percentile of latency by as much as 43% when compared to serving queries directly from the mega DCs. Through careful dissection of the measurement results, we characterize how individual components, including proxy stacks, network protocols, packet losses and network load, can impact the latency. Finally, we shed light on further optimizations that can fully realize the potential of the TCP splitting solution.

2,4,6-Trichlorophenol cytotoxicity involves oxidative stress, endoplasmic reticulum stress, and apoptosis.

PubMed

Zhang, Xiaoning; Zhang, Xiaona; Niu, Zhidan; Qi, Yongmei; Huang, Dejun; Zhang, Yingmei

2014-01-01

This study aims to evaluate the cytotoxicity and potential mechanisms of 2,4,6-trichlorophenol (2,4,6-TCP) in mouse embryonic fibroblasts. Our results show that 2,4,6-TCP causes morphological changes and reduces cell viability. The overproduction of reactive oxygen species, the upregulation of nuclear factor-E2-related factor 2 (Nrf2) and heme oxygenase 1 (HMOX1) messenger RNA (mRNA) expressions, and the nuclear translocation of Nrf2 protein demonstrate that 2,4,6-TCP induces oxidative stress, and the Nrf2/HMOX1 pathway might be involved in 2,4,6-TCP-induced antioxidative response. Simultaneously, our data also demonstrate that 2,4,6-TCP upregulates the expressions of binding immunoglobulin protein, inositol-requiring enzyme/endonuclease 1α, and C/EBP homologous protein; stimulates α subunit of eukaryotic translation initiation factor 2 phosphorylation; and induces the splicing of Xbp1 mRNA, suggesting that endoplasmic reticulum (ER) stress is triggered. Moreover, 2,4,6-TCP alters the mitochondrial membrane potential and increases the apoptosis rate, the caspase 3 activity, and the Bax/Bcl-2 ratio, demonstrating that the mitochondrial pathway is involved in the 2,4,6-TCP-induced apoptosis. Thus, these results show that 2,4,6-TCP induces oxidative stress, ER stress, and apoptosis, which together contribute to its cytotoxicity in vitro. © The Author(s) 2014.

Efficacy of Honeycomb TCP-induced Microenvironment on Bone Tissue Regeneration in Craniofacial Area.

PubMed

Watanabe, Satoko; Takabatake, Kiyofumi; Tsujigiwa, Hidetsugu; Watanabe, Toshiyuki; Tokuyama, Eijiro; Ito, Satoshi; Nagatsuka, Hitoshi; Kimata, Yoshihiro

2016-01-01

Artificial bone materials that exhibit high biocompatibility have been developed and are being widely used for bone tissue regeneration. However, there are no biomaterials that are minimally invasive and safe. In a previous study, we succeeded in developing honeycomb β-tricalcium phosphate (β-TCP) which has through-and-through holes and is able to mimic the bone microenvironment for bone tissue regeneration. In the present study, we investigated how the difference in hole-diameter of honeycomb β-TCP (hole-diameter: 75, 300, 500, and 1600 μm) influences bone tissue regeneration histologically. Its osteoconductivity was also evaluated by implantation into zygomatic bone defects in rats. The results showed that the maximum bone formation was observed on the β-TCP with hole-diameter 300μm, included bone marrow-like tissue and the pattern of bone tissue formation similar to host bone. Therefore, the results indicated that we could control bone tissue formation by creating a bone microenvironment provided by β-TCP. Also, in zygomatic bone defect model with honeycomb β-TCP, the result showed there was osseous union and the continuity was reproduced between the both edges of resected bone and β-TCP, which indicated the zygomatic bone reproduction fully succeeded. It is thus thought that honeycomb β-TCP may serve as an excellent biomaterial for bone tissue regeneration in the head, neck and face regions, expected in clinical applications.

Efficacy of Honeycomb TCP-induced Microenvironment on Bone Tissue Regeneration in Craniofacial Area

PubMed Central

Watanabe, Satoko; Takabatake, Kiyofumi; Tsujigiwa, Hidetsugu; Watanabe, Toshiyuki; Tokuyama, Eijiro; Ito, Satoshi; Nagatsuka, Hitoshi; Kimata, Yoshihiro

2016-01-01

Artificial bone materials that exhibit high biocompatibility have been developed and are being widely used for bone tissue regeneration. However, there are no biomaterials that are minimally invasive and safe. In a previous study, we succeeded in developing honeycomb β-tricalcium phosphate (β-TCP) which has through-and-through holes and is able to mimic the bone microenvironment for bone tissue regeneration. In the present study, we investigated how the difference in hole-diameter of honeycomb β-TCP (hole-diameter: 75, 300, 500, and 1600 μm) influences bone tissue regeneration histologically. Its osteoconductivity was also evaluated by implantation into zygomatic bone defects in rats. The results showed that the maximum bone formation was observed on the β-TCP with hole-diameter 300μm, included bone marrow-like tissue and the pattern of bone tissue formation similar to host bone. Therefore, the results indicated that we could control bone tissue formation by creating a bone microenvironment provided by β-TCP. Also, in zygomatic bone defect model with honeycomb β-TCP, the result showed there was osseous union and the continuity was reproduced between the both edges of resected bone and β-TCP, which indicated the zygomatic bone reproduction fully succeeded. It is thus thought that honeycomb β-TCP may serve as an excellent biomaterial for bone tissue regeneration in the head, neck and face regions, expected in clinical applications. PMID:27279797

Histochemical examination of adipose derived stem cells combined with β-TCP for bone defects restoration under systemic administration of 1α,25(OH)2D3.

PubMed

Feng, Wei; Lv, Shengyu; Cui, Jian; Han, Xiuchun; Du, Juan; Sun, Jing; Wang, Kefeng; Wang, Zhenming; Lu, Xiong; Guo, Jie; Oda, Kimimitsu; Amizuka, Norio; Xu, Xin; Li, Minqi

2015-09-01

The purpose of this study was to evaluate the effects of osteogenic differentiated adipose-derived stem cell (ADSC) loaded beta-tricalcium phosphate (β-TCP) in the restoration of bone defects under intraperitoneal administration of 1α,25-dihydroxyvitamin D3(1α,25(OH)2D3). ADSCs were isolated from the fat tissue of 8 week old Wister rats and co-cultured with β-TCP for 21 days under osteogenic induction. Then the ADSC-β-TCP complexes were implanted into bone defects in the femora of rats. 1α,25(OH)2D3 (VD) or normal saline (NS) was administrated intraperitoneally every other day after the surgery. Femora were harvested at day 7, day 14 and day 28 post-surgery. There were 4 groups for all specimens: β-TCP-NS group; β-TCP-ADSC-NS group; β-TCP-VD group and β-TCP-ADSC-VD group. Alkaline phosphatase (ALP) was up-regulated obviously in ADSC groups compared with non-ADSC groups at day 7, day 14 and day 28, although high expression of runt-related transcription factor 2 (RUNX2) was only seen at day 7. Furthermore, the number of TRAP-positive osteoclasts and the expression of cathepsin K (CK) were significantly decreased in VD groups compared with non-VD groups at day 7 and day 14. As a most significant finding, the β-TCP-ADSC-VD group showed the highest BV/TV ratio compared with the other three groups at day 28. Taken together, ADSC-loaded β-TCP under the administration of 1α,25(OH)2D3 made a promising therapy for bone defects restoration. Copyright © 2015 Elsevier B.V. All rights reserved.

The interaction of adipose-derived human mesenchymal stem cells and polyether ether ketone.

PubMed

Wang, Weiwei; Kratz, Karl; Behl, Marc; Yan, Wan; Liu, Yue; Xu, Xun; Baudis, Stefan; Li, Zhengdong; Kurtz, Andreas; Lendlein, Andreas; Ma, Nan

2015-01-01

Polyether ether ketone (PEEK) as a high-performance, thermoplastic implant material entered the field of medical applications due to its structural function and commercial availability. In bone tissue engineering, the combination of mesenchymal stem cells (MSCs) with PEEK implants may accelerate the bone formation and promote the osseointegration between the implant and the adjacent bone tissue. In this concept the question how PEEK influences the behaviour and functions of MSCs is of great interest. Here the cellular response of human adipose-derived MSCs to PEEK was evaluated and compared to tissue culture plate (TCP) as the reference material. Viability and morphology of cells were not altered when cultured on the PEEK film. The cells on PEEK presented a high proliferation activity in spite of a relatively lower initial cell adhesion rate. There was no significant difference on cell apoptosis and senescence between the cells on PEEK and TCP. The inflammatory cytokines and VEGF secreted by the cells on these two surfaces were at similar levels. The cells on PEEK showed up-regulated BMP2 and down-regulated BMP4 and BMP6 gene expression, whereas no conspicuous differences were observed in the committed osteoblast markers (BGLAP, COL1A1 and Runx2). With osteoinduction the cells on PEEK and TCP exhibited a similar osteogenic differentiation potential. Our results demonstrate the biofunctionality of PEEK for human MSC cultivation and differentiation. Its clinical benefits in bone tissue engineering may be achieved by combining MSCs with PEEK implants. These data may also provide useful information for further modification of PEEK with chemical or physical methods to regulate the cellular processes of MSCs and to consequently improve the efficacy of MSC-PEEK based therapies.

Effect of intermittent administration of teriparatide on the mechanical and histological changes in bone grafted with β-tricalcium phosphate using a rabbit bone defect model

PubMed Central

Komatsu, Jun; Nagura, Nana; Iwase, Hideaki; Igarashi, Mamoru; Ohbayashi, Osamu; Nagaoka, Isao; Kaneko, Kazuo

2018-01-01

Grafting β-tricalcium phosphate (TCP) is a well-established method for restoring bone defects; however, there is concern that the mechanical stability of the grafted β-TCP is not maintained during bone translation. Teriparatide has an anabolic effect, stimulating bone formation and increasing bone mineral density for the treatment of osteoporosis. The aim of the present study was to evaluate the effect of intermittent teriparatide treatment on changes in bone grafted with β-TCP using a rabbit bone defect model. Bone defects (5×15 mm) were created in the distal femoral condyle of Japanese white rabbits, and β-TCP granules of two different total porosities were manually grafted. Teriparatide (40 µg/kg) or 0.2% rabbit serum albumin solution as a vehicle control was subcutaneously injected three times per week following the surgery. At 4 or 8 weeks post-surgery, serum samples were obtained and the levels of γ-carboxylated osteocalcin (Gla-OC) were quantified using ELISA. Histomorphometry was also performed using sections of graft sites following staining for tartrate resistant acid phosphatase. Activity and mechanical strength (maximum shear strength, maximum shear stiffness and total energy absorption) were evaluated using an axial push-out load to failure test. Teriparatide treatment significantly increased (P<0.05) the serum levels of Gla-OC, a specific marker for bone formation, suggesting that teriparatide enhances bone formation in β-TCP-grafted rabbits. Furthermore teriparatide increased the degradation of β-TCP by bone remodeling (P<0.05) and promoted the formation of new bone following application of the graft compared with the control group (P<0.01). Furthermore, teriparatide suppressed the reduction in mechanical strength (P<0.05) during bone translation in bone defects grafted with β-TCP. The results of the present study demonstrate that teriparatide is effective in maintaining the mechanical stability of grafted β-TCP, possibly by promoting new bone formation. PMID:29387179

Biomaterial Property Effects on Platelets and Macrophages: An in Vitro Study.

PubMed

Fernandes, Kelly R; Zhang, Yang; Magri, Angela M P; Renno, Ana C M; van den Beucken, Jeroen J J P

2017-12-11

The purpose of this study was to evaluate the effects of surface properties of bone implants coated with hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) on platelets and macrophages upon implant installation and compare them to grit-blasted Ti and Thermanox used as a control. Surface properties were characterized using scanning electron microscopy, profilometry, crystallography, Fourier transform infrared spectroscopy, and coating stability. For platelets, platelet adherence and morphology were assessed. For macrophages, morphology, proliferation, and polarization were evaluated. Surface characterization showed similar roughness of ∼2.5 μm for grit-blasted Ti discs, both with and without coating. Coating stability assessment showed substantial dissolution of HA and β-TCP coatings. Platelet adherence was significantly higher for grit-blasted Ti, Ti-HA, and Ti-β-TCP coatings compared to that of cell culture control Thermanox. Macrophage cultures revealed a decreased proliferation on both HA and β-TCP coated discs compared to both Thermanox and grit-blasted Ti. In contrast, secretion of pro-inflammatory cytokine TNF-α and anti-inflammatory cytokine TGF-β were marginal for grit-blasted Ti and Thermanox, while a coating-dependent increased secretion of pro- and anti-inflammatory cytokines was observed for HA and β-TCP coatings. The results demonstrated a significantly upregulated pro-inflammatory and anti-inflammatory cytokine secretion and marker gene expression of macrophages on HA and β-TCP coatings. Furthermore, HA induced an earlier M1 macrophage polarization but more M2 phenotype potency than β-TCP. In conclusion, our data showed that material surface affects the behaviors of first cell types attached to implants. Due to the demonstrated crucial roles of platelets and macrophages in bone healing and implant integration, this information will greatly aid the design of metallic implants for a higher rate of success in patients.

Development of a Non-Invasive Biomonitoring Approach to Determine Exposure to the Organophosphorus Insecticide Chlorpyrifos in Rat Saliva

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

Timchalk, Chuck; Campbell, James A.; Liu, Guodong

2007-03-01

Abstract Non-invasive biomonitoring approaches are being developed using reliable portable analytical systems to quantify dosimetry utilizing readily obtainable body fluids, such as saliva. In the current study, rats were given single oral gavage doses (1, 10 or 50 mg/kg) of the insecticide chlorpyrifos (CPF), saliva and blood were collected from groups of animals (4/time-point) at 3, 6, and 12 hr post-dosing, and the samples were analyzed for the CPF metabolite trichlorpyridinol (TCP). Trichlorpyridinol was detected in both blood and saliva at all doses and the TCP concentration in blood exceeded saliva, although the kinetics in blood and saliva were comparable.more » A physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) model for CPF incorporated a compartment model to describe the time-course of TCP in blood and saliva. The model adequately simulated the experimental results over the dose ranges evaluated. A rapid and sensitive sequential injection (SI) electrochemical immunoassay was developed to monitor TCP, and the reported detection limit for TCP in water was 6 ng/L. Computer model simulation in the range of the Allowable Daily Intake (ADI) or Reference Dose (RfD) for CPF (0.01-0.003 mg/kg/day) suggest that the electrochemical immunoassay had adequate sensitivity to detect and quantify TCP in saliva at these low exposure levels. To validate this approach further studies are needed to more fully understand the pharmacokinetics of CPF and TCP excretion in saliva. The utilization of saliva as a biomonitoring matrix, coupled to real-time quantitation and PBPK/PD modeling represents a novel approach with broad application for evaluating both occupational and environmental exposures to insecticides.« less

A prospective, randomized pilot study on the safety and efficacy of recombinant human growth and differentiation factor-5 coated onto β-tricalcium phosphate for sinus lift augmentation.

PubMed

Koch, Felix P; Becker, Jürgen; Terheyden, Hendrik; Capsius, Björn; Wagner, Wilfried

2010-11-01

The aim of this prospective, randomized clinical trial was to investigate the potential of recombinant human growth and differentiation factor-5 (rhGDF-5) coated onto β-tricalcium phosphate (β-TCP) (rhGDF-5/β-TCP) to support bone formation after sinus lift augmentation. In total, 31 patients participated in this multicenter clinical trial. They required a two-stage unilateral maxillary sinus floor augmentation (residual bone height <5 mm). According to a parallel-group design, the patients were randomized to three treatment groups: (a) augmentation with rhGDF-5/β-TCP and a 3-month healing period, (b) augmentation with rhGDF-5/β-TCP and a 4-month healing period and (c) medical device β-TCP mixed with autologous bone and a 4-month healing period. The primary study objective was the area of newly formed bone within the augmented area as assessed by histomorphometric evaluation of trephine bur biopsies. The osseous regeneration was similar in each treatment group; the amount of newly formed bone ranged between 28% (± 15.5%) and 31.8% (± 17.9%). Detailed analysis of histological data will be published elsewhere. As secondary efficacy variables, the augmentation height at the surgery site was measured by radiography. The largest augmentation was radiologically achieved in the rhGDF-5/β-TCP - 3-month and the rhGDF-5/β-TCP - 4-month treatment groups. As safety parameters, adverse events were recorded and anti-drug antibody levels were evaluated. Most of the adverse events were judged as unrelated to the study medication. Four out of 47 (8.5%) implants failed in patients treated with rhGDF-5/β-TCP, a result that is in agreement with the general implant failure rate of 5-15%. Transiently very low amounts of anti-rhGDF-5 antibodies were detected in some patients who received rhGDF-5, which was not related to the bone formation outcome. rhGDF-5/β-TCP was found to be effective and safe as the control treatment with autologous bone mixed β-TCP in sinus floor augmentation. Thus, further investigation regarding efficacy and safety will be carried out in larger patient populations. © 2010 John Wiley & Sons A/S.

Development and evaluation of tetrapod-shaped granular artificial bones.

PubMed

Choi, Sungjin; Liu, I-li; Yamamoto, Kenichi; Igawa, Kazuyo; Mochizuki, Manabu; Sakai, Takamasa; Echigo, Ryosuke; Honnami, Muneki; Suzuki, Shigeki; Chung, Ung-il; Sasaki, Nobuo

2012-07-01

We have developed a novel form of granular artificial bone "Tetrabones" with a homogeneous tetrapod shape and uniform size. Tetrabones are four armed structures that accumulate to form the intergranular pores that allow invasion of cells and blood vessels. In this study we evaluated the physicochemical characteristics of Tetrabones in vitro, and compared their biological and biomechanical properties in vivo to those of conventional β-tricalcium phosphate (β-TCP) granule artificial bone. Both the rupture strength and elastic modulus of Tetrabone particles were higher than those of β-TCP granules in vitro. The connectivity of intergranular pores 100, 300, and 400 μm in size were higher in Tetrabones than in the β-TCP granules. Tetrabones showed similar osteoconductivity and biomechanical stiffness to β-TCP at 2 months after implantation in an in vivo study of canine bone defects. These results suggest that Tetrabones may be a good bone graft material in bone reconstruction. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Biological optimization of simultaneous boost on intra-prostatic lesions (DILs): sensitivity to TCP parameters.

PubMed

Azzeroni, R; Maggio, A; Fiorino, C; Mangili, P; Cozzarini, C; De Cobelli, F; Di Muzio, N G; Calandrino, R

2013-11-01

The aim of this investigation was to explore the potential of biological optimization in the case of simultaneous integrated boost on intra-prostatic dominant lesions (DIL) and evaluating the impact of TCP parameters uncertainty. Different combination of TCP parameters (TD50 and γ50 in the Poisson-like model), were considered for DILs and the prostate outside DILs (CTV) for 7 intermediate/high-risk prostate patients. The aim was to maximize TCP while constraining NTCPs below 5% for all organs at risk. TCP values were highly depending on the parameters used and ranged between 38.4% and 99.9%; the optimized median physical doses were in the range 94-116 Gy and 69-77 Gy for DIL and CTV respectively. TCP values were correlated with the overlap PTV-rectum and the minimum distance between rectum and DIL. In conclusion, biological optimization for selective dose escalation is feasible and suggests prescribed dose around 90-120 Gy to the DILs. The obtained result is critically depending on the assumptions concerning the higher radioresistence in the DILs. In case of very resistant clonogens into the DIL, it may be difficult to maximize TCP to acceptable levels without violating NTCP constraints. Copyright © 2012 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Interlaboratory studies on in vitro test methods for estimating in vivo resorption of calcium phosphate ceramics.

PubMed

Ito, Atsuo; Sogo, Yu; Yamazaki, Atsushi; Aizawa, Mamoru; Osaka, Akiyoshi; Hayakawa, Satoshi; Kikuchi, Masanori; Yamashita, Kimihiro; Tanaka, Yumi; Tadokoro, Mika; de Sena, Lídia Ágata; Buchanan, Fraser; Ohgushi, Hajime; Bohner, Marc

2015-10-01

A potential standard method for measuring the relative dissolution rate to estimate the resorbability of calcium-phosphate-based ceramics is proposed. Tricalcium phosphate (TCP), magnesium-substituted TCP (MgTCP) and zinc-substituted TCP (ZnTCP) were dissolved in a buffer solution free of calcium and phosphate ions at pH 4.0, 5.5 or 7.3 at nine research centers. Relative values of the initial dissolution rate (relative dissolution rates) were in good agreement among the centers. The relative dissolution rate coincided with the relative volume of resorption pits of ZnTCP in vitro. The relative dissolution rate coincided with the relative resorbed volume in vivo in the case of comparison between microporous MgTCPs with different Mg contents and similar porosity. However, the relative dissolution rate was in poor agreement with the relative resorbed volume in vivo in the case of comparison between microporous TCP and MgTCP due to the superimposition of the Mg-mediated decrease in TCP solubility on the Mg-mediated increase in the amount of resorption. An unambiguous conclusion could not be made as to whether the relative dissolution rate is predictive of the relative resorbed volume in vivo in the case of comparison between TCPs with different porosity. The relative dissolution rate may be useful for predicting the relative amount of resorption for calcium-phosphate-based ceramics having different solubility under the condition that the differences in the materials compared have little impact on the resorption process such as the number and activity of resorbing cells. The evaluation and subsequent optimization of the resorbability of calcium phosphate are crucial in the use of resorbable calcium phosphates. Although the resorbability of calcium phosphates has usually been evaluated in vivo, establishment of a standard in vitro method that can predict in vivo resorption is beneficial for accelerating development and commercialization of new resorbable calcium phosphate materials as well as reducing use of animals. However, there are only a few studies to propose such an in vitro method within which direct comparison was carried out between in vitro and in vivo resorption. We propose here an in vitro method based on measuring dissolution rate. The efficacy and limitations of the method were evaluated by international round-robin tests as well as comparison with in vivo resorption studies for future standardization. This study was carried out as one of Versailles Projects on Advanced Materials and Standards (VAMAS). Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Microsphere-Based Scaffolds Encapsulating Tricalcium Phosphate And Hydroxyapatite For Bone Regeneration

PubMed Central

Gupta, Vineet; Lyne, Dina V.; Barragan, Marilyn; Berkland, Cory J.; Detamore, Michael S.

2016-01-01

Bioceramic mixtures of tricalcium phosphate (TCP) and hydroxyapatite (HAp) are widely used for bone regeneration because of their excellent cytocompatibility, osteoconduction, and osteoinduction. Therefore, we hypothesized that incorporation of a mixture of TCP and HAp in microsphere-based scaffolds would enhance osteogenesis of rat bone marrow stromal cells (rBMSCs) compared to a positive control of scaffolds with encapsulated bone-morphogenic protein-2 (BMP-2). Poly(D,L-lactic-co-glycolic acid) (PLGA) microsphere-based scaffolds encapsulating TCP and HAp mixtures in two different ratios (7:3 and 1:1) were fabricated with the same net ceramic content (30 wt%) to evaluate how incorporation of these ceramic mixtures would affect the osteogenesis in rBMSCs. Encapsulation of TCP/HAp mixtures impacted microsphere morphologies and the compressive moduli of the scaffolds. Additionally, TCP/HAp mixtures enhanced the end-point secretion of extracellular matrix (ECM) components relevant to bone tissue compared to the “blank” (PLGA-only) microsphere-based scaffolds as evidenced by the biochemical, gene expression, histology, and immunohistochemical characterization. Moreover, the TCP/HAp mixture groups even surpassed the BMP-2 positive control group in some instances in terms of matrix synthesis and gene expression. Lastly, gene expression data suggested that the rBMSCs responded differently to different TCP/HAp ratios presented to them. Altogether, it can be concluded that TCP/HAp mixtures stimulated the differentiation of rBMSCs toward an osteoblastic phenotype, and therefore may be beneficial in gradient microsphere-based scaffolds for osteochondral regeneration. PMID:27272903

Synthesis and cytotoxicity evaluation of granular magnesium substituted β-tricalcium phosphate.

PubMed

Tavares, Débora dos Santos; Castro, Leticia de Oliveira; Soares, Gloria Dulce de Almeida; Alves, Gutemberg Gomes; Granjeiro, José Mauro

2013-01-01

The aim of this study was to produce dense granules of tricalcium phosphate (β-TCP) and magnesium (Mg) substituted β-TCP, also known as β-TCMP (Mg/Ca=0.15 mol), in order to evaluate the impact of Mg incorporation on the physicochemical parameters and in vitro biocompatibility of this novel material. The materials were characterized using X-ray diffraction (XRD), infrared spectroscopy (FTIR), electron microscopy and inductively coupled plasma (ICP). Biocompatibility was assayed according to ISO 10993-12:2007 and 7405:2008, by two different tests of cell survival and integrity (XTT and CVDE). The XRD profile presented the main peaks of β-TCP (JCPDS 090169) and β-TCMP (JCPDS 130404). The characteristic absorption bands of TCP were also identified by FTIR. The ICP results of β-TCMP granules extract showed a precipitation of calcium and release of Mg into the culture medium. Regarding the cytotoxicity assays, β-TCMP dense granules did not significantly affect the mitochondrial activity and relative cell density in relation to β-TCP dense granules, despite the release of Mg from granules into the cell culture medium. β-TCMP granules were successfully produced and were able to release Mg into media without cytotoxicity, indicating the suitability of this promising material for further biological studies on its adequacy for bone therapy.

SCPS-TP, TCP, and Rate-Based Protocol Evaluation. Revised

NASA Technical Reports Server (NTRS)

Tran, Diepchi T.; Lawas-Grodek, Frances J.; Dimond, Robert P.; Ivancic, William D.

2005-01-01

Tests were performed at Glenn Research Center to compare the performance of the Space Communications Protocol Standard Transport Protocol (SCPS TP, otherwise known as "TCP Tranquility") relative to other variants of TCP and to determine the implementation maturity level of these protocols, particularly for higher speeds. The testing was performed over reasonably high data rates of up to 100 Mbps with delays that are characteristic of near-planetary environments. The tests were run for a fixed packet size, but for variously errored environments. This report documents the testing performed to date.

On the radiobiological impact of metal artifacts in head-and-neck IMRT in terms of tumor control probability (TCP) and normal tissue complication probability (NTCP).

PubMed

Kim, Yusung; Tomé, Wolfgang A

2007-11-01

To investigate the effects of distorted head-and-neck (H&N) intensity-modulated radiation therapy (IMRT) dose distributions (hot and cold spots) on normal tissue complication probability (NTCP) and tumor control probability (TCP) due to dental-metal artifacts. Five patients' IMRT treatment plans have been analyzed, employing five different planning image data-sets: (a) uncorrected (UC); (b) homogeneous uncorrected (HUC); (c) sinogram completion corrected (SCC); (d) minimum-value-corrected (MVC); and (e) streak-artifact-reduction including minimum-value-correction (SAR-MVC), which has been taken as the reference data-set. The effects on NTCP and TCP were evaluated using the Lyman-NTCP model and the Logistic-TCP model, respectively. When compared to the predicted NTCP obtained using the reference data-set, the treatment plan based on the original CT data-set (UC) yielded an increase in NTCP of 3.2 and 2.0% for the spared parotid gland and the spinal cord, respectively. While for the treatment plans based on the MVC CT data-set the NTCP increased by a 1.1% and a 0.1% for the spared parotid glands and the spinal cord, respectively. In addition, the MVC correction method showed a reduction in TCP for target volumes (MVC: delta TCP = -0.6% vs. UC: delta TCP = -1.9%) with respect to that of the reference CT data-set. Our results indicate that the presence of dental-metal-artifacts in H&N planning CT data-sets has an impact on the estimates of TCP and NTCP. In particular dental-metal-artifacts lead to an increase in NTCP for the spared parotid glands and a slight decrease in TCP for target volumes.

Effect of biomimetic zinc-containing tricalcium phosphate (Zn-TCP) on the growth and osteogenic differentiation of mesenchymal stem cells.

PubMed

Chou, Joshua; Hao, Jia; Hatoyama, Hirokazu; Ben-Nissan, Besim; Milthorpe, Bruce; Otsuka, Makoto

2015-07-01

Several studies have shown the effectiveness of zinc-tricalcium phosphate (Zn-TCP) for bone tissue engineering. In this study, marine calcareous foraminifera possessing uniform pore size distribution were hydrothermally converted to Zn-TCP. The ability of a scaffold to combine effectively with mesenchymal stem cells (MSCs) is a key tissue-engineering aim. In order to demonstrate the osteogenic ability of MSCs with Zn-TCP, the scaffolds were cultured in an osteogenic induction medium to elicit an osteoblastic response. The physicochemical properties of Zn-TCP were characterized by XRD, FT-IR and ICP-MS. MSCs were aspirated from rat femurs and cultured for 3 days before indirectly placing four samples into each respective well. After culture for 7, 10 and 14 days, osteoblastic differentiation was evaluated using alizarin red S stain, measurement of alkaline phosphatase (ALP) levels, cell numbers and cell viability. XRD and FT-IR patterns both showed the replacement of CO(3)(2-) with PO(4)(3-). Chemical analysis showed zinc incorporation of 5 mol%. Significant increases in cell numbers were observed at 10 and 14 days in the Zn-TCP group, while maintaining high levels of cell viability (> 90%). ALP activity in the Zn-TCP group was statistically higher at 10 days. Alizarin red S staining also showed significantly higher levels of calcium mineralization in Zn-TCP compared with the control groups. This study showed that MSCs in the presence of biomimetically derived Zn-TCP can accelerate their differentiation to osteoblasts and could potentially be useful as a scaffold for bone tissue engineering. Copyright © 2014 John Wiley & Sons, Ltd.

Low modulus and bioactive Ti/α-TCP/Ti-mesh composite prepared by spark plasma sintering.

PubMed

Guo, Yu; Tan, Yanni; Liu, Yong; Liu, Shifeng; Zhou, Rui; Tang, Hanchun

2017-11-01

A titanium mesh scaffold composite filled with Ti/α-TCP particles was prepared by spark plasma sintering (SPS). The microstructures and interfacial reactions of the composites were investigated by scanning electron microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-ray diffraction (XRD) analyses. The compressive strength and elastic modulus were also measured. In vitro bioactivity and biocompatibility was evaluated by using simulated body fluid and cells culture, respectively. After high temperature sintering, Ti oxides, Ti x P y and CaTiO 3 were formed. The formation of Ti oxides and Ti x P y were resulted from the diffusion of O and P elements from α-TCP to Ti. CaTiO 3 was the reaction product of Ti and α-TCP. The composite of 70Ti/α-TCP incorporated with Ti mesh showed a high compressive strength of 589MPa and a low compressive modulus of 30GPa. The bioactivity test showed the formation of a thick apatite layer on the composite and well-spread cells attachment. A good combination of mechanical properties and bioactivity indicated a high potential application of Ti/α-TCP/Ti-mesh composite for orthopedic implants. Copyright © 2017. Published by Elsevier B.V.

Efficacy and safety of tretinoin 0.025%/clindamycin phosphate 1.2% gel in combination with benzoyl peroxide 6% cleansing cloths for the treatment of facial acne vulgaris.

PubMed

Zeichner, Joshua A; Wong, Vicky; Linkner, Rita V; Haddican, Madelaine

2013-03-01

Combination therapy using medications with complementary mechanisms of action is the standard of care in treating acne. We report results of a clinical trial evaluating the use of a fixed-dose tretinoin 0.025%/clindamycin phosphate 1.2% (T/CP) gel in combination with a benzoyl peroxide 6% foaming cloth compared with T/CP alone for facial acne. At week 12, the combination therapy group showed a trend toward greater efficacy compared with T/CP alone. There was a high success rate observed in the study, which may be attributable to the large percentage of adult female acne patients enrolled. Cutaneous adverse events were not statistically different in using combination therapy compared with T/CP alone.

Evaluation of rhBMP-2/collagen/TCP-HA bone graft with and without bone marrow cells in the canine femoral multi defect model.

PubMed

Luangphakdy, V; Shinohara, K; Pan, H; Boehm, C; Samaranska, A; Muschler, G F

2015-01-12

Recombinant human bone morphogenetic protein-2, when applied to an absorbable type 1 bovine collagen sponge (rhBMP-2/ACS) is an effective therapy in many bone grafting settings. Bone marrow aspirate (BMA) has also been used as a source of transplantable osteogenic connective tissue progenitors. This study was designed to characterize the performance of a scaffold comprising rhBMP-2/ACS in which the sponge wraps around tri-calcium phosphate hydroxyapatite granules (rhBMP-2/ACS/TCP-HA) and to test the hypothesis that addition of BMA will improve the performance of this construct in the Canine Femoral Multi Defect Model. In each subject, two sites were grafted with rhBMP-2/ACS/TCP-HA scaffold loaded with BMA clot and two other sites with rhBMP-2/ACS/TCP-HA scaffold loaded with wound blood (WB). After correction for unresorbed TCP-HA granules, sites grafted with rhBMP-2/ACS/TCP-HA+BMA and rhBMP-2/ACS/TCP-HA+WB were similar, with mean percent bone volumes of 10.9 %±1.2 and 11.2 %±1.2, respectively. No differences were seen in quantitative histomorphometry. While bone formation using both constructs was robust, this study did not support the hypothesis that the addition of unprocessed bone marrow aspirate clot improved bone regeneration in a site engrafted with rhBMP-2/ACS/TCP-HA+BMA. In contrast to prior studies using this model, new bone formation was greater at the center of the defect where TCP-HA was distributed. This finding suggests a potential synergy between rhBMP-2 and the centrally placed ceramic and cellular components of the graft construct. Further optimization may also require more uniform distribution of TCP-HA, alternative cell delivery strategies, and a more rigorous large animal segmental defect model.

Bioactive Molecules Release and Cellular Responses of Alginate-Tricalcium Phosphate Particles Hybrid Gel

PubMed Central

Bang, Sumi; Zhang, Shengmin

2017-01-01

In this article, a hybrid gel has been developed using sodium alginate (Alg) and α-tricalcium phosphate (α-TCP) particles through ionic crosslinking process for the application in bone tissue engineering. The effects of pH and composition of the gel on osteoblast cells (MC3T3) response and bioactive molecules release have been evaluated. At first, a slurry of Alg and α-TCP has been prepared using an ultrasonicator for the homogeneous distribution of α-TCP particles in the Alg network and to achieve adequate interfacial interaction between them. After that, CaCl2 solution has been added to the slurry so that ionic crosslinked gel (Alg-α-TCP) is formed. The developed hybrid gel has been physico-chemically characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and a swelling study. The SEM analysis depicted the presence of α-TCP micro-particles on the surface of the hybrid gel, while cross-section images signified that the α-TCP particles are fully embedded in the porous gel network. Different % swelling ratio at pH 4, 7 and 7.4 confirmed the pH responsiveness of the Alg-α-TCP gel. The hybrid gel having lower % α-TCP particles showed higher % swelling at pH 7.4. The hybrid gel demonstrated a faster release rate of bovine serum albumin (BSA), tetracycline (TCN) and dimethyloxalylglycine (DMOG) at pH 7.4 and for the grade having lower % α-TCP particles. The MC3T3 cells are viable inside the hybrid gel, while the rate of cell proliferation is higher at pH 7.4 compared to pH 7. The in vitro cytotoxicity analysis using thiazolyl blue tetrazolium bromide (MTT), bromodeoxyuridine (BrdU) and neutral red assays ascertained that the hybrid gel is non-toxic for MC3T3 cells. The experimental results implied that the non-toxic and biocompatible Alg-α-TCP hybrid gel could be used as scaffold in bone tissue engineering. PMID:29135939

Long-term absorption of beta-tricalcium phosphate poly-L-lactic acid interference screws.

PubMed

Barber, F Alan; Dockery, William D

2008-04-01

The purpose of this study was to evaluate the long-term in vivo degradation of biodegradable interference screws made of poly-L-lactic acid (PLLA) and beta-tricalcium phosphate (beta-TCP). Twenty patients undergoing patellar tendon autograft anterior cruciate ligament reconstruction fixed at both the femur and tibia with beta-TCP-PLLA screws at least 44 months earlier were evaluated by physical, radiographic, and computed tomography (CT) evaluations. This study was approved by the institutional review board. Lysholm, Tegner, Cincinnati, and International Knee Documentation Committee scores were also obtained. CT data were measured in Hounsfield units. We evaluated 13 male and 7 female patients at a mean of 50 months after surgery (range, 44 to 56 months). CT scans and radiographs showed the bone plug fused to the tunnel wall with no beta-TCP-PLLA screw remaining. The screws were replaced with clearly calcified non-trabecular material, denser than soft tissue. Osteoconductivity was present in 75% of the tunnels and complete in 10%. No positive pivot-shift tests were found. Lysholm, Tegner, and Cincinnati scores improved from 60.4, 3.7, and 53.3, respectively, preoperatively to 90.8, 5.8, and 86.4, respectively, at follow-up. The mean side-to-side difference determined by use of the KT arthrometer (MEDmetric, San Diego, CA) was 0.4 mm. The beta-TCP-PLLA interference screw (Bilok; ArthroCare, Sunnyvale, CA) completely degraded, and no remnant was present 4 years after insertion. Osteoconductivity was confirmed by CT scans at 75% of the screw sites and completely filled the site in 10%. The addition of beta-TCP to PLLA results in a biocomposite interference screw that is osteoconductive. Level IV, therapeutic case series.

Variation of mechanical behavior of β-TCP/collagen two phase composite scaffold with mesenchymal stem cell in vitro.

PubMed

Arahira, Takaaki; Todo, Mitsugu

2016-08-01

The primary aim of this study is to characterize the variational behavior of the compressive mechanical property of bioceramic-based scaffolds using stem cells during the cell culture period. β-Tricalcium phosphate (TCP)/collagen two phase composites and β-TCP scaffolds were fabricated using the polyurethane template technique and a subsequent freeze-drying method. Rat bone-marrow mesenchymal stem cells (rMSCs) were then cultured in these scaffolds for up to 28 days. Compression tests of the scaffolds with rMSCs were periodically conducted. Biological properties, such as the cell number, alkaline phosphatase (ALP) activity, and gene expressions of osteogenesis, were evaluated. The microstructural change due to cell growth and the formation of extracellular matrices was examined using a field-emission scanning electron microscope. The compressive property was then correlated with the biological properties and microstructures to understand the mechanism of the variational behavior of the macroscopic mechanical property. The porous collagen structure in the β-TCP scaffold effectively improved the structural stability of the composite scaffold, whereas the β-TCP scaffold exhibited structural instability with the collapse of the porous structure when immersed in a culture medium. The β-TCP/collagen composite scaffold exhibited higher ALP activity and more active generation of osteoblastic markers than the β-TCP scaffold. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sequential Injection/Electrochemical Immunoassay for Quantifying the Pesticide Metabolite 3, 5, 6-Trichloro-2-Pyridinol

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

Liu, Guodong; Riechers, Shawn L.; Timchalk, Chuck

2005-12-04

An automated and sensitive sequential injection electrochemical immunoassay was developed to monitor a potential insecticide biomarker, 3, 5, 6-trichloro-2-pyridinol. The current method involved a sequential injection analysis (SIA) system equipped with a thin-layer electrochemical flow cell and permanent magnet, which was used to fix 3,5,6-trichloro-2-pyridinol (TCP) antibody coated magnetic beads (TCP-Ab-MBs) in the reaction zone. After competitive immunoreactions among TCP-Ab-MBs, TCP analyte, and horseradish peroxidase (HRP) labeled TCP, a 3, 3?, 5, 5?-tetramethylbenzidine dihydrochloride and hydrogen peroxide (TMB-H2O2) substrate solution was injected to produce an electroactive enzymatic product. The activity of HRP tracers was monitored by a square wave voltammetricmore » scanning electroactive enzymatic product in the thin-layer flow cell. The voltammetric characteristics of the substrate and the enzymatic product were investigated under batch conditions, and the parameters of the immunoassay were optimized in the SIA system. Under the optimal conditions, the system was used to measure as low as 6 ng L-1 (ppt) TCP, which is around 50-fold lower than the value indicated by the manufacturer of the TCP RaPID Assay? kit (0.25 ug/L, colorimetric detection). The performance of the developed immunoassay system was successfully evaluated on tap water and river water samples spiked with TCP. This technique could be readily used for detecting other environmental contaminants by developing specific antibodies against contaminants and is expected to open new opportunities for environmental and biological monitoring.« less

Response of human bone marrow-derived MSCs on triphasic Ca-P substrate with various HA/TCP ratio.

PubMed

Bajpai, Indu; Kim, Duk Yeon; Kyong-Jin, Jung; Song, In-Hwan; Kim, Sukyoung

2017-01-01

Calcium phosphates (Ca-P) are used commonly as artificial bone substitutes to control the biodegradation rate of an implant in the body fluid. This study examined the in vitro proliferation of human bone marrow-derived mesenchymal stem cells (hBMSCs) on triphasic Ca-P samples. For this aspect, hydroxyapatite (HA), dicalcium phosphate dehydrate (DCPD), and calcium hydroxide (Ca(OH) 2 ) were mixed at various ratios, cold compacted, and sintered at 1250°C in air. X-ray diffraction showed that the β-tricalcium phosphate (TCP) to α-TCP phase transformation increased with increasing DCPD/HA ratio. The micro-hardness deceased with increasing TCP content, whereas the mean grain size and porosity increased with increasing TCP concentration. To evaluate the in vitro degree of adhesion and proliferation on the HA/TCP samples, human BMSCs were incubated on the HA/TCP samples and analyzed by a cells proliferation assay, expression of the extracellular matrix (ECM) genes, such as α-smooth muscle actin (α-SMA) and fibronectin (FN), and FITC-phalloidin fluorescent staining. In terms of the interactions of human BMSCs with the triphasic Ca-P samples, H50T50 (Ca/P = 1.59) markedly enhanced cell spreading, proliferation, FN, and α-SMA compared with H100T0 (Ca/P = 1.67). Interestingly, these results show that among the five HA/TCP samples, H50T50 is the optimal Ca-P composition for in vitro cell proliferation. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 72-80, 2017. © 2015 Wiley Periodicals, Inc.

CARDIOPATHIC EFFECT OF 1,2,3-TRICHLOROPROPANE AFTER SUBACUTE AND SUBCHRONIC EXPOSURE IN RATS

EPA Science Inventory

1,2,3-Trichloropropane (1,2,3-TCP) is an industrial water contaminant with potential for human exposure by the oral route. The systemic toxicology of 1,2,3-TCP was evaluated after subacute or subchronic exposure in male and female Sprague Dawley rate. Animals were treated with 0....

Combined Quarterly Technical Report Number 23. SATNET Development and Operation. Pluribus Satellite IMP Development. Remote Site Maintenance. Internet Operations and Maintenance. Mobile Access Terminal Network. TCP for the HP3000. TCP-TAC. TCP for VAX-UNIX

DTIC Science & Technology

1981-11-01

evaluate and test these ideas in the Internet research context. 4. Field third-generation gateways. At this point in time, we purposely avoid selecting a...plan to cover the period from now until the time when a gateway system can be fielded which implements the results of the current work in the Internet ... research community. The current gateway system is inadequate from both a functionality and a• performance standpoint, and therefore the transition

Biodegradation of 2,4,6-trichlorophenol in a packed-bed biofilm reactor equipped with an internal net draft tube riser for aeration and liquid circulation.

PubMed

Jesús, A Gómez-De; Romano-Baez, F J; Leyva-Amezcua, L; Juárez-Ramírez, C; Ruiz-Ordaz, N; Galíndez-Mayer, J

2009-01-30

For the aerobic biodegradation of the fungicide and defoliant 2,4,6-trichlorophenol (2,4,6-TCP), a bench-scale packed-bed bioreactor equipped with a net draft tube riser for liquid circulation and oxygenation (PB-ALR) was constructed. To obtain a high packed-bed volume relative to the whole bioreactor volume, a high A(D)/A(R) ratio was used. Reactor's downcomer was packed with a porous support of volcanic stone fragments. PB-ALR hydrodynamics and oxygen mass transfer behavior was evaluated and compared to the observed behavior of the unpacked reactor operating as an internal airlift reactor (ALR). Overall gas holdup values epsilon(G), and zonal oxygen mass transfer coefficients determined at various airflow rates in the PB-ALR, were higher than those obtained with the ALR. When comparing mixing time values obtained in both cases, a slight increment in mixing time was observed when reactor was operated as a PB-ALR. By using a mixed microbial community, the biofilm reactor was used to evaluate the aerobic biodegradation of 2,4,6-TCP. Three bacterial strains identified as Burkholderia sp., Burkholderia kururiensis and Stenotrophomonas sp. constituted the microbial consortium able to cometabolically degrade the 2,4,6-TCP, using phenol as primary substrate. This consortium removed 100% of phenol and near 99% of 2,4,6-TCP. Mineralization and dehalogenation of 2,4,6-TCP was evidenced by high COD removal efficiencies ( approximately 95%), and by the stoichiometric release of chloride ions from the halogenated compound ( approximately 80%). Finally, it was observed that the microbial consortium was also capable to metabolize 2,4,6-TCP without phenol as primary substrate, with high removal efficiencies (near 100% for 2,4,6-TCP, 92% for COD and 88% for chloride ions).

A Randomized Clinical Trial Evaluating rh-FGF-2/β-TCP in Periodontal Defects.

PubMed

Cochran, D L; Oh, T-J; Mills, M P; Clem, D S; McClain, P K; Schallhorn, R A; McGuire, M K; Scheyer, E T; Giannobile, W V; Reddy, M S; Abou-Arraj, R V; Vassilopoulos, P J; Genco, R J; Geurs, N C; Takemura, A

2016-05-01

Biological mediators have been used to enhance periodontal regeneration. The aim of this prospective randomized controlled study was to evaluate the safety and effectiveness of 3 doses of fibroblast growth factor 2 (FGF-2) when combined with a β-tricalcium phosphate (β-TCP) scaffold carrier placed in vertical infrabony periodontal defects in adult patients. In this double-blinded, dose-verification, externally monitored clinical study, 88 patients who required surgical intervention to treat a qualifying infrabony periodontal defect were randomized to 1 of 4 treatment groups-β-TCP alone (control) and 0.1% recombinant human FGF-2 (rh-FGF-2), 0.3% rh-FGF-2, and 0.4% rh-FGF-2 with β-TCP-following scaling and root planing of the tooth prior to a surgical appointment. Flap surgery was performed with EDTA conditioning of the root prior to device implantation. There were no statistically significant differences in patient demographics and baseline characteristics among the 4 treatment groups. When a composite outcome of gain in clinical attachment of 1.5 mm was used with a linear bone growth of 2.5 mm, a dose response pattern detected a plateau in the 0.3% and 0.4% rh-FGF-2/β-TCP groups with significant improvements over control and 0.1% rh-FGF-2/β-TCP groups. The success rate at 6 mo was 71% in the 2 higher-concentration groups, as compared with 45% in the control and lowest treatment groups. Percentage bone fill in the 2 higher-concentration groups was 75% and 71%, compared with 63% and 61% in the control and lowest treatment group. No increases in specific antibody to rh-FGF-2 were detected, and no serious adverse events related to the products were reported. The results from this multicenter trial demonstrated that the treatment of infrabony vertical periodontal defects can be enhanced with the addition of rh-FGF-2/β-TCP (ClinicalTrials.gov NCT01728844). © International & American Associations for Dental Research 2016.

Effects of silica and zinc oxide doping on mechanical and biological properties of 3D printed tricalcium phosphate tissue engineering scaffolds.

PubMed

Fielding, Gary A; Bandyopadhyay, Amit; Bose, Susmita

2012-02-01

To evaluate the effects of silica (SiO(2)) (0.5 wt%) and zinc oxide (ZnO) (0.25 wt%) dopants on the mechanical and biological properties of tricalcium phosphate (TCP) scaffolds with three dimensionally (3D) interconnected pores. Scaffolds were created with a commercial 3D printer. Post sintering phase analysis was determined by X-ray diffraction. Surface morphology of the scaffolds was examined by field emission scanning electron microscopy (FESEM). Mechanical strength was evaluated with a screw driven universal testing machine. MTT assay was used for cellular proliferation characteristics and cellular morphology was examined by FESEM. Addition of dopants into TCP increased the average density of pure TCP from 90.8 ± 0.8% to 94.1 ± 1.6% and retarded the β to α phase transformation at high sintering temperatures, which resulted in up to 2.5 fold increase in compressive strength. In vitro cell-materials interaction studies, carried out using hFOB cells, confirmed that the addition of SiO(2) and ZnO to the scaffolds facilitated faster cell proliferation when compared to pure TCP scaffolds. Addition of SiO(2) and ZnO dopants to the TCP scaffolds showed increased mechanical strength as well as increased cellular proliferation. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Evaluation of suitable porosity for sintered porous {beta}-tricalcium phosphate as a bone substitute

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

Park, Jin-Hong; Bae, Ji-Yong; Shim, Jaebum

2012-09-15

Structural and mechanical characterization is performed for sintered porous beta tricalcium phosphate ({beta}-TCP) to determine the appropriate porosity for use as a bone substitute. Four different types of porous {beta}-TCP specimen with different porosities are fabricated through a sintering process. For structural characterization, scanning electron microscopy and a Microfocus X-ray computed tomography system are used to investigate the pore openings on the specimen's surface, pore size, pore distribution, and pore interconnections. Compression tests of the specimens are performed, and mechanical properties such as the elastic modulus and compressive strength are obtained. Also, the geometric shape and volume of the {beta}-TCPmore » around the contact region of two pores, which need to be initially resolved after implantation in order to increase the size of the pore openings, are evaluated through simple calculations. The results show that porous {beta}-TCP with 42.1% porosity may be a suitable bone substitute candidate in terms of sustaining external loads, and inducing and cultivating bone cells. - Highlights: Black-Right-Pointing-Pointer Structural and mechanical characterization was performed for sintered porous {beta}-TCP specimens. Black-Right-Pointing-Pointer For structural characterization, SEM and Microfocus X-ray CT system were used. Black-Right-Pointing-Pointer For mechanical characterization, compression tests were performed. Black-Right-Pointing-Pointer Porous {beta}-TCP with 42.1% porosity may be a suitable bone substitute.« less

Analysis of the role of Arabidopsis class I TCP genes AtTCP7, AtTCP8, AtTCP22, and AtTCP23 in leaf development

PubMed Central

Aguilar-Martínez, José A.; Sinha, Neelima

2013-01-01

TCP family of plant-specific transcription factors regulates plant form through control of cell proliferation and differentiation. This gene family is comprised of two groups, class I and class II. While the role of class II TCP genes in plant development is well known, data about the function of some class I TCP genes is lacking. We studied a group of phylogenetically related class I TCP genes: AtTCP7, AtTCP8, AtTCP22, and AtTCP23. The similar expression pattern in young growing leaves found for this group suggests similarity in gene function. Gene redundancy is characteristic in this group, as also seen in the class II TCP genes. We generated a pentuple mutant tcp8 tcp15 tcp21 tcp22 tcp23 and show that loss of function of these genes results in changes in leaf developmental traits. We also determined that these factors are able to mutually interact in a yeast two-hybrid assay and regulate the expression of KNOX1 genes. To circumvent the issue of genetic redundancy, dominant negative forms with SRDX repressor domain were used. Analysis of transgenic plants expressing AtTCP7-SRDX and AtTCP23-SRDX indicate a role of these factors in the control of cell proliferation. PMID:24137171

Analysis of the role of Arabidopsis class I TCP genes AtTCP7, AtTCP8, AtTCP22, and AtTCP23 in leaf development.

PubMed

Aguilar-Martínez, José A; Sinha, Neelima

2013-01-01

TCP family of plant-specific transcription factors regulates plant form through control of cell proliferation and differentiation. This gene family is comprised of two groups, class I and class II. While the role of class II TCP genes in plant development is well known, data about the function of some class I TCP genes is lacking. We studied a group of phylogenetically related class I TCP genes: AtTCP7, AtTCP8, AtTCP22, and AtTCP23. The similar expression pattern in young growing leaves found for this group suggests similarity in gene function. Gene redundancy is characteristic in this group, as also seen in the class II TCP genes. We generated a pentuple mutant tcp8 tcp15 tcp21 tcp22 tcp23 and show that loss of function of these genes results in changes in leaf developmental traits. We also determined that these factors are able to mutually interact in a yeast two-hybrid assay and regulate the expression of KNOX1 genes. To circumvent the issue of genetic redundancy, dominant negative forms with SRDX repressor domain were used. Analysis of transgenic plants expressing AtTCP7-SRDX and AtTCP23-SRDX indicate a role of these factors in the control of cell proliferation.

An in vitro Comparative Evaluation of Three Remineralizing Agents using Confocal Microscopy

PubMed Central

Chokshi, Achala; Konde, Sapna; Shetty, Sunil Raj; Chandra, Kumar Narayan; Jana, Sinjana; Mhambrey, Sanjana; Thakur, Sneha

2016-01-01

Introduction The caries process has been thought to be irreversible, resulting in the permanent loss of tooth substance and eventually the development of a cavity. Recent approaches focused on application of remineralizing agents to incipient carious lesions, aim at controlling demineralization and promoting remineralization. Remineralizing agents create a supersaturated environment around the lesion; thus, preventing mineral loss and forces calcium and phosphate ions in the vacant areas. Aim To compare and evaluate the remineralization potential of Fluoride Varnish, CPP-ACP Paste (Casein Phosphopeptide-Amorphous Calcium Phosphate) and fTCP Paste (functionalized Tricalcium Phosphate) using confocal microscope. Materials and Methods Two windows of 3X3mm were created on the labial cervical and incisal thirds in 60 permanent maxillary central incisors. The teeth were demineralized to create artificial caries and divided into three groups of 20 each. Group I specimens were coated with Fluoride Varnish once whereas those in CPP-ACP paste group and fTCP group were brushed for 2 minutes, twice daily for 20 and 40 days. The specimens were stored in artificial saliva during the study period and were later sectioned and observed under confocal microscope. Data obtained was statistically analyzed using Fischer’s exact test, ANOVA and post-hoc Bonferroni’s test. Results Fluoride Varnish, CPP-ACP Paste and fTCP Paste showed remineralization of artificial carious lesions at both the time intervals. Fluoride varnish showed the highest remineralization followed by CPP-ACP Paste and fTCP Paste. A statistically significant increase in remineralization potential of CPP-ACP Paste and fTCP Paste was observed at the end of 40 days as compared to 20 days. Conclusion Fluoride varnish showed the greatest remineralization potential of artificial carious lesions followed by CPP-ACP Paste and fTCP Paste respectively. PMID:27504408

BMP-7 Preserves Surface Integrity of Degradable-ceramic Cranioplasty in a Göttingen Minipig Model

PubMed Central

Schulz, Peter; Klünter, Tim; Deisinger, Ulrike; Diez, Claudius; Waiss, Waltraud; Kirschneck, Christian; Reichert, Torsten E.; Detsch, Rainer

2017-01-01

Background: The aim of the study was to evaluate the integrity of a craniotomy grafted site in a minipig model using different highly porous calcium phosphate ceramic scaffolds either loaded or nonloaded with bone morphogenetic protein-7 (BMP-7). Methods: Four craniotomies with a diameter of 15 mm (critical-size defect) were grafted with different highly porous (92–94 vol%) calcium phosphate ceramics [hydroxyapatite (HA), tricalcium phosphate (TCP), and biphasic calcium phosphate (BCP; a mixture of HA and TCP)] in 10 Göttingen minipigs: (a) group I (n = 5): HA versus BCP; (b) group II (n = 5): TCP versus BCP. One scaffold of each composition was supplied with 250 μg of BMP-7. In vivo computed tomography scan and fluorochrome bone labeling were performed. Specimens were evaluated 14 weeks after surgery by environmental scanning electron microscopy, fluorescence microscopy, and Giemsa staining histology. Results: BMP-7 significantly enhanced bone formation in TCP (P = 0.047). Slightly enhanced bone formation was observed in BCP (P = 0.059) but not in HA implants. BMP-7 enhanced ceramic degradation in TCP (P = 0.05) and BCP (P = 0.05) implants but not in HA implants. Surface integrity of grafted site was observed in all BMP-7-loaded implants after successful creeping substitution by the newly formed bone. In 9 of 10 HA implants without BMP-7, partial collapse of the implant site was observed. All TCP implants without BMP-7 collapsed. Fluorescent labeling showed bone formation at week 1 in BMP-7-stimulated implants. Conclusions: BMP-7 supports bone formation, ceramic degradation, implant integration, and surface integrity of the grafted site. PMID:28458969

Assessment of tricalcium phosphate/collagen (TCP/collagene)nanocomposite scaffold compared with hydroxyapatite (HA) on healing of segmental femur bone defect in rabbits.

PubMed

Mohseni, Mahmoud; Jahandideh, Alireza; Abedi, Gholamreza; Akbarzadeh, Abolfazl; Hesaraki, Saeed

2018-03-01

Bone regeneration is an important objective in clinical practice and has been used for different applications. The aim of this study was to evaluate the effectiveness of nanocomposite tricalcium phosphate (TCP)/collagen scaffolds combined with hydroxyapatite scaffold for bone healing in surgery of femoral defects in rabbits. In this study, 45 mature male New Zealand white rabbits between 6 and 8 months old and weighting between 3 and 3.5 kg were examined. Rabbits were divided into three groups. Surgical procedures were performed after intramuscular injection of Ketamine 10% (ketamine hydrochloride, 50 mg/kg) and Rompun 5% (xylazine, 5 mg/kg). Then an approximately 6 mm diameter-5 mm cylinder bone defect was created in the femur of one of the hind limbs. After inducing the surgical wound, all rabbits were coloured and randomly divided into three experimental groups of 15 animals each. Group 1 received pure medical nanocomposite TCP/collagen granules, group 2 received hydroxyapatite, and third group was a control group which received no treatment. Histopathological evaluation was performed on days 15, 30, and 45 after surgery. On days 15, 30, and 45 after surgery, the quantity and the velocity of stages of bone formation at the healing site in nanocomposite TCP/collagen group were better than HA and control groups and the quantity of newly formed lamellar bone at the healing site in nanocomposite TCP/collagen group were better than onward compared with HA and control groups. In conclusion, it seems that TCP/collagen nanocomposite has a significant role in the reconstruction of bone defects and can be used as scaffold in bone fractures.

Frame Transmission Efficiency-Based Cross-Layer Congestion Notification Scheme in Wireless Ad Hoc Networks.

PubMed

He, Huaguang; Li, Taoshen; Feng, Luting; Ye, Jin

2017-07-15

Different from the traditional wired network, the fundamental cause of transmission congestion in wireless ad hoc networks is medium contention. How to utilize the congestion state from the MAC (Media Access Control) layer to adjust the transmission rate is core work for transport protocol design. However, recent works have shown that the existing cross-layer congestion detection solutions are too complex to be deployed or not able to characterize the congestion accurately. We first propose a new congestion metric called frame transmission efficiency (i.e., the ratio of successful transmission delay to the frame service delay), which describes the medium contention in a fast and accurate manner. We further present the design and implementation of RECN (ECN and the ratio of successful transmission delay to the frame service delay in the MAC layer, namely, the frame transmission efficiency), a general supporting scheme that adjusts the transport sending rate through a standard ECN (Explicit Congestion Notification) signaling method. Our method can be deployed on commodity switches with small firmware updates, while making no modification on end hosts. We integrate RECN transparently (i.e., without modification) with TCP on NS2 simulation. The experimental results show that RECN remarkably improves network goodput across multiple concurrent TCP flows.

Beta-tricalcium phosphate granules improve osteogenesis in vitro and establish innovative osteo-regenerators for bone tissue engineering in vivo.

PubMed

Gao, Peng; Zhang, Haoqiang; Liu, Yun; Fan, Bo; Li, Xiaokang; Xiao, Xin; Lan, Pingheng; Li, Minghui; Geng, Lei; Liu, Dong; Yuan, Yulin; Lian, Qin; Lu, Jianxi; Guo, Zheng; Wang, Zhen

2016-03-22

The drawbacks of traditional bone-defect treatments have prompted the exploration of bone tissue engineering. This study aimed to explore suitable β-tricalcium phosphate (β-TCP) granules for bone regeneration and identify an efficient method to establish β-TCP-based osteo-regenerators. β-TCP granules with diameters of 1 mm and 1-2.5 mm were evaluated in vitro. The β-TCP granules with superior osteogenic properties were used to establish in vivo bioreactors, referred to as osteo-regenerators, which were fabricated using two different methods. Improved proliferation of bone mesenchymal stem cells (BMSCs), glucose consumption and ALP activity were observed for 1-2.5 mm β-TCP compared with 1-mm granules (P < 0.05). In addition, BMSCs incubated with 1-2.5 mm β-TCP expressed significantly higher levels of the genes for runt-related transcription factor-2, alkaline phosphatase, osteocalcin, osteopontin, and collagen type-1 and the osteogenesis-related proteins alkaline phosphatase, collagen type-1 and runt-related transcription factor-2 compared with BMSCs incubated with 1 mm β-TCP (P < 0.05). Fluorochrome labelling, micro-computed tomography and histological staining analyses indicated that the osteo-regenerator with two holes perforating the femur promoted significantly greater bone regeneration compared with the osteo-regenerator with a periosteum incision (P < 0.05). This study provides an alternative to biofunctionalized bioreactors that exhibits improved osteogenesis.

Beta-tricalcium phosphate granules improve osteogenesis in vitro and establish innovative osteo-regenerators for bone tissue engineering in vivo

PubMed Central

Gao, Peng; Zhang, Haoqiang; Liu, Yun; Fan, Bo; Li, Xiaokang; Xiao, Xin; Lan, Pingheng; Li, Minghui; Geng, Lei; Liu, Dong; Yuan, Yulin; Lian, Qin; Lu, Jianxi; Guo, Zheng; Wang, Zhen

2016-01-01

The drawbacks of traditional bone-defect treatments have prompted the exploration of bone tissue engineering. This study aimed to explore suitable β-tricalcium phosphate (β-TCP) granules for bone regeneration and identify an efficient method to establish β-TCP-based osteo-regenerators. β-TCP granules with diameters of 1 mm and 1–2.5 mm were evaluated in vitro. The β-TCP granules with superior osteogenic properties were used to establish in vivo bioreactors, referred to as osteo-regenerators, which were fabricated using two different methods. Improved proliferation of bone mesenchymal stem cells (BMSCs), glucose consumption and ALP activity were observed for 1–2.5 mm β-TCP compared with 1-mm granules (P < 0.05). In addition, BMSCs incubated with 1–2.5 mm β-TCP expressed significantly higher levels of the genes for runt-related transcription factor-2, alkaline phosphatase, osteocalcin, osteopontin, and collagen type-1 and the osteogenesis-related proteins alkaline phosphatase, collagen type-1 and runt-related transcription factor-2 compared with BMSCs incubated with 1 mm β-TCP (P < 0.05). Fluorochrome labelling, micro-computed tomography and histological staining analyses indicated that the osteo-regenerator with two holes perforating the femur promoted significantly greater bone regeneration compared with the osteo-regenerator with a periosteum incision (P < 0.05). This study provides an alternative to biofunctionalized bioreactors that exhibits improved osteogenesis. PMID:27000963

On the Generation and Use of TCP Acknowledgments

NASA Technical Reports Server (NTRS)

Allman, Mark

1998-01-01

This paper presents a simulation study of various TCP acknowledgment generation and utilization techniques. We investigate the standard version of TCP and the two standard acknowledgment strategies employed by receivers: those that acknowledge each incoming segment and those that implement delayed acknowledgments. We show the delayed acknowledgment mechanism hurts TCP performance, especially during slow start. Next we examine three alternate mechanisms for generating and using acknowledgments designed to mitigate the negative impact of delayed acknowledgments. The first method is to generate delayed ACKs only when the sender is not using the slow start algorithm. The second mechanism, called byte counting, allows TCP senders to increase the amount of data being injected into the network based on the amount of data acknowledged rather than on the number of acknowledgments received. The last mechanism is a limited form of byte counting. Each of these mechanisms is evaluated in a simulated network with no competing traffic, as well as a dynamic environment with a varying amount of competing traffic. We study the costs and benefits of the alternate mechanisms when compared to the standard algorithm with delayed ACKs.

A new iron calcium phosphate material to improve the osteoconductive properties of a biodegradable ceramic: a study in rabbit calvaria.

PubMed

Manchón, Angel; Hamdan Alkhraisat, Mohammad; Rueda-Rodriguez, Carmen; Prados-Frutos, Juan Carlos; Torres, Jesús; Lucas-Aparicio, Julia; Ewald, Andrea; Gbureck, Uwe; López-Cabarcos, Enrique

2015-10-20

β-tricalcium phosphate (β-TCP) is an osteoconductive and biodegradable material used in bone regeneration procedures, while iron has been suggested as a tool to improve the biological performance of calcium phosphate-based materials. However, the mechanisms of interaction between these materials and human cells are not fully understood. In order to clarify this relationship, we have studied the iron role in β-TCP ceramics. Iron-containing β-TCPs were prepared by replacing CaCO3 with C6H5FeO7 at different molar ratios. X-ray diffraction analysis indicated the occurrence of β-TCP as the sole phase in the pure β-TCP and iron-containing ceramics. The incorporation of iron ions in the β-TCP lattice decreased the specific surface area as the pore size was shifted toward meso- and/or macropores. Furthermore, the human osteoblastlike cell line MG-63 was cultured onto the ceramics to determine cell proliferation and viability, and it was observed that the iron-β-TCP ceramics have better cytocompatibility than pure β-TCP. Finally, in vivo assays were performed using rabbit calvaria as a bone model. The scaffolds were implanted for 8 and 12 weeks in the defects created in the skullcap with pure β-TCP as the control. The in vivo behavior, in terms of new bone formed, degradation, and residual graft material were investigated using sequential histological evaluations and histomorphometric analysis. The in vivo implantation of the ceramics showed enhanced bone tissue formation and scaffold degradation for iron-β-TCPs. Thus, iron appears to be a useful tool to enhance the osteoconductive properties of calcium phosphate ceramics.

Human Urine Derived Stem Cells in Combination with β-TCP Can Be Applied for Bone Regeneration.

PubMed

Guan, Junjie; Zhang, Jieyuan; Li, Haiyan; Zhu, Zhenzhong; Guo, Shangchun; Niu, Xin; Wang, Yang; Zhang, Changqing

2015-01-01

Bone tissue engineering requires highly proliferative stem cells that are easy to isolate. Human urine stem cells (USCs) are abundant and can be easily harvested without using an invasive procedure. In addition, in our previous studies, USCs have been proved to be able to differentiate into osteoblasts, chondrocytes, and adipocytes. Therefore, USCs may have great potential and advantages to be applied as a cell source for tissue engineering. However, there are no published studies that describe the interactions between USCs and biomaterials and applications of USCs for bone tissue engineering. Therefore, the objective of the present study was to evaluate the interactions between USCs with a typical bone tissue engineering scaffold, beta-Tricalcium Phosphate (β-TCP), and to determine whether the USCs seeded onto β-TCP scaffold can promote bone regeneration in a segmental femoral defect of rats. Primary USCs were isolated from urine and seeded on β-TCP scaffolds. Results showed that USCs remained viable and proliferated within β-TCP. The osteogenic differentiation of USCs within the scaffolds was demonstrated by increased alkaline phosphatase activity and calcium content. Furthermore, β-TCP with adherent USCs (USCs/β-TCP) were implanted in a 6-mm critical size femoral defect of rats for 12 weeks. Bone regeneration was determined using X-ray, micro-CT, and histologic analyses. Results further demonstrated that USCs in the scaffolds could enhance new bone formation, which spanned bone defects in 5 out of 11 rats while β-TCP scaffold alone induced modest bone formation. The current study indicated that the USCs can be used as a cell source for bone tissue engineering as they are compatible with bone tissue engineering scaffolds and can stimulate the regeneration of bone in a critical size bone defect.

Effects of concomitant use of fibroblast growth factor (FGF)-2 with beta-tricalcium phosphate ({beta}-TCP) on the beagle dog 1-wall periodontal defect model

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

Anzai, Jun, E-mail: anzai_jun@kaken.co.jp; Department of Periodontology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871; Kitamura, Masahiro, E-mail: kitamura@dent.osaka-u.ac.jp

Research highlights: {yields} Concomitant use of FGF-2 and {beta}-TCP (an osteo-conductive scaffold) significantly promotes periodontal regeneration in the severe periodontitis model (1-wall defect model) of beagle dog. {yields} FGF-2 enhanced new bone formation via {beta}-TCP at the defects. {yields} In particular, FGF-2 dramatically regenerated new periodontal ligament and cementum formations at the defects, that is one of the most important healing outcomes during the process of periodontal regeneration. {yields} Epithelial downgrowth (undesirable wound healing) was decreased by administration of FGF-2. {yields} This manuscript indicates for the first time that concomitant use of FGF-2 and {beta}-TCP is efficacious in regenerating periodontalmore » tissue following severe destruction of the tissue by progression of periodontitis. -- Abstract: The effects of concomitant use of fibroblast growth factor-2 (FGF-2) and beta-tricalcium phosphate ({beta}-TCP) on periodontal regeneration were investigated in the beagle dog 1-wall periodontal defect model. One-wall periodontal defects were created in the mesial portion of both sides of the mandibular first molars, and 0.3% FGF-2 plus {beta}-TCP or {beta}-TCP alone was administered. Radiographic evaluation was performed at 0, 3, and 6 weeks. At 6 weeks, the periodontium with the defect site was removed and histologically analyzed. Radiographic findings showed that co-administration of FGF-2 significantly increased bone mineral contents of the defect sites compared with {beta}-TCP alone. Histologic analysis revealed that the length of the regenerated periodontal ligament, the cementum, distance to the junctional epithelium, new bone height, and area of newly formed bone were significantly increased in the FGF-2 group. No abnormal inflammatory response or ankylosis was observed in either group. These findings indicate the efficacy of concomitant use of FGF-2 and {beta}-TCP as an osteoconductive material for periodontal regeneration following severe destruction by progressive periodontitis.« less

Guided bone regeneration with local zoledronic acid and titanium barrier: An experimental study.

PubMed

Dundar, Serkan; Ozgur, Cem; Yaman, Ferhan; Cakmak, Omer; Saybak, Arif; Ozercan, Ibrahim Hanifi; Alan, Hilal; Artas, Gokhan; Nacakgedigi, Onur

2016-10-01

The aim of this study was to evaluate the effects on new bone formation of autogenous blood alone or in combination with zoledronic acid (ZA), a β-tricalcium phosphate (β-TCP) graft or ZA plus a β-TCP graft placed under titanium barriers. For this purpose, eight adult male New Zealand white rabbits were used in the study, each with four titanium barriers fixed around four sets of nine holes drilled in the calvarial bones. The study included four groups, each containing 2 rabbits. In the autogenous blood (AB group), only autogeneous blood was placed under the titanium barriers. The three experimental groups were the AB+ZA group, with autogenous blood plus ZA, the AB+β-TCP group, with autogeneous blood plus a β-TCP graft, and the AB+β-TCP+ZA group, with autogeneous blood plus a β-TCP graft and ZA mixture under the titanium barriers. The animals were sacrificed after 3 months. The amounts of new bone formation identified histomorphometrically were found to be higher after 3 months than at the time of surgery in all groups. The differences between the groups were examined with histomorphometric analysis, and statistically significant differences were identified at the end of the 3 months. The bone formation rate in the AB+β-TCP+ZA group was determined to be significantly higher than that in the other groups (P<0.05). In the AB+ZA and AB+β-TCP groups, the bone formation rate was determined to be significantly higher than that in the AB group (P<0.05). No statistically significant difference in bone formation rate was observed between the AB+β-TCP and AB+ZA groups. Local ZA used with autogeneous blood and/or graft material appears to be a more effective method than the use of autogeneous blood or graft alone in bone augmentation executed with a titanium barrier.

Fabrication of 3D porous SF/β-TCP hybrid scaffolds for bone tissue reconstruction.

PubMed

Park, Hyun Jung; Min, Kyung Dan; Lee, Min Chae; Kim, Soo Hyeon; Lee, Ok Joo; Ju, Hyung Woo; Moon, Bo Mi; Lee, Jung Min; Park, Ye Ri; Kim, Dong Wook; Jeong, Ju Yeon; Park, Chan Hum

2016-07-01

Bio-ceramic is a biomaterial actively studied in the field of bone tissue engineering. But, only certain ceramic materials can resolve the corrosion problem and possess the biological affinity of conventional metal biomaterials. Therefore, the recent development of composites of hybrid composites and polymers has been widely studied. In this study, we aimed to select the best scaffold of silk fibroin and β-TCP hybrid for bone tissue engineering. We fabricated three groups of scaffold such as SF (silk fibroin scaffold), GS (silk fibroin/small granule size of β-TCP scaffold) and GM (silk fibroin/medium granule size of β-TCP scaffold), and we compared the characteristics of each group. During characterization of the scaffold, we used scanning electron microscopy (SEM) and a Fourier transform infrared spectroscopy (FTIR) for structural analysis. We compared the physiological properties of the scaffold regarding the swelling ratio, water uptake and porosity. To evaluate the mechanical properties, we examined the compressive strength of the scaffold. During in vitro testing, we evaluated cell attachment and cell proliferation (CCK-8). Finally, we confirmed in vivo new bone regeneration from the implanted scaffolds using histological staining and micro-CT. From these evaluations, the fabricated scaffold demonstrated high porosity with good inter-pore connectivity, showed good biocompatibility and high compressive strength and modulus. In particular, the present study indicates that the GM scaffold using β-TCP accelerates new bone regeneration of implanted scaffolds. Accordingly, our scaffold is expected to act a useful application in the field of bone tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1779-1787, 2016. © 2016 Wiley Periodicals, Inc.

EVALUATION OF N-METHYL-N-TERT-BUTYLDIMETHYLSILYLTRIFLUOROACETAMIDE FOR ENVIRONMENTAL ANALYSIS UNDER BOTH EIMS AND ELECTRON CAPTURE NICIMS CONDITIONS AND COMPARISON TO TRIMETHYLSILYL REAGENTS UNDER EIMS

EPA Science Inventory

Sewage effluent was analyzed for 3,5,6-trichloropyridinol (TCP) by extracting one liter of water using liquid-liquid extraction and determined by GC/MS operated in the negative ion chemical ionization (electron capture) mode, TCP is the major metabolite of the commonly used insec...

Behavior of Osteoblast-Like Cells on a β-Tricalcium Phosphate Synthetic Scaffold Coated With Calcium Phosphate and Magnesium.

PubMed

Park, Ki-Deog; Jung, Young-Suk; Lee, Kyung-Ku; Park, Hong-Ju

2016-06-01

Tricalcium phosphate (TCP) is one of the most useful synthetic scaffolds for bone grafts and has several advantages. However, the rapid degradation of TCP makes it less osteoconductive than the other candidates, and represents a major shortcoming. To overcome this problem, the authors investigated magnesium (Mg) and/or hydroxyapatite (HA) coating on a β-TCP substrate using a sputtering technique. Biocompatibility tests were carried out on β-TCP discs that were either uncoated (TCP), coated with HA by radio frequency magnetron sputtering (HA-TCP), coated with Mg by DC sputtering (Mg-TCP), or multicoated with Mg and HA by DC and radio frequency magnetron sputtering (MgHA-TCP). Cells showed similar morphology in all 4 groups, and were widely spread, had flattened elongated shapes, and were connected to adjacent cells by pseudopods. An MTT assay revealed higher cell proliferation on HA-TCP, Mg-TCP, and MgHA-TCP compared with TCP at 3 and 5 days. MgHA-TCP also showed significantly higher alkaline phosphatase activity levels compared with TCP, HA-TCP, and Mg-TCP (P < 0.05). Results suggest that Mg-coated β-TCP could have great potential as a bone graft material for future applications in hard tissue regeneration.

Physico-Mechanical Properties of HA/TCP Pellets and Their Three-Dimensional Biological Evaluation In Vitro.

PubMed

Kamalaldin, Nurulain 'Atikah; Jaafar, Mariatti; Zubairi, Saiful Irwan; Yahaya, Badrul Hisham

2018-01-04

The use of bioceramics, especially the combination of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), as a three-dimensional scaffold in bone engineering is essential because together these elements constitute 60% of the bone content. Different ratios of HA and β-TCP were previously tested for their ability to produce suitable bioceramic scaffolds, which must be able to withstand high mechanical load. In this study, two ratios of HA/TCP (20:80 and 70:30) were used to create pellets, which then were evaluated in vitro to identify any adverse effects of using the material in bone grafting. Diametral tensile strength (DTS) and density testing was conducted to assess the mechanical strength and porosity of the pellets. The pellets then were tested for their toxicity to normal human fibroblast cells. In the toxicity assay, cells were incubated with the pellets for 3 days. At the end of the experiment, cell morphological changes were assessed, and the absorbance was read using PrestoBlue Cell Viability Reagent™. An inversely proportional relationship between DTS and porosity percentage was detected. Fibroblasts showed normal cell morphology in both treatments, which suggests that the HA/TCP pellets were not toxic. In the osteoblast cell attachment assay, cells were able to attach to the surface of both ratios, but cells were also able to penetrate inside the scaffold of the 70:30 pellets. This finding suggests that the 70:30 ratio had better osteoconduction properties than the 20:80 ratio.

Regenerative effect of basic fibroblast growth factor on periodontal healing in two-wall intrabony defects in dogs.

PubMed

Shirakata, Yoshinori; Taniyama, Katsuyoshi; Yoshimoto, Takehiko; Miyamoto, Motoharu; Takeuchi, Naoshi; Matsuyama, Takashi; Noguchi, Kazuyuki

2010-04-01

The aim of the present study was to evaluate the effect of a basic fibroblast growth factor (bFGF) candidate treatment on periodontal healing in two-wall intrabony defects in dogs. Two-wall intrabony defects (5 x 5 x 5 mm) were created surgically on the distal and mesial sides of bilateral mandibular second and fourth premolars in four Beagle dogs. bFGF, enamel matrix derivative (EMD) and platelet-derived growth factor with beta-tricalcium phosphate (PDGF/beta-TCP) treatments, and sham-surgery (OFD) were rotated among the four defects in each animal, EMD and PDGF/beta-TCP serving as benchmark controls. The animals were euthanized for radiographic and histologic evaluation at 8 weeks. Bone formation was significantly greater in the bFGF group (4.11 +/- 0.77 mm) than in the EMD (3.32 +/- 0.71 mm; p<0.05) and OFD (3.09 +/- 0.52 mm; p<0.01) groups. The EMD (4.59 +/- 1.19 mm) and PDGF/beta-TCP (4.66 +/- 0.7 mm) groups exhibited significantly greater cementum regeneration with periodontal ligament-like tissue than the OFD group (2.96 +/- 0.69 mm; p<0.01). No significant differences were observed between the bFGF and the PDGF/beta-TCP groups in any of the histometric parameters. The candidate bFGF treatment supported periodontal regeneration comparable with that of established benchmarks: EMD and PDGF/beta-TCP.

Evaluation of Phosphate Fertilizers for the Immobilization of Cd in Contaminated Soils

PubMed Central

Yan, Yin; Zhou, Yi Qun; Liang, Cheng Hua

2015-01-01

A laboratory investigation was conducted to evaluate the efficiency of four phosphate fertilizers, including diammonium phosphate (DAP), potassium phosphate monobasic (MPP), calcium superphosphateon (SSP), and calcium phosphate tribasic (TCP), in terms of the toxicity and bioavailability of Cd in contaminated soils. The efficiency of immobilization was evaluated on the basis of two criteria: (a) the reduction of extractable Cd concentration below the TCLP regulatory level and (b) the Cd changes associated with specific operational soil fractions on the basis of sequential extraction data. Results showed that after 50 d immobilization, the extractable concentrations of Cd in DAP, MPP, SSP, and TCP treated soils decreased from 42.64 mg/kg (in the control) to 23.86, 21.86, 33.89, and 35.59 mg/kg, respectively, with immobilization efficiency in the order of MPP > DAP > SSP > TCP. Results from the assessment of Cd speciation via the sequential extraction procedure revealed that the soluble exchangeable fraction of Cd in soils treated with phosphate fertilizers, especially TCP, was considerably reduced. In addition, the reduction was correspondingly related to the increase in the more stable forms of Cd, that is, the metal bound to manganese oxides and the metal bound to crystalline iron oxides. Treatment efficiency increased as the phosphate dose (according to the molar ratio of PO4/Cd) increased. Immobilization was the most effective under the molar ratio of PO4/Cd at 4:1. PMID:25915051

Cell cycle dependent intracellular distribution of two spliced isoforms of TCP/ILF3 proteins.

PubMed

Xu, You Hai; Leonova, Tatyana; Grabowski, Gregory A

2003-12-01

TCP80 is an approximately 80kDa mammalian cytoplasmic protein that binds to a set of mRNAs and inhibits their translation in vitro and ex vivo. This protein has high sequence similarity to interleukin-2 enhancer-binding factors (NF90/ILF3) and the M-phase phosphoprotein (MPP4)/DRBP76. A 110kDa immunologic isoform of TCP80/NF90/MPP4/DRBP76, termed TCP110, also is present in cytoplasm and nuclei of many types of cells. A cDNA sequence coding for TCP110 was derived by 5(')RACE. The TCP110 sequence is identical to ILF3. The gene coding for TCP110/ILF3 mapped to human chromosome 19 and the gene organization was analyzed using TCP80 and TCP110/ILF3 cDNA sequences. The TCP/ILF3 gene spans >34.8kb and contains 21 exons. At least one alternatively spliced product involving exons 19-21 exists and predicts the formation of either TCP80 or TCP110/ILF3. However, the functional relationships of TCP80 and TCP110/ILF3 required elucidation. The metabolic turnover rates and subcellular distribution of TCP80 and TCP110/ILF3 during the cell cycle showed TCP80 to be relatively stable (t(1/2)=5 days) in the cytoplasmic compartment. In comparison, TCP110/ILF3 migrated between the cytoplasmic and nuclear compartments during the cell cycle. The TCP110 C-terminal segment contains an additional nuclear localizing signal that plays a role in its nuclear translocation. This study indicates that the multiple cellular functions, i.e., translation control, interleukin-2 enhancer binding, or cell division, of TCP/ILF3 are fulfilled by alternatively spliced isoforms.

On the use of biomathematical models in patient-specific IMRT dose QA

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

Zhen Heming; Nelms, Benjamin E.; Tome, Wolfgang A.

2013-07-15

Purpose: To investigate the use of biomathematical models such as tumor control probability (TCP) and normal tissue complication probability (NTCP) as new quality assurance (QA) metrics.Methods: Five different types of error (MLC transmission, MLC penumbra, MLC tongue and groove, machine output, and MLC position) were intentionally induced to 40 clinical intensity modulated radiation therapy (IMRT) patient plans (20 H and N cases and 20 prostate cases) to simulate both treatment planning system errors and machine delivery errors in the IMRT QA process. The changes in TCP and NTCP for eight different anatomic structures (H and N: CTV, GTV, both parotids,more » spinal cord, larynx; prostate: CTV, rectal wall) were calculated as the new QA metrics to quantify the clinical impact on patients. The correlation between the change in TCP/NTCP and the change in selected DVH values was also evaluated. The relation between TCP/NTCP change and the characteristics of the TCP/NTCP curves is discussed.Results:{Delta}TCP and {Delta}NTCP were summarized for each type of induced error and each structure. The changes/degradations in TCP and NTCP caused by the errors vary widely depending on dose patterns unique to each plan, and are good indicators of each plan's 'robustness' to that type of error.Conclusions: In this in silico QA study the authors have demonstrated the possibility of using biomathematical models not only as patient-specific QA metrics but also as objective indicators that quantify, pretreatment, a plan's robustness with respect to possible error types.« less

Doped tricalcium phosphate bone tissue engineering scaffolds using sucrose as template and microwave sintering: enhancement of mechanical and biological properties.

PubMed

Ke, Dongxu; Bose, Susmita

2017-09-01

β-tricalcium phosphate (β-TCP) is a widely used biocompatible ceramic in orthopedic and dental applications. However, its osteoinductivity and mechanical properties still require improvements. In this study, porous β-TCP and MgO/ZnO-TCP scaffolds were prepared by the thermal decomposition of sucrose. Crack-free cylindrical scaffolds could only be prepared with the addition of MgO and ZnO due to their stabilization effects. Porous MgO/ZnO-TCP scaffolds with a density of 61.39±0.66%, an estimated pore size of 200μm and a compressive strength of 24.96±3.07MPa were prepared by using 25wt% sucrose after conventional sintering at 1250°C. Microwave sintering further increased the compressive strength to 37.94±6.70MPa, but it decreased the open interconnected porosity to 8.74±1.38%. In addition, the incorporation of polycaprolactone (PCL) increased 22.36±3.22% of toughness while maintaining its compressive strength at 25.45±2.21MPa. Human osteoblast cell line was seeded on scaffolds to evaluate the effects of MgO/ZnO and PCL on the biological property of β-TCP in vitro. Both MgO/ZnO and PCL improved osteoinductivity of β-TCP. PCL also decreased osteoblastic apoptosis due to its particular surface chemistry. This novel porous MgO/ZnO-TCP scaffold with PCL shows improved mechanical and biological properties, which has great potential in bone tissue engineering applications. Copyright © 2017. Published by Elsevier B.V.

Repair of calvarial bone defects in mice using electrospun polystyrene scaffolds combined with β-TCP or gold nanoparticles.

PubMed

Terranova, Lisa; Dragusin, Diana Maria; Mallet, Romain; Vasile, Eugeniu; Stancu, Izabela-Cristina; Behets, Catherine; Chappard, Daniel

2017-02-01

Non-biodegradable porous polystyrene (PS) scaffolds, composed of microfibers, have been prepared by electrospinning for the reconstruction of large bone defects. PS microfibers were prepared by incorporating β-TCP grains inside the polymer or grafting gold nanoparticles surface functionalized with mercaptosuccinic acid. Cytocompatibility of the three types of scaffolds (PS, β-TCP-PS and Au-PS) was studied by seeding human mesenchymal stem cells. Biocompatibility was evaluated by implanting β-TCP-PS and Au-PS scaffolds into a critical size (4mm) calvarial defect in mice. Calvaria were taken 6, 9, and 12 weeks after implantation; newly formed bone and cellular response was analyzed by microcomputed tomography (microCT) and histology. β-TCP-PS scaffolds showed a significantly higher cell proliferation in vitro than on PS or Au-PS alone; clearly, the presence of β-TCP grains improved cytocompatibility. Biocompatibility study in the mouse calvaria model showed that β-TCP-PS scaffolds were significantly associated with more newly-formed bone than Au-PS. Bone developed by osteoconduction from the defect margins to the center. A dense fibrous connective tissue containing blood vessels was identified histologically in both types of scaffolds. There was no inflammatory foci nor giant cell in these areas. AuNPs aggregates were identified histologically in the fibrosis and also incorporated in the newly-formed bone matrix. Although the different types of PS microfibers appeared cytocompatible during the in vitro experiment, they appeared biotolerated in vivo since they induced a fibrotic reaction associated with newly formed bone. Copyright © 2016 Elsevier Ltd. All rights reserved.

In vitro testing of calcium phosphate (HA, TCP, and biphasic HA-TCP) whiskers.

PubMed

Jalota, Sahil; Bhaduri, Sarit B; Tas, A Cuneyt

2006-09-01

Calcium phosphate [single-phase hydroxyapatite (HA, Ca(10)(PO(4))(6)(OH)(2)), single-phase tricalcium phosphate (beta-TCP, Ca(3)(PO(4))(2)), and biphasic HA-TCP] whiskers were formed by using a novel microwave-assisted molten salt mediated process. Aqueous solutions containing NaNO(3), HNO(3), Ca(NO(3))(2) x 4H(2)O, and KH(2)PO(4) (with or without urea) were used as starting reagents. These solutions were irradiated in a household microwave oven for 5 min. As-recovered precursors were then simply stirred in water at room temperature for 1 h to obtain the whiskers of the desired calcium phosphate (CaP) bioceramics. These whiskers were evaluated, respectively, in vitro by (1) soaking those in synthetic body fluid (SBF) solutions at 37 degrees C for one week, and (2) performing cell attachment and total protein assay tests on the neat whiskers by using a mouse osteoblast cell line (7F2). beta-TCP, HA, and HA-TCP biphasic whiskers were all found to possess apatite-inducing ability when soaked in SBF. SBF-soaked whiskers were found to have BET surface areas ranging from 45 to 112 m(2)/g. Although the osteoblast viability and protein concentrations were found to be the highest on the neat HA whiskers, cells were attached and proliferated on all the whiskers.

Osteoblast adhesion on novel machinable calcium phosphate/lanthanum phosphate composites for orthopedic applications.

PubMed

Ergun, Celaletdin; Liu, Huinan; Webster, Thomas J

2009-06-01

Lanthanum phosphate (LaPO(4), LP) was combined with either hydroxyapatite (HA) or tricalcium phosphate (TCP) to form novel composites for orthopedic applications. In this study, these composites were prepared by wet chemistry synthesis and subsequent powder mixing. These HA/LP and TCP/LP composites were characterized in terms of phase stability and microstructure evolution during sintering using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Their machinability was evaluated using a direct drilling test. For HA/LP composites, LP reacted with HA during sintering and formed a new phase, Ca(8)La(2)(PO(4))(6)O(2), as a reaction by-product. However, TCP/LP composites showed phase stability and the formation of a weak interface between TCP and LP machinability when sintered at 1100 degrees C, which is crucial for achieving desirable properties. Thus, these novel TCP/LP composites fulfilled the requirements for machinability, a key consideration for manufacturing orthopedic implants. Moreover, the biocompatibility of these novel LP composites was studied, for the first time, in this paper. In vitro cell culture tests demonstrated that the LP and its composites supported osteoblast (bone-forming cell) adhesion similar to natural bioceramics (such as HA and TCP). In conclusion, these novel LP composites should be further studied and developed for more effectively treating bone related diseases or injuries. 2008 Wiley Periodicals, Inc.

Crystal structure of the Vibrio cholerae colonization factor TcpF and identification of a functional immunogenic site.

PubMed

Megli, Christina J; Yuen, Alex S W; Kolappan, Subramaniapillai; Richardson, Malcolm R; Dharmasena, Madushini N; Krebs, Shelly J; Taylor, Ronald K; Craig, Lisa

2011-06-03

Vibrio cholerae relies on two main virulence factors--toxin-coregulated pilus (TCP) and cholera toxin--to cause the gastrointestinal disease cholera. TCP is a type IV pilus that mediates bacterial autoagglutination and colonization of the intestine. TCP is encoded by the tcp operon, which also encodes TcpF, a protein of unknown function that is secreted by V. cholerae in a TCP-dependent manner. Although TcpF is not required for TCP biogenesis, a tcpF mutant has a colonization defect in the infant mouse cholera model that is as severe as a pilus mutant. Furthermore, TcpF antisera protect against V. cholerae infection. TcpF has no apparent sequence homology to any known protein. Here, we report the de novo X-ray crystal structure of TcpF and the identification of an epitope that is critical for its function as a colonization factor. A monoclonal antibody recognizing this epitope is protective against V. cholerae challenge and adds to the protection provided by an anti-TcpA antibody. These data suggest that TcpF has a novel function in V. cholerae colonization and define a region crucial for this function. Copyright © 2011 Elsevier Ltd. All rights reserved.

Age-dependent pharmacokinetic and pharmacodynamic response in preweanling rats following oral exposure to the organophosphorus insecticide chlorpyrifos

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

Timchalk, Chuck; Poet, Torka S.; Kousba, Ahmed A.

2006-03-01

Juvenile rats are more susceptible than adults to the acute toxicity of organophosphorus insecticides like chlorpyrifos (CPF). Age- and dose-dependent differences in metabolism may be responsible. Of importance is CYP450 activation and detoxification of CPF to CPF-oxon and 3,5,6-trichloro-2-pyridinol (TCP), as well as B-esterase (cholinesterase; ChE) and A-esterase (PON-1) detoxification of CPF-oxon to TCP. The pharmacokinetics of CPF, TCP, and the extent of blood (plasma/RBC), and brain ChE inhibition in rats were determined on postnatal days (PND) -5, -12, and -17 following oral gavage administration of 1 and 10 mg CPF/kg of body weight. For all neonatal ages the bloodmore » TCP exceeded the CPF concentration, and within each age group there was no evidence of non-linear kinetics over the dose range evaluated. Younger animals demonstrated a greater sensitivity to ChE inhibition as evident by the dose- and age-dependent inhibition of plasma, RBC, and brain ChE. Of particular importance was the observation that even in rats as young as PND-5, the CYP450 metabolic capacity was adequate to metabolize CPF to both TCP and CPF-oxon based on the detection of TCP in blood and extensive ChE inhibition (biomarker of CPF-oxon) at all ages. In addition, the increase in the blood TCP concentration ({approx}3-fold) in PND-17 rats relative to the response in the younger animals, and the higher blood concentrations of CPF in neonatal rats (1.7 to 7.5-fold) relative to adults was consistent with an increase in CYP450 metabolic capacity with age. This is the first reported study that evaluated both the pharmacokinetics of the parent pesticide, the major metabolite and the extent of ChE inhibition dynamics in the same animals as a function of neonatal age. The results suggest that in the neonatal rat, CPF was rapidly absorbed and metabolized, and the extent of metabolism was age-dependent.« less

Organization of tcp, acf, and toxT genes within a ToxT-dependent operon.

PubMed

Brown, R C; Taylor, R K

1995-05-01

The toxin coregulated pilus (TCP) is required for Vibrio cholerae to colonize the human intestine. The expression of the pilin gene, tcpA, is dependent upon ToxR and upon ToxT. The toxT gene was recently mapped within the TCP biogenesis gene cluster and shown to be capable of activating a tcpA::TnphoA fusion when cloned in Escherichia coli. In this study, we determined that ToxR/ToxT activation occurs at the level of tcpA transcription. ToxT expressed in E. coli could activate a tcp operon fusion, while ToxR, ToxR with ToxS, or a ToxR-PhoA fusion failed to activate the tcp operon fusion and we could not demonstrate binding of a ToxR extract to the tcpA promoter region in DNA mobility-shift assays. The start site for the regulated promoter was shown by primer extension to lie 75 bp upstream of the first codon of tcpA. An 800-base tcpA message was identified, by Northern analysis, that correlates by size to the distance between the transcriptional start and a hairpin-loop sequence between tcpA and tcpB. The more-sensitive assay of RNase protection analysis demonstrated that a regulated transcript probably extends through the rest of the downstream tcp genes, including toxT and the adjacent accessory colonization factor (acf) genes. An in-frame tcpA deletion, but not a polar tcpA::TnphoA fusion, could be complemented for pilus surface expression by providing tcpA in trans. This evidence suggests that the tcp genes, including toxT, are organized in an operon directly activated by ToxT in a ToxR-dependent manner. Most of the toxT expression under induced conditions requires transcription of the tcpA promoter. Further investigation of how tcp::TnphoA insertions that are polar on toxT expression retain regulation showed that a low basal level of toxT expression is present in toxR and tcp::TnphoA strains. Overall, these observations support the ToxR/ToxT cascade of regulation for tcp. Once induced, toxT expression becomes autoregulatory via the tcp promoter, linking tcp expression to that of additional colonization factors, exotoxin production, and genes of unknown function in cholera pathogenesis.

The Arabidopsis class I TCP transcription factor AtTCP11 is a developmental regulator with distinct DNA-binding properties due to the presence of a threonine residue at position 15 of the TCP domain.

PubMed

Viola, Ivana L; Uberti Manassero, Nora G; Ripoll, Rodrigo; Gonzalez, Daniel H

2011-04-01

The TCP domain is a DNA-binding domain present in plant transcription factors that modulate different processes. In the present study, we show that Arabidopsis class I TCP proteins are able to interact with a dyad-symmetric sequence composed of two GTGGG half-sites. TCP20 establishes symmetric interactions with the 5' half of each strand, whereas TCP11 interacts mainly with the 3' half. SELEX (systematic evolution of ligands by exponential enrichment) experiments with TCP15 and TCP20 indicated that these proteins have similar, although not identical, DNA-binding preferences and are able to interact with non-palindromic binding sites of the type GTGGGNCCNN. TCP11 shows a different DNA-binding specificity, with a preference for the sequence GTGGGCCNNN. The distinct DNA-binding properties of TCP11 are due to the presence of a threonine residue at position 15 of the TCP domain, a position that is occupied by an arginine residue in most TCP proteins. TCP11 also forms heterodimers with TCP15 that have increased DNA-binding efficiency. The expression in plants of a repressor form of TCP11 demonstrated that this protein is a developmental regulator that influences the growth of leaves, stems and petioles, and pollen development. The results suggest that changes in DNA-binding preferences may be one of the mechanisms through which class I TCP proteins achieve functional specificity.

Spatial Control of Gene Expression by miR319-Regulated TCP Transcription Factors in Leaf Development.

PubMed

Bresso, Edgardo G; Chorostecki, Uciel; Rodriguez, Ramiro E; Palatnik, Javier F; Schommer, Carla

2018-02-01

The characteristic leaf shapes we see in all plants are in good part the outcome of the combined action of several transcription factor networks that translate into cell division activity during the early development of the organ. We show here that wild-type leaves have distinct transcriptomic profiles in center and marginal regions. Certain transcripts are enriched in margins, including those of CINCINNATA -like TCPs ( TEOSINTE BRANCHED, CYCLOIDEA and PCF1/2 ) and members of the NGATHA and STYLISH gene families. We study in detail the contribution of microRNA319 (miR319)-regulated TCP transcription factors to the development of the center and marginal regions of Arabidopsis ( Arabidopsis thaliana ) leaves. We compare in molecular analyses the wild type, the tcp2 tcp4 mutant that has enlarged flat leaves, and the tcp2 tcp3 tcp4 tcp10 mutant with strongly crinkled leaves. The different leaf domains of the tcp mutants show changed expression patterns for many photosynthesis-related genes, indicating delayed differentiation, especially in the marginal parts of the organ. At the same time, we found an up-regulation of cyclin genes and other genes that are known to participate in cell division, specifically in the marginal regions of tcp2 tcp3 tcp4 tcp10 Using GUS reporter constructs, we confirmed extended mitotic activity in the tcp2 tcp3 tcp4 tcp10 leaf, which persisted in small defined foci in the margins when the mitotic activity had already ceased in wild-type leaves. Our results describe the role of miR319-regulated TCP transcription factors in the coordination of activities in different leaf domains during organ development. © 2018 American Society of Plant Biologists. All Rights Reserved.

TCP transcription factors are critical for the coordinated regulation of isochorismate synthase 1 expression in Arabidopsis thaliana.

PubMed

Wang, Xiaoyan; Gao, Jiong; Zhu, Zheng; Dong, Xianxin; Wang, Xiaolei; Ren, Guodong; Zhou, Xin; Kuai, Benke

2015-04-01

Salicylic acid (SA) plays an important role in various aspects of plant development and responses to stresses. To elucidate the sophisticated regulatory mechanism of SA synthesis and signaling, we used a yeast one-hybrid system to screen for regulators of isochorismate synthase 1 (ICS1), a gene encoding the key enzyme in SA biosynthesis in Arabidopsis thaliana. A TCP family transcription factor AtTCP8 was initially identified as a candidate regulator of ICS1. The regulation of ICS1 by TCP proteins is supported by the presence of a typical TCP binding site in the ICS1 promoter. The binding of TCP8 to this site was confirmed by in vitro and in vivo assays. Expression patterns of TCP8 and its corresponding gene TCP9 largely overlapped with ICS1 under pathogen attack. A significant reduction in the expression of ICS1 during immune responses was observed in the tcp8 tcp9 double mutant. We also detected strong interactions between TCP8 and SAR deficient 1 (SARD1), WRKY family transcription factor 28 (WRKY28), NAC (NAM/ATAF1,ATAF2/CUC2) family transcription factor 019 (NAC019), as well as among TCP8, TCP9 and TCP20, suggesting a complex coordinated regulatory mechanism underlying ICS1 expression. Our results collectively demonstrate that TCP proteins are involved in the orchestrated regulation of ICS1 expression, with TCP8 and TCP9 being verified as major representatives. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Exosomes/tricalcium phosphate combination scaffolds can enhance bone regeneration by activating the PI3K/Akt signaling pathway.

PubMed

Zhang, Jieyuan; Liu, Xiaolin; Li, Haiyan; Chen, Chunyuan; Hu, Bin; Niu, Xin; Li, Qing; Zhao, Bizeng; Xie, Zongping; Wang, Yang

2016-09-20

Recently, accumulating evidence has shown that exosomes, the naturally secreted nanocarriers of cells, can exert therapeutic effects in various disease models in the absence of parent cells. However, application of exosomes in bone defect repair and regeneration has been rarely reported, and little is known regarding their underlying mechanisms. Exosomes derived from human-induced pluripotent stem cell-derived mesenchymal stem cells (hiPS-MSC-Exos) were combined with tricalcium phosphate (β-TCP) to repair critical-sized calvarial bone defects, and the efficacy was assessed by histological examination. We evaluated the in vitro effects of hiPSC-MSC-Exos on the proliferation, migration, and osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs) by cell-counting, scratch assays, and qRT-PCR, respectively. Gene expression profiling and bioinformatics analyses were also used to identify the underlying mechanisms in the repair. We found that the exosome/β-TCP combination scaffolds could enhance osteogenesis as compared to pure β-TCP scaffolds. In vitro assays showed that the exosomes could release from β-TCP and could be internalized by hBMSCs. In addition, the internalization of exosomes into hBMSCs could profoundly enhance the proliferation, migration, and osteogenic differentiation of hBMSCs. Furthermore, gene expression profiling and bioinformatics analyses demonstrated that exosome/β-TCP combination scaffolds significantly altered the expression of a network of genes involved in the PI3K/Akt signaling pathway. Functional studies further confirmed that the PI3K/Akt signaling pathway was the critical mediator during the exosome-induced osteogenic responses of hBMSCs. We propose that the exosomes can enhance the osteoinductivity of β-TCP through activating the PI3K/Akt signaling pathway of hBMSCs, which means that the exosome/β-TCP combination scaffolds possess better osteogenesis activity than pure β-TCP scaffolds. These results indicate that naturally secreted nanocarriers-exosomes can be used as a bioactive material to improve the bioactivity of the biomaterials, and that hiPS-MSC-Exos combined with β-TCP scaffolds can be potentially used for repairing bone defects.

Reverse Anterior Cruciate Ligament Reconstruction Fixation: A Biomechanical Comparison Study of Tibial Cross-Pin and Femoral Interference Screw Fixation.

PubMed

Lawley, Richard J; Klein, Samuel E; Chudik, Steven C

2017-03-01

To evaluate the biomechanical performance of tibial cross-pin (TCP) fixation relative to femoral cross-pin (FCP), femoral interference screw (FIS), and tibial interference screw (TIS) fixation. We randomized 40 porcine specimens (20 tibias and 20 femurs) to TIS fixation (group 1, n = 10), FIS fixation (group 2, n = 10), TCP fixation (group 3, n = 10), or FCP fixation (group 4, n = 10) and performed biomechanical testing to compare ultimate load, stiffness, yield load, cyclic displacement, and load at 5-mm displacement. We performed cross-pin fixation of the looped end and interference screw fixation of the free ends of 9-mm-diameter bovine extensor digitorum communis tendon grafts. Graft fixation constructs were cyclically loaded and then loaded to failure in line with the tunnels. Regarding yield load, FIS was superior to TIS (704 ± 125 N vs 504 ± 118 N, P = .002), TCP was superior to TIS (1,449 ± 265 N vs 504 ± 118 N, P < .001), and TCP was superior to FCP (1,449 ± 265 N vs 792 ± 397 N, P < .001). Cyclic displacement for FCP was superior to TCP. Cyclic displacement for TIS versus FIS showed no statistically significant difference (2.5 ± 1.0 mm vs 2.2 ± 0.6 mm, P = .298). Interference screw fixation consistently failed by graft slippage, whereas TCP fixation failed by tibial bone failure. FCP fixation failed by either femoral bone failure or failure elsewhere in the testing apparatus. Regarding yield load, TCP fixation performed biomechanically superior to the clinically proven FCP at time zero. Because TIS fixation shows the lowest yield strength, it represents the weak link, and combined TCP-FIS fixation theoretically would be biomechanically superior relative to combined FCP-TIS fixation with regard to yield load. Cyclic displacement showed a small difference in favor of FCP over TCP fixation and no difference between TIS and FIS. Time-zero biomechanics of TCP fixation paired with FIS fixation show that this method of fixation can be considered a potential alternative to current practice and may pose clinical benefits in different clinical scenarios of anterior cruciate ligament reconstruction. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Use of Concept of Chemotherapy-Equivalent Biologically Effective Dose to Provide Quantitative Evaluation of Contribution of Chemotherapy to Local Tumor Control in Chemoradiotherapy Cervical Cancer Trials

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

Plataniotis, George A.; Dale, Roger G.

2008-12-01

Purpose: To express the magnitude of the contribution of chemotherapy to local tumor control in chemoradiotherapy cervical cancer trials in terms of the concept of the biologically effective dose. Methods and Materials: The local control rates of both arms of each study (radiotherapy vs. radiotherapy plus chemotherapy) reported from randomized controlled trials of concurrent chemoradiotherapy for cervical cancer were reviewed and expressed using the Poisson model for tumor control probability (TCP) as TCP = exp(-exp E), where E is the logarithm of cell kill. By combining the two TCP values from each study, we calculated the chemotherapy-related log cell killmore » as Ec = ln[(lnTCP{sub Radiotherapy})/(lnTCP{sub Chemoradiotherapy})]. Assuming a range of radiosensitivities ({alpha} = 0.1-0.5 Gy{sup -1}) and taking the calculated log cell kill, we calculated the chemotherapy-BED, and using the linear quadratic model, the number of 2-Gy fractions corresponding to each BED. The effect of a range of tumor volumes and radiosensitivities ({alpha} Gy{sup -1}) on the TCP was also explored. Results: The chemotherapy-equivalent number of 2-Gy fractions range was 0.2-4 and was greater in tumors with lower radiosensitivity. In those tumors with intermediate radiosensitivity ({alpha} = 0.3 Gy{sup -1}), the equivalent number of 2-Gy fractions was 0.6-1.3, corresponding to 120-260 cGy of extra dose. The opportunities for clinically detectable improvement are only available in tumors with intermediate radiosensitivity with {alpha} = 0.22-0.28 Gy{sup -1}. The dependence of TCP on the tumor volume decreases as the radiosensitivity increases. Conclusion: The results of our study have shown that the contribution of chemotherapy to the TCP in cervical cancer is expected to be clinically detectable in larger and less-radiosensitive tumors.« less

Long-term degradation of a poly-lactide co-glycolide/β-tricalcium phosphate biocomposite interference screw.

PubMed

Barber, F Alan; Dockery, W D; Hrnack, Scott A

2011-05-01

To evaluate the long-term in vivo degradation of biodegradable interference screws made of poly-L-lactide co-glycolide (poly-L-lactic acid [PLLA]/polyglycolic acid [PGA]) and β-tricalcium phosphate (β-TCP). To study in vivo the biological behavior of a PLLA/PGA/β-TCP biocomposite screw (Milagro; DePuy Mitek, Raynham, MA), an institutional review board-approved program using anterior cruciate ligament (ACL) interference fixation screws was initiated in 2005. Thirteen patients who had bone-patellar tendon-bone ACL reconstruction fixed at both the femur and tibia with PLLA/PGA/β-TCP screws at least 24 months earlier were evaluated by physical, radiographic, and computed tomography (CT) evaluations. Lysholm, Tegner, Cincinnati, and International Knee Documentation Committee scores were also obtained. Radiographs and CT scans of the operated knee were obtained. CT scan data measured in Hounsfield units (HU) evaluated the material density at the screw and bone plug sites. Soft-tissue and cancellous and cortical bone site readings were also taken. Osteoconductivity scores were determined at the screw sites by use of an ossification quality score (range, 1 to 4). Eleven men and two women were evaluated at a mean of 38 months after surgery (range, 24 to 49 months). CT scans and radiographs showed the bone plug fused to the tunnel wall with no PLLA/PGA/β-TCP screw remaining. The screws were replaced with material that was calcified and non-trabecular. Osteoconductivity was present in 21 of 26 tunnels (81%) and complete (type 4 ossification) in 5 of 26 (19%). Mean screw site densities (femoral, 159 HU; tibial, 157 HU) were not different from the mean cancellous bone density (femoral, 146 HU; tibial, 140 HU). No positive pivot-shift tests were found. Lysholm, Tegner, and Cincinnati scores improved from 44, 3.7, and 37 preoperatively to 93, 6, and 87 at follow-up, respectively. The mean KT arthrometer (MEDmetric, San Diego, CA) difference was 0.8 mm. The PLLA/PGA/β-TCP interference screw completely degraded, and no remnant was present 3 years after implantation for a bone-patellar tendon-bone graft ACL reconstruction. Osteoconductivity was confirmed in 21 of 26 screw sites (81%) and completely filled the site in 5 of 26 (19%). The PLLA/PGA/β-TCP biocomposite interference screw is osteoconductive. Level IV, therapeutic case series. Copyright © 2011 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Method of Performance-Aware Security of Unicast Communication in Hybrid Satellite Networks

NASA Technical Reports Server (NTRS)

Baras, John S. (Inventor); Roy-Chowdhury, Ayan (Inventor)

2014-01-01

A method and apparatus utilizes Layered IPSEC (LES) protocol as an alternative to IPSEC for network-layer security including a modification to the Internet Key Exchange protocol. For application-level security of web browsing with acceptable end-to-end delay, the Dual-mode SSL protocol (DSSL) is used instead of SSL. The LES and DSSL protocols achieve desired end-to-end communication security while allowing the TCP and HTTP proxy servers to function correctly.

Transcriptome - Scale characterization of salt responsive bean TCP transcription factors.

PubMed

İlhan, Emre; Büyük, İlker; İnal, Behcet

2018-02-05

TEOSINTE-BRANCHED1/CYCLOIDEA/PCF (TCP) proteins are important regulators of growth and developmental processes including branching, floral organ morphogenesis and leaf growth as well as stress response. This study identified 27 TCP genes of Phaseolus vulgaris (common bean), which were divided into three clusters based on phylogenetic relationship. In addition, this study showed that some of TCP genes such as Pvul-TCP-4 and Pvul-TCP-15 located on chromosomes 3 and 7, Pvul-TCP-7 and Pvul-TCP-20 located on chromosome 7 and 9, were segmentally duplicated. On the other hand, a total of 20 Pvul-TCP genes have predicted to be targeted by microRNAs (miRNA). Most of the miRNA-target genes were Pvul-TCP-1, -11, -13 and -27, which were targeted by 13, 17, 22 and 13 plant miRNAs, respectively. miR319 was one of the highly represented regulatory miRNAs to target TCP transcripts. Promoter region analysis of TCP genes resulted that the GT-1 motif, which was related to salt stress, was found in 14 different Pvul-TCP genes. Expression profiling of 10 Pvul-TCP genes based on RNA-sequencing data further confirmed with quantitative real-time RT-PCR measurements identified that Pvul-TCP genes under salt stress are expressed in a cultivar- and tissue-specific manner. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of 3D printed PCL/PLGA/β-TCP versus collagen membranes for guided bone regeneration in a beagle implant model.

PubMed

Won, J-Y; Park, C-Y; Bae, J-H; Ahn, G; Kim, C; Lim, D-H; Cho, D-W; Yun, W-S; Shim, J-H; Huh, J-B

2016-10-07

Here, we compared 3D-printed polycaprolactone/poly(lactic-co-glycolic acid)/β-tricalcium phosphate (PCL/PLGA/β-TCP) membranes with the widely used collagen membranes for guided bone regeneration (GBR) in beagle implant models. For mechanical property comparison in dry and wet conditions and cytocompatibility determination, we analyzed the rate and pattern of cell proliferation of seeded fibroblasts and preosteoblasts using the cell counting kit-8 assay and scanning electron microscopy. Osteogenic differentiation was verified using alizarin red S staining. At 8 weeks following implantation in vivo using beagle dogs, computed tomography and histological analyses were performed after sacrifice. Cell proliferation rates in vitro indicated that early cell attachment was higher in collagen than in PCL/PLGA/β-TCP membranes; however, the difference subsided by day 7. Similar outcomes were found for osteogenic differentiation, with approximately 2.5 times greater staining in collagen than PCL/PLGA/β-TCP, but without significant difference by day 14. In vivo, bone regeneration in the defect area, represented by new bone formation and bone-to-implant contact, paralleled those associated with collagen membranes. However, tensile testing revealed that whereas the PCL/PLGA/β-TCP membrane mechanical properties were conserved in both wet and dry states, the tensile property of collagen was reduced by 99% under wet conditions. Our results demonstrate in vitro and in vivo that PCL/PLGA/β-TCP membranes have similar levels of biocompatibility and bone regeneration as collagen membranes. In particular, considering that GBR is always applied to a wet environment (e.g. blood, saliva), we demonstrated that PCL/PLGA/β-TCP membranes maintained their form more reliably than collagen membranes in a wet setting, confirming their appropriateness as a GBR membrane.

Enhanced bone formation in the vicinity of porous β-TCP scaffolds exhibiting slow release of collagen-derived tripeptides.

PubMed

Kamikura, Keita; Minatoya, Tsutomu; Terada-Nakaishi, Michiko; Yamamoto, Shoko; Sakai, Yasuo; Furusawa, Toshitake; Matsushima, Yuta; Unuma, Hidero

2017-09-01

It has been experimentally proven that orally ingested collagen-derived tripeptides (Ctp) are quickly absorbed in the body and effectively promote the regeneration of connective tissues including bone and skin. Ctp are capable to activate osteoblasts and fibroblasts, which eventually promotes tissue regeneration. Based on these findings, a hypothesis was formulated in this study that direct delivery of Ctp to bone defect would also facilitate tissue regeneration as well as oral administration. To test the hypothesis, we prepared a bone augmentation material with the ability to slowly release Ctp, and investigated its in vivo bone regeneration efficacy. The implant material was porous β-tricalcium phosphate (β-TCP) scaffold which was coated with a co-precipitated layer of bone-like hydroxyapatite and Ctp. The β-TCP was impregnated with approximately 0.8%(w/w) Ctp. Then, the Ctp-modified β-TCP was implanted into bone defects of Wistar rats to evaluate in vivo efficacy of Ctp directly delivered from the material to the bone defects. The control was pristine porous β-TCP. In vitro tests showed that Ctp were steadily released from the co-precipitated layer for approximately two weeks. The Ctp-modified scaffolds significantly promoted new bone formation in vivo in their vicinity as compared with pristine β-TCP scaffolds; 6 weeks after the implantation, Ctp-modified scaffolds promoted twice as much bone formation as the control implants. Consequently, we achieved the slow and steady release of Ctp, and found that direct delivery of Ctp from implant materials was effective for bone regeneration as well as oral administration. A β-TCP scaffold capable of slowly releasing bone-enhancing substances significantly promoted bone formation.

SU-E-T-578: On Definition of Minimum and Maximum Dose for Target Volume

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

Gong, Y; Yu, J; Xiao, Y

Purpose: This study aims to investigate the impact of different minimum and maximum dose definitions in radiotherapy treatment plan quality evaluation criteria by using tumor control probability (TCP) models. Methods: Dosimetric criteria used in RTOG 1308 protocol are used in the investigation. RTOG 1308 is a phase III randomized trial comparing overall survival after photon versus proton chemoradiotherapy for inoperable stage II-IIIB NSCLC. The prescription dose for planning target volume (PTV) is 70Gy. Maximum dose (Dmax) should not exceed 84Gy and minimum dose (Dmin) should not go below 59.5Gy in order for the plan to be “per protocol” (satisfactory).A mathematicalmore » model that simulates the characteristics of PTV dose volume histogram (DVH) curve with normalized volume is built. The Dmax and Dmin are noted as percentage volumes Dη% and D(100-δ)%, with η and d ranging from 0 to 3.5. The model includes three straight line sections and goes through four points: D95%= 70Gy, Dη%= 84Gy, D(100-δ)%= 59.5 Gy, and D100%= 0Gy. For each set of η and δ, the TCP value is calculated using the inhomogeneously irradiated tumor logistic model with D50= 74.5Gy and γ50=3.52. Results: TCP varies within 0.9% with η; and δ values between 0 and 1. With η and η varies between 0 and 2, TCP change was up to 2.4%. With η and δ variations from 0 to 3.5, maximum of 8.3% TCP difference is seen. Conclusion: When defined maximum and minimum volume varied more than 2%, significant TCP variations were seen. It is recommended less than 2% volume used in definition of Dmax or Dmin for target dosimetric evaluation criteria. This project was supported by NIH grants U10CA180868, U10CA180822, U24CA180803, U24CA12014 and PA CURE Grant.« less

The Development of a Service-Learning Program for First-Year Students Based on the Hallmarks of High Quality Service-Learning and Rigorous Program Evaluation

ERIC Educational Resources Information Center

Smith, Bradley H.; Gahagan, James; McQuillin, Samuel; Haywood, Benjamin; Cole, Caroline Pender; Bolton, Clay; Wampler, Mary Katherine

2011-01-01

We describe six hallmarks of high quality service-learning and explain how these considerations guided the development of a Transitional Coaching Program (TCP) during the first three years of implementation. We have demonstrated that the TCP is acceptable, feasible, and sustainable. Improvements have been seen in the degree of impact on learning…

Therapeutic effects of transdermal systems containing zinc-related materials on thermal burn rats.

PubMed

Otsuka, Makoto; Hatakeyama, Haruna; Shikamura, Masayuki; Otsuka, Kuniko; Ito, Atsuo

2015-01-01

The aim of the present study is to evaluate the efficacy of slow zinc (Zn) release from β-tricalcium phosphate powder (ZnTCP) containing 10 mol% Zn on rats with thermal burns. The first-aid tapes were contained zinc sulfate (ZnSO4) solution, ZnTCP suspensions or zinc oxide ointment. After thermal burn treatments were performed on Zn-deficient rats, the groups D1, D2 and D3 were treated with tapes containing ZnTCP, ZnSO4 and zinc oxide ointment. The effects of the tapes on wound area, plasma Zn levels and alkaline phosphatase activity (Alp) were investigated. The wound area profiles of all rat groups could be separated into before and after the scab formation at around day 6. The area under the curve (Aw-AUC) for wound area profiles, therefore, was evaluated as an index of therapeutic scores for the thermal wound. The order of Aw-AUC was D3>C>D2>D1. The degree of expansion at the initial stage by thermal burns of group D1 was the lowest and that of group D2 was the highest, and the order was D1

Genetic mapping of secretion and functional determinants of the Vibrio cholerae TcpF colonization factor.

PubMed

Krebs, Shelly J; Kirn, Thomas J; Taylor, Ronald K

2009-06-01

Colonization of the human small intestine by Vibrio cholerae requires the type IV toxin-coregulated pilus (TCP). TcpF, which is encoded within the tcp operon, is secreted from the bacterial cell by the TCP apparatus and is also essential for colonization. Bacteria lacking tcpF are deficient in colonization, and anti-TcpF antibodies are protective in the infant mouse cholera model. In order to elucidate the regions of the protein that are required for secretion through the TCP apparatus and for its function in colonization, random mutagenesis of tcpF was performed. Analysis of these mutants suggests that multiple regions throughout the protein influence extracellular secretion and that determinants near the C terminus are important for the function of TcpF in colonization. The TcpF proteins of certain environmental V. cholerae isolates with 31% to 66% identity to pathogenic V. cholerae TcpF showed higher similarity in regions identified as secretion determinants but diverged in regions found to be important for colonization. These environmental TcpF proteins are secreted from the pathogenic strain; however, they do not mediate colonization in the infant mouse model. Here we provide genetic evidence pointing toward regions of TcpF that influence secretion, as well as regions that play an important role in in vivo colonization.

The synthesis of branched TCP chromophores and the research on their electro-optical properties

NASA Astrophysics Data System (ADS)

Bo, Shuhui; Chen, Zhuo; Gao, Wu; Zhen, Zhen; Liu, Xinhou

2012-10-01

In order to minimize the intermolecular electrostatic interactions and effectively translate high value of chromophore into macroscopic electro-optical (EO) coeffcient (r33), the shape-modification of aniline-pyrroline (TCP) chromophore by combining three kinds of dendritic groups respectively to the N atom of pyrroline acceptor produced three kinds of dendritic chromophores. Their spherical structures can minimize intermolecular electrostatic interactions, and thus the poling efficience was higher than the chromophores without dendritic groups when chromophores as a guest in the host polymer APC. A large electro-optical (EO) coefficient was achieved as high as 75 pm/V at 1315 nm with 9% chromophores loading in APC film. On the basis of the above TCP chromophores, two kinds of novel molecular glasses based on self-assembly dendritic chromophores are also designed and synthesized as second-order nonlinear optical (NLO) materials, which named ETO and ETF. The NLO chromophore glasses ETO and ETF showed excellent filmforming ability by themselves. Their glass transition temperatures (Tg) were determined at 41° and 39°, respectively. The in-situ second harmonic generation (SHG) measurement revealed the resonant electro-optical (EO) coefficient (d33) values of 38 and 32 pm/V for the poled films of ETO and ETF, respectively. The results indicate molecular glasses provide a new possible way different from the conventional polymer approach to prepare second-order NLO materials.

Arabidopsis Class I and Class II TCP Transcription Factors Regulate Jasmonic Acid Metabolism and Leaf Development Antagonistically1[C][W

PubMed Central

Danisman, Selahattin; van der Wal, Froukje; Dhondt, Stijn; Waites, Richard; de Folter, Stefan; Bimbo, Andrea; van Dijk, Aalt DJ; Muino, Jose M.; Cutri, Lucas; Dornelas, Marcelo C.; Angenent, Gerco C.; Immink, Richard G.H.

2012-01-01

TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR1 (TCP) transcription factors control developmental processes in plants. The 24 TCP transcription factors encoded in the Arabidopsis (Arabidopsis thaliana) genome are divided into two classes, class I and class II TCPs, which are proposed to act antagonistically. We performed a detailed phenotypic analysis of the class I tcp20 mutant, showing an increase in leaf pavement cell sizes in 10-d-old seedlings. Subsequently, a glucocorticoid receptor induction assay was performed, aiming to identify potential target genes of the TCP20 protein during leaf development. The LIPOXYGENASE2 (LOX2) and class I TCP9 genes were identified as TCP20 targets, and binding of TCP20 to their regulatory sequences could be confirmed by chromatin immunoprecipitation analyses. LOX2 encodes for a jasmonate biosynthesis gene, which is also targeted by class II TCP proteins that are under the control of the microRNA JAGGED AND WAVY (JAW), although in an antagonistic manner. Mutation of TCP9, the second identified TCP20 target, resulted in increased pavement cell sizes during early leaf developmental stages. Analysis of senescence in the single tcp9 and tcp20 mutants and the tcp9tcp20 double mutants showed an earlier onset of this process in comparison with wild-type control plants in the double mutant only. Both the cell size and senescence phenotypes are opposite to the known class II TCP mutant phenotype in JAW plants. Altogether, these results point to an antagonistic function of class I and class II TCP proteins in the control of leaf development via the jasmonate signaling pathway. PMID:22718775

Redox-Dependent Modulation of Anthocyanin Biosynthesis by the TCP Transcription Factor TCP15 during Exposure to High Light Intensity Conditions in Arabidopsis1[OPEN

PubMed Central

Viola, Ivana L.; Gonzalez, Daniel H.

2016-01-01

TCP proteins integrate a family of transcription factors involved in the regulation of developmental processes and hormone responses. It has been shown that most members of class I, one of the two classes in which the TCP family is divided, contain a conserved Cys that leads to inhibition of DNA binding when oxidized. In this work, we describe that the class-I TCP protein TCP15 inhibits anthocyanin accumulation during exposure of plants to high light intensity by modulating the expression of transcription factors involved in the induction of anthocyanin biosynthesis genes, as suggested by the study of plants that express TCP15 from the 35SCaMV promoter and mutants in TCP15 and the related gene TCP14. In addition, the effect of TCP15 on anthocyanin accumulation is lost after prolonged incubation under high light intensity conditions. We provide evidence that this is due to inactivation of TCP15 by oxidation of Cys-20 of the TCP domain. Thus, redox modulation of TCP15 activity in vivo by high light intensity may serve to adjust anthocyanin accumulation to the duration of exposure to high irradiation conditions. PMID:26574599

Preparation of a new composite combining strengthened β-tricalcium phosphate with platelet-rich plasma as a potential scaffold for the repair of bone defects

PubMed Central

WANG, CHENGGONG; ZHONG, DA; ZHOU, XING; YIN, KE; LIAO, QIANDE; KONG, LINGYU; LIU, ANSONG

2014-01-01

β-tricalcium phosphate (β-TCP) and platelet-rich plasma (PRP) are commonly used in bone tissue engineering. In the present study, a new composite combining strengthened β-TCP and PRP was prepared and its morphological and mechanical properties were investigated by scanning electron microscopy (SEM) and material testing. The biocompatibility was evaluated by measuring the adhesion rate and cytotoxicity of bone marrow stromal cells (BMSCs). The strengthened β-TCP/PRP composite had an appearance like the fungus Boletus kermesinus with the PRP gel distributed on the surface of the micropores. The maximum load and load intensity were 945.6±86.4 N and 13.1±0.5 MPa, which were significantly higher than those of β-TCP (110.1±14.3 N and 1.6±0.2 MPa; P<0.05). The BMSC adhesion rate on the strengthened β-TCP/PRP composite was >96% after 24 h, with a cell cytotoxicity value of zero. SEM micrographs revealed that following seeding of BMSCs onto the composite in high-glucose Dulbecco’s modified Eagle’s medium culture for two weeks, the cells grew well and exhibited fusiform, spherical and polygonal morphologies, as well as pseudopodial connections. The strengthened β-TCP/PRP composite has the potential to be used as a scaffold in bone tissue engineering due to its effective biocompatibility and mechanical properties. PMID:25187800

Bacterial inhibition potential of 3D rapid-prototyped magnesium-based porous composite scaffolds–an in vitro efficacy study

PubMed Central

Ma, Rui; Lai, Yu-xiao; Li, Long; Tan, Hong-lue; Wang, Jia-li; Li, Ye; Tang, Ting-ting; Qin, Ling

2015-01-01

Bone infections are common in trauma-induced open fractures with bone defects. Therefore, developing anti-infection scaffolds for repairing bone defects is desirable. This study develoepd novel Mg-based porous composite scaffolds with a basal matrix composed of poly(lactic-co-glycolicacid) (PLGA) and tricalcium phosphate (TCP). A unique low-temperature rapid prototyping technology was used to fabricate the scaffolds, including PLGA/TCP (PT), PLGA/TCP/5%Mg (PT5M), PLGA/TCP/10%Mg (PT10M), and PLGA/TCP/15%Mg (PT15M). The bacterial adhesion and biofilm formation of Staphylococcus aureus were evaluated. The results indicated that the Mg-based scaffolds significantly inhibited bacterial adhesion and biofilm formation compared to PT, and the PT10M and PT15M exhibited significantly stronger anti-biofilm ability than PT5M. In vitro degratation tests revealed that the degradation of the Mg-based scaffolds caused an increase of pH, Mg2+ concentration and osmolality, and the increased pH may be one of the major contributing factors to the antibacterial function of the Mg-based scaffolds. Additionally, the PT15M exhibited an inhibitory effect on cell adhesion and proliferation of MC3T3-E1 cells. In conclusion, the PLGA/TCP/Mg scaffolds could inhibit bacterial adhesion and biofilm formation, and the PT10M scaffold was considered to be an effective composition with considerable antibacterial ability and good cytocompatibility. PMID:26346217

Structure, mechanical property and corrosion behaviors of (HA+β-TCP)/Mg-5Sn composite with interpenetrating networks.

PubMed

Wang, X; Li, J T; Xie, M Y; Qu, L J; Zhang, P; Li, X L

2015-11-01

In this paper, a novel (Hydroxyapatite+β-tricalcium phosphate)/Mg-5Sn ((HA+β-TCP)/Mg-5Sn) composite with interpenetrating networks was fabricated by infiltrating Mg-5Sn alloy into porous HA+β-TCP using suction casting technique. The structure, mechanical property and corrosion behaviors of the composite have been evaluated by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), mechanical testing, electrochemical and immersion test. It is shown that the molten Mg-5Sn alloy has infiltrated not only into the pores but also into the struts of the HA+β-TCP scaffold to forming a compact composite. The microstructure observation also shows that the Mg alloy contacts to the HA+β-TCP closely, and no reaction layer can be found between Mg-5Sn alloy and scaffold. The ultimate compressive strength of the composite is as high as 176MPa, which is about four fifths of the strength of the Mg-5Sn bulk alloy. The electrochemical and immersion tests indicate that the corrosion resistance of the composite is better than that of the Mg-5Sn bulk alloy. The corrosion products on the composite surface are mainly Mg(OH)2, Ca3(PO4)2 and HA. Appropriate mechanical and corrosion properties of the (HA+β-TCP)/Mg-5Sn composite indicate its possibility for new bone tissue implant materials. Copyright © 2015 Elsevier B.V. All rights reserved.

One Approach for Transitioning the iNET Standards into the IRIG 106 Telemetry Standards

DTIC Science & Technology

2015-05-26

Protocol Suite. Figure 1 illustrates the Open Systems Interconnection ( OSI ) Model, the corresponding TCP/IP Model, and the major components of the TCP...IP Protocol Suite. Figure 2 represents the iNET-specific protocols layered onto the TCP/IP Model. Figure 1. OSI and TCP/IP Model with TCP/IP...Protocol Suite TCP/IP Protocol Suite Major Components IPv4 IPv6 TCP/IP Model OSI Model Application Presentation

Identification and expression profiling analysis of TCP family genes involved in growth and development in maize.

PubMed

Chai, Wenbo; Jiang, Pengfei; Huang, Guoyu; Jiang, Haiyang; Li, Xiaoyu

2017-10-01

The TCP family is a group of plant-specific transcription factors. TCP genes encode proteins harboring bHLH structure, which is implicated in DNA binding and protein-protein interactions and known as the TCP domain. TCP genes play important roles in plant development and have been evolutionarily and functionally elaborated in various plants, however, no overall phylogenetic analysis or expression profiling of TCP genes in Zea mays has been reported. In the present study, a systematic analysis of molecular evolution and functional prediction of TCP family genes in maize ( Z . mays L.) has been conducted. We performed a genome-wide survey of TCP genes in maize, revealing the gene structure, chromosomal location and phylogenetic relationship of family members. Microsynteny between grass species and tissue-specific expression profiles were also investigated. In total, 29 TCP genes were identified in the maize genome, unevenly distributed on the 10 maize chromosomes. Additionally, ZmTCP genes were categorized into nine classes based on phylogeny and purifying selection may largely be responsible for maintaining the functions of maize TCP genes. What's more, microsynteny analysis suggested that TCP genes have been conserved during evolution. Finally, expression analysis revealed that most TCP genes are expressed in the stem and ear, which suggests that ZmTCP genes influence stem and ear growth. This result is consistent with the previous finding that maize TCP genes represses the growth of axillary organs and enables the formation of female inflorescences. Altogether, this study presents a thorough overview of TCP family in maize and provides a new perspective on the evolution of this gene family. The results also indicate that TCP family genes may be involved in development stage in plant growing conditions. Additionally, our results will be useful for further functional analysis of the TCP gene family in maize.

Long-Term Degradation of Self-Reinforced Poly-Levo (96%)/Dextro (4%)-Lactide/β-Tricalcium Phosphate Biocomposite Interference Screws.

PubMed

Barber, F Alan; Dockery, W D

2016-04-01

To evaluate the long-term in vivo degradation of biocomposite interference screws made with self-reinforced poly-levo (96%)/dextro (4%)-lactide/β-tricalcium phosphate [SR-PL(96)/D(4)LA/β-TCP]. A study of the in vivo biologic behavior of an SR-PL(96)/D(4)LA/β-TCP biocomposite interference screw was initiated in 2011 using an anterior cruciate ligament (ACL) reconstruction model. Eight patients undergoing a bone-patellar tendon-bone ACL reconstruction fixed at both the femur and tibia with an SR-PL(96)/D(4)LA/β-TCP screw at least 36 months earlier were evaluated by physical, radiographic, and computed tomography (CT) evaluations. Lysholm, Tegner, Cincinnati, and International Knee Documentation Committee scores were obtained. After incomplete degradation was observed in these 8 patients, a subsequent series of 17 patients were evaluated at a minimum of 48 months after surgery. By use of CT scans, Hounsfield unit (HU) data were obtained at the femoral and tibial screw and other bone sites. An ossification quality score (range, 1 to 4) was used to determine osteoconductivity at the screw sites. Eleven male and 6 female patients evaluated by CT scan and radiographs at a mean of 50 months (range, 48 to 61 months) after surgery showed bone plug healing to the tunnel wall and the SR-PL(96)/D(4)LA/β-TCP screws were replaced with material that was calcified and non-trabecular. Osteoconductivity was present in 24 of 34 tunnels (70.58%) and nearly complete or complete (type 3 or 4 ossification) in 11 of 34 (32.35%). Mean screw site densities (femoral, 242 HU; tibial, 240 HU) were consistent with cancellous bone density. One positive pivot-shift test was found. Lysholm, Cincinnati, Tegner, and International Knee Documentation Committee activity scores improved from 44.5, 40.7, 2.3, and 1.4, respectively, preoperatively to 92, 92.4, 5.7, and 3.3, respectively, at follow-up (P < .0001). The average postoperative Single Assessment Numeric Evaluation score was 92. The mean KT arthrometer (MEDmetric, San Diego, CA) difference was 1.25 mm. The SR-PL(96)/D(4)LA/β-TCP interference screw was replaced with calcified, non-trabecular material 4 years after implantation in a bone-patellar tendon-bone ACL reconstruction model. Osteoconductivity was confirmed in 24 of 34 screw sites (71%), with nearly complete or complete filling in 11 of 34 (33%). The SR-PL(96)/D(4)LA/β-TCP biocomposite interference screw is osteoconductive. Level IV, therapeutic case series. Copyright © 2016 The Arthroscopy Association of North America. All rights reserved.

Redox-Dependent Modulation of Anthocyanin Biosynthesis by the TCP Transcription Factor TCP15 during Exposure to High Light Intensity Conditions in Arabidopsis.

PubMed

Viola, Ivana L; Camoirano, Alejandra; Gonzalez, Daniel H

2016-01-01

TCP proteins integrate a family of transcription factors involved in the regulation of developmental processes and hormone responses. It has been shown that most members of class I, one of the two classes in which the TCP family is divided, contain a conserved Cys that leads to inhibition of DNA binding when oxidized. In this work, we describe that the class-I TCP protein TCP15 inhibits anthocyanin accumulation during exposure of plants to high light intensity by modulating the expression of transcription factors involved in the induction of anthocyanin biosynthesis genes, as suggested by the study of plants that express TCP15 from the 35SCaMV promoter and mutants in TCP15 and the related gene TCP14. In addition, the effect of TCP15 on anthocyanin accumulation is lost after prolonged incubation under high light intensity conditions. We provide evidence that this is due to inactivation of TCP15 by oxidation of Cys-20 of the TCP domain. Thus, redox modulation of TCP15 activity in vivo by high light intensity may serve to adjust anthocyanin accumulation to the duration of exposure to high irradiation conditions. © 2016 American Society of Plant Biologists. All Rights Reserved.

Fabrication of interconnected porous β-tricalcium phosphate (β-TCP) based on a setting reaction of β-TCP granules with HNO3 followed by heat treatment.

PubMed

Ishikawa, Kunio; Putri, Tansza Setiana; Tsuchiya, Akira; Tanaka, Keisuke; Tsuru, Kanji

2018-03-01

β-Tricalcium phosphate [β-TCP] is the typical bone substitute due to its excellent osteoconductivity and bioresorbability. One of the keys to improve its potential as bone substitute is to introduce porous structure and its regulation. In this study, interconnected porous β-TCP blocks were fabricated through a setting reaction of β-TCP granules and subsequent heat treatment. First, β-TCP granules were mixed with HNO 3 . Upon mixing, β-TCP granules were bridged with dicalcium phosphate dihydrate [DCPD: CaHPO 4 ·2H 2 O] containing Ca(NO 3 ) 2 . Then, the DCPD-bridged β-TCP was heated at 1100°C. During the heating process, DCPD containing Ca(NO 3 ) 2 transformed into β-TCP and bonded with β-TCP granules. As a result, an interconnected porous β-TCP block formed. The diametral tensile strength and porosity of the interconnected porous β-TCP block fabricated from 200-300-μm β-TCP granules and 5 N HNO 3 and then heated at 1,100°C were 1.4 ± 0.2 MPa and 57% ± 2%, respectively. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 797-804, 2018. © 2017 Wiley Periodicals, Inc.

β-tricalcium phosphate composite ceramics with high compressive strength, enhanced osteogenesis and inhibited osteoclastic activities.

PubMed

Tian, Ye; Lu, Teliang; He, Fupo; Xu, Yubin; Shi, Haishan; Shi, Xuetao; Zuo, Fei; Wu, Shanghua; Ye, Jiandong

2018-04-13

β-tricalcium phosphate (β-TCP) is well known as a resorbable bone repair material due to its inherent excellent biocompatibility and osteoconductivity. However, β-TCP is encountered with osteostimulation-deficiency and poor mechanical strength because of poor sinterability. Herein, we prepared novel β-TCP composite ceramics (TCP/SPGs) by introducing strontium-containing phosphate-based glass (SPG; 45P 2 O 5 -32SrO-23Na 2 O) as sintering additive. The SPG helped to achieve efficient liquid-phase sintering of β-TCP at 1100 °C. The compressive strength of TCP/SPGs with 15 wt.% SPG (TCP/SPG15) was 2.65 times as high as that of plain β-TCP ceramic. The SPG reacted with β-TCP, and the Sr 2+ and Na 2+ from SPG replaced Ca 2+ in the lattice structure of β-TCP, enabling the sustained release of strontium from TCP/SPGs. In vitro cytological test indicated that TCP/SPGs with certain amount of SPG were highly biocompatible, and noticeably promoted osteogenesis, and inhibited osteoclastic activities. Our results suggested that the TCP/SPG15 might be potential high-strength bone grafts used for bone defect repair, especially in the osteoporotic condition. Copyright © 2018 Elsevier B.V. All rights reserved.

IRIS TOXICOLOGICAL REVIEW AND SUMMARY ...

EPA Pesticide Factsheets

EPA's assessment of the noncancer health effects and carcinogenic potential of 1,2,3-trichloropropane (TCP) was added to the IRIS database in 1990. The IRIS program is updating the IRIS assessment for TCP. This update will incorporate health effects information published since the last assessment was prepared as well as new risk assessment methods. The IRIS assessment for TCP will consist of a Toxicological Review and IRIS Summary. The Toxicological Review is a critical review of the physicochemical and toxicokinetic properties of the chemical and its toxicity in humans and experimental systems. The assessment will present reference values for noncancer effects of TCP (RfD and RfC) and a cancer assessment. The Toxicological Review and IRIS Summary will be subject to internal peer consultation, Agency review, and external scientific peer review. The final products will constitute the Agency's opinion on the toxicity of TCP. EPA is undertaking an Integrated Risk Information System (IRIS) health assessment for 1,2,3-trichloropropane. IRIS is an EPA database containing the Agency's consensus scientific positions on potential adverse human effects that may result from chronic (or lifetime) exposure to chemicals in the environment. IRIS contains chemical-specific summaries of qualitative and quantitative health information in support of two steps of the risk assessment process, i.e., hazard identification and dose-response evaluation. IRIS assessments are used in

Recharge monitoring in an interplaya setting

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

Scanlon, B.R.; Reedy, R.C.; Liang, J.

1999-03-01

The objective of this investigation is to monitor infiltration in response to precipitation events in an interplaya setting. The authors evaluated data gathered from the interplaya recharge monitoring installation at the Pantex Plant from March through December 1998. They monitored thermocouple psychrometer (TCP) instruments to measure water potential and time-domain reflectometry (TDR) probes to measure water content and bulk soil conductivity. Heat-dissipation sensor (HDS) instruments were monitored to supplement the TCP data.

Role of UV photolysis in accelerating the biodegradation of 2,4,6-TCP.

PubMed

Wang, Wenbing; Kirumba, George; Zhang, Yongming; Wu, Yanqing; Rittmann, Bruce E

2015-09-18

2,4,6-TCP, a kind of chlorinated aromatic and aliphatic compound, is difficult to be biodegraded by ordinary microorganisms. UV photolysis and biodegradation of 2,4,6-TCP by Bacillus amyloliquefaciens intimate coupling is a potential means to accelerate its biotransformation. The initial steps of 2,4,6-TCP biodegradation involve mono-oxygenation reactions that have molecular oxygen and an intracellular electron carrier as cosubstrates. It was demonstrated that B. amyloliquefaciens has the 2,4,6-TCP monooxygenase gene tcpA which could encode 2,4,6-TCP monooxygenase (TCP-MO). TCP-MO would catalytically decompose 2,4,6-TCP into 2,6-DCHQ. We employed an internal loop photolytic biofilm reactor for 2,4,6-TCP degradation. Sequentially coupled photolysis and biodegradation experimental results suggested that 2,4,6-TCP removal rate in P + B (TCP(UV) + phenol) protocol was higher by 77 and 103 % when compared to B (TCP + phenol) and B (TCP-only) protocols respectively. The corresponding loss rate coefficient (k) values were 0.069, 0.039, 0.034 mg/L·min -1 respectively. This is because UV photolysis converted 2,4,6-TCP into its intermediates: 2,4-dichlorophenol (2,4-DCP), 4-monochlorophenol (4-MCP), phenol, 2,6-dichloro-p-hydroquinone (2,6-DCHQ), with all displaying less inhibition to bacterial action. In addition, phenol was the crucial UV-photolysis product from 2,4,6-TCP, its catabolic oxidation generating internal electron carriers that may accelerate the initial steps of 2,4,6-TCP biodegradation. Intimately coupled photolysis and biodegradation experimental results suggested that 2,4,6-TCP removal rate in P&B (TCP + phenol) protocol was higher by 166 and 681 % when compared to P&B (TCP-only) and P + B protocols respectively. The corresponding loss rate coefficient (k) values were 0.539, 0.203, 0.069 mg/L·min -1 respectively. It provided sufficient evidence to demonstrate that intimately coupled photolysis and biodegradation accelerated 2,4,6-TCP removal much faster than sequentially coupled photolysis and biodegradation. In addition, oxidation of phenol was the mechanism by which intimately coupled photolysis and biodegradation accelerated rapid 2,4,6-TCP removal producing electron equivalents that stimulated the initial mono-oxygenation reactions for 2,4,6-TCP biodegradation. It is important to note that 2,6-DCHQ (produced from UV-photolysis products or initial mono-oxygenation reactions) would be catalytically decomposed into 6-chlorohydroxyquinol (6-CHQ). Based on this, a tentative reaction mechanism for the photo-biodegradation 2,4,6-TCP was proposed.

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

Bhaskar,; Kumari, Neeti; Goyal, Neena, E-mail: neenacdri@yahoo.com

Highlights: Black-Right-Pointing-Pointer The study presents cloning and characterization of TCP1{gamma} gene from L. donovani. Black-Right-Pointing-Pointer TCP1{gamma} is a subunit of T-complex protein-1 (TCP1), a chaperonin class of protein. Black-Right-Pointing-Pointer LdTCP{gamma} exhibited differential expression in different stages of promastigotes. Black-Right-Pointing-Pointer LdTCP{gamma} co-localized with actin, a cytoskeleton protein. Black-Right-Pointing-Pointer The data suggests that this gene may have a role in differentiation/biogenesis. Black-Right-Pointing-Pointer First report on this chapronin in Leishmania. -- Abstract: T-complex protein-1 (TCP1) complex, a chaperonin class of protein, ubiquitous in all genera of life, is involved in intracellular assembly and folding of various proteins. The gamma subunit of TCP1 complexmore » (TCP1{gamma}), plays a pivotal role in the folding and assembly of cytoskeleton protein(s) as an individual or complexed with other subunits. Here, we report for the first time cloning, characterization and expression of the TCP1{gamma} of Leishmania donovani (LdTCP1{gamma}), the causative agent of Indian Kala-azar. Primary sequence analysis of LdTCP1{gamma} revealed the presence of all the characteristic features of TCP1{gamma}. However, leishmanial TCP1{gamma} represents a distinct kinetoplastid group, clustered in a separate branch of the phylogenic tree. LdTCP1{gamma} exhibited differential expression in different stages of promastigotes. The non-dividing stationary phase promastigotes exhibited 2.5-fold less expression of LdTCP1{gamma} as compared to rapidly dividing log phase parasites. The sub-cellular distribution of LdTCP1{gamma} was studied in log phase promastigotes by employing indirect immunofluorescence microscopy. The protein was present not only in cytoplasm but it was also localized in nucleus, peri-nuclear region, flagella, flagellar pocket and apical region. Co-localization of LdTCP1{gamma} with actin suggests that, this gene may have a role in maintaining the structural dynamics of cytoskeleton of parasite.« less

TCP3 interacts with R2R3-MYB proteins, promotes flavonoid biosynthesis and negatively regulates the auxin response in Arabidopsis thaliana.

PubMed

Li, Shutian; Zachgo, Sabine

2013-12-01

TCP proteins belong to the plant-specific bHLH transcription factor family, and function as key regulators of diverse developmental processes. Functional redundancy amongst family members and post-transcriptional down-regulation by miRJAW of several TCP genes complicate their functional characterization. Here, we explore the role of TCP3 by analyzing transgenic plants expressing miRJAW-resistant mTCP3 and dominant-negative TCP3SRDX. Seedlings and seeds of mTCP3 plants were found to hyper-accumulate flavonols, anthocyanins and proanthocyanidins, whereas levels of proanthocyanidins were slightly reduced in TCP3SRDX plants. R2R3-MYB proteins control not only early flavonoid biosynthetic steps but also activate late flavonoid biosynthetic genes by forming ternary R2R3-MYB/bHLH/WD40 (MBW) complexes. TCP3 interacted in yeast with R2R3-MYB proteins, which was further confirmed in planta using BiFC experiments. Yeast three-hybrid assays revealed that TCP3 significantly strengthened the transcriptional activation capacity of R2R3-MYBs bound by the bHLH protein TT8. Transcriptome analysis of mTCP3 and TCP3SRDX plants supported a role for TCP3 in enhancing flavonoid biosynthesis. Moreover, several auxin-related developmental abnormalities were observed in mTCP3 plants. Transcriptome data coupled with studies of an auxin response reporter and auxin efflux carriers showed that TCP3 negatively modulates the auxin response, probably by compromising auxin transport capacity. Genetic experiments revealed that the chalcone synthase mutant tt4-11 lacking flavonoid biosynthesis abrogated the auxin-related defects caused by mTCP3. Together, these data suggest that TCP3 interactions with R2R3-MYBs lead to enhanced flavonoid production, which further negatively modulates the auxin response. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

Effects of Iron on Physical and Mechanical Properties, and Osteoblast Cell Interaction in β-Tricalcium Phosphate

PubMed Central

Vahabzadeh, Sahar; Bose, Susmita

2017-01-01

Iron (Fe) is a vital element and its deficiency causes abnormal bone metabolism. We investigated the effects of Fe and its concentration in β-tricalcium phosphate (β-TCP) on physicomechanical properties and in vitro proliferation and differentiation of osteoblasts. Our results showed that Fe addition at concentrations of 0.5 wt. % (0.5 Fe-TCP) and 1.0 wt. % (1.0 Fe-TCP) inhibits the β-TCP to α-TCP phase transformation at sintering temperature of 1250 °C. Addition of 0.25 wt. % Fe (0.25 Fe-TCP) increased the compressive strength of β-TCP from 167.27±16.2 MPa to 227.10±19.3 MPa. After 3 days of culture, surfaces of 0.5 Fe-TCP and 1.0 Fe-TCP samples were covered by osteoblast cells, compared to that of pure and 0.25 Fe-TCP. Cells grew to confluency on all Fe-doped samples after 7 days of culture and monolayer sheetlike cellular structure was found at 11 days. Optical cell density and alkaline phosphatase activity were significantly higher on Fe-doped samples and the highest values were found in 0.5 Fe-TCP samples. Our results show that Fe concentration had significant effect on physical and mechanical properties of TCP ceramics, and also on the in vitro osteoblast cellular interactions in TCP ceramics. PMID:27896489

A transport level approach for TCP to support differentiated services

NASA Astrophysics Data System (ADS)

Xian, Yong-Ju; Tao, Yang; Xu, Chang-Biao

2004-04-01

Recently, there is an increasing interests in providing differentiated services in Internet. However, research efforts have almost exclusively focused on routers by improving their policies of packet scheduling and queue management. There has been much less work on transport level approaches to support differentiated services. The mechanism presented by Chang-Biao Xu, DSAS-TCP and MulTCP are the only pieces of the works in this direction known to the authors. Up to now, there is no paper to discuss the interrelation between these mechanisms. Regarding throughput as TCP criteria to support proportional-differentiated-services (PDS), this paper deeply explores the variants of AIMD(a,b)-based TCP congestion control and their effect on differentiated services, and presents a transport level approach for TCP to support PDS, namely PDS_TCP which can be obtained by introducing weighted factor to a or b of AIMD(a,b)-based TCP congestion control. PDS_TCP also takes into account the influence of slow start for timeout. From the analysis, this paper draws the conclusion that the existing mechanisms are only variants of PDS_TCP. For the example of PDS_TCP, the principles, implementation and simulation results of PDS_a_TCP are discussed in detail. The theory analysis and simulation results show that the proposed mechanism PDS_TCP can be implemented with lower additional overheads and support controlled PDS very well without the loss of flexibility.

Role of Side-Chain Molecular Features in Tuning Lower Critical Solution Temperatures (LCSTs) of Oligoethylene Glycol Modified Polypeptides.

PubMed

Gharakhanian, Eric G; Deming, Timothy J

2016-07-07

A series of thermoresponsive polypeptides has been synthesized using a methodology that allowed facile adjustment of side-chain functional groups. The lower critical solution temperature (LCST) properties of these polymers in water were then evaluated relative to systematic molecular modifications in their side-chains. It was found that in addition to the number of ethylene glycol repeats in the side-chains, terminal and linker groups also have substantial and predictable effects on cloud point temperatures (Tcp). In particular, we found that the structure of these polypeptides allowed for inclusion of polar hydroxyl groups, which significantly increased their hydrophilicity and decreased the need to use long oligoethylene glycol repeats to obtain LCSTs. The thioether linkages in these polypeptides were found to provide an additional structural feature for reversible switching of both polypeptide conformation and thermoresponsive properties.

Study and Simulation of Enhancements for TCP Performance Over Noisy High Latency Links

NASA Technical Reports Server (NTRS)

Partridge, Craig

1999-01-01

The goal of this study is to better understand how TCP behaves over noisy, high-latency links such as satellite links and propose improvements to TCP implementations such that TCP might better handle such links. This report is comprised of a series of smaller reports, presentations and recommendations. Included in these documents are a summary of the TCP enhancement techniques for large windows, protect against wrap around (PAWS), use of selective acknowledgements (SACK), increasing TCP's initial window and recommendations to implement TCP pacing.

Genome-Wide Identification and Characterization of BrrTCP Transcription Factors in Brassica rapa ssp. rapa.

PubMed

Du, Jiancan; Hu, Simin; Yu, Qin; Wang, Chongde; Yang, Yunqiang; Sun, Hang; Yang, Yongping; Sun, Xudong

2017-01-01

The teosinte branched1/cycloidea/proliferating cell factor (TCP) gene family is a plant-specific transcription factor that participates in the control of plant development by regulating cell proliferation. However, no report is currently available about this gene family in turnips ( Brassica rapa ssp. rapa ). In this study, a genome-wide analysis of TCP genes was performed in turnips. Thirty-nine TCP genes in turnip genome were identified and distributed on 10 chromosomes. Phylogenetic analysis clearly showed that the family was classified as two clades: class I and class II. Gene structure and conserved motif analysis showed that the same clade genes have similar gene structures and conserved motifs. The expression profiles of 39 TCP genes were determined through quantitative real-time PCR. Most CIN-type BrrTCP genes were highly expressed in leaf. The members of CYC/TB1 subclade are highly expressed in flower bud and weakly expressed in root. By contrast, class I clade showed more widespread but less tissue-specific expression patterns. Yeast two-hybrid data show that BrrTCP proteins preferentially formed heterodimers. The function of BrrTCP2 was confirmed through ectopic expression of BrrTCP2 in wild-type and loss-of-function ortholog mutant of Arabidopsis. Overexpression of BrrTCP2 in wild-type Arabidopsis resulted in the diminished leaf size. Overexpression of BrrTCP2 in triple mutants of tcp2/4/10 restored the leaf phenotype of tcp2/4/10 to the phenotype of wild type. The comprehensive analysis of turnip TCP gene family provided the foundation to further study the roles of TCP genes in turnips.

The application of PRP combined with TCP in repairing avascular necrosis of the femoral head after femoral neck fracture in rabbit.

PubMed

Zhang, X-L; Wang, Y-M; Chu, K; Wang, Z-H; Liu, Y-H; Jiang, L-H; Chen, X; Zhou, Z-Y; Yin, G

2018-02-01

In view of the high occurrence of avascular necrosis of the femoral head (ANFH) after femoral neck fracture and the difficulties in the treatment, our work aimed to explore the effects of platelet-rich plasma (PRP) combined with tri-calcium phosphate (TCP) on the repair of ANFH after femoral neck fracture and to provide reference for clinical treatment. Thirty New Zealand white rabbits were randomly divided into control group, TCP group, and PRP+TCP group. The rabbit ANFH model was established and femoral head tissues were collected. HE staining was used for histological observation. Image analysis and statistical analysis were used to calculate the New Bone Area fraction (NBA %). The levels of bone morphogenetic protein (BMP)-7, transforming growth factor (TGF)-β1, basic fibroblast growth factor (bFGF), interleukin (IL)-6 and tumor necrosis factor (TNF)-a in serum were detected by Enzyme-Linked ImmunoSorbent Assay (ELISA). The new bone area of TCP group was significantly lower than that of PRP+TCP group (p<0.05). Compared with the control group, the levels of BMP-7, TGF-β1 and bFGF were significantly increased in both TCP and PRP+TCP groups (p<0.05), and the increase in PRP+TCP group was higher than that in TCP group. TCP and PRP+TCP can both significantly reduce the content of IL-6 and TNF-a (p<0.05); however, higher decrease was found in PRP+TCP group compared with the TCP group at 8 weeks after injection. PRP combined with TCP, which can promote new bone formation and inhibit inflammatory response, showed higher efficiency in repairing ANFH than internal fixation alone.

Fabrication of polycaprolactone-silanated β-tricalcium phosphate-heparan sulfate scaffolds for spinal fusion applications.

PubMed

Bhakta, Gajadhar; Ekaputra, Andrew K; Rai, Bina; Abbah, Sunny A; Tan, Tuan Chun; Le, Bach Quang; Chatterjea, Anindita; Hu, Tao; Lin, Tingxuan; Arafat, M Tarik; van Wijnen, Andre J; Goh, James; Nurcombe, Victor; Bhakoo, Kishore; Birch, William; Xu, Li; Gibson, Ian; Wong, Hee-Kit; Cool, Simon M

2018-05-01

Interbody spinal fusion relies on the use of external fixation and the placement of a fusion cage filled with graft materials (scaffolds) without regard for their mechanical performance. Stability at the fusion site is instead reliant on fixation hardware combined with a selected cage. Ideally, scaffolds placed into the cage should both support the formation of new bone and contribute to the mechanical stability at the fusion site. We recently developed a scaffold consisting of silane-modified PCL-TCP (PCL-siTCP) with mechanical properties that can withstand the higher loads generated in the spine. To ensure the scaffold more closely mimicked the bone matrix, we incorporated collagen (Col) and a heparan sulfate glycosaminoglycan sugar (HS3) with increased affinity for heparin-binding proteins such as bone morphogenetic protein-2 (BMP-2). The osteostimulatory characteristic of this novel device delivering exogenous BMP2 was assessed in vitro and in vivo as a prelude to future spinal fusion studies with this device. A combination of cell-free assays (BMP2 release), progenitor cell-based assays (BMP2 bioactivity, cell proliferation and differentiation), and rodent ectopic bone formation assays was used to assess the osteostimulatory characteristics of the PCL-siTCP-based scaffolds. Freshly prepared rat mesenchymal stem cells were used to determine reparative cell proliferation and differentiation on the PCL-siTCP-based scaffolds over a 28-day period in vitro. The bioactivity of BMP2 released from the scaffolds was assessed on progenitor cells over a 28-day period using ALP activity assays and release kinetics as determined by enzyme-linked immunosorbent assay. For ectopic bone formation, intramuscular placement of scaffolds into Sprague Dawley rats (female, 4 weeks old, 120-150 g) was achieved in five animals, each receiving four treatments randomized for location along the limb. The four groups tested were (1) PCL-siTCP/Col (5-mm diameter×1-mm thickness), PCL-siTCP/Col/BMP2 (5 µg), (3) PCL-siTCP/Col/HS3 (25 µg), and (4) PCL-siTCP/Col/HS3/BMP2 (25 and 5 µg, respectively). Bone formation was evaluated at 8 weeks post implantation by microcomputed tomography (µCT) and histology. Progenitor cell-based assays (proliferation, mRNA transcripts, and ALP activity) confirmed that BMP2 released from PCL-siTCP/Col/HS3 scaffolds increased ALP expression and mRNA levels of the osteogenic biomarkers Runx2, Col1a2, ALP, and bone gla protein-osteocalcin compared with devices without HS3. When the PCL-siTCP/Col/HS3/BMP2 scaffolds were implanted into rat hamstring muscle, increased bone formation (as determined by two-dimensional and three-dimensional µCTs and histologic analyses) was observed compared with scaffolds lacking BMP2. More consistent increases in the amount of ectopic bone were observed for the PCL-siTCP/Col/HS3/BMP2 implants compared with PCL-siTCP/Col/BMP2. Also, increased mineralizing tissue within the pores of the scaffold was seen with modified-tetrachrome histology, a result confirmed by µCT, and a modest but detectable increase in both the number and the thickness of ectopic bone structures were observed with the PCL-siTCP/Col/HS3/BMP2 implants. The combination of PCL-siTCP/Col/HS3/BMP2 thus represents a promising avenue for further development as a bone graft alternative for spinal fusion surgery. Copyright © 2017 Elsevier Inc. All rights reserved.

Comparison of neurotoxic effects and potential risks from oral administration or ingestion of tricresyl phosphate and jet engine oil containing tricresyl phosphate.

PubMed

Mackerer, C R; Barth, M L; Krueger, A J; Chawla, B; Roy, T A

1999-07-09

Neurotoxicity of tricresyl phosphates (TCPs) and jet engine oil (JEO) containing TCPs were evaluated in studies conducted in both rat and hen. Results for currently produced samples ("conventional" and "low-toxicity") were compared with published findings on older samples to identify compositional changes and relate those changes to neurotoxic potential. Finally, a human risk assessment for exposure by oral ingestion of currently produced TCPs in JEO at 3% (JEO + 3%) was conducted. TCPs and certain other triaryl phosphates administered as single doses inhibited brain neuropathy target esterase (B-NTE; neurotoxic esterase) in the rat and the hen (hen 3.25 times as sensitive), and both species were deemed acceptable for initial screening purposes. Neither rat nor hen was sensitive enough to detect statistically significant inhibition of B-NTE after single doses of IEO + 3% "conventional" TCP. Subacute administration of 2 g/kg/d of JEO + 3% "conventional" TCP to the hen produced B-NTE inhibition (32%), which did not result in organophosphorus-induced delayed neurotoxicity (OPIDN). Subchronic administration of JEO + 3% TCP but not JEO + 1% TCP at 2 g/kg/d produced OPIDN. Thus, the threshold for OPIDN was between 20 and 60 mg "conventional" TCP/kg/d in JEO for 10 wk. The current "conventional" TCPs used in JEO and new "low-toxicity" TCPs now used in some JEO are synthesized from phenolic mixtures having reduced levels of ortho-cresol and ortho-xylenols resulting in TCPs of very high content of meta- and para-substituted phenyl moieties; this change in composition results in lower toxicity. The "conventional" TCPs still retain enough inhibitory activity to produce OPIDN, largely because of the presence of ortho-xylyl moieties; the "low-toxicity" TCPs are largely devoid of ortho substituents and have extremely low potential to cause OPIDN. The TCPs produced in the 1940s and 1950s were more than 400 times as toxic as the "low-toxicity" TCPs produced today. Analysis of the doses required to produce OPIDN in a subchronic hen study suggests that the minimum toxic dose of "conventional" TCP for producing OPIDN in a 70-kg person would be 280 mg/d, and for JEO containing 3% TCP, 9.4 g/d. Food products could be inadvertently contaminated with neat "conventional" TCP but it is unlikely that food such as cooking oil would be contaminated with enough JEO + 3% TCP to cause toxicity. Further, at the dosage required for neurotoxicity, it would be virtually impossible for a person to receive enough JEO + 3% TCP in the normal workplace (or in an aircraft) to cause such toxicity. There is no record of a JEO formulated with the modern "conventional" TCP causing human neurotoxicity.

Genome-wide identification and expression analysis of TCP transcription factors in Gossypium raimondii.

PubMed

Ma, Jun; Wang, Qinglian; Sun, Runrun; Xie, Fuliang; Jones, Don C; Zhang, Baohong

2014-10-16

Plant-specific TEOSINTE-BRANCHED1/CYCLOIDEA/PCF (TCP) transcription factors play versatile functions in multiple aspects of plant growth and development. However, no systematical study has been performed in cotton. In this study, we performed for the first time the genome-wide identification and expression analysis of the TCP transcription factor family in Gossypium raimondii. A total of 38 non-redundant cotton TCP encoding genes were identified. The TCP transcription factors were divided into eleven subgroups based on phylogenetic analysis. Most TCP genes within the same subfamily demonstrated similar exon and intron organization and the motif structures were highly conserved among the subfamilies. Additionally, the chromosomal distribution pattern revealed that TCP genes were unevenly distributed across 11 out of the 13 chromosomes; segmental duplication is a predominant duplication event for TCP genes and the major contributor to the expansion of TCP gene family in G. raimondii. Moreover, the expression profiles of TCP genes shed light on their functional divergence.

Genome-wide identification and expression analysis of TCP transcription factors in Gossypium raimondii

PubMed Central

Ma, Jun; Wang, Qinglian; Sun, Runrun; Xie, Fuliang; Jones, Don C.; Zhang, Baohong

2014-01-01

Plant-specific TEOSINTE-BRANCHED1/CYCLOIDEA/PCF (TCP) transcription factors play versatile functions in multiple aspects of plant growth and development. However, no systematical study has been performed in cotton. In this study, we performed for the first time the genome-wide identification and expression analysis of the TCP transcription factor family in Gossypium raimondii. A total of 38 non-redundant cotton TCP encoding genes were identified. The TCP transcription factors were divided into eleven subgroups based on phylogenetic analysis. Most TCP genes within the same subfamily demonstrated similar exon and intron organization and the motif structures were highly conserved among the subfamilies. Additionally, the chromosomal distribution pattern revealed that TCP genes were unevenly distributed across 11 out of the 13 chromosomes; segmental duplication is a predominant duplication event for TCP genes and the major contributor to the expansion of TCP gene family in G. raimondii. Moreover, the expression profiles of TCP genes shed light on their functional divergence. PMID:25322260

Roles of miR319 and TCP Transcription Factors in Leaf Development1[OPEN

PubMed Central

2017-01-01

Sophisticated regulation of gene expression, including microRNAs (miRNAs) and their target genes, is required for leaf differentiation, growth, and senescence. The impact of miR319 and its target TEOSINTE BRANCHED1, CYCLOIDEA, and PROLIFERATING CELL NUCLEAR ANTIGEN BINDING FACTOR (TCP) genes on leaf development has been extensively investigated, but the redundancies of these gene families often interfere with the evaluation of their function and regulation in the developmental context. Here, we present the genetic evidence of the involvement of the MIR319 and TCP gene families in Arabidopsis (Arabidopsis thaliana) leaf development. Single mutations in MIR319A and MIR319B genes moderately inhibited the formation of leaf serrations, whereas double mutations increased the extent of this inhibition and resulted in the formation of smooth leaves. Mutations in MIR319 and gain-of-function mutations in the TCP4 gene conferred resistance against miR319 and impaired the cotyledon boundary and leaf serration formation. These mutations functionally associated with CUP-SHAPED COTYLEDON genes, which regulate the cotyledon boundary and leaf serration formation. In contrast, loss-of-function mutations in miR319-targeted and nontargeted TCP genes cooperatively induced the formation of serrated leaves in addition to changes in the levels of their downstream gene transcript. Taken together, these findings demonstrate that the MIR319 and TCP gene families underlie robust and multilayer control of leaf development. This study also provides a framework toward future researches on redundant miRNAs and transcription factors in Arabidopsis and crop plants. PMID:28842549

Roles of miR319 and TCP Transcription Factors in Leaf Development.

PubMed

Koyama, Tomotsugu; Sato, Fumihiko; Ohme-Takagi, Masaru

2017-10-01

Sophisticated regulation of gene expression, including microRNAs (miRNAs) and their target genes, is required for leaf differentiation, growth, and senescence. The impact of miR319 and its target TEOSINTE BRANCHED1 , CYCLOIDEA , and PROLIFERATING CELL NUCLEAR ANTIGEN BINDING FACTOR ( TCP ) genes on leaf development has been extensively investigated, but the redundancies of these gene families often interfere with the evaluation of their function and regulation in the developmental context. Here, we present the genetic evidence of the involvement of the MIR319 and TCP gene families in Arabidopsis ( Arabidopsis thaliana ) leaf development. Single mutations in MIR319A and MIR319B genes moderately inhibited the formation of leaf serrations, whereas double mutations increased the extent of this inhibition and resulted in the formation of smooth leaves. Mutations in MIR319 and gain-of-function mutations in the TCP4 gene conferred resistance against miR319 and impaired the cotyledon boundary and leaf serration formation. These mutations functionally associated with CUP-SHAPED COTYLEDON genes, which regulate the cotyledon boundary and leaf serration formation. In contrast, loss-of-function mutations in miR319-targeted and nontargeted TCP genes cooperatively induced the formation of serrated leaves in addition to changes in the levels of their downstream gene transcript. Taken together, these findings demonstrate that the MIR319 and TCP gene families underlie robust and multilayer control of leaf development. This study also provides a framework toward future researches on redundant miRNAs and transcription factors in Arabidopsis and crop plants. © 2017 American Society of Plant Biologists. All Rights Reserved.

Novel functions of the Arabidopsis transcription factor TCP5 in petal development and ethylene biosynthesis.

PubMed

van Es, Sam W; Silveira, Sylvia R; Rocha, Diego I; Bimbo, Andrea; Martinelli, Adriana P; Dornelas, Marcelo C; Angenent, Gerco C; Immink, Richard G H

2018-06-01

The flowers of most dicotyledons have petals that, together with the sepals, initially protect the reproductive organs. Later during development petals are required to open the flower and to attract pollinators. This diverse set of functions demands tight temporal and spatial regulation of petal development. We studied the functioning of the Arabidopsis thaliana TCP5-like transcription factors (TFs) in petals. Overexpression of TCP5 in petal epidermal cells results in smaller petals, whereas tcp5 tcp13 tcp17 triple knockout lines have wider petals with an increased surface area. Comprehensive expression studies revealed effects of TCP5-like TFs on the expression of genes related to the cell cycle, growth regulation and organ growth. Additionally, the ethylene biosynthesis genes 1-amino-cyclopropane-1-carboxylate (ACC) synthase 2 (ACS2) and ACC oxidase 2 (ACO2) and several ETHYLENE RESPONSE FACTORS (ERFs) are found to be differentially expressed in TCP5 mutant and overexpression lines. Chromatin immunoprecipitation-quantitative PCR showed direct binding of TCP5 to the ACS2 locus in vivo. Ethylene is known to influence cell elongation, and the petal phenotype of the tcp5 tcp13 tcp17 mutant could be complemented by treatment of the plants with an ethylene pathway inhibitor. Taken together, this reveals a novel role for TCP5-like TFs in the regulation of ethylene-mediated petal development and growth. © 2018 The Authors The Plant Journal published by John Wiley & Sons Ltd and Society for Experimental Biology.

Adsorption of 1,2,3-Trichloropropane (TCP) to meet a MCL of 5 ppt.

PubMed

Babcock, Roger W; Harada, Bryce K; Lamichhane, Krishna M; Tsubota, Korey T

2018-02-01

1,2,3-Trichloropropane (TCP) is a groundwater contaminant in the drinking water aquifers in Hawaii and some other states. Granular activated carbon (GAC) has been used for 30 years to treat approximately 60 million gallons per day of TCP-contaminated groundwater in Hawaii. The State of Hawaii's current maximum contaminant level (MCL) for TCP is 600 ng/L (ppt), and consideration is being given to lower the MCL to 5 ppt. There is no EPA MCL for TCP. A study was conducted to determine if any GAC could meet a 5 ppt MCL for TCP, and if so, how many bedvolumes (BVs) could be treated prior to breakthrough. Constant Diffusivity-Rapid Small-Scale Column Tests (CD-RSSCTs) were performed to evaluate GAC adsorption of TCP. Three different groundwaters and six different GACs were utilized. The RSSCTs with the currently-utilized GAC were predictive of the performance of the GAC contactors (50,000 BVs to breakthrough). Any of the six GACs could meet a MCL of 5 ppt and some could do so for 150,000 or more BVs. No single GAC was optimal for all three well sites, indicating effects of subtle undefined differences in the water matrix and/or GAC physiochemical properties. The coal-based direct-activated carbon currently being used is the least optimal for all three well sites with respect to meeting a potential new TCP MCL of 5 ppt. The most effective GACs for Kunia were the Calgon coal-based GAC and the Siemens enhanced coconut shell GAC, while the most effective for Waipahu were the Siemens regular and enhanced coconut shell GACs, and the most effective for Mililani was the Calgon coal-based GAC. Choosing just one GAC for use at all three well sites (rather than the optimal for each site) would result in a reduction of treatment run time of 1 year at one well site (63% reduction). Copyright © 2017 Elsevier Ltd. All rights reserved.

Is the foot elevation the optimal position for wound healing of a diabetic foot?

PubMed

Park, D J; Han, S K; Kim, W K

2010-03-01

In managing diabetic foot ulcers, foot elevation has generally been recommended to reduce oedema and prevent other sequential problems. However, foot elevation may decrease tissue oxygenation of the foot more than the dependent position since the dependent position is known to increase blood flow within the arterial system. In addition, diabetic foot ulcers, which have peripheral vascular insufficiency, generally have less oedema than other wounds. Therefore, we argue that foot elevation may not be helpful for healing of vascularly compromised diabetic foot ulcers since adequate tissue oxygenation is an essential factor in diabetic wound healing. The purpose of this study was to evaluate the influence of foot height on tissue oxygenation and to determine the optimal foot position to accelerate wound healing of diabetic foot ulcers. This study included 122 cases (73 males and 47 females; two males had bilateral disease) of diabetic foot ulcer patients aged 40-93 years. Trans-cutaneous partial oxygen tension (TcpO(2)) values of diabetic feet were measured before and after foot elevation (n=21). Elevation was achieved by placing a foot over four cushions. We also measured foot TcpO(2) values before and after lowering the feet (n=122). Feet were lowered to the patient's tibial height, approximately 30-35 cm, beside a bed handrail. Due to the large number of lowering measurements, we divided them into five sub-groups according to initial TcpO(2.) Tissue oxygenation values were compared. Foot-elevation-lowered TcpO(2) values before and after elevation were 32.5+/-22.2 and 23.8+/-23.1 mmHg (p<0.01), respectively. Foot-lowering-augmented TcpO(2) values before and after lowering were 44.6+/-23.8 and 58.0+/-25.9 mmHg (p<0.01), respectively. The lower the initial TcpO(2) level, the more the TcpO(2) level increased. The foot lowering, rather than elevation, significantly augments TcpO(2) and may stimulate healing of diabetic foot ulcers. (c) 2008 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Effect of Alendronate with β - TCP Bone Substitute in Surgical Therapy of Periodontal Intra-Osseous Defects: A Randomized Controlled Clinical Trial.

PubMed

Naineni, Rohini; Ravi, Vishali; Subbaraya, Dwijendra Kocherlakota; Prasanna, Jammula Surya; Panthula, Veerendranath Reddy; Koduganti, Rekha Rani

2016-08-01

Alendronate (ALN), an aminobisphosphonate, inhibits osteoclastic bone resorption and also stimulates osteogenesis. Beta-Tricalcium Phosphate (β-TCP) is an osteoconductive graft material which provides a scaffold for bone formation and also a widely used drug delivery vehicle for growth factors and antibiotics. Drug delivery vehicles, like β-TCP, improve the potency of the drugs by specific local site delivery of the drug, optimal release characteristics and easy handling. The aim of the this study was to evaluate the bone formation potential of 400μg ALN delivered in β-TCP in the treatment of periodontal intra-osseous defects. Thirty patients with periodontal defects were randomly assigned to 400μg ALN + β-TCP + Saline (test) group and β-TCP + Saline (active-control) group. Clinical parameters like Clinical Attachment Level (CAL) gain, Probing Depth (PD) reduction, post-operative Gingival Recession (GR) were assessed from the baseline, 3 months and 6 months recordings. Radiographic parameters like Linear Bone Growth (LBG), Percentage Bone Fill (%BF), and change in alveolar crest height (ACH) were assessed from baseline and 6 months radiographs. Mean measurements in the ALN test group for CAL gain (3.4 ± 0.74 mm), PD reduction (4.33 ± 0.82 mm), LBG (2.88 ± 0.88 mm), and %BF (51.98 ± 15.84%) were significantly greater with a p-value <0.05 compared to the mean measurements of CAL gain (2.20 ± 0.86 mm), PD reduction (3.20 ± 1.15 mm), LBG (1.70 ± 0.39 mm), and %BF (30.35 ± 6.88%) of the control group. There was mild alveolar crestal apposition (0.32 ± 0.68 mm) in the ALN test group and mild alveolar crestal resorption (-0.24 ± 0.40 mm) in the control group. 400μg ALN combined with β-TCP bone graft material was effective in improving soft tissue parameters, inhibiting alveolar crestal resorption and enhancing bone formation, compared to β-TCP alone.

Paradoxical tunnel enlargement after ACL reconstruction with hamstring autografts when using β-TCP containing interference screws for tibial aperture fixation- prospectively comparative study.

PubMed

Wang, Joon Ho; Lee, Eun Su; Lee, Byung Hoon

2017-09-16

Tibial aperture fixation with a bioabsorbable interference screw is a popular fixation method in anterior cruciate ligament reconstruction (ACLR). An interference screw containing β-tricalcium phosphate (β-TCP) to improve bony integration and biocompatibility was recently introduced. This study aims to compare the clinical outcomes and radiological results of tunnel enlargement effect between the 2 bioabsorbable fixative devices of pure poly-L-lactic acid (PLLA) interference screws and β-TCP-containing screws, for tibial interference fixation in ACLR using hamstring autografts. Eighty consecutive patients who had undergone double-bundle ACLR between 2011 to 2012 were prospectively reviewed and randomly divided into two groups based on the type of tibial interference screw: 28 were assigned to the pure PLLA screw group (Group A), while the other 29 were assigned to the β-TCP-containing screw fixation group (Group B). Clinical evaluations and radiological analyses were conducted in both groups with a minimum 2- year follow-up. There was no significant difference in subjective or objective clinical outcome between the 2 groups. In radiological analyses, the use of a β-TCP-containing screw reduced tunnel widening in the portion of the tunnel with screw engagement compared to the pure PLLA screw, while the use of a β-TCP-containing screw resulted in greater tunnel enlargement in the proximal portion of the tunnel without screw engagement than use of a pure PLLA screw. Use of a β-TCP-containing interference screw in tibial aperture fixation reduced tunnel enlargement in the vicinity of the screw, whereas greater enlargement occurred proximal to the screw end relative to use of a pure PLLA interference screw. These paradoxical enlargements in use of β-TCP containing screws suggest that for reducing tunnel enlargement, the length of the interference screw should be as fit as possible with tunnel length in terms of using soft grafts. II, Prospectively comparative study. Retrospectively registered with ClinicalTrials.gov. (NCT02754674) , Date of trial registration: February 10, 2016.

Laser Doppler Flowmetry and Transcutaneous Oximetry in Chronic Skin Ulcers: A Comparative Evaluation.

PubMed

Raposio, Edoardo; Bertozzi, Nicolò; Moretti, Rebecca; Grignaffini, Eugenio; Grieco, Michele P

2017-07-01

Laser Doppler Flowmetry (LDF) and transcutaneous oximetry (TcpO2) are established methods for investigating cutaneous perfusion. To date, no study previously performed has compared data obtained from these 2 methodologies in cases of chronic cutaneous ulcers. Laser Doppler Flowmetry and TcpO2 were performed in 25 consecutive outpatients with chronic lower limb ulcers (group A, experimental; 9 women and 16 men; mean age 67 years [range, 52-81 years]) and 25 age- and sex-matched healthy control subjects (group B, control) enrolled for the study. Ulcer aetiologies included 12 peripheral arterial occlusive disease, 9 chronic venous insufficiencies, and 4 pressure ulcers. Data were analyzed with Shapiro-Wilk and Wilcoxon-Mann-Whitney tests. A statistically significant difference (P < .05) was found between LDF values of the 2 groups. No statistically significant differences were found between the 2 groups regarding the TcpO2 measurements. The data confirmed the soundness of LDF while investigating local perfusion in patients with chronic cutaneous ulcers. The same diagnostic accuracy was not obtained by means of TcpO2.

Identification, cloning and characterization of the tomato TCP transcription factor family.

PubMed

Parapunova, Violeta; Busscher, Marco; Busscher-Lange, Jacqueline; Lammers, Michiel; Karlova, Rumyana; Bovy, Arnaud G; Angenent, Gerco C; de Maagd, Ruud A

2014-06-06

TCP proteins are plant-specific transcription factors, which are known to have a wide range of functions in different plant species such as in leaf development, flower symmetry, shoot branching, and senescence. Only a small number of TCP genes has been characterised from tomato (Solanum lycopersicum). Here we report several functional features of the members of the entire family present in the tomato genome. We have identified 30 Solanum lycopersicum SlTCP genes, most of which have not been described before. Phylogenetic analysis clearly distinguishes two homology classes of the SlTCP transcription factor family - class I and class II. Class II differentiates in two subclasses, the CIN-TCP subclass and the CYC/TB1 subclass, involved in leaf development and axillary shoots formation, respectively. The expression patterns of all members were determined by quantitative PCR. Several SlTCP genes, like SlTCP12, SlTCP15 and SlTCP18 are preferentially expressed in the tomato fruit, suggesting a role during fruit development or ripening. These genes are regulated by RIN (RIPENING INHIBITOR), CNR (COLORLESS NON-RIPENING) and SlAP2a (APETALA2a) proteins, which are transcription factors with key roles in ripening. With a yeast one-hybrid assay we demonstrated that RIN binds the promoter fragments of SlTCP12, SlTCP15 and SlTCP18, and that CNR binds the SlTCP18 promoter. This data strongly suggests that these class I SlTCP proteins are involved in ripening. Furthermore, we demonstrate that SlTCPs bind the promoter fragments of members of their own family, indicating that they regulate each other. Additional yeast one-hybrid studies performed with Arabidopsis transcription factors revealed binding of the promoter fragments by proteins involved in the ethylene signal transduction pathway, contributing to the idea that these SlTCP genes are involved in the ripening process. Yeast two-hybrid data shows that SlTCP proteins can form homo and heterodimers, suggesting that they act together in order to form functional protein complexes and together regulate developmental processes in tomato. The comprehensive analysis we performed, like phylogenetic analysis, expression studies, identification of the upstream regulators and the dimerization specificity of the tomato TCP transcription factor family provides the basis for functional studies to reveal the role of this family in tomato development.

Identification, cloning and characterization of the tomato TCP transcription factor family

PubMed Central

2014-01-01

Background TCP proteins are plant-specific transcription factors, which are known to have a wide range of functions in different plant species such as in leaf development, flower symmetry, shoot branching, and senescence. Only a small number of TCP genes has been characterised from tomato (Solanum lycopersicum). Here we report several functional features of the members of the entire family present in the tomato genome. Results We have identified 30 Solanum lycopersicum SlTCP genes, most of which have not been described before. Phylogenetic analysis clearly distinguishes two homology classes of the SlTCP transcription factor family - class I and class II. Class II differentiates in two subclasses, the CIN-TCP subclass and the CYC/TB1 subclass, involved in leaf development and axillary shoots formation, respectively. The expression patterns of all members were determined by quantitative PCR. Several SlTCP genes, like SlTCP12, SlTCP15 and SlTCP18 are preferentially expressed in the tomato fruit, suggesting a role during fruit development or ripening. These genes are regulated by RIN (RIPENING INHIBITOR), CNR (COLORLESS NON-RIPENING) and SlAP2a (APETALA2a) proteins, which are transcription factors with key roles in ripening. With a yeast one-hybrid assay we demonstrated that RIN binds the promoter fragments of SlTCP12, SlTCP15 and SlTCP18, and that CNR binds the SlTCP18 promoter. This data strongly suggests that these class I SlTCP proteins are involved in ripening. Furthermore, we demonstrate that SlTCPs bind the promoter fragments of members of their own family, indicating that they regulate each other. Additional yeast one-hybrid studies performed with Arabidopsis transcription factors revealed binding of the promoter fragments by proteins involved in the ethylene signal transduction pathway, contributing to the idea that these SlTCP genes are involved in the ripening process. Yeast two-hybrid data shows that SlTCP proteins can form homo and heterodimers, suggesting that they act together in order to form functional protein complexes and together regulate developmental processes in tomato. Conclusions The comprehensive analysis we performed, like phylogenetic analysis, expression studies, identification of the upstream regulators and the dimerization specificity of the tomato TCP transcription factor family provides the basis for functional studies to reveal the role of this family in tomato development. PMID:24903607

Bone augmentation using a highly porous PLGA/β-TCP scaffold containing fibroblast growth factor-2.

PubMed

Yoshida, T; Miyaji, H; Otani, K; Inoue, K; Nakane, K; Nishimura, H; Ibara, A; Shimada, A; Ogawa, K; Nishida, E; Sugaya, T; Sun, L; Fugetsu, B; Kawanami, M

2015-04-01

Beta-tricalcium phosphate (β-TCP), a bio-absorbable ceramic, facilitates bone conductivity. We constructed a highly porous three-dimensional scaffold, using β-TCP, for bone tissue engineering and coated it with co-poly lactic acid/glycolic acid (PLGA) to improve the mechanical strength and biological performance. The aim of this study was to examine the effect of implantation of the PLGA/β-TCP scaffold loaded with fibroblast growth factor-2 (FGF-2) on bone augmentation. The β-TCP scaffold was fabricated by the replica method using polyurethane foam, then coated with PLGA. The PLGA/β-TCP scaffold was characterized by scanning electron miscroscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction, compressive testing, cell culture and a subcutaneous implant test. Subsequently, a bone-forming test was performed using 52 rats. The β-TCP scaffold, PLGA-coated scaffold, and β-TCP and PLGA-coated scaffolds loaded with FGF-2, were implanted into rat cranial bone. Histological observations were made at 10 and 35 d postsurgery. SEM and TEM observations showed a thin PLGA layer on the β-TCP particles after coating. High porosity (> 90%) of the scaffold was exhibited after PLGA coating, and the compressive strength of the PLGA/β-TCP scaffold was six-fold greater than that of the noncoated scaffold. Good biocompatibility of the PLGA/β-TCP scaffold was found in the culture and implant tests. Histological samples obtained following implantation of PLGA/β-TCP scaffold loaded with FGF-2 showed significant bone augmentation. The PLGA coating improved the mechanical strength of β-TCP scaffolds while maintaining high porosity and tissue compatibility. PLGA/β-TCP scaffolds, in combination with FGF-2, are bioeffective for bone augmentation. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

TCP10L acts as a tumor suppressor by inhibiting cell proliferation in hepatocellular carcinoma

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

Zuo, Jie; Cai, Hao; Wu, Yanhua

2014-03-28

Highlights: • TCP10L was down-regulated in clinical hepatocellular carcinoma (HCC). • Expression of TCP10L correlated significantly with tumor size and Milan criteria. • Overexpression of TCP10L attenuated growth of HCC cells both in vitro and in vivo. • Knocking down TCP10L promoted cell proliferation and tumorigenesis of HCC cells. - Abstract: TCP10L (T-complex 10 (mouse)-like) has been identified as a liver and testis-specific gene. Although a potential transcriptional suppression function of TCP10L has been reported previously, biological function of this gene still remains largely elusive. In this study, we reported for the first time that TCP10L was significantly down-regulated inmore » clinical hepatocellular carcinoma (HCC) samples when compared to the corresponding non-tumorous liver tissues. Furthermore, TCP10L expression was highly correlated with advanced cases exceeding the Milan criteria. Overexpression of TCP10L in HCC cells suppressed colony formation, inhibited cell cycle progression through G0/G1 phase, and attenuated cell growth in vivo. Consistently, silencing of TCP10L promoted cell cycle progression and cell growth. Therefore, our study has revealed a novel suppressor role of TCP10L in HCC, by inhibiting proliferation of HCC cells, which may facilitate the diagnosis and molecular therapy in HCC.« less

Genome-wide identification and expression analysis of the ClTCP transcription factors in Citrullus lanatus.

PubMed

Shi, Pibiao; Guy, Kateta Malangisha; Wu, Weifang; Fang, Bingsheng; Yang, Jinghua; Zhang, Mingfang; Hu, Zhongyuan

2016-04-12

The plant-specific TCP transcription factor family, which is involved in the regulation of cell growth and proliferation, performs diverse functions in multiple aspects of plant growth and development. However, no comprehensive analysis of the TCP family in watermelon (Citrullus lanatus) has been undertaken previously. A total of 27 watermelon TCP encoding genes distributed on nine chromosomes were identified. Phylogenetic analysis clustered the genes into 11 distinct subgroups. Furthermore, phylogenetic and structural analyses distinguished two homology classes within the ClTCP family, designated Class I and Class II. The Class II genes were differentiated into two subclasses, the CIN subclass and the CYC/TB1 subclass. The expression patterns of all members were determined by semi-quantitative PCR. The functions of two ClTCP genes, ClTCP14a and ClTCP15, in regulating plant height were confirmed by ectopic expression in Arabidopsis wild-type and ortholog mutants. This study represents the first genome-wide analysis of the watermelon TCP gene family, which provides valuable information for understanding the classification and functions of the TCP genes in watermelon.

RNS60, a charge-stabilized nanostructure saline alters Xenopus Laevis oocyte biophysical membrane properties by enhancing mitochondrial ATP production

PubMed Central

Choi, Soonwook; Yu, Eunah; Kim, Duk-Soo; Sugimori, Mutsuyuki; Llinás, Rodolfo R

2015-01-01

We have examined the effects of RNS60, a 0.9% saline containing charge-stabilized oxygen nanobubble-based structures. RNS60 is generated by subjecting normal saline to Taylor–Couette–Poiseuille (TCP) flow under elevated oxygen pressure. This study, implemented in Xenopus laevis oocytes, addresses both the electrophysiological membrane properties and parallel biological processes in the cytoplasm. Intracellular recordings from defolliculated X. laevis oocytes were implemented in: (1) air oxygenated standard Ringer's solution, (2) RNS60-based Ringer's solution, (3) RNS10.3 (TCP-modified saline without excess oxygen)-based Ringer's, and (4) ONS60 (saline containing high pressure oxygen without TCP modification)-based Ringer's. RNS60-based Ringer's solution induced membrane hyperpolarization from the resting membrane potential. This effect was prevented by: (1) ouabain (a blocker of the sodium/potassium ATPase), (2) rotenone (a mitochondrial electron transfer chain inhibitor preventing usable ATP synthesis), and (3) oligomycin A (an inhibitor of ATP synthase) indicating that RNS60 effects intracellular ATP levels. Increased intracellular ATP levels following RNS60 treatment were directly demonstrated using luciferin/luciferase photon emission. These results indicate that RNS60 alters intrinsic the electrophysiological properties of the X. laevis oocyte membrane by increasing mitochondrial-based ATP synthesis. Ultrastructural analysis of the oocyte cytoplasm demonstrated increased mitochondrial length in the presence of RNS60-based Ringer's solution. It is concluded that the biological properties of RNS60 relate to its ability to optimize ATP synthesis. PMID:25742953

Effects of polycaprolactone-tricalcium phosphate, recombinant human bone morphogenetic protein-2 and dog mesenchymal stem cells on bone formation: pilot study in dogs.

PubMed

Kim, Sun-Jong; Kim, Myung-Rae; Oh, Jin-Sub; Han, Inho; Shin, Sang-Wan

2009-12-31

The aim of this study was to evaluate the survival, proliferation, and bone formation of dog mesenchymal stem cells (dMSCs) in the graft material by using Polycaprolactone-tricalcium phosphate (PCL-TCP), auto-fibrin glue (AFG), recombinant human bone morphogenetic protein-2 (rhBMP-2), and dMSCs after a transplantation to the scapula of adult beagle dogs. The subjects were two beagle dogs. Total dose of rhBMP-2 on each block was 10 microg with 50 microg/mg concentration. The cortical bone of the scapula of the dog was removed which was the same size of PCL-TCP block (Osteopore International Pte, Singapore; 5.0x5.0x8.0 mm in size), and the following graft material then was fixed with orthodontic mini-implant, Dual-top (Titanium alloy, Jeil Co. Seoul, Korea). Four experimental groups were prepared for this study, Group 1: PCL-TCP + aFG; Group 2: PCL-TCP + aFG + dMSCs; Group 3: PCL-TCP + aFG + dMSCs + rhBMP-2; Group 4: PCL-TCP + aFG + dMSCs + rhBMP-2 + PCL membrane. The survival or proliferation of dMSCs cells was identified with an extracted tissue through a fluorescence microscope, H-E staining and Von-Kossa staining in two weeks and four weeks after the transplantation. The survival and proliferation of dMSCs were identified through a fluorescence microscope from both Group 1 and Group 2 in two weeks and four weeks after the transplantation. Histological observation also found that the injected cells were proliferating well in the G2, G3, and G4 scaffolds. This study concluded that bone ingrowth occurred in PCL-TCP scaffold which was transplanted with rhBMP-2, and MSCs did not affect bone growth. More sufficient healing time would be needed to recognize effects of dMSCs on bone formation.

Incorporation of RANKL promotes osteoclast formation and osteoclast activity on β-TCP ceramics.

PubMed

Choy, John; Albers, Christoph E; Siebenrock, Klaus A; Dolder, Silvia; Hofstetter, Wilhelm; Klenke, Frank M

2014-12-01

β-Tricalcium phosphate (β-TCP) ceramics are approved for the repair of osseous defects. In large defects, however, the substitution of the material by authentic bone is inadequate to provide sufficient long-term mechanical stability. We aimed to develop composites of β-TCP ceramics and receptor activator of nuclear factor κ-B ligand (RANKL) to enhance the formation of osteoclasts and promote cell mediated calcium phosphate resorption. RANKL was adsorbed superficially onto β-TCP ceramics or incorporated into a crystalline layer of calcium phosphate by the use of a co-precipitation technique. Murine osteoclast precursors were seeded onto the ceramics. After 15 days, the formation of osteoclasts was quantified cytologically and colorimetrically with tartrate-resistant acidic phosphatase (TRAP) staining and TRAP activity measurements, respectively. Additionally, the expression of transcripts encoding the osteoclast gene products cathepsin K, calcitonin receptor, and of the sodium/hydrogen exchanger NHA2 were quantified by real-time PCR. The activity of newly formed osteoclasts was evaluated by means of a calcium phosphate resorption assay. Superficially adsorbed RANKL did not induce the formation of osteoclasts on β-TCP ceramics. When co-precipitated onto β-TCP ceramics RANKL supported the formation of mature osteoclasts. The development of osteoclast lineage cells was further confirmed by the increased expression of cathepsin K, calcitonin receptor, and NHA2. Incorporated RANKL stimulated the cells to resorb crystalline calcium phosphate. Our in vitro study shows that RANKL incorporated into β-TCP ceramics induces the formation of active, resorbing osteoclasts on the material surface. Once formed, osteoclasts mediate the release of RANKL thereby perpetuating their differentiation and activation. In vivo, the stimulation of osteoclast-mediated resorption may contribute to a coordinated sequence of material resorption and bone formation. Further in vivo studies are needed to confirm the current in vitro findings. Copyright © 2014 Elsevier Inc. All rights reserved.

SU-E-J-30: Benchmark Image-Based TCP Calculation for Evaluation of PTV Margins for Lung SBRT Patients

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

Li, M; Chetty, I; Zhong, H

2014-06-01

Purpose: Tumor control probability (TCP) calculated with accumulated radiation doses may help design appropriate treatment margins. Image registration errors, however, may compromise the calculated TCP. The purpose of this study is to develop benchmark CT images to quantify registration-induced errors in the accumulated doses and their corresponding TCP. Methods: 4DCT images were registered from end-inhale (EI) to end-exhale (EE) using a “demons” algorithm. The demons DVFs were corrected by an FEM model to get realistic deformation fields. The FEM DVFs were used to warp the EI images to create the FEM-simulated images. The two images combined with the FEM DVFmore » formed a benchmark model. Maximum intensity projection (MIP) images, created from the EI and simulated images, were used to develop IMRT plans. Two plans with 3 and 5 mm margins were developed for each patient. With these plans, radiation doses were recalculated on the simulated images and warped back to the EI images using the FEM DVFs to get the accumulated doses. The Elastix software was used to register the FEM-simulated images to the EI images. TCPs calculated with the Elastix-accumulated doses were compared with those generated by the FEM to get the TCP error of the Elastix registrations. Results: For six lung patients, the mean Elastix registration error ranged from 0.93 to 1.98 mm. Their relative dose errors in PTV were between 0.28% and 6.8% for 3mm margin plans, and between 0.29% and 6.3% for 5mm-margin plans. As the PTV margin reduced from 5 to 3 mm, the mean TCP error of the Elastix-reconstructed doses increased from 2.0% to 2.9%, and the mean NTCP errors decreased from 1.2% to 1.1%. Conclusion: Patient-specific benchmark images can be used to evaluate the impact of registration errors on the computed TCPs, and may help select appropriate PTV margins for lung SBRT patients.« less

SU-E-T-471: Improvement of Gamma Knife Treatment Planning Through Tumor Control Probability for Metastatic Brain Tumors

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

Huang, Z; Feng, Y; Lo, S

2015-06-15

Purpose: The dose–volume histogram (DVH) has been normally accepted as a tool for treatment plan evaluation. However, spatial information is lacking in DVH. As a supplement to the DVH in three-dimensional treatment planning, the differential DVH (DDVH) provides the spatial variation, the size and magnitude of the different dose regions within a region of interest, which can be incorporated into tumor control probability model. This study was to provide a method in evaluating and improving Gamma Knife treatment planning. Methods: 10 patients with brain metastases from different primary tumors including melanoma (#1,#4,#5, #10), breast cancer (#2), prostate cancer (#3) andmore » lung cancer (#6–9) were analyzed. By using Leksell GammaPlan software, two plans were prepared for each patient. Special attention was given to the DDVHs that were different for different plans and were used for a comparison between two plans. Dose distribution inside target and tumor control probability (TCP) based on DDVH were calculated, where cell density and radiobiological parameters were adopted from literature. The plans were compared based on DVH, DDVH and TCP. Results: Using DVH, the coverage and selectivity were the same between plans for 10 patients. DDVH were different between two plans for each patient. The paired t-test showed no significant difference in TCP between the two plans. For brain metastases from melanoma (#1, #4–5), breast cancer (#2) and lung cancer (#6–8), the difference in TCP was less than 5%. But the difference in TCP was about 6.5% for patient #3 with the metastasis from prostate cancer, 10.1% and 178.7% for two patients (#9–10) with metastasis from lung cancer. Conclusion: Although DVH provides average dose–volume information, DDVH provides differential dose– volume information with respect to different regions inside the tumor. TCP provides radiobiological information and adds additional information on improving treatment planning as well as adaptive radiotherapy. Further clinical validation is necessary.« less

Osteoclastogenesis and Osteoclastic Resorption of Tricalcium Phosphate: Effect of Strontium and Magnesium Doping

PubMed Central

Roy, Mangal; Bose, Susmita

2012-01-01

Bone substitute materials are required to support the remodeling process, which consists of osteoclastic resorption and osteoblastic synthesis. Osteoclasts, the bone resorbing cells, generate from differentiation of hemopoietic mononuclear cells. In the present study we have evaluated the effects of 1.0 wt% strontium (Sr) and 1.0 wt% magnesium (Mg) doping in beta-tricalcium phosphate (β-TCP) on the differentiation of mononuclear cells into osteoclast-like cells and its resorptive activity. In vitro osteoclast-like cell formation, adhesion, and resorption were studied using osteoclast precursor RAW 264.7 cell, supplemented with receptor activator of nuclear factor κβ ligand (RANKL). Osteoclast-like cell formation was noticed on pure and Sr doped β-TCP samples at day 8 which was absent on Mg doped β-TCP samples indicating decrease in initial osteoclast differentiation due to Mg doping. After 21 days of culture, osteoclast-like cell formation was evident on all samples with osteoclastic markers such as actin ring, multiple nuclei, and presence of vitronectin receptor αvβ3 integrin. After osteoclast differentiation, all substrates showed osteoclast-like cell mediated degradation, however; significantly restricted for Mg doped β-TCP samples. Our present results indicated substrate chemistry controlled osteoclast differentiation and resorptive activity which can be used in designing TCP based resorbable bone substitutes with controlled degradation properties. PMID:22566212

Osteoclastogenesis and osteoclastic resorption of tricalcium phosphate: effect of strontium and magnesium doping.

PubMed

Roy, Mangal; Bose, Susmita

2012-09-01

Bone substitute materials are required to support the remodeling process, which consists of osteoclastic resorption and osteoblastic synthesis. Osteoclasts, the bone-resorbing cells, generate from differentiation of hemopoietic mononuclear cells. In the present study, we have evaluated the effects of 1.0 wt % strontium (Sr) and 1.0 wt % magnesium (Mg) doping in beta-tricalcium phosphate (β-TCP) on the differentiation of mononuclear cells into osteoclast-like cells and its resorptive activity. In vitro osteoclast-like cell formation, adhesion, and resorption were studied using osteoclast precursor RAW 264.7 cell, supplemented with receptor activator of nuclear factor κβ ligand (RANKL). Osteoclast-like cell formation was noticed on pure and Sr-doped β-TCP samples at day 8, which was absent on Mg-doped β-TCP samples indicating decrease in initial osteoclast differentiation due to Mg doping. After 21 days of culture, osteoclast-like cell formation was evident on all samples with osteoclastic markers such as actin ring, multiple nuclei, and presence of vitronectin receptor α(v)β(3) integrin. After osteoclast differentiation, all substrates showed osteoclast-like cell-mediated degradation, however, significantly restricted for Mg-doped β-TCP samples. Our present results indicated that substrate chemistry controlled osteoclast differentiation and resorptive activity, which can be used in designing TCP-based resorbable bone substitutes with controlled degradation properties. Copyright © 2012 Wiley Periodicals, Inc.

Using Machine Learning for Behavior-Based Access Control: Scalable Anomaly Detection on TCP Connections and HTTP Requests

DTIC Science & Technology

2013-11-01

machine learning techniques used in BBAC to make predictions about the intent of actors establishing TCP connections and issuing HTTP requests. We discuss pragmatic challenges and solutions we encountered in implementing and evaluating BBAC, discussing (a) the general concepts underlying BBAC, (b) challenges we have encountered in identifying suitable datasets, (c) mitigation strategies to cope...and describe current plans for transitioning BBAC capabilities into the Department of Defense together with lessons learned for the machine learning

The thermal stability of hydroxyapatite in biphasic calcium phosphate ceramics.

PubMed

Nilen, R W N; Richter, P W

2008-04-01

Biphasic calcium phosphate ceramics (BCP) comprising a mix of non-resorbable hydroxyapatite (HA) and resorbable beta-tricalcium phosphate (beta-TCP) are particularly suitable materials for synthetic bone substitute applications. In this study, HA synthesised by solid state reaction was mechanically mixed with beta-TCP, then sintered to form a suite of BCP materials with a wide range of HA/beta-TCP phase content ratios. The influence of sintering temperature and composition on the HA thermal stability was quantified by X-ray diffraction (XRD). The pre-sinter beta-TCP content was found to strongly affect the post-sinter HA/beta-TCP ratio by promoting the thermal decomposition of HA to beta-TCP, even at sintering temperatures as low as 850 degrees C. For BCP material with pre-sinter HA/beta-TCP = 40/60 wt%, approximately 80% of the HA decomposed to beta-TCP during sintering at 1000 degrees C. Furthermore, the HA content appeared to influence the reverse transformation of alpha-TCP to beta-TCP expected upon gradual cooling from sintering temperatures greater than 1125 degrees C. Because the HA/beta-TCP ratio dominantly determines the rate and extent of BCP resorption in vivo, the possible thermal decomposition of HA during BCP synthesis must be considered, particularly if high temperature treatments are involved.

North Atlantic Tropical Cyclone Precipitation and Climate Interactions Using a High-Resolution Dataset for the Eastern United States, 1948-2015.

NASA Astrophysics Data System (ADS)

Bregy, J. C.; Maxwell, J. T.; Robeson, S. M.

2017-12-01

Tropical cyclone (TC) impacts are typically concentrated along the coast, yet some TC hazards have wider spatial distributions and affect inland regions. For example, large volumes of TC precipitation (TCP) can cause severe inland flooding, initiate slope failure, and create large sinkholes. Previous studies show that TCP contributes substantially to seasonal precipitation budgets in the eastern United States. However, present knowledge of TCP climatology in the US is limited by the spatial coverage of weather stations. Here we develop a new high resolution (0.25°x0.25°) TCP climatology using HURDAT2 and CPC US Unified Precipitation data (1948-2015). From June to November (JJASON), maximum total TCP for the study period ranges from 2200 to 3800 mm along much of the coast and decreases inland. Likewise, spatial patterns of TCP contribution to total JJASON precipitation largely mirror those of total TCP, with maxima (6-8%) located in coastal Texas and North Carolina. Similar spatial patterns are seen in the mean JJASON TCP and mean TCP contribution over the study period, with maxima extending beyond coastal Texas and North Carolina. JJASON TCP (total, mean, and contribution) was correlated with mean annual JJASON values for the Bermuda High Index (BHI), El Niño-Southern Oscillation combined Niño3.4/Southern Oscillation Index (ENSO-BEST), and North Atlantic Oscillation (NAO). Correlations between climate indices and JJASON TCP show the degree to which BHI, ENSO-BEST, and NAO influence spatiotemporal changes in TCP. Of the three indices, the BHI had the strongest and most spatially consistent correlation with TCP, with significant correlations in the interior of the southeast. These results indicate a strong regional relationship between the North Atlantic Subtropical High (NASH; represented by the BHI) and regional TCP distribution. TCP distribution depends on TC track direction, and is therefore connected to the NASH, which acts as a steering mechanism for TCs. Our derived high resolution TCP climatology further aids our understanding of TC-climate interactions. Moreover, it can be used to understand hazards associated with TCs, serving as an invaluable tool in hazard mitigation efforts.

Hierarchical bioceramic scaffolds with 3D-plotted macropores and mussel-inspired surface nanolayers for stimulating osteogenesis

NASA Astrophysics Data System (ADS)

Xu, Mengchi; Zhai, Dong; Xia, Lunguo; Li, Hong; Chen, Shiyi; Fang, Bing; Chang, Jiang; Wu, Chengtie

2016-07-01

The hierarchical structure of biomaterials plays an important role in the process of tissue reconstruction and regeneration. 3D-plotted scaffolds have been widely used for bone tissue engineering due to their controlled macropore structure and mechanical properties. However, the lack of micro- or nano-structures on the strut surface of 3D-plotted scaffolds, especially for bioceramic scaffolds, limits their biological activity. Inspired by the adhesive versatility of mussels and the active ion-chelating capacity of polydopamine, we set out to prepare a hierarchical bioceramic scaffold with controlled macropores and mussel-inspired surface nanolayers by combining the 3D-plotting technique with the polydopamine/apatite hybrid strategy in order to synergistically accelerate the osteogenesis and angiogenesis. β-Tricalcium phosphate (TCP) scaffolds were firstly 3D-plotted and then treated in dopamine-Tris/HCl and dopamine-SBF solutions to obtain TCP-DOPA-Tris and TCP-DOPA-SBF scaffolds, respectively. It was found that polydopamine/apatite hybrid nanolayers were formed on the surface of both TCP-DOPA-Tris and TCP-DOPA-SBF scaffolds and TCP-DOPA-SBF scaffolds induced apatite mineralization for the second time during the cell culture. As compared to TCP scaffolds, both TCP-DOPA-Tris and TCP-DOPA-SBF scaffolds significantly promoted the osteogenesis of bone marrow stromal cells (BMSCs) as well as the angiogenesis of human umbilical vein endothelial cells (HUVECs), and the TCP-DOPA-SBF group presented the highest in vitro osteogenic/angiogenic activity among the three groups. Furthermore, both TCP-DOPA-Tris and TCP-DOPA-SBF scaffolds significantly improved the formation of new bone in vivo as compared to TCP scaffolds without a nanostructured surface. Our results suggest that the utilization of a mussel-inspired Ca, P-chelated polydopamine nanolayer on 3D-plotted bioceramic scaffolds is a viable and effective strategy to construct a hierarchical structure for synergistically accelerating osteogenesis.The hierarchical structure of biomaterials plays an important role in the process of tissue reconstruction and regeneration. 3D-plotted scaffolds have been widely used for bone tissue engineering due to their controlled macropore structure and mechanical properties. However, the lack of micro- or nano-structures on the strut surface of 3D-plotted scaffolds, especially for bioceramic scaffolds, limits their biological activity. Inspired by the adhesive versatility of mussels and the active ion-chelating capacity of polydopamine, we set out to prepare a hierarchical bioceramic scaffold with controlled macropores and mussel-inspired surface nanolayers by combining the 3D-plotting technique with the polydopamine/apatite hybrid strategy in order to synergistically accelerate the osteogenesis and angiogenesis. β-Tricalcium phosphate (TCP) scaffolds were firstly 3D-plotted and then treated in dopamine-Tris/HCl and dopamine-SBF solutions to obtain TCP-DOPA-Tris and TCP-DOPA-SBF scaffolds, respectively. It was found that polydopamine/apatite hybrid nanolayers were formed on the surface of both TCP-DOPA-Tris and TCP-DOPA-SBF scaffolds and TCP-DOPA-SBF scaffolds induced apatite mineralization for the second time during the cell culture. As compared to TCP scaffolds, both TCP-DOPA-Tris and TCP-DOPA-SBF scaffolds significantly promoted the osteogenesis of bone marrow stromal cells (BMSCs) as well as the angiogenesis of human umbilical vein endothelial cells (HUVECs), and the TCP-DOPA-SBF group presented the highest in vitro osteogenic/angiogenic activity among the three groups. Furthermore, both TCP-DOPA-Tris and TCP-DOPA-SBF scaffolds significantly improved the formation of new bone in vivo as compared to TCP scaffolds without a nanostructured surface. Our results suggest that the utilization of a mussel-inspired Ca, P-chelated polydopamine nanolayer on 3D-plotted bioceramic scaffolds is a viable and effective strategy to construct a hierarchical structure for synergistically accelerating osteogenesis. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01952h

Genome-wide analysis of TCP family in tobacco.

PubMed

Chen, L; Chen, Y Q; Ding, A M; Chen, H; Xia, F; Wang, W F; Sun, Y H

2016-05-23

The TCP family is a transcription factor family, members of which are extensively involved in plant growth and development as well as in signal transduction in the response against many physiological and biochemical stimuli. In the present study, 61 TCP genes were identified in tobacco (Nicotiana tabacum) genome. Bioinformatic methods were employed for predicting and analyzing the gene structure, gene expression, phylogenetic analysis, and conserved domains of TCP proteins in tobacco. The 61 NtTCP genes were divided into three diverse groups, based on the division of TCP genes in tomato and Arabidopsis, and the results of the conserved domain and sequence analyses further confirmed the classification of the NtTCP genes. The expression pattern of NtTCP also demonstrated that majority of these genes play important roles in all the tissues, while some special genes exercise their functions only in specific tissues. In brief, the comprehensive and thorough study of the TCP family in other plants provides sufficient resources for studying the structure and functions of TCPs in tobacco.

Characterization of TCP-1 probes for molecular imaging of colon cancer.

PubMed

Liu, Zhonglin; Gray, Brian D; Barber, Christy; Bernas, Michael; Cai, Minying; Furenlid, Lars R; Rouse, Andrew; Patel, Charmi; Banerjee, Bhaskar; Liang, Rongguang; Gmitro, Arthur F; Witte, Marlys H; Pak, Koon Y; Woolfenden, James M

2016-10-10

Molecular probes capable of detecting colorectal cancer (CRC) are needed for early CRC diagnosis. The objective of this study was to characterize c[CTPSPFSHC]OH (TCP-1), a small peptide derived from phage display selection, for targeting human CRC xenografts using technetium-99m ((99m)Tc)-labeled TCP-1 and fluorescent cyanine-7 (Cy7)-labeled form of the peptide (Cy7-TCP-1). (99m)Tc-TCP-1 was generated by modifying TCP-1 with succinimidyl-6-hydrazino-nicotinamide (S-HYNIC) followed by radiolabeling. In vitro saturation binding experiments were performed for (99m)Tc-TCP-1 in human HCT116 colon cancer cells. SCID mice with human HCT116 cancer xenografts were imaged with (99m)Tc-TCP-1 or control peptide using a small-animal SPECT imager: Group I (n=5) received no blockade; Group II (n=5) received a blocking dose of non-radiolabeled TCP-1. Group III (n=5) were imaged with (99m)Tc-labeled control peptide (inactive peptide). SCID mice with human PC3 prostate cancer xenografts (Group IV, n=5) were also imaged with (99m)Tc-TCP-1. Eight additional SCID mice bearing HCT116 xenografts in dorsal skinfold window chambers (DSWC) were imaged by direct positron imaging of (18)F-fluorodeoxyglucose ((18)F-FDG) and fluorescence microscopy of Cy7-TCP-1. In vitro(99m)Tc-HYNIC-TCP-1 binding assays on HCT 116 cells indicated a mean Kd of 3.04±0.52nM. In cancer xenografts, (99m)Tc-TCP-1 radioactivity (%ID/g) was 1.01±0.15 in the absence of blockade and was reduced to 0.26±0.04 (P<0.01) with blockade. No radioactive uptake was observed in the PC3 tumors with (99m)Tc-TCP-1 or HCT116 tumors with inactive peptide. Cy7-TCP-1 activity localized not only in metabolically active tumors, as defined by (18)F-FDG imaging, but also in peritumoral microvasculature. In conclusion, TCP-1 probes may have a distinct targeting mechanism with high selectivity for CRC and tumor-associated vasculature. Molecular imaging with TCP-1 probes appears promising to detect malignant colorectal lesions. Copyright © 2016 Elsevier B.V. All rights reserved.

Allogeneic stem cells from deciduous teeth in treatment for periodontitis in miniature swine.

PubMed

Fu, Xiaoru; Jin, Luyuan; Ma, Ping; Fan, Zhipeng; Wang, Songlin

2014-06-01

Regeneration of lost periodontium in periodontitis is a challenge in that alveolar bone, cementum, and periodontal ligament need to be restored to their original architecture. Stem cells from exfoliated deciduous teeth (SHEDs) appear to be an attractive candidate for periodontium tissue regeneration. Previously, the authors successfully regenerated periodontal defects using autologous and allogeneic periodontal ligament stem cells (PDLSCs). The purpose of the present study is to investigate the ability of allogeneic SHEDs to regenerate lost periodontium in a swine periodontitis model. Animal models of periodontitis were established in miniature pigs, and allogeneic stem cells were isolated from miniature pig deciduous teeth (SPDs). The animal models were treated with SPDs plus hydroxyapatite/tricalcium phosphate (HA/TCP). Allogeneic PDLSCs plus HA/TCP or HA/TCP alone were set as positive control or control, respectively. Clinical assessments, computed tomography (CT) scanning, and histologic examination were used to evaluate the outcome of tissue regeneration. Clinical indices including probing depth, gingival recession, and attachment loss showed significant restoration in the SPD and PDLSC treatment groups, compared to the HA/TCP group 12 weeks post-transplantation. Meanwhile, CT scans showed that 75% of the samples had successful hard-tissue regeneration in both PDLSC and SPD groups, compared to the HA/TCP group, where the success rate was only 25%. In addition, histologic examination demonstrated that SPD and PDLSC treatment brought about remarkable regeneration of periodontal tissues, whereas periodontal regeneration was rare in the HA/TCP group. Allogeneic SPDs can effectively repair hard and soft tissue loss brought about by periodontitis in a swine model. Allogeneic SHEDs, which are easily accessible, may be applied to treat periodontitis in clinics in the future.

Influence of Partial O₂ Pressure on the Adhesion, Proliferation, and Osteogenic Differentiation of Human Dental Pulp Stem Cells on β-Tricalcium Phosphate Scaffold.

PubMed

Viña-Almunia, Jose; Mas-Bargues, Cristina; Borras, Consuelo; Gambini, Juan; El Alami, Marya; Sanz-Ros, Jorge; Peñarrocha, Miguel; Vina, Jose

To analyze, in vitro, the influence of O₂ pressure on the adhesion, proliferation, and osteogenic differentiation of human dental pulp stem cells (DPSC) on β-tricalcium phosphate (β-TCP) scaffold. DPSC, positive for the molecular markers CD133, Oct4, Nestin, Stro-1, and CD34, and negative for CD45, were isolated from extracted third molars. Experiments were started by seeding 200,000 cells on β-TCP cultured under 3% or 21% O₂ pressure. No osteogenic medium was used. Eight different cultures were performed at each time point under each O₂ pressure condition. Cell adhesion, proliferation, and differentiation over the biomaterial were evaluated at 7, 13, 18, and 23 days of culture. Cell adhesion was determined by light microscopy, proliferation by DNA quantification, and osteogenic differentiation by alkaline phosphatase (ALP) activity analysis. DPSC adhered to β-TCP with both O₂ conditions. Cell proliferation was found from day 7 of culture. Higher values were recorded at 3% O₂ in each time point. Statistically significant differences were recorded at 23 days of culture (P = .033). ALP activity was not detectable at 7 days. There was, however, an increase in ALP activity over time in both groups. At 13, 18, and 23 days of culture, higher ALP activity was recorded under 3% O₂ pressure. Statistical differences were found at day 23 (P = .014). DPSC display capacity of adhering to β-TCP under 3% or 21% O₂ pressure conditions. Cell proliferation on β-TCP phosphate is significantly higher at 3% than at 21% O₂ pressure, the most frequently used O₂ tension. β-TCP can itself promote osteogenic differentiation of DPSC and is enhanced under 3% O₂ compared with 21%.

Assessment of bone repair in critical-size defect in the calvarium of rats after the implantation of tricalcium phosphate beta (β-TCP).

PubMed

de Freitas Silva, Leonardo; de Carvalho Reis, Erik Neiva Ribeiro; Barbara, Tânia Aparecida; Bonardi, João Paulo; Garcia, Idelmo Rangel; de Carvalho, Paulo Sérgio Perri; Ponzoni, Daniela

2017-07-01

Evaluating the osteoconductive property of tricalcium phosphate beta (β-TCP) in comparison to that of inorganic bovine bone for repair in a critical-size defect in the rat calvarium. Critical-size defects of 7mm were made with a trephine in the calvaria of 48 Wistar rats. The animals were divided into four groups, and the defects in each group were filled with tricalcium phosphate beta (β-TCP), inorganic bovine bone (Bio-Oss), autogenous bone, or left empty. The animals were euthanized at two different time points (30 and 60days post-operation). All defects were recovered with a absorbable membrane of bovine cortical bone. Histological, histometric, and immunohistochemical (osteocalcin) assessments were carried out at 30 and 60days post-operation. At 30days post-operation, all groups showed areas of bone formation, predominantly when autogenous grafts were used. However, there were no statistically significant differences between the treatment groups (p>0.05). After 60days, there were similarities in the bone formation patterns between the β-TCP (26.32±) and Bio-Oss (17.35±) groups (p=0.549). In terms of the immunohistochemical assessment of osteocalcin, the clot group showed light to moderate staining at 30 and 60days. The autogenous group showed moderate staining at 30days and moderate to intense staining after 60days. The Bio-Oss group showed light to moderate staining after 30days and intense staining at 60days. The β-TCP group showed moderate staining at 30 and 60days post-operation. β-TCP is a good osteoconductive material with similar effects to those of inorganic bovine bone graft and is suitable for utilization in the repair of bone defects. Copyright © 2017 Elsevier GmbH. All rights reserved.

Histologic effect of pure-phase beta-tricalcium phosphate on bone regeneration in human artificial jawbone defects.

PubMed

Trisi, Paolo; Rao, Walter; Rebaudi, Alberto; Fiore, Peter

2003-02-01

The effect of the pure-phase beta-tricalcium phosphate (beta-TCP) Cerasorb on bone regeneration was evaluated in hollow titanium cylinders implanted in the posterior jaws of five volunteers. Beta-TCP particles were inserted inside the cylinders and harvested 6 months after placement. The density of the newly formed bone inside the bone-growing chambers measured 27.84% +/- 24.67% in test and 17.90% +/- 4.28% in control subjects, without a statistically significant difference. Analysis of the histologic specimens revealed that the density of the regenerated bone was related to the density of the surrounding bone. The present study demonstrates the spontaneous healing of infrabony artificial defects, 2.5 mm diameter, in the jaw. The pure beta-TCP was resorbed simultaneously with new bone formation, without interference with the bone matrix formation.

Biocompatibility of a Sonicated Silk Gel for Cervical Injection During Pregnancy

PubMed Central

Critchfield, Agatha S.; Mccabe, Reid; Klebanov, Nikolai; Richey, Lauren; Socrate, Simona; Norwitz, Errol R.; Kaplan, David L.; House, Michael

2014-01-01

Objective: To evaluate the biocompatibility of silk gel for cervical injection. Study Design: Silk gel was injected into the cervix of pregnant rats on day 13 (n = 11) and harvested at day 17. Histology of silk gel was compared with suture controls. Also, human cervical fibroblasts were cultured on silk gel and tissue culture plastic (TCP) in vitro. Cell viability, proliferation, metabolic activity, gene expression (COL1A1, COL3A1, and COX2), and release of proinflammatory mediators (interleukin [IL] 6 and IL-8) were evaluated. Results: In vivo, a mild foreign body response was seen surrounding the silk gel and suture controls. In vitro, cervical fibroblasts were viable, metabolically active, and proliferating at 72 hours. Release of IL-6 and IL-8 was similar on silk gel and TCP. Collagen and COX2 gene expression was similar or slightly decreased compared with TCP. Conclusions: Silk gel was well tolerated in vivo and in vitro, which supports continuing efforts to develop silk gels as an alternative to cervical cerclage. PMID:24520079

Analysis of functional redundancies within the Arabidopsis TCP transcription factor family.

PubMed

Danisman, Selahattin; van Dijk, Aalt D J; Bimbo, Andrea; van der Wal, Froukje; Hennig, Lars; de Folter, Stefan; Angenent, Gerco C; Immink, Richard G H

2013-12-01

Analyses of the functions of TEOSINTE-LIKE1, CYCLOIDEA, and PROLIFERATING CELL FACTOR1 (TCP) transcription factors have been hampered by functional redundancy between its individual members. In general, putative functionally redundant genes are predicted based on sequence similarity and confirmed by genetic analysis. In the TCP family, however, identification is impeded by relatively low overall sequence similarity. In a search for functionally redundant TCP pairs that control Arabidopsis leaf development, this work performed an integrative bioinformatics analysis, combining protein sequence similarities, gene expression data, and results of pair-wise protein-protein interaction studies for the 24 members of the Arabidopsis TCP transcription factor family. For this, the work completed any lacking gene expression and protein-protein interaction data experimentally and then performed a comprehensive prediction of potential functional redundant TCP pairs. Subsequently, redundant functions could be confirmed for selected predicted TCP pairs by genetic and molecular analyses. It is demonstrated that the previously uncharacterized class I TCP19 gene plays a role in the control of leaf senescence in a redundant fashion with TCP20. Altogether, this work shows the power of combining classical genetic and molecular approaches with bioinformatics predictions to unravel functional redundancies in the TCP transcription factor family.

Analysis of functional redundancies within the Arabidopsis TCP transcription factor family

PubMed Central

Danisman, Selahattin; de Folter, Stefan; Immink, Richard G. H.

2013-01-01

Analyses of the functions of TEOSINTE-LIKE1, CYCLOIDEA, and PROLIFERATING CELL FACTOR1 (TCP) transcription factors have been hampered by functional redundancy between its individual members. In general, putative functionally redundant genes are predicted based on sequence similarity and confirmed by genetic analysis. In the TCP family, however, identification is impeded by relatively low overall sequence similarity. In a search for functionally redundant TCP pairs that control Arabidopsis leaf development, this work performed an integrative bioinformatics analysis, combining protein sequence similarities, gene expression data, and results of pair-wise protein–protein interaction studies for the 24 members of the Arabidopsis TCP transcription factor family. For this, the work completed any lacking gene expression and protein–protein interaction data experimentally and then performed a comprehensive prediction of potential functional redundant TCP pairs. Subsequently, redundant functions could be confirmed for selected predicted TCP pairs by genetic and molecular analyses. It is demonstrated that the previously uncharacterized class I TCP19 gene plays a role in the control of leaf senescence in a redundant fashion with TCP20. Altogether, this work shows the power of combining classical genetic and molecular approaches with bioinformatics predictions to unravel functional redundancies in the TCP transcription factor family. PMID:24129704

A New TCP Congestion Control Supporting RTT-Fairness

NASA Astrophysics Data System (ADS)

Ogura, Kazumine; Nemoto, Yohei; Su, Zhou; Katto, Jiro

This paper focuses on RTT-fairness of multiple TCP flows over the Internet, and proposes a new TCP congestion control named “HRF (Hybrid RTT-Fair)-TCP”. Today, it is a serious problem that the flows having smaller RTT utilize more bandwidth than others when multiple flows having different RTT values compete in the same network. This means that a user with longer RTT may not be able to obtain sufficient bandwidth by the current methods. This RTT fairness issue has been discussed in many TCP papers. An example is CR (Constant Rate) algorithm, which achieves RTT-fairness by multiplying the square of RTT value in its window increment phase against TCP-Reno. However, the method halves its windows size same as TCP-Reno when a packet loss is detected. This makes worse its efficiency in certain network cases. On the other hand, recent proposed TCP versions essentially require throughput efficiency and TCP-friendliness with TCP-Reno. Therefore, we try to keep these advantages in our TCP design in addition to RTT-fairness. In this paper, we make intuitive analytical models in which we separate resource utilization processes into two cases: utilization of bottleneck link capacity and that of buffer space at the bottleneck link router. These models take into account three characteristic algorithms (Reno, Constant Rate, Constant Increase) in window increment phase where a sender receives an acknowledgement successfully. Their validity is proved by both simulations and implementations. From these analyses, we propose HRF-TCP which switches two modes according to observed RTT values and achieves RTT fairness. Experiments are carried out to validate the proposed method. Finally, HRF-TCP outperforms conventional methods in RTT-fairness, efficiency and friendliness with TCP-Reno.

The Arabidopsis immune adaptor SRFR1 interacts with TCP transcription factors that redundantly contribute to effector-triggered immunity.

PubMed

Kim, Sang Hee; Son, Geon Hui; Bhattacharjee, Saikat; Kim, Hye Jin; Nam, Ji Chul; Nguyen, Phuong Dung T; Hong, Jong Chan; Gassmann, Walter

2014-06-01

The plant immune system must be tightly controlled both positively and negatively to maintain normal plant growth and health. We previously identified SUPPRESSOR OF rps4-RLD1 (SRFR1) as a negative regulator specifically of effector-triggered immunity. SRFR1 is localized in both a cytoplasmic microsomal compartment and in the nucleus. Its TPR domain has sequence similarity to TPR domains of transcriptional repressors in other organisms, suggesting that SRFR1 may negatively regulate effector-triggered immunity via transcriptional control. We show here that excluding SRFR1 from the nucleus prevented complementation of the srfr1 phenotype. To identify transcription factors that interact with SRFR1, we screened an Arabidopsis transcription factor prey library by yeast two-hybrid assay and isolated six class I members of the TEOSINTE BRANCHED1/CYCLOIDEA/PCF (TCP) transcription factor family. Specific interactions were verified in planta. Although single or double T-DNA mutant tcp8, tcp14 or tcp15 lines were not more susceptible to bacteria expressing AvrRps4, the triple tcp8 tcp14 tcp15 mutant displayed decreased effector-triggered immunity mediated by the resistance genes RPS2, RPS4, RPS6 and RPM1. In addition, expression of PATHOGENESIS-RELATED PROTEIN2 was attenuated in srfr1-4 tcp8-1 tcp14-5 tcp15-3 plants compared to srfr1-4 plants. To date, TCP transcription factors have been implicated mostly in developmental processes. Our data indicate that one function of a subset of TCP proteins is to regulate defense gene expression in antagonism to SRFR1, and suggest a mechanism for an intimate connection between plant development and immunity. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

The Vibrio cholerae Minor Pilin TcpB Initiates Assembly and Retraction of the Toxin-Coregulated Pilus.

PubMed

Ng, Dixon; Harn, Tony; Altindal, Tuba; Kolappan, Subramania; Marles, Jarrad M; Lala, Rajan; Spielman, Ingrid; Gao, Yang; Hauke, Caitlyn A; Kovacikova, Gabriela; Verjee, Zia; Taylor, Ronald K; Biais, Nicolas; Craig, Lisa

2016-12-01

Type IV pilus (T4P) systems are complex molecular machines that polymerize major pilin proteins into thin filaments displayed on bacterial surfaces. Pilus functions require rapid extension and depolymerization of the pilus, powered by the assembly and retraction ATPases, respectively. A set of low abundance minor pilins influences pilus dynamics by unknown mechanisms. The Vibrio cholerae toxin-coregulated pilus (TCP) is among the simplest of the T4P systems, having a single minor pilin TcpB and lacking a retraction ATPase. Here we show that TcpB, like its homolog CofB, initiates pilus assembly. TcpB co-localizes with the pili but at extremely low levels, equivalent to one subunit per pilus. We used a micropillars assay to demonstrate that TCP are retractile despite the absence of a retraction ATPase, and that retraction relies on TcpB, as a V. cholerae tcpB Glu5Val mutant is fully piliated but does not induce micropillars movements. This mutant is impaired in TCP-mediated autoagglutination and TcpF secretion, consistent with retraction being required for these functions. We propose that TcpB initiates pilus retraction by incorporating into the growing pilus in a Glu5-dependent manner, which stalls assembly and triggers processive disassembly. These results provide a framework for understanding filament dynamics in more complex T4P systems and the closely related Type II secretion system.

ALP gene expression in cDNA samples from bone tissue engineering using a HA/TCP/Chitosan scaffold

NASA Astrophysics Data System (ADS)

Stephanie, N.; Katarina, H.; Amir, L. R.; Gunawan, H. A.

2017-08-01

This study examined the potential use of hydroxyapatite (HA)/tricalcium phosphate (TCP)/Chitosan as a bone tissue engineering scaffold. The potential for using HA/TCP/chitosan as a scaffold was analyzed by measuring expression of the ALP osteogenic gene in cDNA from bone biopsies from four Macaque nemestrina. Experimental conditions included control (untreated), treatment with HA/TCP 70:30, HA/TCP 50:50, and HA/TCP/chitosan. cDNA samples were measured quantitively with Real-Time PCR (qPCR) and semi-quantitively by gel electrophoresis. There were no significant differences in ALP gene expression between treatment subjects after two weeks, but the HA/TCP/chitosan treatment gave the highest level of expression after four weeks. The scaffold using the HA/TCP/chitosan combination induced a higher level of expression of the osteogenic gene ALP than did scaffold without chitosan.

Controlled release of NELL-1 protein from chitosan/hydroxyapatite-modified TCP particles.

PubMed

Zhang, Yulong; Dong, Rui; Park, Yujin; Bohner, Marc; Zhang, Xinli; Ting, Kang; Soo, Chia; Wu, Benjamin M

2016-09-10

NEL-like molecule-1 (NELL-1) is a novel osteogenic protein that showing high specificity to osteochondral cells. It was widely used in bone regeneration research by loading onto carriers such as tricalcium phosphate (TCP) particles. However, there has been little research on protein controlled release from this material and its potential application. In this study, TCP was first modified with a hydroxyapatite coating followed by a chitosan coating to prepare chitosan/hydroxyapatite-coated TCP particles (Chi/HA-TCP). The preparation was characterized by SEM, EDX, FTIR, XRD, FM and Zeta potential measurements. The NELL-1 loaded Chi/HA-TCP particles and the release kinetics were investigated in vitro. It was observed that the Chi/HA-TCP particles prepared with the 0.3% (wt/wt) chitosan solution were able to successfully control the release of NELL-1 and maintain a slow, steady release for up to 28 days. Furthermore, more than 78% of the loaded protein's bioactivity was preserved in Chi/HA-TCP particles over the period of the investigation, which was significantly higher than that of the protein released from hydroxyapatite coated TCP (HA-TCP) particles. Collectively, this study suggests that the osteogenic protein NELL-1 showed a sustained release pattern after being encapsulated into the modified Chi/HA-TCP particles, and the NELL-1 integrated composite of Chi/HA-TCP showed a potential to function as a protein delivery carrier and as an improved bone matrix for use in bone regeneration research. Copyright © 2016 Elsevier B.V. All rights reserved.

Ground settlement monitoring based on temporarily coherent points between two SAR acquisitions

USGS Publications Warehouse

Zhang, L.; Ding, X.; Lu, Z.

2011-01-01

An InSAR analysis approach for identifying and extracting the temporarily coherent points (TCP) that exist between two SAR acquisitions and for determining motions of the TCP is presented for applications such as ground settlement monitoring. TCP are identified based on the spatial characteristics of the range and azimuth offsets of coherent radar scatterers. A method for coregistering TCP based on the offsets of TCP is given to reduce the coregistration errors at TCP. An improved phase unwrapping method based on the minimum cost flow (MCF) algorithm and local Delaunay triangulation is also proposed for sparse TCP data. The proposed algorithms are validated using a test site in Hong Kong. The test results show that the algorithms work satisfactorily for various ground features.

Fabrication and characterization of two-layered nanofibrous membrane for guided bone and tissue regeneration application.

PubMed

Masoudi Rad, Maryam; Nouri Khorasani, Saied; Ghasemi-Mobarakeh, Laleh; Prabhakaran, Molamma P; Foroughi, Mohammad Reza; Kharaziha, Mahshid; Saadatkish, Niloufar; Ramakrishna, Seeram

2017-11-01

Membranes used in dentistry act as a barrier to prevent invasion of intruder cells to defected area and obtains spaces that are to be subsequently filled with new bone and provide required bone volume for implant therapy when there is insufficient volume of healthy bone at implant site. In this study a two-layered bioactive membrane were fabricated by electrospinning whereas one layer provides guided bone regeneration (GBR) and fabricated using poly glycerol sebacate (PGS)/polycaprolactone (PCL) and Beta tri-calcium phosphate (β-TCP) (5, 10 and 15%) and another one containing PCL/PGS and chitosan acts as guided tissue regeneration (GTR). The morphology, chemical, physical and mechanical characterizations of the membranes were studied using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), tensile testing, then biodegradability and bioactivity properties were evaluated. In vitro cell culture study was also carried out to investigate proliferation and mineralization of cells on different membranes. Transmission electron microscope (TEM) and SEM results indicated agglomeration of β-TCP nanoparticles in the structure of nanofibers containing 15% β-TCP. Moreover by addition of β-TCP from 5% to 15%, contact angle decreased due to hydrophilicity of nanoparticles and bioactivity was found to increase. Mechanical properties of the membrane increased by incorporation of 5% and 10% of β-TCP in the structure of nanofibers, while addition of 15% of β-TCP was found to deteriorate mechanical properties of nanofibers. Although the presence of 5% and 10% of nanoparticles in the nanofibers increased proliferation of cells on GBR layer, cell proliferation was observed to decrease by addition of 15% β-TCP in the structure of nanofibers which is likely due to agglomeration of nanoparticles in the nanofiber structure. Our overall results revealed PCL/PGS containing 10% β-TCP could be selected as the optimum GBR membrane in view point of physical and mechanical properties along with cell behavior. PCL/PGS nanofibers containing 10% β-TCP were electrospun on the GTR layer for fabrication of final membrane. Addition of chitosan in the structure of PCL/PGS nanofibers was found to decrease fiber diameter, contact angle and porosity which are favorable for GTR layer. Two-layered dental membrane fabricated in this study can serve as a suitable substrate for application in dentistry as it provides appropriate osteoconductivity and flexibility along with barrier properties. Copyright © 2017 Elsevier B.V. All rights reserved.

Development and Characterization of Biphasic Hydroxyapatite/β-TCP Cements.

PubMed

Gallinetti, Sara; Canal, Cristina; Ginebra, Maria-Pau; Ferreira, J

2014-04-01

Biphasic calcium phosphate bioceramics composed of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) have relevant properties as synthetic bone grafts, such as tunable resorption, bioactivity, and intrinsic osteoinduction. However, they have some limitations associated to their condition of high-temperature ceramics. In this work self-setting Biphasic Calcium Phosphate Cements (BCPCs) with different HA/β-TCP ratios were obtained from self-setting α-TCP/β-TCP pastes. The strategy used allowed synthesizing BCPCs with modulated composition, compressive strength, and specific surface area. Due to its higher solubility, α-TCP was fully hydrolyzed to a calcium-deficient HA (CDHA), whereas β-TCP remained unreacted and completely embedded in the CDHA matrix. Increasing amounts of the non-reacting β-TCP phase resulted in a linear decrease of the compressive strength, in association to the decreasing amount of precipitated HA crystals, which are responsible for the mechanical consolidation of apatitic cements. Ca 2+ release and degradation in acidic medium was similar in all the BCPCs within the timeframe studied, although differences might be expected in longer term studies once β-TCP, the more soluble phase was exposed to the surrounding media.

Identification of Specific DNA Binding Residues in the TCP Family of Transcription Factors in Arabidopsis[W

PubMed Central

Aggarwal, Pooja; Das Gupta, Mainak; Joseph, Agnel Praveen; Chatterjee, Nirmalya; Srinivasan, N.; Nath, Utpal

2010-01-01

The TCP transcription factors control multiple developmental traits in diverse plant species. Members of this family share an ∼60-residue-long TCP domain that binds to DNA. The TCP domain is predicted to form a basic helix-loop-helix (bHLH) structure but shares little sequence similarity with canonical bHLH domain. This classifies the TCP domain as a novel class of DNA binding domain specific to the plant kingdom. Little is known about how the TCP domain interacts with its target DNA. We report biochemical characterization and DNA binding properties of a TCP member in Arabidopsis thaliana, TCP4. We have shown that the 58-residue domain of TCP4 is essential and sufficient for binding to DNA and possesses DNA binding parameters comparable to canonical bHLH proteins. Using a yeast-based random mutagenesis screen and site-directed mutants, we identified the residues important for DNA binding and dimer formation. Mutants defective in binding and dimerization failed to rescue the phenotype of an Arabidopsis line lacking the endogenous TCP4 activity. By combining structure prediction, functional characterization of the mutants, and molecular modeling, we suggest a possible DNA binding mechanism for this class of transcription factors. PMID:20363772

Class I TCP-DELLA interactions in inflorescence shoot apex determine plant height.

PubMed

Davière, Jean-Michel; Wild, Michael; Regnault, Thomas; Baumberger, Nicolas; Eisler, Herfried; Genschik, Pascal; Achard, Patrick

2014-08-18

Regulation of plant height, one of the most important agronomic traits, is the focus of intensive research for improving crop performance. Stem elongation takes place as a result of repeated cell divisions and subsequent elongation of cells produced by apical and intercalary meristems. The gibberellin (GA) phytohormones have long been known to control stem and internodal elongation by stimulating the degradation of nuclear growth-repressing DELLA proteins; however, the mechanism allowing GA-responsive growth is only slowly emerging. Here, we show that DELLAs directly regulate the activity of the plant-specific class I TCP transcription factor family, key regulators of cell proliferation. Our results demonstrate that class I TCP factors directly bind the promoters of core cell-cycle genes in Arabidopsis inflorescence shoot apices while DELLAs block TCP function by binding to their DNA-recognition domain. GAs antagonize such repression by promoting DELLA destruction and therefore cause a concomitant accumulation of TCP factors on promoters of cell-cycle genes. Consistent with this model, the quadruple mutant tcp8 tcp14 tcp15 tcp22 exhibits severe dwarfism and reduced responsiveness to GA action. Altogether, we conclude that GA-regulated DELLA-TCP interactions in inflorescence shoot apex provide a novel mechanism to control plant height. Copyright © 2014 Elsevier Ltd. All rights reserved.

The TCP4 transcription factor of Arabidopsis blocks cell division in yeast at G1 {yields} S transition

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

Aggarwal, Pooja; Padmanabhan, Bhavna; Bhat, Abhay

2011-07-01

Highlights: {yields} TCP4 is a class II TCP transcription factor, that represses cell division in Arabidopsis. {yields} TCP4 expression in yeast retards cell division by blocking G1 {yields} S transition. {yields} Genome-wide expression studies and Western analysis reveals stabilization of cell cycle inhibitor Sic1, as possible mechanism. -- Abstract: The TCP transcription factors control important aspects of plant development. Members of class I TCP proteins promote cell cycle by regulating genes directly involved in cell proliferation. In contrast, members of class II TCP proteins repress cell division. While it has been postulated that class II proteins induce differentiation signal, theirmore » exact role on cell cycle has not been studied. Here, we report that TCP4, a class II TCP protein from Arabidopsis that repress cell proliferation in developing leaves, inhibits cell division by blocking G1 {yields} S transition in budding yeast. Cells expressing TCP4 protein with increased transcriptional activity fail to progress beyond G1 phase. By analyzing global transcriptional status of these cells, we show that expression of a number of cell cycle genes is altered. The possible mechanism of G1 {yields} S arrest is discussed.« less

A Simulation Study of Paced TCP

NASA Technical Reports Server (NTRS)

Kulik, Joanna; Coulter, Robert; Rockwell, Dennis; Partridge, Craig

2000-01-01

In this paper, we study the performance of paced TCP, a modified version of TCP designed especially for high delay- bandwidth networks. In typical networks, TCP optimizes its send-rate by transmitting increasingly large bursts, or windows, of packets, one burst per round-trip time, until it reaches a maximum window-size, which corresponds to the full capacity of the network. In a network with a high delay-bandwidth product, however, Transmission Control Protocol's (TCPs) maximum window-size may be larger than the queue size of the intermediate routers, and routers will begin to drop packets as soon as the windows become too large for the router queues. The TCP sender then concludes that the bottleneck capacity of the network has been reached, and it limits its send-rate accordingly. Partridge proposed paced TCP as a means of solving the problem of queueing bottlenecks. A sender using paced TCP would release packets in multiple, small bursts during a round-trip time in which ordinary TCP would release a single, large burst of packets. This approach allows the sender to increase its send-rate to the maximum window size without encountering queueing bottlenecks. This paper describes the performance of paced TCP in a simulated network and discusses implementation details that can affect the performance of paced TCP.

Fabrication of Porous α-TCP/Gellan Gum Scaffold for Bone Tissue Engineering.

PubMed

Wen, Jian; Kim, Ill Yong; Kikuta, Koichi; Ohtsuki, Chikara

2016-03-01

α-tricalcium phosphate (α-TCP, α-Ca3(PO4)2) receives great attention for bone repairing due to its biodegradability and capability of transformation to human bone's main inorganic components, hydroxyapatite (HAp). α-TCP porous scaffold is easily procurable by sintering of the low-temperature polymorph of TCP, β-TCR Still, porous body of α-TCP is too brittle to being handled and shaped, limiting its clinical application as implant materials. To improve mechanical properties of α-TCP porous scaffold, the present study focused on coating of a type of polysaccharides on α-TCP scaffolds. Gellan gum was chosen as the polysaccharide for coating because of its biodegradability as well as the potential acting as substrate for HAp deposition during hydration of α-TCP after exposure to body fluid. After coating of gellan gum on α-TCP scaffolds with porosity of 75 vol%, the compressive strength increased from 0.45 MPa to around 2.00 MPa. Among the coated scaffold, the maximum compressive strength, 3.97 MPa, was obtained on the scaffold with porosity of 63 vol%. Improvement of mechanical properties of α-TCP/gellan gum composites was achieved to show easy handling performance for a bone substitute for tissue repairing. The dissolving rate of the coated scaffolds was also controlled by adjusting the concentration of GG solutions.

Luminescence properties and color identification of Eu doped Ca3(PO4)2 phosphors calcined in air

NASA Astrophysics Data System (ADS)

Tong, Chao; Zhu, Yangguang; Xu, Chuanyan; Yang, Lei; Li, Yadong

2017-09-01

The Ca3(PO4)2：Eu (TCP) phosphor was synthesized by a high-temperature solid-state reaction in air atmosphere. X-ray powder diffraction(XRD) analysis indicates that the α-TCP↔β-TCP phase transition takes place under different calcination and cooling conditions. The luminescence properties of the two different phases of TCP were discussed according to the luminescence spectra during the heating and cooling transition. The CIE chromaticity coordinates of β-TCP phase located at the red region, α-TCP phase at bluish-green region because of the coexistence of Eu2+ and Eu3+ ions. The color-tunable emission of the products could also be directly observed under UV lamp. Pure red and bluish-green-emitting particles were observed respectively for the pure β-TCP phase and α-TCP phase samples whereas bluish-green and red mixture emitting particles were traced for the α-TCP /β-TCP phase co-existence samples. Therefore, results of this study suggested that Eu ion could be used as a spectroscopic probe to qualitatively identify the crystalline phase of TCP by a simple and convenient way to observe the color-tunable emission of the samples when irradiating it under 365 nm UV lamp.

Obtaining resources for evidence-based public health initiatives at the local level: insights from the Central Sydney Tobacco Control Plan.

PubMed

Rissel, C; McMaugh, K; O'Connor, D; Balafas, A; Ward, J

1999-02-01

In response to inquiries regarding the processes of developing a Tobacco Control Plan (TCP) for the Central Sydney Area Health Service (which in 1997 allocated dedicated funding of $ 800,000 over 2 1/2 years to implement the plan), this article describes the strengths and weaknesses of the TCP and outlines the process which contributed to its funding. Consistent with national and state priorities, the TCP recommended strategies based on best available evidence in the four action areas: reducing sales of cigarettes to minors, marketing, passive smoking and smoking cessation. Funding of this amount for a single public health issue at a local level represents a unique achievement in the application of an evidence-based approach to population health. Key elements of our advocacy methods included the involvement of all key primary health care and clinical stakeholders; comprehensive background research to identify evidence-based strategies; careful attention to budget options; strategic lobbying of senior staff and decision makers; the proposal for a multidisciplinary management structure for the TCP and specifications for funding allocation and evaluation. Early achievements and other reflections are discussed.

In vitro calcium availability in bakery products fortified with tuna bone powder as a natural calcium source.

PubMed

Nemati, Mahnaz; Kamilah, Hanisah; Huda, Nurul; Ariffin, Fazilah

2015-08-01

Avoidance of dairy products due to lactose intolerance can lead to insufficiency of calcium (Ca) in the body. In an approach to address this problem, tuna bone powder (TBP) was formulated as a calcium supplement to fortify bakery products. In a study, TBP recovered by alkaline treatment contained 38.16 g/100 g of calcium and 23.31 g/100 g of phosphorus. The ratio of Ca:P that was close to 2:1 was hence comparable to that in human bones. The availability of calcium in TBP was 53.93%, which was significantly higher than most calcium salts, tricalcium phosphate (TCP) being the exception. In vitro availability of calcium in TBP-fortified cookies or TCP-fortified cookies were comparable at 38.9% and 39.5%, respectively. These values were higher than the readings from TBP-fortified bread (36.7%) or TCP-fortified bread (37.4%). Sensory evaluation of bakery products containing TBP or TCP elicited comparable scores for the two additives from test panels. Hence, TBP could be used in the production of high calcium bakery products that would enjoy consumer acceptance.

Effect of citric acid on setting reaction and tissue response to β-TCP granular cement.

PubMed

Fukuda, Naoyuki; Tsuru, Kanji; Mori, Yoshihide; Ishikawa, Kunio

2017-02-24

We recently reported that when an acidic calcium phosphate solution is mixed with β-tricalcium phosphate (β-TCP) granules, the resulting dicalcium phosphate dihydrate (DCPD) crystals form bridges between the β-TCP granules, creating a set interconnected porous structure in approximately 1 min. Although this self-setting β-TCP granular cement (β-TCPGC) is useful for clinical applications, the short setting time is a key drawback for handling. In this study, the setting time of β-TCPGC was adjusted with the addition of citric acid, which is a known inhibiter of DCPD crystal growth. As the concentration of citric acid in the acidic calcium phosphate solution increased, the amount of DCPD formation in the set β-TCPGC decreased, and the crystal morphology of DCPD became elongated. β-TCPGC prepared with various citric acid concentrations were used as grafting material in rat calvarial bone defects to evaluate bone regeneration in vivo. Four weeks after implantation, no inflammatory reaction and approximately 20% new bone formation were observed, regardless of the presence or absence of citric acid in the liquid phase of β-TCPGC. We concluded, therefore, that citric acid might be a useful retarder of β-TCPGC setting times.

Development of PLGA-coated β-TCP scaffolds containing VEGF for bone tissue engineering.

PubMed

Khojasteh, Arash; Fahimipour, Farahnaz; Eslaminejad, Mohamadreza Baghaban; Jafarian, Mohammad; Jahangir, Shahrbanoo; Bastami, Farshid; Tahriri, Mohammadreza; Karkhaneh, Akbar; Tayebi, Lobat

2016-12-01

Bone tissue engineering is sought to apply strategies for bone defects healing without limitations and short-comings of using either bone autografts or allografts and xenografts. The aim of this study was to fabricate a thin layer poly(lactic-co-glycolic) acid (PLGA) coated beta-tricalcium phosphate (β-TCP) scaffold with sustained release of vascular endothelial growth factor (VEGF). PLGA coating increased compressive strength of the β-TCP scaffolds significantly. For in vitro evaluations, canine mesenchymal stem cells (cMSCs) and canine endothelial progenitor cells (cEPCs) were isolated and characterized. Cell proliferation and attachment were demonstrated and the rate of cells proliferation on the VEGF released scaffold was significantly more than compared to the scaffolds with no VEGF loading. A significant increase in expression of COL1 and RUNX2 was indicated in the scaffolds loaded with VEGF and MSCs compared to the other groups. Consequently, PLGA coated β-TCP scaffold with sustained and localized release of VEGF showed favourable results for bone regeneration in vitro, and this scaffold has the potential to use as a drug delivery device in the future. Copyright © 2016. Published by Elsevier B.V.

Identification and Transcript Analysis of the TCP Transcription Factors in the Diploid Woodland Strawberry Fragaria vesca

PubMed Central

Wei, Wei; Hu, Yang; Cui, Meng-Yuan; Han, Yong-Tao; Gao, Kuan; Feng, Jia-Yue

2016-01-01

Plant-specific TEOSINTE BRANCHED 1, CYCLOIDEA, and PROLIFERATING CELL FACTORS (TCP) transcription factors play versatile functions in multiple processes of plant growth and development. However, no systematic study has been performed in strawberry. In this study, 19 FvTCP genes were identified in the diploid woodland strawberry (Fragaria vesca) accession Heilongjiang-3. Phylogenetic analysis suggested that the FvTCP genes were classified into two main classes, with the second class further divided into two subclasses, which was supported by the exon-intron organizations and the conserved motif structures. Promoter analysis revealed various cis-acting elements related to growth and development, hormone and/or stress responses. We analyzed FvTCP gene transcript accumulation patterns in different tissues and fruit developmental stages. Among them, 12 FvTCP genes exhibited distinct tissue-specific transcript accumulation patterns. Eleven FvTCP genes were down-regulated in different fruit developmental stages, while five FvTCP genes were up-regulated. Transcripts of FvTCP genes also varied with different subcultural propagation periods and were induced by hormone treatments and biotic and abiotic stresses. Subcellular localization analysis showed that six FvTCP-GFP fusion proteins showed distinct localizations in Arabidopsis mesophyll protoplasts. Notably, transient over-expression of FvTCP9 in strawberry fruits dramatically affected the expression of a series of genes implicated in fruit development and ripening. Taken together, the present study may provide the basis for functional studies to reveal the role of this gene family in strawberry growth and development. PMID:28066489

Protection and attachment of Vibrio cholerae mediated by the toxin-coregulated pilus in the infant mouse model.

PubMed

Krebs, Shelly J; Taylor, Ronald K

2011-10-01

Colonization of the human small intestine by Vibrio cholerae is an essential step in pathogenesis that requires the type IV toxin-coregulated pilus (TCP). To date, three functions of TCP have been characterized: it serves as the CTXΦ receptor, secretes the colonization factor TcpF, and functions in microcolony formation by mediating bacterium-bacterium interactions. Although type IV pili in other pathogenic bacteria have been characterized as playing a major role in attachment to epithelial cells, there are very few studies to suggest that TCP acts as an attachment factor. Taking this into consideration, we investigated the function of TCP in attachment to Caco-2 cells and found that mutants lacking TCP were defective in attachment compared to the wild type. Overexpression of ToxT, the activator of TCP, significantly increased attachment of wild-type V. cholerae to Caco-2 cells. Using field-emission scanning electron microscopy (FESEM), we also observed TCP-mediated attachment to the small intestines of infected infant mice by using antibodies specific to TCP and V. cholerae. Remarkably, we also visualized matrices comprised of TCP appearing to engulf V. cholerae during infection, and we demonstrated that these matrices protected the bacteria from a component of bile, disclosing a possible new role of this pilus in protection of the bacterial cells from antimicrobial agents. This study provides new insights into TCP's function in V. cholerae colonization of the small intestine, describing additional roles in mediating attachment and protection of V. cholerae bacterial cells.

The Vibrio cholerae Minor Pilin TcpB Initiates Assembly and Retraction of the Toxin-Coregulated Pilus

PubMed Central

Harn, Tony; Spielman, Ingrid; Gao, Yang; Kovacikova, Gabriela; Biais, Nicolas

2016-01-01

Type IV pilus (T4P) systems are complex molecular machines that polymerize major pilin proteins into thin filaments displayed on bacterial surfaces. Pilus functions require rapid extension and depolymerization of the pilus, powered by the assembly and retraction ATPases, respectively. A set of low abundance minor pilins influences pilus dynamics by unknown mechanisms. The Vibrio cholerae toxin-coregulated pilus (TCP) is among the simplest of the T4P systems, having a single minor pilin TcpB and lacking a retraction ATPase. Here we show that TcpB, like its homolog CofB, initiates pilus assembly. TcpB co-localizes with the pili but at extremely low levels, equivalent to one subunit per pilus. We used a micropillars assay to demonstrate that TCP are retractile despite the absence of a retraction ATPase, and that retraction relies on TcpB, as a V. cholerae tcpB Glu5Val mutant is fully piliated but does not induce micropillars movements. This mutant is impaired in TCP-mediated autoagglutination and TcpF secretion, consistent with retraction being required for these functions. We propose that TcpB initiates pilus retraction by incorporating into the growing pilus in a Glu5-dependent manner, which stalls assembly and triggers processive disassembly. These results provide a framework for understanding filament dynamics in more complex T4P systems and the closely related Type II secretion system. PMID:27992883

Prospective Randomized Controlled Trial of Hindfoot and Ankle Fusions Treated With rhPDGF-BB in Combination With a β-TCP-Collagen Matrix.

PubMed

Daniels, Timothy R; Younger, Alastair S E; Penner, Murray J; Wing, Kevin J; Le, Ian L D; Russell, Iain S; Lalonde, Karl-André; Evangelista, Peter T; Quiton, Jovelyn D; Glazebrook, Mark; DiGiovanni, Christopher W

2015-07-01

Ankle and hindfoot arthrodesis is often supplemented with autograft to promote bony union. Autograft harvest can lead to increased perioperative morbidity. Purified recombinant human platelet-derived growth factor BB homodimer (rhPDGF-BB) has stimulated bone formation in mandibular defects and hindfoot fusion. This randomized controlled trial evaluated the efficacy and safety of rhPDGF-BB combined with an injectable, osteoconductive beta-tricalcium phosphate (β-TCP)-collagen matrix versus autograft in ankle and hindfoot fusions. Seventy-five patients requiring ankle or hindfoot fusion were randomized 5:1 for rhPDGF-BB/β-TCP-collagen (treatment, n = 63) or autograft (control, n = 12). Prospective analysis included 142 autograft control subjects from another clinical trial with identical study protocols. Standardized operative and postoperative protocols were used. Patients underwent standard internal fixation augmented with autograft or 0.3 mg/mL rhPDGF-BB/β-TCP-collagen. Radiologic, clinical, and quality-of-life outcomes were assessed over 52 weeks. Primary outcome was joint fusion (50% or more osseous bridging on computed tomography) at 24 weeks. Secondary outcomes included radiographs, clinical healing status, visual analog scale pain score, American Orthopaedic Foot & Ankle Society Ankle-Hindfoot Scale score, Foot Function Index score, and Short Form-12 score. Noninferiority P values were calculated. Complete fusion of all involved joints at 24 weeks as indicated by computed tomography was achieved in 53 of 63 (84%) rhPDGF-BB/β-TCP-collagen-treated patients and 100 of 154 (65%) autograft-treated patients (P < .001). Mean time to fusion was 14.3 ± 8.9 weeks for rhPDGF-BB/β-TCP-collagen patients versus 19.7 ± 11.5 weeks for autograft patients (P < .01). Clinical success at 52 weeks was achieved in 57 of 63 (91%) rhPDGF-BB/β-TCP-collagen patients and 120 of 154 (78%) autograft patients (P < .001). Safety-related outcomes were equivalent. Autograft controls had 2 bone graft harvest infections. Application of rhPDGF-BB/β-TCP-collagen was a safe, effective alternative to autograft for ankle and hindfoot fusions, eliminating the pain and morbidity associated with autograft harvesting. Level I, prospective randomized study. © The Author(s) 2015.

Ridge Preservation After Maxillary Third Molar Extraction Using 30% Porosity PLGA/HA/β-TCP Scaffolds With and Without Simvastatin: A Pilot Randomized Controlled Clinical Trial.

PubMed

Noronha Oliveira, Miguel; Rau, Levy Hermes; Marodin, Aline; Corrêa, Márcio; Corrêa, Letícia Ruhland; Aragones, Aguedo; Magini, Ricardo de Souza

2017-12-01

To evaluate clinically and radiographically, in humans, the healing of maxillary third molars postextraction sockets after application of different ridge preservation techniques 3 months after tooth extraction. Twenty-six sockets (13 patients) were randomly assigned to 4 treatment modalities: deproteinized bovine bone mineral with 10% collagen (DBBM-C), poly(D,L-lactide-co-glycolide) with hydroxyapatite/β-TCP scaffold (PLGA/HA), PLGA/HA/β-TCP with 2.0% simvastatin scaffold (PLGA/HA/S), and spontaneous healing (control). Clinical complications were assessed, and cone-beam computed tomographies were taken in 5 patients 3 months after surgeries. For statistical purposes, the Fisher exact test was used (P < 0.05). After 3 months, 6 of 9 grafts from the PLGA/HA group were lost (P < 0.05). PLGA/HA/S' loss was only 2 of 8 (P > 0.05), but no loss was observed in the DBBM-C group. Pain was present in 3 of 8 sites that lost the graft (37.5%) (P > 0.05) and infection in 1 of 8 (12.5%) (P > 0.05), with these only occurring in the PLGA/HA group. Poly (D, L-lactide-co-glycolide) with hydroxyapatite/β-TCP (PLGA/HA/β-TCP) scaffolds, with and without simvastatin, failed to obtain the initial expected results and presented more complications. Scaffolds with simvastatin showed to be superior, with less clinical complications than scaffolds without simvastatin.

The influence of bone substitute materials on the bone volume after maxillary sinus augmentation: a microcomputerized tomography study.

PubMed

Kühl, Sebastian; Brochhausen, Christoph; Götz, Hermann; Filippi, Andreas; Payer, Michael; d'Hoedt, Bernd; Kreisler, Matthias

2013-03-01

This study aims to evaluate the effect of adding bone substitute materials (BSM) to particulated autogenous bone (PAB) on the volume fraction (Vf) of newly formed bone after maxillary sinus augmentation. Thirty healthy patients undergoing maxillary sinus augmentation were included. PAB (N = 10), mixtures of PAB and beta-tricalciumphosphate (PAB/β-TCP) (N = 10), as well as PAB and β-TCP and hydroxyapatite (PAB/HA/β-TCP) (N = 10) were randomly used for sinus augmentation. A sample of the graft material was maintained from each patient at time of maxillary sinus augmentation, and Vfs of the PAB and/or BSM in the samples were determined by means of microcomputerized tomography (μ-CT). Five months later, samples of the grafted areas were harvested during implantation using a trephine bur. μ-CT analysis of these samples was performed, and the Vf of bone and BSM were compared with the data obtained 5 months earlier from the original material. The mean Vf of the bone showed a statistically significant increase (p < 0.05) in all groups after a healing period of 5 months without statistically significant difference between the groups. With regard to the increase of bone volume, it is not relevant if PAB is used alone or combined with β-TCP or HA/β-TCP. The amount of PAB and associated donor site morbidity may be reduced by adding BSM for maxillary sinus augmentation.

Optimizing the ASC WAN: evaluating network performance tools for comparing transport protocols.

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

Lydick, Christopher L.

2007-07-01

The Advanced Simulation & Computing Wide Area Network (ASC WAN), which is a high delay-bandwidth network connection between US Department of Energy National Laboratories, is constantly being examined and evaluated for efficiency. One of the current transport-layer protocols which is used, TCP, was developed for traffic demands which are different from that on the ASC WAN. The Stream Control Transport Protocol (SCTP), on the other hand, has shown characteristics which make it more appealing to networks such as these. Most important, before considering a replacement for TCP on any network, a testing tool that performs well against certain criteria needsmore » to be found. In order to try to find such a tool, two popular networking tools (Netperf v.2.4.3 & v.2.4.6 (OpenSS7 STREAMS), and Iperf v.2.0.6) were tested. These tools implement both TCP and SCTP and were evaluated using four metrics: (1) How effectively can the tool reach a throughput near the bandwidth? (2) How much of the CPU does the tool utilize during operation? (3) Is the tool freely and widely available? And, (4) Is the tool actively developed? Following the analysis of those tools, this paper goes further into explaining some recommendations and ideas for future work.« less

Fabrication and evaluation of interconnected porous carbonate apatite from alpha tricalcium phosphate spheres.

PubMed

Ishikawa, Kunio; Arifta, Tya Indah; Hayashi, Koichiro; Tsuru, Kanji

2018-03-26

Carbonate apatite (CO 3 Ap) blocks have attracted considerable attention as an artificial bone substitute material because CO 3 Ap is a component of and shares properties with bone, including high osteoconductivity and replacement by bone similar to autografts. In this study, we fabricated an interconnected porous CO 3 Ap block using α-tricalcium phosphate (TCP) spheres and evaluated the tissue response to this material in a rabbit tibial bone defect model. Interconnected porous α-TCP, the precursor of interconnected porous CO 3 Ap, could not be fabricated directly by sintering α-TCP spheres. It was therefore made via a setting reaction with α-TCP spheres, yielding interconnected porous calcium-deficient hydroxyapatite that was subjected to heat treatment. Immersing the interconnected porous α-TCP in Na-CO 3 -PO 4 solution produced CO 3 Ap, which retained the interconnected porous structure after the dissolution-precipitation reaction. The diametral tensile strength and porosity of the porous CO 3 Ap were 1.8 ± 0.4 MPa and 55% ± 3.2%, respectively. Both porous and dense (control) CO 3 Ap showed excellent tissue response and good osteoconductivity. At 4 weeks after surgery, approximately 15% ± 4.9% of the tibial bone defect was filled with new bone when reconstruction was performed using porous CO 3 Ap; this amount was five times greater than that obtained with dense CO 3 Ap. At 12 weeks after surgery, for porous CO 3 Ap, approximately 47% of the defect was filled with new bone as compared to 16% for dense CO 3 Ap. Thus, the interconnected porous CO 3 Ap block is a promising artificial bone substitute material for the treatment of bone defects caused by large fractures or bone tumor resection. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2018. © 2018 Wiley Periodicals, Inc.

The cotton transcription factor TCP14 functions in auxin-mediated epidermal cell differentiation and elongation.

PubMed

Wang, Miao-Ying; Zhao, Pi-Ming; Cheng, Huan-Qing; Han, Li-Bo; Wu, Xiao-Min; Gao, Peng; Wang, Hai-Yun; Yang, Chun-Lin; Zhong, Nai-Qin; Zuo, Jian-Ru; Xia, Gui-Xian

2013-07-01

Plant-specific TEOSINTE-BRANCHED1/CYCLOIDEA/PCF (TCP) transcription factors play crucial roles in development, but their functional mechanisms remain largely unknown. Here, we characterized the cellular functions of the class I TCP transcription factor GhTCP14 from upland cotton (Gossypium hirsutum). GhTCP14 is expressed predominantly in fiber cells, especially at the initiation and elongation stages of development, and its expression increased in response to exogenous auxin. Induced heterologous overexpression of GhTCP14 in Arabidopsis (Arabidopsis thaliana) enhanced initiation and elongation of trichomes and root hairs. In addition, root gravitropism was severely affected, similar to mutant of the auxin efflux carrier PIN-FORMED2 (PIN2) gene. Examination of auxin distribution in GhTCP14-expressing Arabidopsis by observation of auxin-responsive reporters revealed substantial alterations in auxin distribution in sepal trichomes and root cortical regions. Consistent with these changes, expression of the auxin uptake carrier AUXIN1 (AUX1) was up-regulated and PIN2 expression was down-regulated in the GhTCP14-expressing plants. The association of GhTCP14 with auxin responses was also evidenced by the enhanced expression of auxin response gene IAA3, a gene in the AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) family. Electrophoretic mobility shift assays showed that GhTCP14 bound the promoters of PIN2, IAA3, and AUX1, and transactivation assays indicated that GhTCP14 had transcription activation activity. Taken together, these results demonstrate that GhTCP14 is a dual-function transcription factor able to positively or negatively regulate expression of auxin response and transporter genes, thus potentially acting as a crucial regulator in auxin-mediated differentiation and elongation of cotton fiber cells.

The Cotton Transcription Factor TCP14 Functions in Auxin-Mediated Epidermal Cell Differentiation and Elongation1[C][W

PubMed Central

Wang, Miao-Ying; Zhao, Pi-Ming; Cheng, Huan-Qing; Han, Li-Bo; Wu, Xiao-Min; Gao, Peng; Wang, Hai-Yun; Yang, Chun-Lin; Zhong, Nai-Qin; Zuo, Jian-Ru; Xia, Gui-Xian

2013-01-01

Plant-specific TEOSINTE-BRANCHED1/CYCLOIDEA/PCF (TCP) transcription factors play crucial roles in development, but their functional mechanisms remain largely unknown. Here, we characterized the cellular functions of the class I TCP transcription factor GhTCP14 from upland cotton (Gossypium hirsutum). GhTCP14 is expressed predominantly in fiber cells, especially at the initiation and elongation stages of development, and its expression increased in response to exogenous auxin. Induced heterologous overexpression of GhTCP14 in Arabidopsis (Arabidopsis thaliana) enhanced initiation and elongation of trichomes and root hairs. In addition, root gravitropism was severely affected, similar to mutant of the auxin efflux carrier PIN-FORMED2 (PIN2) gene. Examination of auxin distribution in GhTCP14-expressing Arabidopsis by observation of auxin-responsive reporters revealed substantial alterations in auxin distribution in sepal trichomes and root cortical regions. Consistent with these changes, expression of the auxin uptake carrier AUXIN1 (AUX1) was up-regulated and PIN2 expression was down-regulated in the GhTCP14-expressing plants. The association of GhTCP14 with auxin responses was also evidenced by the enhanced expression of auxin response gene IAA3, a gene in the AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) family. Electrophoretic mobility shift assays showed that GhTCP14 bound the promoters of PIN2, IAA3, and AUX1, and transactivation assays indicated that GhTCP14 had transcription activation activity. Taken together, these results demonstrate that GhTCP14 is a dual-function transcription factor able to positively or negatively regulate expression of auxin response and transporter genes, thus potentially acting as a crucial regulator in auxin-mediated differentiation and elongation of cotton fiber cells. PMID:23715527

β-Tricalcium phosphate/poly(glycerol sebacate) scaffolds with robust mechanical property for bone tissue engineering.

PubMed

Yang, Kai; Zhang, Jing; Ma, Xiaoyu; Ma, Yifan; Kan, Chao; Ma, Haiyan; Li, Yulin; Yuan, Yuan; Liu, Changsheng

2015-11-01

Despite good biocompatibility and osteoconductivity, porous β-TCP scaffolds still lack the structural stability and mechanical robustness, which greatly limit their application in the field of bone regeneration. The hybridization of β-TCP with conventional synthetic biodegradable PLA and PCL only produced a limited toughening effect due to the plasticity of the polymers in nature. In this study, a β-TCP/poly(glycerol sebacate) scaffold (β-TCP/PGS) with well interconnected porous structure and robust mechanical property was prepared. Porous β-TCP scaffold was first prepared with polyurethane sponge as template and then impregnated into PGS pre-polymer solution with moderate viscosity, followed by in situ heat crosslinking and freezing-drying process. The results indicated that the freezing-drying under vacuum process could further facilitate crosslinking of PGS and formation of Ca(2+)-COO(-) ionic complexing and thus synergistically improved the mechanical strength of the β-TCP/PGS with in situ heat crosslinking. Particularly, the β-TCP/PGS with 15% PGS content after heat crosslinking at 130°C and freezing-drying at -50°C under vacuum exhibited an elongation at break of 375±25% and a compressive strength of 1.73MPa, 3.7-fold and 200-fold enhancement compared to the β-TCP, respectively. After the abrupt drop of compressive load, the β-TCP/PGS scaffolds exhibited a full recovery of their original shape. More importantly, the PGS polymer in the β-TCP/PGS scaffolds could direct the biomineralization of Ca/P from particulate shape into a nanofiber-interweaved structure. Furthermore, the β-TCP/PGS scaffolds allowed for cell penetration and proliferation, indicating a good cytobiocompatibility. It is believed that β-TCP/PGS scaffolds have great potential application in rigid tissue regeneration. Copyright © 2015 Elsevier B.V. All rights reserved.

Creation of bony microenvironment with CaP and cell-derived ECM to enhance human bone-marrow MSC behavior and delivery of BMP-2

PubMed Central

Kang, Yunqing; Kim, Sungwoo; Khademhosseini, Ali; Yang, Yunzhi

2011-01-01

Extracellular matrix (ECM) comprises a rich meshwork of proteins and proteoglycans, which not only contains biological cues for cell behavior, but is also a reservoir for binding growth factors and controlling their release. Here we aimed to create a suitable bony microenvironment with cell-derived ECM and biodegradable β-tricalcium phosphate (β-TCP). More specifically, we investigated whether the ECM produced by bone marrow-derived mesenchymal stem cells (hBMSC) on a β-TCP scaffold can bind bone morphogenetic protein-2 (BMP-2) and control its release in a sustained manner, and further examined the effect of ECM and the BMP-2 released from ECM on cell behaviors. The ECM was obtained through culturing the hBMSC on a β-TCP porous scaffold and performing decellularization and sterilization. SEM, XPS, FTIR, and immunofluorescent staining results indicated the presence of ECM on the β-TCP and the amount of ECM increased with the incubation time. BMP-2 was loaded onto the β-TCP with and without ECM by immersing the scaffolds in the BMP-2 solution. The loading and release kinetics of the BMP-2 on the β-TCP/ECM were significantly slower than those on the β-TCP. The β-TCP/ECM exhibited a sustained release profile of the BMP-2, which was also affected by the amount of ECM. This is probably because the β-TCP/ECM has different binding mechanisms with BMP-2. The β-TCP/ECM promoted cell proliferation. Furthermore, the BMP-2-loaded β-TCP/ECM stimulated reorganization of the actin cytoskeleton, increased expression of alkaline phosphatase and calcium deposition by the cells compared to those without BMP-2 loading and the β-TCP with BMP-2 loading. PMID:21632105

MBG-Modified β-TCP Scaffold Promotes Mesenchymal Stem Cells Adhesion and Osteogenic Differentiation via a FAK/MAPK Signaling Pathway.

PubMed

Liu, Yutong; Ma, Yifan; Zhang, Jing; Xie, Qing; Wang, Zi; Yu, Shuang; Yuan, Yuan; Liu, Changsheng

2017-09-13

The β-TCP scaffold has been widely used as a bone graft substitute, but the traditional PMMA molding method-induced undesirable mechanical strength and poor interconnectivity still have not been addressed until now. In this study, a MBG-based PU foam templating method was developed to fabricate β-TCP scaffolds with desirable microtopography. The MBG gel, as both binder and modifier, prepared by a modified sol-gel method with controlled viscosity is incorporated with β-TCP powder and thereafter is impregnated into PU foam. The resultant hybrid scaffolds exhibited interconnected macropores (200-500 μm) and distinctive micropores (0.2-1.5 μm), especially for the TCP/25MBG (with 25 wt % content MBG). As expected, the compression strength of β-TCP/MBG composite scaffolds was enhanced with increasing MBG content, and TCP/50MBG (with 50 wt % content MBG) exhibited almost 100-fold enhancement compared to the pure β-TCP. Intriguingly, the cell affinity and osteogenic capacity of rBMSCs were also dramatically improved the best on TCP/25MBG. Further investigation found that the subtle, grainy-like microtopography, not the chemical composition, of the TCP/25MBG favored the adsorption of Fn and expression of integrin α5β1 and further facilitated FA formation and the expression of p-FAK, following activation of the MAPK/ERK signaling pathway and ultimately upregulated expression of osteogenic genes. Further in vivo experiments confirmed the promoted osteogenesis of TCP/25MBG in vivo. The results suggest that such a novel MBG-based PU foam templating method offers new guidance to construct hierarchically porous scaffolds, and the prepared MBG-modified β-TCP scaffold will have great potential for future use in bone tissue regeneration.

In vivo labeling of phencyclidine (PCP) receptors with sup 3 H-TCP in the mouse brain

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

Maurice, T.; Vignon, J.

1990-07-01

The phencyclidine (PCP) derivative N-(1-(2-thienyl)cyclohexyl)-piperidine (3H-TCP) was used to label in vivo the N-methyl-D-aspartate (NMDA) receptor-associated ionic channel in the mouse brain. After the injection of a tracer dose of 3H-TCP, a spread labeling throughout the brain was observed, but was the highest in the cerebellum. Preadministration of unlabeled TCP (30 mg/kg) resulted in a 90% reduction of 3H-TCP binding. PCP, TCP, MK-801, dexoxadrol, ketamine, and SKF 10,047 isomers dose-dependently prevented the in vivo 3H-TCP binding. ID50 determined in the cerebrum and the cerebellum were respectively correlated with K0.5 for 3H TCP high (rat cortex) and low affinity (rat cerebellum)more » sites in vitro. The pharmacological specificity of the 3H-TCP binding site in the cerebellum was significantly different from that in the cerebrum. ID50 values were generally higher than in the cerebrum and, particularly, MK-801, the most potent drug in the cerebrum, was without significant effect in the cerebellum, at any time and at doses as high as 30 mg/kg. N-(1-(2-benzo(b) thiophenyl)cyclohexyl)piperidine (BTCP), desipramine, and atropine showed a more efficient prevention of 3H-TCP binding in the cerebellum than in the cerebrum. The prevention of the binding by TCP or PCP, at doses close to their ID50 values, was rapid and then decreased slowly. The effect of MK-801 was long-lasting. This study confirm previous in vitro studies: 3H-TCP is an efficient tool for the labeling of the NMDA receptor-associated ionic channel.« less

Topologically Close-packed Phase Formation in High Entropy Alloys: A Review of Calphad and Experimental Results

NASA Astrophysics Data System (ADS)

Guruvidyathri, K.; Hari Kumar, K. C.; Yeh, J. W.; Murty, B. S.

2017-11-01

One of the major challenges in high entropy alloy (HEA) research is to obtain single-phase solid solutions by proper selection of components and processing techniques. Often one encounters situations where topologically close-packed (TCP) phases are present in the HEA microstructures. TCP phases are a class of intermetallic phases that are in general considered undesirable. The ability to predict these phases in HEAs using the Calphad (CALculation of PHAse Diagrams) method has been shown to accelerate the identification of promising compositions. In this review, an analysis of the reported Calphad studies and corresponding microstructural information on HEAs is done to evaluate the success of the Calphad method for TCP phases. A total of 52 alloys with 123 post-heat treatment microstructures reported so far have been compared. Challenges and issues in experiments and calculations are brought out with a possible way forward.

Treatment of osteomyelitis defects by a vancomycin-loaded gelatin/β-tricalcium phosphate composite scaffold

PubMed Central

Zhou, J.; Zhou, X. G.; Wang, J. W.; Zhou, H.; Dong, J.

2018-01-01

Objective In the present study, we aimed to assess whether gelatin/β-tricalcium phosphate (β-TCP) composite porous scaffolds could be used as a local controlled release system for vancomycin. We also investigated the efficiency of the scaffolds in eliminating infections and repairing osteomyelitis defects in rabbits. Methods The gelatin scaffolds containing differing amounts of of β-TCP (0%, 10%, 30% and 50%) were prepared for controlled release of vancomycin and were labelled G-TCP0, G-TCP1, G-TCP3 and G-TCP5, respectively. The Kirby-Bauer method was used to examine the release profile. Chronic osteomyelitis models of rabbits were established. After thorough debridement, the osteomyelitis defects were implanted with the scaffolds. Radiographs and histological examinations were carried out to investigate the efficiency of eliminating infections and repairing bone defects. Results The prepared gelatin/β-TCP scaffolds exhibited a homogeneously interconnected 3D porous structure. The G-TCP0 scaffold exhibited the longest duration of vancomycin release with a release duration of eight weeks. With the increase of β-TCP contents, the release duration of the β-TCP-containing composite scaffolds was decreased. The complete release of vancomycin from the G-TCP5 scaffold was achieved within three weeks. In the treatment of osteomyelitis defects in rabbits, the G-TCP3 scaffold showed the most efficacious performance in eliminating infections and repairing bone defects. Conclusions The composite scaffolds could achieve local therapeutic drug levels over an extended duration. The G-TCP3 scaffold possessed the optimal porosity, interconnection and controlled release performance. Therefore, this scaffold could potentially be used in the treatment of chronic osteomyelitis defects. Cite this article: J. Zhou, X. G. Zhou, J. W. Wang, H. Zhou, J. Dong. Treatment of osteomyelitis defects by a vancomycin-loaded gelatin/β-tricalcium phosphate composite scaffold. Bone Joint Res 2018;7:46–57. DOI: 10.1302/2046-3758.71.BJR-2017-0129.R2. PMID:29330343

Genome-wide identification and characterization of TCP transcription factor genes in upland cotton (Gossypium hirsutum).

PubMed

Li, Wen; Li, Deng-Di; Han, Li-Hong; Tao, Miao; Hu, Qian-Qian; Wu, Wen-Ying; Zhang, Jing-Bo; Li, Xue-Bao; Huang, Geng-Qing

2017-08-31

TCP proteins are plant-specific transcription factors (TFs), and perform a variety of physiological functions in plant growth and development. In this study, 74 non-redundant TCP genes were identified in upland cotton (Gossypium hirsutum L.) genome. Cotton TCP family can be classified into two classes (class I and class II) that can be further divided into 11 types (groups) based on their motif composition. Quantitative RT-PCR analysis indicated that GhTCPs display different expression patterns in cotton tissues. The majority of these genes are preferentially or specifically expressed in cotton leaves, while some GhTCP genes are highly expressed in initiating fibers and/or elongating fibers of cotton. Yeast two-hybrid results indicated that GhTCPs can interact with each other to form homodimers or heterodimers. In addition, GhTCP14a and GhTCP22 can interact with some transcription factors which are involved in fiber development. These results lay solid foundation for further study on the functions of TCP genes during cotton fiber development.

GSDO Program Hexavalent Chrome Alternatives: Final Pretreatments Test Report

NASA Technical Reports Server (NTRS)

Kessel, Kurt

2013-01-01

Hexavalent chrome free pretreatments should be considered for use on Ground Support Equipment (OSE) and Electrical Ground Support Equipment (EOSE). Both of the hexavalent chrome free pretreatments (Metalast TCP HF and SurTec 650C) evaluated by this project met, and in some instances exceeded, the requirements ofMIL-DTL-5541 "Chemical Conversion Coatings on Aluminum and Aluminum Alloys". For DC resistance measurements, both Metalast TCP HF and SurTec (!50C met initial requirements following assembly and in many cases continued to maintain passing readings for the duration of testing.

Apple FLOWERING LOCUS T proteins interact with transcription factors implicated in cell growth and organ development.

PubMed

Mimida, Naozumi; Kidou, Shin-Ichiro; Iwanami, Hiroshi; Moriya, Shigeki; Abe, Kazuyuki; Voogd, Charlotte; Varkonyi-Gasic, Erika; Kotoda, Nobuhiro

2011-05-01

Understanding the flowering process in apple (Malus × domestica Borkh.) is essential for developing methods to shorten the breeding period and regulate fruit yield. It is known that FLOWERING LOCUS T (FT) acts as a transmissible floral inducer in the Arabidopsis flowering network system. To clarify the molecular network of two apple FT orthologues, MdFT1 and MdFT2, we performed a yeast two-hybrid screen to identify proteins that interact with MdFT1. We identified several transcription factors, including two members of the TCP (TEOSINTE BRANCHED1, CYCLOIDEA and PROLIFERATING CELL FACTORs) family, designated MdTCP2 and MdTCP4, and an Arabidopsis thaliana VOZ1 (Vascular plant One Zinc finger protein1)-like protein, designated MdVOZ1. MdTCP2 and MdVOZ1 also interacted with MdFT2 in yeast. The expression domain of MdTCP2 and MdVOZ1 partially overlapped with that of MdFT1 and MdFT2, most strikingly in apple fruit tissue, further suggesting a potential interaction in vivo. Constitutive expression of MdTCP2, MdTCP4 and MdVOZ1 in Arabidopsis affected plant size, leaf morphology and the formation of leaf primordia on the adaxial side of cotyledons. On the other hand, chimeric MdTCP2, MdTCP4 and MdVOZ1 repressors that included the ethylene-responsive transcription factors (ERF)-associated amphiphilic repression (EAR) domain motif influenced reproduction and inflorescence architecture in transgenic Arabidopsis. These results suggest that MdFT1 and/or MdFT2 might be involved in the regulation of cellular proliferation and the formation of new tissues and that they might affect leaf and fruit development by interacting with TCP- and VOZ-family proteins. DDBJ accession nos. AB531019 (MdTCP2a mRNA), AB531020 (MdTCP2b mRNA), AB531021 (MdTCP4a mRNA), AB531022 (MdTCP4b mRNA) and AB531023 (MdVOZ1a mRNA). © The Author 2011. Published by Oxford University Press. All rights reserved.

Effect of PDGF-BB and beta-tricalcium phosphate (β-TCP) on bone formation around dental implants: a pilot study in sheep.

PubMed

Choo, Tina; Marino, Victor; Bartold, P Mark

2013-02-01

The aim of this investigation was to examine the effect of a combination of purified recombinant human platelet-derived growth factor (rhPDGF-BB) mixed with a synthetic beta-tricalcium phosphate (β-TCP) on bone healing around dental implants with critical size circumferential defects. Three critical size circumferential defects were prepared in the ilium of six sheep. Three dental implants were placed into the centre of each defect and the 3.25 mm circumferential gap was filled with (a) blood clot alone; (b) β-TCP; (c) rhPDGF-BB (0.3 mg/ml) with β-TCP. All the defects in each group were covered with a Bio-Gide(®) resorbable barrier membrane. The sheep were sacrificed at 2 and 4 weeks and histological and histomorphometric analyses were performed to determine the percentage of new mineralized bone formation and residual β-TCP graft particles in the defects. Defects filled with rhPDGF-BB/β-TCP showed the highest rate of bone formation after 2 and 4 weeks with limited degradation of the β-TCP particles over 4 weeks. Defects filled with β-TCP showed the least bone fill after 2 and 4 weeks, and faster degradation of the β-TCP particles over 4 weeks compared with defects filled with rhPDGF-BB/β-TCP. Percentage of new mineralized bone was comparable in defects to blood clot alone and β-TCP after 4 weeks of healing, but there was a collapse in the defect area in defects with blood clot alone. In comparison, the space was maintained when β-TCP was used in defects at 4 weeks. Defects which had β-TCP alone showed an inhibition in bone healing at 2 and 4 weeks; however, the combination of rhPDGF-BB with β-TCP enhanced bone regeneration in these peri-implant bone defects at the same time intervals. © 2011 John Wiley & Sons A/S.

UV photolysis for enhanced phenol biodegradation in the presence of 2,4,6-trichlorophenol (TCP).

PubMed

Song, Jiaxiu; Wang, Wenbing; Li, Rongjie; Zhu, Jun; Zhang, Yongming; Liu, Rui; Rittmann, Bruce E

2016-02-01

A bacterial strain isolated from activated sludge and identified as Bacillus amyloliquefaciens could biodegrade phenol, but 2,4,6-trichlorophenol (TCP) inhibited phenol biodegradation and biomass growth. UV photolysis converted TCP into dichlorocatechol, monochlorophenol, and dichlorophenol, and this relieved inhibition by TCP. Phenol-removal and biomass-growth rates were significantly accelerated after UV photolysis: the monod maximum specific growth rate (μ(max)) increased by 9% after TCP photolysis, and the half-maximum-rate concentration (K(S)) decreased by 36%. Thus, the major benefit of UV photolysis in this case was to transform TCP into a set of much-less-inhibitory products.

Biotype-specific tcpA genes in Vibrio cholerae.

PubMed

Iredell, J R; Manning, P A

1994-08-01

The tcpA gene, encoding the structural subunit of the toxin-coregulated pilus, has been isolated from a variety of clinical isolates of Vibrio cholerae, and the nucleotide sequence determined. Strict biotype-specific conservation within both the coding and putative regulatory regions was observed, with important differences between the El Tor and classical biotypes. V. cholerae O139 Bengal strains appear to have El Tor-type tcpA genes. Environmental O1 and non-O1 isolates have sequences that bind an El Tor-specific tcpA DNA probe and that are weakly and variably amplified by tcpA-specific polymerase chain reaction primers, under conditions of reduced stringency. The data presented allow the selection of primer pairs to help distinguish between clinical and environmental isolates, and to distinguish El Tor (and Bengal) biotypes from classical biotypes of V. cholerae. While the role of TcpA in cholera vaccine preparations remains unclear, the data strongly suggest that TcpA-containing vaccines directed at O1 strains need include only the two forms of TcpA, and that such vaccines directed at (O139) Bengal strains should include the TcpA of El Tor biotype.

Development and Characterization of Biphasic Hydroxyapatite/β-TCP Cements

PubMed Central

Gallinetti, Sara; Canal, Cristina; Ginebra, Maria-Pau; Ferreira, J

2014-01-01

Biphasic calcium phosphate bioceramics composed of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) have relevant properties as synthetic bone grafts, such as tunable resorption, bioactivity, and intrinsic osteoinduction. However, they have some limitations associated to their condition of high-temperature ceramics. In this work self-setting Biphasic Calcium Phosphate Cements (BCPCs) with different HA/β-TCP ratios were obtained from self-setting α-TCP/β-TCP pastes. The strategy used allowed synthesizing BCPCs with modulated composition, compressive strength, and specific surface area. Due to its higher solubility, α-TCP was fully hydrolyzed to a calcium-deficient HA (CDHA), whereas β-TCP remained unreacted and completely embedded in the CDHA matrix. Increasing amounts of the non-reacting β-TCP phase resulted in a linear decrease of the compressive strength, in association to the decreasing amount of precipitated HA crystals, which are responsible for the mechanical consolidation of apatitic cements. Ca2+ release and degradation in acidic medium was similar in all the BCPCs within the timeframe studied, although differences might be expected in longer term studies once β-TCP, the more soluble phase was exposed to the surrounding media. PMID:25866411

Arabidopsis TCP Transcription Factors Interact with the SUMO Conjugating Machinery in Nuclear Foci

PubMed Central

Mazur, Magdalena J.; Spears, Benjamin J.; Djajasaputra, André; van der Gragt, Michelle; Vlachakis, Georgios; Beerens, Bas; Gassmann, Walter; van den Burg, Harrold A.

2017-01-01

In Arabidopsis more than 400 proteins have been identified as SUMO targets, both in vivo and in vitro. Among others, transcription factors (TFs) are common targets for SUMO conjugation. Here we aimed to exhaustively screen for TFs that interact with the SUMO machinery using an arrayed yeast two-hybrid library containing more than 1,100 TFs. We identified 76 interactors that foremost interact with the SUMO conjugation enzyme SCE1 and/or the SUMO E3 ligase SIZ1. These interactors belong to various TF families, which control a wide range of processes in plant development and stress signaling. Amongst these interactors, the TCP family was overrepresented with several TCPs interacting with different proteins of the SUMO conjugation cycle. For a subset of these TCPs we confirmed that the catalytic site of SCE1 is essential for this interaction. In agreement, TCP1, TCP3, TCP8, TCP14, and TCP15 were readily SUMO modified in an E. coli sumoylation assay. Strikingly, these TCP-SCE1 interactions were found to redistribute these TCPs into nuclear foci/speckles, suggesting that these TCP foci represent sites for SUMO (conjugation) activity. PMID:29250092

The Arabidopsis transcription factor AtTCP15 regulates endoreduplication by modulating expression of key cell-cycle genes.

PubMed

Li, Zi-Yu; Li, Bin; Dong, Ai-Wu

2012-01-01

Plant cells frequently undergo endoreduplication, a modified cell cycle in which genome is repeatedly replicated without cytokinesis. As the key step to achieve final size and function for cells, endoreduplication is prevalent during plant development. However, mechanisms to control the balance between endoreduplication and mitotic cell division are still poorly understood. Here, we show that the Arabidopsis TCP (CINCINNATA-like TEOSINTE BRANCHED1-CYCLOIDEA-PCF)-family transcription factor gene AtTCP15 is expressed in trichomes, as well as in rapidly dividing and vascular tissues. Expression of AtTCP15SRDX, AtTCP15 fused with a SRDX repressor domain, induces extra endoreduplication in trichomes and cotyledon cells in transgenic Arabidopsis. On the contrary, overexpression of AtTCP15 suppresses endoreduplication in trichomes and other examined cells. Misregulation of AtTCP15 affects the expression of several important genes involved in cell-cycle regulation. AtTCP15 protein binds directly to the promoter regions of CYCA2;3 and RETINOBLASTOMA-RELATED (RBR) genes, which play key roles in endoreduplication. Taken together, AtTCP15 plays an important role in regulating endoreduplication during Arabidopsis development.

Tricresyl phosphate and the aerotoxic syndrome of flight crew members--current gaps in knowledge.

PubMed

de Boer, Jacob; Antelo, Angel; van der Veen, Ike; Brandsma, Sicco; Lammertse, Nienke

2015-01-01

Tricresyl phosphate (TCP), and in particular its tri-ortho substituted isomer (o,o,o-TCP), has been frequently used in aircraft engine oil. Bleed air, provided to the flight deck and cabin can contain traces of TCP. TCP can cause neurotoxic effects in humans. Regularly, airline pilots complain about loss of memory, headaches, dizziness, tunnel vision and other neurotoxic effects. The concentrations of TCP reported in flight deck air (max. ca. 50-100 ng m(-3) total TCP) do not exceed provisional toxicity thresholds. These thresholds, however, contain a very high uncertainty and need further underpinning. The many non-detects and relatively low TCP concentrations reported suggest that TCP on its own is not likely to be responsible for the reported health problems of pilots. Specific conditions in air planes and other toxic compounds present in bleed air, whether or not in combination with TCP, may be responsible for the reported neurotoxic syndromes. Sensitivity of individuals seems to be an important factor as well. The clinical signs observed with a selected group of pilots are serious enough to call for further elucidation of this issue. Copyright © 2014 Elsevier Ltd. All rights reserved.

Potential performance bottleneck in Linux TCP

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

Wu, Wenji; Crawford, Matt; /Fermilab

2006-12-01

TCP is the most widely used transport protocol on the Internet today. Over the years, especially recently, due to requirements of high bandwidth transmission, various approaches have been proposed to improve TCP performance. The Linux 2.6 kernel is now preemptible. It can be interrupted mid-task, making the system more responsive and interactive. However, we have noticed that Linux kernel preemption can interact badly with the performance of the networking subsystem. In this paper we investigate the performance bottleneck in Linux TCP. We systematically describe the trip of a TCP packet from its ingress into a Linux network end system tomore » its final delivery to the application; we study the performance bottleneck in Linux TCP through mathematical modeling and practical experiments; finally we propose and test one possible solution to resolve this performance bottleneck in Linux TCP.« less

A novel vascular-targeting peptide for gastric cancer delivers low-dose TNFα to normalize the blood vessels and improve the anti-cancer efficiency of 5-fluorouracil.

PubMed

Lu, Lan; Li, Zhi Jie; Li, Long Fei; Shen, Jing; Zhang, Lin; Li, Ming Xing; Xiao, Zhan Gang; Wang, Jian Hao; Cho, Chi Hin

2017-11-01

Various vascular-targeted agents fused with tumor necrosis factor α (TNFα) have been shown to improve drug absorption into tumor tissues and enhance tumor vascular function. TCP-1 is a peptide selected through in vivo phage library biopanning against a mouse orthotopic colorectal cancer model and is a promising agent for drug delivery. This study further investigated the targeting ability of TCP-1 phage and peptide to blood vessels in an orthotopic gastric cancer model in mice and assessed the synergistic anti-cancer effect of 5-fluorouracil (5-FU) with subnanogram TNFα targeted delivered by TCP-1 peptide. In vivo phage targeting assay and in vivo colocalization analysis were carried out to test the targeting ability of TCP-1 phage/peptide. A targeted therapy for improvement of the therapeutic efficacy of 5-FU and vascular function was performed through administration of TCP-1/TNFα fusion protein in this model. TCP-1 phage exhibited strong homing ability to the orthotopic gastric cancer after phage injection. Immunohistochemical staining suggested that and TCP-1 phage/TCP-1 peptide could colocalize with tumor vascular endothelial cells. TCP-1/TNFα combined with 5-FU was found to synergistically inhibit tumor growth, induce apoptosis and reduce cell proliferation without evident toxicity. Simultaneously, subnanogram TCP-1/TNFα treatment normalized tumor blood vessels. Targeted delivery of low-dose TNFα by TCP-1 peptide can potentially modulate the vascular function of gastric cancer and increase the drug delivery of chemotherapeutic drugs. Copyright © 2017. Published by Elsevier Inc.

In vitro biological evaluation of beta-TCP/HDPE--A novel orthopedic composite: a survey using human osteoblast and fibroblast bone cells.

PubMed

Homaeigohar, S Sh; Shokrgozar, M A; Khavandi, A; Sadi, A Yari

2008-02-01

Beta-tricalcium phosphate reinforced high density polyethylene (beta-TCP/HDPE) was prepared to simulate bone composition and to study its capacity to act as bone tissue. This material was produced by replacing the mineral component and collagen soft tissue of the bone with beta-TCP and HDPE, respectively. The biocompatibility of the composite samples with different volume fractions of TCP (20, 30 and 40 vol %) was examined in vitro using two osteoblast cell lines G-292 and Saos-2, and also a type of fibroblast cell isolated from bone tissue, namely human bone fibroblast (HBF) by proliferation, and cell adhesion assays. Cell-material interaction with the surface of the composite samples was examined by scanning electron microscopy (SEM). The effect of beta-TCP/HDPE on the behavior of osteoblast and fibroblast cells was compared with those of composite and negative control samples; polyethylene (PE) and tissue culture polystyrene (TPS), respectively. In general, the results showed that the composite samples containing beta-TCP as reinforcement supported a higher rate of proliferation by various bone cells after 3, 7, and 14 days of incubation compared to the composite control sample. Furthermore, more osteoblast cells were attached to the surface of the composite samples when compared to the composite control samples after the above incubation periods (p < 0.05), while in the case of HBF an equal or even higher number of cells adhered to PE was observed. The number of adhered osteoblast cells was almost equal and in some days even higher than the number of adhered cells on negative control sample, while in the case of fibroblast this difference was significantly higher than TPS (p < 0.05). Adhered cells presented a normal morphology by SEM and many of the cells were observed to be undergoing cell division. These findings indicate that beta-TCP/HDPE composites are biocompatible, nontoxic, and act to stimulate proliferation and adhesion of the cells, whether osteoblast or fibroblast. (c) 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008.

Cu2+, Co2+ and Cr3+ doping of a calcium phosphate cement influences materials properties and response of human mesenchymal stromal cells.

PubMed

Schamel, Martha; Bernhardt, Anne; Quade, Mandy; Würkner, Claudia; Gbureck, Uwe; Moseke, Claus; Gelinsky, Michael; Lode, Anja

2017-04-01

The application of biologically active metal ions to stimulate cellular reactions is a promising strategy to accelerate bone defect healing. Brushite-forming calcium phosphate cements were modified with low doses of Cu 2+ , Co 2+ and Cr 3+ . The modified cements released the metal ions in vitro in concentrations which were shown to be non-toxic for cells. The release kinetics correlated with the solubility of the respective metal phosphates: 17-45 wt.-% of Co 2+ and Cu 2+ , but <1 wt.-% of Cr 3+ were released within 28days. Moreover, metal ion doping led to alterations in the exchange of calcium and phosphate ions with cell culture medium. In case of cements modified with 50mmol Cr 3+ /mol β-tricalcium phosphate (β-TCP), XRD and SEM analyses revealed a significant amount of monetite and a changed morphology of the cement matrix. Cell culture experiments with human mesenchymal stromal cells indicated that the observed cell response is not only influenced by the released metal ions but also by changed cement properties. A positive effect of modifications with 50mmol Cr 3+ or 10mmol Cu 2+ per mol β-TCP on cell behaviour was observed in indirect and direct culture. Modification with Co 2+ resulted in a clear suppression of cell proliferation and osteogenic differentiation. In conclusion, metal ion doping of the cement influences cellular activities in addition to the effect of released metal ions by changing properties of the ceramic matrix. Copyright © 2016 Elsevier B.V. All rights reserved.

Calcium sources and their interaction with the different levels of non-phytate phosphorus affect performance and bone mineralization in broiler chickens.

PubMed

Hamdi, M; Solà-Oriol, D; Davin, R; Perez, J F

2015-09-01

An experiment was conducted to evaluate the influence of different Ca sources (limestone, Ca chloride, and Lipocal, a fat-encapsulated tricalcium phosphate, TCP) in conjunction with 4 dietary levels of non-phytate P (NPP) on performance, ileal digestibility of Ca and P, and bone mineralization in broiler chickens. Calcium sources were also evaluated in vitro to measure acid-binding capacity (ABC) and Ca solubility at different pH values. Ca chloride showed the highest solubility of Ca, with TCP showing the highest ABC. Ross male broiler-chicks were sorted by BW at 1 d post-hatch and assigned to 5 cages per diet with 5 birds per cage. Twelve diets were arranged in a 3×4 factorial of the 3 Ca sources and 4 levels of NPP (0.3%, 0.35%, 0.4% or 0.45%) consisting of 4 added P levels (Ca(H2PO4)2) with a high dose of phytase (1,150 U/kg) in all diets. On d 14 post-hatch, 3 birds were euthanized, and ileal digesta and the right tibia were collected to determine ileal Ca and P digestibility and bone mineralization, respectively. Feed intake (FI) and weight gain (WG) on d 14 was higher (P<0.01) with TCP and limestone than with Ca chloride. Added P increased the tibia weight and tibia ash content in chicks fed TCP up to 0.4% NPP and limestone up to 0.35% NPP. Calcium ileal digestibility was higher (P<0.01) with Ca chloride (73.7%) than with limestone (67.1%) or TCP (66.8%), which increased (P<0.05) with added levels of P from monocalcium phosphate. Phosphorus ileal digestibility was not affected by the Ca source and increased (P<0.001) with added levels of NPP. It can be concluded that starting broilers responded better to low-soluble Ca sources compared to high-soluble sources. A level of 0.35%-0.40% NPP with a high dose of phytase (1,150 U/kg) in diets including limestone or TCP is sufficient to guarantee performance and bone formation for broiler chickens from d 0 to d 14. © 2015 Poultry Science Association Inc.

A Holistic Approach to Evaluating Vocational Education: Traditional Chinese Physicians (TCP) Model.

ERIC Educational Resources Information Center

Lee, Lung-Sheng; Chang, Liang-Te

Conventional approaches to evaluating vocational education have often been criticized for failing to deal holistically with the institution or program being evaluated. Integrated quantitative and qualitative evaluation methods have documented benefits; therefore, it would be useful to consider possibility of developing a model for evaluating…

The TCP4 transcription factor of Arabidopsis blocks cell division in yeast at G1→S transition.

PubMed

Aggarwal, Pooja; Padmanabhan, Bhavna; Bhat, Abhay; Sarvepalli, Kavitha; Sadhale, Parag P; Nath, Utpal

2011-07-01

The TCP transcription factors control important aspects of plant development. Members of class I TCP proteins promote cell cycle by regulating genes directly involved in cell proliferation. In contrast, members of class II TCP proteins repress cell division. While it has been postulated that class II proteins induce differentiation signal, their exact role on cell cycle has not been studied. Here, we report that TCP4, a class II TCP protein from Arabidopsis that repress cell proliferation in developing leaves, inhibits cell division by blocking G1→S transition in budding yeast. Cells expressing TCP4 protein with increased transcriptional activity fail to progress beyond G1 phase. By analyzing global transcriptional status of these cells, we show that expression of a number of cell cycle genes is altered. The possible mechanism of G1→S arrest is discussed. Copyright © 2011 Elsevier Inc. All rights reserved.

Bioelectrochemical Magnetic Immunosensing of Trichloropyridinol: A Potential Insecticide Biomarker

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

Liu, Guodong; Timchalk, Chuck; Lin, Yuehe

2006-07-01

A magnetic beads-based bioelectrochemical magnetic immunosensor was developed for the fast and sensitive determination of the trichloropyridinol (TCP) biomarker in environmental samples. After liquid phrase competitive immunoreaction among a limited amount of TCP antibody coated-magnetic beads (Ab-MBs), TCP analyte, and horseradish peroxidase (HRP) labeled TCP (HRP-TCP), a magnet/glassy carbon (MGC) electrode was used to collect a TCP-Abs-MBs and a HRP-TCP-Ab-MBs immunocomplex assembly. The activity of HRP tracers bound to the beads was monitored with highly sensitive square wave voltammetry (SWV) by accumulating an electroactive enzymatic product to the MGC electrode surface under constant potential (0.5 V) during enzymatic reaction inmore » the presence of 3’,3’,5’,5’-tetramethylbenzidine (TMB)-H2O2 substrate solution. The electrochemical characteristics of substrate and product were investigated, and the parameters of the immunoassay were optimized.« less

Improved Heat Dissipation of High-Power LED Lighting by a Lens Plate with Thermally-Conductive Plastics.

PubMed

Lee, Dong Kyu; Park, Hyun Jung; Cha, Yu-Jung; Kim, Hyeong Jin; Kwak, Joon Seop

2018-03-01

The junction temperature of high-power LED lighting was reduced effectively using a lens plate made from a thermally-conductive plastics (TCP). TCP has an excellent thermal conductivity, approximately 5 times that of polymethylmethacrylate (PMMA). Two sets of high-power LED lighting were designed using a multi array LED package with a lens plate for thermal simulation. The difference between two models was the materials of the lens plate. The lens plates of first and second models were fabricated by PMMA (PMMA lighting) and TCP (TCP lighting), respectively. At the lens plate, the simulated temperature of the TCP lighting was higher than that of the PMMA lighting. Near the LED package, the temperature of the TCP lighting was 2 °C lower than that of the PMMA lighting. This was well matched with the measured temperature of the fabricated lighting with TCP and PMMA.

Cloning of the chaperonin t-complex polypeptide 1 gene from Schistosoma mansoni and studies of its expression levels under heat shock and oxidative stress.

PubMed

Campos, E G; Hamdan, F F

2000-03-01

The protein TCP-1 (t-complex polypeptide 1) is a subunit of the hetero-oligomeric complex CCT (chaperonin containing TCP- 1) present in the eukaryotic cytosol. Chaperone function may be critical for the development and survival of the different life stages of Schistosoma mansoni, a parasite that is exposed to drastic environmental changes during its development. We isolated a full-length S. mansoni TCP-1 cDNA (SmTCP-1A) encoding a protein highly homologous with TCP-1. The deduced SmTCP-1A amino-acid sequence shows up to 65% identity with other eukaryotic CCT family members. Semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed that the mRNA expression levels of SmTCP-1A in adult S. mansoni were down-regulated in worms subjected to heat shock and oxidative stress conditions. This down-regulation of SmTCP-1A mRNA may reflect a switch in CCT subunits as an adaptive response to heat shock and oxidative stress conditions.

RABBIT EARS regulates the transcription of TCP4 during petal development in Arabidopsis.

PubMed

Li, Jing; Wang, Yanzhi; Zhang, Yongxia; Wang, Weiyao; Irish, Vivian F; Huang, Tengbo

2016-12-01

Plant organ growth requires the proper transition from cell proliferation to cell expansion and differentiation. The CIN-TCP transcription factor gene TCP4 and its post-transcriptional regulator microRNA319 play a pivotal role in this process. In this study, we identified a pathway in which the product of the C2H2 zinc finger gene RABBIT EARS (RBE) regulates the transcription of TCP4 during Arabidopsis (Arabidopsis thaliana) petal development. RBE directly represses TCP4 during the early stages of petal development; this contributes to the role of RBE in controlling the growth of petal primordia. We also found that the rbe-1 mutant strongly enhanced the petal phenotypes of tcp4soj6 and mir319a, two mutants with compromised miR319 regulation of TCP4 Our results show that transcriptional and post-transcriptional regulation function together to pattern the spatial and temporal expression of TCP4 This in turn controls petal size and shape in Arabidopsis. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Thymic progenitor homing and lymphocyte homeostasis are linked via S1P-controlled expression of thymic P-selectin/CCL25.

PubMed

Gossens, Klaus; Naus, Silvia; Corbel, Stephane Y; Lin, Shujun; Rossi, Fabio M V; Kast, Jürgen; Ziltener, Hermann J

2009-04-13

Thymic T cell progenitor (TCP) importation is a periodic, gated event that is dependent on the expression of functional P-selectin ligands on TCPs. Occupancy of intrathymic TCP niches is believed to negatively regulate TCP importation, but the nature of this feedback mechanism is not yet resolved. We show that P-selectin and CCL25 are periodically expressed in the thymus and are essential parts of the thymic gate-keeping mechanism. Periodicity of thymic TCP receptivity and the size of the earliest intrathymic TCP pool were dependent on the presence of functional P-selectin ligand on TCPs. Furthermore, we show that the numbers of peripheral blood lymphocytes directly affected thymic P-selectin expression and TCP receptivity. We identified sphingosine-1-phosphate (S1P) as one feedback signal that could mediate influence of the peripheral lymphocyte pool on thymic TCP receptivity. Our findings suggest a model whereby thymic TCP importation is controlled by both early thymic niche occupancy and the peripheral lymphocyte pool via S1P.

The adsorption and thermal decomposition of tricresylphosphate (TCP) on iron and gold

NASA Technical Reports Server (NTRS)

Wheeler, D. R.; Faut, O. D.

1983-01-01

Because tricresyl-phosphate (TCP) is a common antiwear additive in lubricants, there is great interest in its interactions with metal substrates. The TCP was allowed to adsorb on polycrystalline iron and gold at room temperature. X-ray photoelectron spectroscopy (XPS) was used to analyze the adsorbed species. The substrate was then heated in steps to 330 C, and the changes in the adsorbate were analyzed after each step. On both substrates saturation adsorption occurred at about one monolayer, but the sticking coefficient was less on gold than on iron. Comparison of the XPS spectra of TCP on each substrate with the spectrum from condensed TCP indicated nondissociative adsorption on gold, possibly by dipole-induced dipole interaction. On iron, there was apparently additional interaction between the substrate and the tolyl groups on the TCP molecule. TCP began to desorb molecularly from gold as soon as the gold was heated above room temperature. The desorption was complete by 200 C. However, when the iron substrate was heated, TCP did not desorb but decomposed between 150 and 250 C.

SDTCP: Towards Datacenter TCP Congestion Control with SDN for IoT Applications.

PubMed

Lu, Yifei; Ling, Zhen; Zhu, Shuhong; Tang, Ling

2017-01-08

The Internet of Things (IoT) has gained popularity in recent years. Today's IoT applications are now increasingly deployed in cloud platforms to perform Big Data analytics. In cloud data center networks (DCN), TCP incast usually happens when multiple senders simultaneously communicate with a single receiver. However, when TCP incast happens, DCN may suffer from both throughput collapse for TCP burst flows and temporary starvation for TCP background flows. In this paper, we propose a software defined network (SDN)-based TCP congestion control mechanism, referred to as SDTCP, to leverage the features, e.g., centralized control methods and the global view of the network, in order to solve the TCP incast problems. When we detect network congestion on an OpenFlow switch, our controller can select the background flows and reduce their bandwidth by adjusting the advertised window of TCP ACK packets of the corresponding background flows so as to reserve more bandwidth for burst flows. SDTCP is transparent to the end systems and can accurately decelerate the rate of background flows by leveraging the global view of the network gained via SDN. The experiments demonstrate that our SDTCP can provide high tolerance for burst flows and achieve better flow completion time for short flows. Therefore, SDTCP is an effective and scalable solution for the TCP incast problem.

Fabrication and characterization of toughness-enhanced scaffolds comprising β-TCP/POC using the freeform fabrication system with micro-droplet jetting.

PubMed

Gao, Li; Li, Cuidi; Chen, Fangping; Liu, Changsheng

2015-06-24

A novel elastomeric material, poly(1,8-octanediol-co-citrate) (POC), has demonstrated tremendous versatility because of its advantageous toughness, tunable degradation properties, and efficient drug release capability. In this study, POC was used to improve the mechanical performance of β-tricalcium phosphate (β-Ca3(PO4)2, β-TCP). (3D) β-TCP/POC composite scaffolds were fabricated by a 3D printing technique based on the freeform fabrication system with micro-droplet jetting (FFS-MDJ). The physiochemical properties, compressive modulus, drug release behavior, and cell response of β-TCP/POC composite scaffolds were systematically investigated. The results showed that β-TCP/POC scaffolds had uniform macropores of 300-400 μm, porosity of approximately 45%, biodegradability in phosphate-buffered saline, and high compressive modulus of 50-75 MPa. With the incorporation of POC into β-TCP, the toughness of the composite scaffolds was improved significantly. Moreover, β-TCP/POC scaffolds exhibited sustained drug (ibuprofen (IBU)) release capability. Additionally, β-TCP/POC scaffolds facilitated C2C12 cell attachment and proliferation. It was indicated that the 3D-printed porous β-TCP/POC scaffolds with high compressive modulus and good drug delivery performance might be a promising candidate for bone defect repair.

Characterization and Expression Pattern Analysis of the T-Complex Protein-1 Zeta Subunit in Musca domestica L (Diptera).

PubMed

Zhao, Xuejun; Xiu, Jiangfan; Li, Yan; Ma, Huiling; Wu, Jianwei; Wang, Bo; Guo, Guo

2017-07-01

Chaperonins, belonging to the T-complex protein-1 (TCP-1) family, assist in the correct folding of nascent and misfolded proteins. It is well-known that in mammals, the zeta subunit of the TCP-1 complex (TCP-1ζ) plays a vital role in the folding and assembly of cytoskeleta proteins. This study reported for the first time the cloning, characterization and expression pattern analysis of the TCP-1ζ from Musca domestica, which was named as MdTCP-1ζ. The MdTCP-1ζ cDNA is 1,803 bp long with a 1,596 bp open reading frame that encodes a protein with 531 bp amino acids. The analysis of the transcriptional profile of MdTCP-1ζ using qRT-PCR revealed relatively high expression in the salivary glands and trachea at the tissues while among the developmental stages. The highest expression was observed only in the eggs suggesting that the MdTCP-1ζ may play a role in embryonic development. The expression of MdTCP-1ζ was also significantly induced after exposure to short-term heat shock and infection by Escherichia coli, Staphylococcus aureus, or Candida albicans. This suggested that MdTCP-1ζ may take part in the immune responses of housefly and perhaps contribute to the protection against cellular injury. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

Expression of caveolin-1 in the early phase of beta-TCP implanted in dog mandible.

PubMed

Chou, Cherng-Tzeh; Bhawal, Ujjal K; Watanabe, Nobuyuki; Kuboyama, Noboru; Chang, Wei-Jen; Lee, Sheng-Yang; Abiko, Yoshimitsu

2013-07-01

Caveolin is an essential and signature protein of caveolae. Caveolin-1 participates in signal transduction processes by acting as a scaffolding protein that concentrates, organizes and functional regulates signalling molecules within caveolar membranes. Beta-tricalcium phosphate (β-TCP) has been widely used for scaffold in tissue engineering due to its high biodegradability, osteoconductivity, easy manipulation, and lack of histotoxicity. To better understand the role of caveolin-1 in bone homeostasis and response to β-TCP scaffold, β-TCP was implanted into the dog mandible defects in beagle dogs, and gene expression profiles were examined focused on the molecular components involved in caveolin-1 regulation. Here we showed the quantitative imageology analysis characterized using in vivo micro-computed tomography (CT) images at 4 and 7 days after β-TCP implanted in dog mandibles. The bone reformation by using the β-TCP scaffolds began within 4 days of surgery, and was healing well at 7 days after surgery. Higher mRNA level of caveolin-1 was observed in β-TCP-implanted Beagle dog mandibles compared with controls at day 4 and day 7 post-surgery. The enhancement of caveolin-1 by β-TCP was further confirmed by immunohistochemistry and immunofluorescence analysis. We further revealed increased Smad7 and Phospho Stat3 expression in β-TCP-implanted specimens. Taken together, these results suggest that the enhancement of caveolin-1 play an important role in accelerating bone formation by β-TCP. Copyright © 2013 Wiley Periodicals, Inc.

Socket preservation by beta-tri-calcium phosphate with collagen compared to platelet-rich fibrin: A clinico-radiographic study

PubMed Central

Das, Swati; Jhingran, Rajesh; Bains, Vivek Kumar; Madan, Rohit; Srivastava, Ruchi; Rizvi, Iram

2016-01-01

Objectives: This study was primarily designed to determine the clinico-radiographic efficacy of platelet-rich fibrin (PRF) and beta-tri-calcium phosphate with collagen (β-TCP-Cl) in preserving extraction sockets. Materials and Methods: For Group I (PRF), residual sockets (n = 15) were filled with autologous PRF obtained from patients' blood; and for Group II (β-TCP-Cl), residual sockets (n = 15) were filled with β-TCP-Cl. For the sockets randomly selected for Group II (β-TCP-Cl), the reshaped Resorbable Tissue Replacement cone was inserted into the socket. Results: Clinically, there was a significantly greater decrease in relative socket depth, but apposition in midcrestal height in Group II (β-TCP-Cl) as compared to Group I (PRF), whereas more decrease in buccolingual width of Group I (PRF) than Group II (β-TCP-Cl) after 6 months. Radiographically, the mean difference in socket height, residual ridge, and width (coronal, middle, and apical third of socket) after 6 months was higher in Group I (PRF) as compared to Group II (β-TCP-Cl). The mean density (in Hounsfield Units) at coronal, middle, and apical third of socket was higher in Group I (PRF) as compared to Group II (β-TCP-Cl). There were statistically significant apposition and resorption for Group I (PRF) whereas nonsignificant resorption and significant apposition for Group II (β-TCP-Cl) in buccal and lingual/palatal cortical plate, respectively, at 6 months on computerized tomography scan. Conclusion: The use of either autologous PRF or β-TCP-Cl was effective in socket preservation. Results obtained from PRF were almost similar to β-TCP-Cl; therefore being autologous, nonimmune, cost-effective, easily procurable regenerative biomaterial, PRF proves to be an insight into the future biofuel for regeneration. PMID:27095909

Socket preservation by beta-tri-calcium phosphate with collagen compared to platelet-rich fibrin: A clinico-radiographic study.

PubMed

Das, Swati; Jhingran, Rajesh; Bains, Vivek Kumar; Madan, Rohit; Srivastava, Ruchi; Rizvi, Iram

2016-01-01

This study was primarily designed to determine the clinico-radiographic efficacy of platelet-rich fibrin (PRF) and beta-tri-calcium phosphate with collagen (β-TCP-Cl) in preserving extraction sockets. For Group I (PRF), residual sockets (n = 15) were filled with autologous PRF obtained from patients' blood; and for Group II (β-TCP-Cl), residual sockets (n = 15) were filled with β-TCP-Cl. For the sockets randomly selected for Group II (β-TCP-Cl), the reshaped Resorbable Tissue Replacement cone was inserted into the socket. Clinically, there was a significantly greater decrease in relative socket depth, but apposition in midcrestal height in Group II (β-TCP-Cl) as compared to Group I (PRF), whereas more decrease in buccolingual width of Group I (PRF) than Group II (β-TCP-Cl) after 6 months. Radiographically, the mean difference in socket height, residual ridge, and width (coronal, middle, and apical third of socket) after 6 months was higher in Group I (PRF) as compared to Group II (β-TCP-Cl). The mean density (in Hounsfield Units) at coronal, middle, and apical third of socket was higher in Group I (PRF) as compared to Group II (β-TCP-Cl). There were statistically significant apposition and resorption for Group I (PRF) whereas nonsignificant resorption and significant apposition for Group II (β-TCP-Cl) in buccal and lingual/palatal cortical plate, respectively, at 6 months on computerized tomography scan. The use of either autologous PRF or β-TCP-Cl was effective in socket preservation. Results obtained from PRF were almost similar to β-TCP-Cl; therefore being autologous, nonimmune, cost-effective, easily procurable regenerative biomaterial, PRF proves to be an insight into the future biofuel for regeneration.

The class I protein AtTCP15 modulates plant development through a pathway that overlaps with the one affected by CIN-like TCP proteins.

PubMed

Uberti-Manassero, Nora G; Lucero, Leandro E; Viola, Ivana L; Vegetti, Abelardo C; Gonzalez, Daniel H

2012-01-01

The function of the class I TCP transcription factor TCP15 from Arabidopsis thaliana has been studied through the analysis of plants that express a fusion of this protein to the EAR repressor domain. Constitutive expression of TCP15-EAR produces growth arrest at the seedling stage, before leaf emergence. Expression of the repressor fusion from the AtTCP15 promoter produces small plants with leaves whose margins progressively curve upwards, starting from the basal part of the lamina. Leaves contain smaller and less differentiated cells, both on the adaxial and abaxial sides. The abaxial domain is relatively enlarged, with disorganized cells separated by empty spaces. TCP15-EAR also affects the growth of leaf petioles, flower pedicels, and anther filaments. Flowers show reduced elongation of the three outer whorls and altered gynoecia with irregular carpel surfaces and enlarged repla. Ectopic stigma-like structures develop from medial and basal parts of the replum. TCP15-EAR produces an increase in expression of the boundary-specific genes LOB, CUC1, and CUC2. Changes in CUC1 and CUC2 expression can be explained by the existence of lower levels of miR164 in leaves and the repression of IAA3/SHY2 and the SAUR-like gene At1g29460 in leaves and flowers. TCP15 binds to the promoter regions of IAA3/SHY2 and At1g29460, suggesting that these genes may be direct targets of the transcription factor. The results indicate that TCP15 regulates the expression of boundary-specific genes through a pathway that affects auxin homeostasis and partially overlaps with the one modulated by class II CIN-like TCP proteins.

Bone regeneration by means of a three-dimensional printed scaffold in a rat cranial defect.

PubMed

Kwon, Doo Yeon; Park, Ji Hoon; Jang, So Hee; Park, Joon Yeong; Jang, Ju Woong; Min, Byoung Hyun; Kim, Wan-Doo; Lee, Hai Bang; Lee, Junhee; Kim, Moon Suk

2018-02-01

Recently, computer-designed three-dimensional (3D) printing techniques have emerged as an active research area with almost unlimited possibilities. In this study, we used a computer-designed 3D scaffold to drive new bone formation in a bone defect. Poly-L-lactide (PLLA) and bioactive β-tricalcium phosphate (TCP) were simply mixed to prepare ink. PLLA + TCP showed good printability from the micronozzle and solidification within few seconds, indicating that it was indeed printable ink for layer-by-layer printing. In the images, TCP on the surface of (and/or inside) PLLA in the printed PLLA + TCP scaffold looked dispersed. MG-63 cells (human osteoblastoma) adhered to and proliferated well on the printed PLLA + TCP scaffold. To assess new bone formation in vivo, the printed PLLA + TCP scaffold was implanted into a full-thickness cranial bone defect in rats. The new bone formation was monitored by microcomputed tomography and histological analysis of the in vivo PLLA + TCP scaffold with or without MG-63 cells. The bone defect was gradually spontaneously replaced with new bone tissues when we used both bioactive TCP and MG-63 cells in the PLLA scaffold. Bone formation driven by the PLLA + TCP30 scaffold with MG-63 cells was significantly greater than that in other experimental groups. Furthermore, the PLLA + TCP scaffold gradually degraded and matched well the extent of the gradual new bone formation on microcomputed tomography. In conclusion, the printed PLLA + TCP scaffold effectively supports new bone formation in a cranial bone defect. Copyright © 2017 John Wiley & Sons, Ltd.

Periodontal tissue engineering by nano beta-tricalcium phosphate scaffold and fibroblast growth factor-2 in one-wall infrabony defects of dogs.

PubMed

Ogawa, K; Miyaji, H; Kato, A; Kosen, Y; Momose, T; Yoshida, T; Nishida, E; Miyata, S; Murakami, S; Takita, H; Fugetsu, B; Sugaya, T; Kawanami, M

2016-12-01

Nanoparticle bioceramics are being investigated for biomedical applications. We fabricated a regenerative scaffold comprising type I collagen and beta-tricalcium phosphate (β-TCP) nanoparticles. Fibroblast growth factor-2 (FGF-2) is a bioeffective signaling molecule that stimulates cell proliferation and wound healing. This study examined the effects, on bioactivity, of a nano-β-TCP/collagen scaffold loaded with FGF-2, particularly on periodontal tissue wound healing. Beta-tricalcium phosphate was pulverized into nanosize particles (84 nm) and was then dispersed. A nano-β-TCP scaffold was prepared by coating the surface of a collagen scaffold with a nanosize β-TCP dispersion. Scaffolds were characterized using scanning electron microscopy, compressive testing, cell seeding and rat subcutaneous implant testing. Then, nano-β-TCP scaffold, nano-β-TCP scaffold loaded with FGF-2 and noncoated collagen scaffold were implanted into a dog one-wall infrabony defect model. Histological observations were made at 10 d and 4 wk postsurgery. Scanning electron microscopy images show that TCP nanoparticles were attached to collagen fibers. The nano-β-TCP scaffold showed higher compressive strength and cytocompatibility compared with the noncoated collagen scaffold. Rat subcutaneous implant tests showed that the DNA contents of infiltrating cells in the nano-β-TCP scaffold and the FGF-2-loaded scaffold were approximately 2.8-fold and 3.7-fold greater, respectively, than in the collagen scaffold. Histological samples from the periodontal defect model showed about five-fold greater periodontal tissue repair following implantation of the nano-β-TCP scaffold loaded with FGF-2 compared with the collagen scaffold. The β-TCP nanoparticle coating strongly improved the collagen scaffold bioactivity. Nano-β-TCP scaffolds containing FGF-2 are anticipated for use in periodontal tissue engineering. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Research of osteoblastic induced rat bone marrow mesenchymal stem cells cultured on β-TCP/PLLA porous scaffold.

PubMed

Yang, Yi; Wu, Jiang; Jin, Gele; Li, Liang; Li, Zhongwei; Li, Cao

2015-01-01

Ceramic and polymer composite scaffolds are widely used in tissue engineering for bone tissue regeneration. Composite of β-tricalcium phosphate (β-TCP) and poly L-lactic acid (PLLA), due to its biocompatibility and biodegradability, is widely used in bioengineering. However, optimal ratio, porosity and pore size of this kind of scaffolds were not very clear yet. We cultured osteoblastic induced rMSCs on β-TCP/PLLA scaffolds to investigate the optimum construction, which owned better properties for supporting cells growth, proliferation and differentiation. A total of 24 mice were divided into three groups: rMSCs + β-TCP/PLLA, osteoblastic rMSCs + β-TCP/PLLA and β-TCP/PLLA without cells. 8 rude mice were implanted with rMSCs + β-TCP/PLLA in the left thighs and β-TCP/PLLA without cells in the right thighs. 8 rude mice were implanted with osteoblastic rMSCs + β-TCP/PLLA in the left thighs and the same treatments in the right thighs as the above. After 8 and 12 weeks, the mice were sacrificed and implants with the surrounding tissues were harvested together. Paraffin sections were got and HE stain and Masson-Goldner stain were employed to observe the ectopic bone formation. The scaffolds of β-TCP/PLLA = 2:1 significantly increased osteocalcin production of the cells. In addition, scaffolds with NaCl = 70 wt%, pore size 200~450 μm showed better compatibility to these seeding cells. A significantly larger area of bone formation in the osteoblastic rMSCs and β-TCP/PLLA composite than that in rMSCs/scaffold and in the scaffold without cells in vivo. compounds of osteoblastic induced rMSCs and the scaffold with β-TCP/PLLA = 2:1, NaCl = 70 wt%, pore size = 200-450 μm had good properties as a kind of bone substitute.

Beta-tricalcium phosphate plugs for press-fit fixation in ACL reconstruction--a mechanical analysis in bovine bone.

PubMed

Mayr, Hermann O; Hube, Robert; Bernstein, Anke; Seibt, Alexander B; Hein, Werner; von Eisenhart-Rothe, Ruediger

2007-06-01

The goal of this study was to test fixation properties of microporous pure beta-tricalcium phosphate (TCP) plugs (porosity 40%) for press-fit fixation of the ACL graft using patellar tendons with and without bone blocks. We set out to establish whether it is possible, in this way, to obtain results comparable with those of interference screw fixation of bone-tendon-bone (BTB) grafts in terms of cyclic loading and load-to-failure. In a bovine model 30 ACL grafts were fixed in tibial drill holes, divided into three groups: 10 BTB grafts fixed with TCP press-fit plugs (7x25 mm), 10 pure patellar tendon grafts with TCP press-fit plugs (7x25 mm), and 10 BTB grafts with metal interference screws (7x25 mm). All grafts were tested by cyclic loading (50-200 N) and loaded until failure in a tensiometer. Under cyclic loading one interference screw fixation failed. None of the TCP plug fixations failed. After 1500 cycles the displacement of the graft in the drill hole for BTB fixed with screws was 3.6+/-7.8 mm, for BTB/TCP plugs 1.6+/-3.4 mm, and for the pure tendon/TCP grafts 1.4+/-0.4 mm. Regarding cyclic loading the pure tendon/TCP system was significantly superior to BTB (p=0.007). The load-to-failure for the BTB/interference screw group was 908+/-539 N with a stiffness of 94+/-36 N/mm, 936+/-245 N for the BTB/TCP cylinder group with a stiffness of 98+/-12 N/mm, and 673+/-159 N for the pure tendon/TCP group with a stiffness of 117+/-9 N/mm. In terms of pull-out load the BTB/TCP system was significantly better than the pure tendon/TCP group (p=0.011). However, pure tendon/TCP grafts achieved significantly greater stiffness (p=0.002) than the BTB system. Press-fit fixation with microporous pure beta-TCP plugs of BTB grafts or patellar tendon grafts without bone blocks for ACL reconstruction leads to primary stability comparable with that achieved by fixation with metal interference screws in case of BTB grafts.

Feasibility of TCP-based dose painting by numbers applied to a prostate case with (18)F-choline PET imaging.

PubMed

Dirscherl, Thomas; Rickhey, Mark; Bogner, Ludwig

2012-02-01

A biologically adaptive radiation treatment method to maximize the TCP is shown. Functional imaging is used to acquire a heterogeneous dose prescription in terms of Dose Painting by Numbers and to create a patient-specific IMRT plan. Adapted from a method for selective dose escalation under the guidance of spatial biology distribution, a model, which translates heterogeneously distributed radiobiological parameters into voxelwise dose prescriptions, was developed. At the example of a prostate case with (18)F-choline PET imaging, different sets of reported values for the parameters were examined concerning their resulting range of dose values. Furthermore, the influence of each parameter of the linear-quadratic model was investigated. A correlation between PET signal and proliferation as well as cell density was assumed. Using our in-house treatment planning software Direct Monte Carlo Optimization (DMCO), a treatment plan based on the obtained dose prescription was generated. Gafchromic EBT films were irradiated for evaluation. When a TCP of 95% was aimed at, the maximal dose in a voxel of the prescription exceeded 100Gy for most considered parameter sets. One of the parameter sets resulted in a dose range of 87.1Gy to 99.3Gy, yielding a TCP of 94.7%, and was investigated more closely. The TCP of the plan decreased to 73.5% after optimization based on that prescription. The dose difference histogram of optimized and prescribed dose revealed a mean of -1.64Gy and a standard deviation of 4.02Gy. Film verification showed a reasonable agreement of planned and delivered dose. If the distribution of radiobiological parameters within a tumor is known, this model can be used to create a dose-painting by numbers plan which maximizes the TCP. It could be shown, that such a heterogeneous dose distribution is technically feasible. Copyright © 2012. Published by Elsevier GmbH.

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

Walsh, Seán, E-mail: walshsharp@gmail.com; Department of Oncology, Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford OX3 7DQ; Roelofs, Erik

Purpose: A fully heterogeneous population averaged mechanistic tumor control probability (TCP) model is appropriate for the analysis of external beam radiotherapy (EBRT). This has been accomplished for EBRT photon treatment of intermediate-risk prostate cancer. Extending the TCP model for low and high-risk patients would be beneficial in terms of overall decision making. Furthermore, different radiation treatment modalities such as protons and carbon-ions are becoming increasingly available. Consequently, there is a need for a complete TCP model. Methods: A TCP model was fitted and validated to a primary endpoint of 5-year biological no evidence of disease clinical outcome data obtained frommore » a review of the literature for low, intermediate, and high-risk prostate cancer patients (5218 patients fitted, 1088 patients validated), treated by photons, protons, or carbon-ions. The review followed the preferred reporting item for systematic reviews and meta-analyses statement. Treatment regimens include standard fractionation and hypofractionation treatments. Residual analysis and goodness of fit statistics were applied. Results: The TCP model achieves a good level of fit overall, linear regression results in a p-value of <0.000 01 with an adjusted-weighted-R{sup 2} value of 0.77 and a weighted root mean squared error (wRMSE) of 1.2%, to the fitted clinical outcome data. Validation of the model utilizing three independent datasets obtained from the literature resulted in an adjusted-weighted-R{sup 2} value of 0.78 and a wRMSE of less than 1.8%, to the validation clinical outcome data. The weighted mean absolute residual across the entire dataset is found to be 5.4%. Conclusions: This TCP model fitted and validated to clinical outcome data, appears to be an appropriate model for the inclusion of all clinical prostate cancer risk categories, and allows evaluation of current EBRT modalities with regard to tumor control prediction.« less

High-Speed TCP Testing

NASA Technical Reports Server (NTRS)

Brooks, David E.; Gassman, Holly; Beering, Dave R.; Welch, Arun; Hoder, Douglas J.; Ivancic, William D.

1999-01-01

Transmission Control Protocol (TCP) is the underlying protocol used within the Internet for reliable information transfer. As such, there is great interest to have all implementations of TCP efficiently interoperate. This is particularly important for links exhibiting long bandwidth-delay products. The tools exist to perform TCP analysis at low rates and low delays. However, for extremely high-rate and lone-delay links such as 622 Mbps over geosynchronous satellites, new tools and testing techniques are required. This paper describes the tools and techniques used to analyze and debug various TCP implementations over high-speed, long-delay links.

Discrete time modeling and stability analysis of TCP Vegas

NASA Astrophysics Data System (ADS)

You, Byungyong; Koo, Kyungmo; Lee, Jin S.

2007-12-01

This paper presents an analysis method for TCP Vegas network model with single link and single source. Some papers showed global stability of several network models, but those models are not a dual problem where dynamics both exist in sources and links such as TCP Vegas. Other papers studied TCP Vegas as a dual problem, but it did not fully derive an asymptotic stability region. Therefore we analyze TCP Vegas with Jury's criterion which is necessary and sufficient condition. So we use state space model in discrete time and by using Jury's criterion, we could find an asymptotic stability region of TCP Vegas network model. This result is verified by ns-2 simulation. And by comparing with other results, we could know our method performed well.

Formation of Biphasic Hydroxylapatite-Beta Magnesium Tricalcium Phosphate in Heat Treated Salmonid Vertebrae.

PubMed

Butler, Don H; Shahack-Gross, Ruth

2017-06-15

Ichthyoarchaeological evidence is uncommon at ancient hunter-gatherer sites from various regions and timeframes. This research contributes to the development of microarchaeological techniques useful for identifying fishing economies in situations where classifiable bones are unavailable. Specifically, traces of heat altered bone mineral in domestic hearths are expected to provide markers for discarded fish remains. We used a series of laboratory incineration experiments to characterize the mineralogy of burned salmonid vertebrae. Fourier transform infrared spectroscopy and x-ray diffraction distinguished the formation of beta magnesium tricalcium phosphate (βMgTCP) at temperatures as low as 600 °C. Bones from a sample of game mammals and birds did not form this phase at temperatures below 1,000 °C. We propose that this neoformed mineral can serve as a proxy for hunter-gatherer salmonid fishing when typical ichthyoarchaeological evidence is absent. Using Fourier transform infrared spectroscopy, it will be possible to rapidly and inexpensively determine the presence of βMgTCP in fragmentary burned bone remains associated with combustion features. The occurrence of βMgTCP in archaeological hearth features will offer a new means of further evaluating the temporal, geographic, and cultural scope of salmonid harvesting. We also acknowledge the value of biphasic hydroxylapatite-βMgTCP recovered from Atlantic salmon vertebrae as a bioceramic.

Characterization of bone marrow mononuclear cells on biomaterials for bone tissue engineering in vitro.

PubMed

Henrich, Dirk; Verboket, René; Schaible, Alexander; Kontradowitz, Kerstin; Oppermann, Elsie; Brune, Jan C; Nau, Christoph; Meier, Simon; Bonig, Halvard; Marzi, Ingo; Seebach, Caroline

2015-01-01

Bone marrow mononuclear cells (BMCs) are suitable for bone tissue engineering. Comparative data regarding the needs of BMC for the adhesion on biomaterials and biocompatibility to various biomaterials are lacking to a large extent. Therefore, we evaluated whether a surface coating would enhance BMC adhesion and analyze the biocompatibility of three different kinds of biomaterials. BMCs were purified from human bone marrow aspirate samples. Beta tricalcium phosphate (β-TCP, without coating or coated with fibronectin or human plasma), demineralized bone matrix (DBM), and bovine cancellous bone (BS) were assessed. Seeding efficacy on β-TCP was 95% regardless of the surface coating. BMC demonstrated a significantly increased initial adhesion on DBM and β-TCP compared to BS. On day 14, metabolic activity was significantly increased in BMC seeded on DBM in comparison to BMC seeded on BS. Likewise increased VEGF-synthesis was observed on day 2 in BMC seeded on DBM when compared to BMC seeded on BS. The seeding efficacy of BMC on uncoated biomaterials is generally high although there are differences between these biomaterials. Beta-TCP and DBM were similar and both superior to BS, suggesting either as suitable materials for spatial restriction of BMC used for regenerative medicine purposes in vivo.

Characterization of Bone Marrow Mononuclear Cells on Biomaterials for Bone Tissue Engineering In Vitro

PubMed Central

Verboket, René; Kontradowitz, Kerstin; Oppermann, Elsie; Brune, Jan C.; Nau, Christoph; Meier, Simon; Bonig, Halvard; Marzi, Ingo; Seebach, Caroline

2015-01-01

Bone marrow mononuclear cells (BMCs) are suitable for bone tissue engineering. Comparative data regarding the needs of BMC for the adhesion on biomaterials and biocompatibility to various biomaterials are lacking to a large extent. Therefore, we evaluated whether a surface coating would enhance BMC adhesion and analyze the biocompatibility of three different kinds of biomaterials. BMCs were purified from human bone marrow aspirate samples. Beta tricalcium phosphate (β-TCP, without coating or coated with fibronectin or human plasma), demineralized bone matrix (DBM), and bovine cancellous bone (BS) were assessed. Seeding efficacy on β-TCP was 95% regardless of the surface coating. BMC demonstrated a significantly increased initial adhesion on DBM and β-TCP compared to BS. On day 14, metabolic activity was significantly increased in BMC seeded on DBM in comparison to BMC seeded on BS. Likewise increased VEGF-synthesis was observed on day 2 in BMC seeded on DBM when compared to BMC seeded on BS. The seeding efficacy of BMC on uncoated biomaterials is generally high although there are differences between these biomaterials. Beta-TCP and DBM were similar and both superior to BS, suggesting either as suitable materials for spatial restriction of BMC used for regenerative medicine purposes in vivo. PMID:25802865

Bone regeneration of critical calvarial defect in goat model by PLGA/TCP/rhBMP-2 scaffolds prepared by low-temperature rapid-prototyping technology.

PubMed

Yu, D; Li, Q; Mu, X; Chang, T; Xiong, Z

2008-10-01

Active artificial bone composed of poly lactide-co-glycolide (PLGA)/ tricalcium phosphate (TCP) was prefabricated using low-temperature rapid-prototyping technology so that the process of osteogenesis could be observed in it. PLGA and TCP were the primary materials, they were molded at low temperature, then recombinant human bone morphogenetic protein-2 (rhBMP-2) was added to form an active artificial bone. Goats with standard cranial defects were randomly divided into experimental (implants with rhBMP-2 added) and control (implants without rhBMP-2) groups, and osteogenesis was observed and evaluated by imaging and biomechanical and histological examinations. The PLGA-TCP artificial bone scaffold (90% porosity) had large and small pores of approximately 360microm and 3-5microm diameter. Preliminary and complete repair of the cranial defect in the goats occurred 12 and 24 weeks after surgery, respectively. The three-point bending strength of the repaired defects attained that of the normal cranium. In conclusion, low-temperature rapid-prototyping technology can preserve the biological activity of this scaffold material. The scaffold has a good three-dimensional structure and it becomes an active artificial bone after loading with rhBMP-2 with a modest degradation rate and excellent osteogenesis in the goat.

Proliferation and osteoblastic differentiation of human bone marrow-derived stromal cells on akermanite-bioactive ceramics.

PubMed

Sun, Hongli; Wu, Chengtie; Dai, Kerong; Chang, Jiang; Tang, Tingting

2006-11-01

In the present study, the effects of a calcium magnesium silicate bioactive ceramic (akermanite) on proliferation and osteoblastic differentiation of human bone marrow stromal cells (hBMSC) have been investigated and compared with the classical ceramic (beta-tricalcium phosphate, beta-TCP). Akermanite and beta-TCP disks were seeded with hBMSC and kept in growth medium or osteogenic medium for 10 days. Proliferation and osteoblastic differentiation were evaluated on day 1, 4, 7 and 10. The data from the Alamar Blue assay and lactic acid production assay showed that hBMSC proliferated more significantly on akermanite than on beta-TCP. The analysis of osteoblast-related genes, including alkaline phosphatase (ALP), osteopontin (OPN), bone sialoprotein (BSP) and osteocalcin (OC), indicated that akermanite ceramics enhanced the expression of osteoblast-related genes, but type I collagen (COL I) showed no noticeable difference among akermanite and beta-TCP ceramics. Furthermore, this stimulatory effect was observed not only in osteogenic medium, but also in normal growth medium without osteogenic reagents such as l-ascorbic acid, glycerophosphate and dexamethasone. This result suggests that akermanite can promote osteoblastic differentiation of hBMSC in vitro even without osteogenic reagents, and may be used as a bioactive material for bone regeneration and tissue engineering applications.

Osteogenic effect of tricalcium phosphate substituted by magnesium associated with Genderm® membrane in rat calvarial defect model.

PubMed

Costa, Neusa M F; Yassuda, Debora H; Sader, Marcia S; Fernandes, Gustavo V O; Soares, Glória D A; Granjeiro, José M

2016-04-01

Beta-tricalcium phosphate (β-TCP) is one of the most widely employed bioresorbable materials for bone repair since it shows excellent biological compatibility, osteoconductivity and resorbability. The incorporation of divalent cations such as magnesium onto the β-TCP structure (β-TCMP) may improve the biological response to the material through the release of bioactive ions. The objective of this study was to evaluate, on a rat calvarial critical size grafting model, the bone regeneration process using β-TCP and β-TMCP granules by histomorphometric analysis. Results demonstrated that six months after bone grafting, the association of GBR (guided bone regeneration) using a membrane (GenDerm®) and granules of β-TCP and β-TCMP significantly improves bone repair in the treatment of critical-size defect in rat skulls, in comparison to untreated defects or GBR alone, leading to a bone level approximately four to five-fold greater than in the blood clot group. The β-TCMP+GenDerm® membrane group presented 40.5% of the defect area filled by newly-formed bone, even at the central part of the defect, rather than only at the border, as seen in the other experimental groups. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluation of Swift Start TCP in Long-Delay Environment

NASA Technical Reports Server (NTRS)

Lawas-Grodek, Frances J.; Tran, Diepchi T.

2004-01-01

This report presents the test results of the Swift Start algorithm in single-flow and multiple-flow testbeds under the effects of high propagation delays, various slow bottlenecks, and small queue sizes. Although this algorithm estimates capacity and implements packet pacing, the findings were that in a heavily congested link, the Swift Start algorithm will not be applicable. The reason is that the bottleneck estimation is falsely influenced by timeouts induced by retransmissions and the expiration of delayed acknowledgment (ACK) timers, thus causing the modified Swift Start code to fall back to regular transmission control protocol (TCP).

GbTCP, a cotton TCP transcription factor, confers fibre elongation and root hair development by a complex regulating system.

PubMed

Hao, Juan; Tu, Lili; Hu, Haiyan; Tan, Jiafu; Deng, Fenglin; Tang, Wenxin; Nie, Yichun; Zhang, Xianlong

2012-10-01

As the most important natural raw material for textile industry, cotton fibres are an excellent model for studying single-cell development. Although expression profiling and functional genomics have provided some data, the mechanism of fibre development is still not well known. A class I TCP transcription factor (designated GbTCP), encoding 344 amino acids, was isolated from the normalized cDNA library of sea-island cotton fibre (from -2 to 25 days post anthesis). GbTCP was preferentially expressed in the elongating cotton fibre from 5 to 15 days post anthesis. Some expression was also observed in stems, apical buds, and petals. RNAi silencing of GbTCP produced shorter fibre, a reduced lint percentage, and a lower fibre quality than the wild-type plants. Overexpression of GbTCP enhanced root hair initiation and elongation in Arabidopsis and regulated branching. Solexa sequencing and Affymetrix GeneChip analysis indicated that GbTCP positively regulates the level of jasmonic acid (JA) and, as a result, activates downstream genes (reactive oxygen species, calcium signalling, ethylene biosynthesis and response, and several NAC and WRKY transcription factors) necessary for elongation of fibres and root hairs. JA content analysis in cotton also confirmed that GbTCP has a profound effect on JA biosynthesis. In vitro ovule culture showed that an appropriate concentration of JA promoted fibre elongation. The results suggest that GbTCP is an important transcription factor for fibre and root hair development by regulating JA biosynthesis and response and other pathways, including reactive oxygen species, calcium channel and ethylene signalling.

GbTCP, a cotton TCP transcription factor, confers fibre elongation and root hair development by a complex regulating system

PubMed Central

Zhang, Xianlong

2012-01-01

As the most important natural raw material for textile industry, cotton fibres are an excellent model for studying single-cell development. Although expression profiling and functional genomics have provided some data, the mechanism of fibre development is still not well known. A class I TCP transcription factor (designated GbTCP), encoding 344 amino acids, was isolated from the normalized cDNA library of sea-island cotton fibre (from –2 to 25 days post anthesis). GbTCP was preferentially expressed in the elongating cotton fibre from 5 to 15 days post anthesis. Some expression was also observed in stems, apical buds, and petals. RNAi silencing of GbTCP produced shorter fibre, a reduced lint percentage, and a lower fibre quality than the wild-type plants. Overexpression of GbTCP enhanced root hair initiation and elongation in Arabidopsis and regulated branching. Solexa sequencing and Affymetrix GeneChip analysis indicated that GbTCP positively regulates the level of jasmonic acid (JA) and, as a result, activates downstream genes (reactive oxygen species, calcium signalling, ethylene biosynthesis and response, and several NAC and WRKY transcription factors) necessary for elongation of fibres and root hairs. JA content analysis in cotton also confirmed that GbTCP has a profound effect on JA biosynthesis. In vitro ovule culture showed that an appropriate concentration of JA promoted fibre elongation. The results suggest that GbTCP is an important transcription factor for fibre and root hair development by regulating JA biosynthesis and response and other pathways, including reactive oxygen species, calcium channel and ethylene signalling. PMID:23105133

The TCP4 transcription factor regulates trichome cell differentiation by directly activating GLABROUS INFLORESCENCE STEMS in Arabidopsis thaliana.

PubMed

Vadde, Batthula Vijaya Lakshmi; Challa, Krishna Reddy; Nath, Utpal

2018-01-01

Trichomes are the first cell type to be differentiated during the morphogenesis of leaf epidermis and serve as an ideal model to study cellular differentiation. Many genes involved in the patterning and differentiation of trichome cells have been studied over the past decades, and the majority of these genes encode transcription factors that specifically regulate epidermal cell development. However, the upstream regulators of these genes that link early leaf morphogenesis with cell type differentiation are less studied. The TCP proteins are the plant-specific transcription factors involved in regulating diverse aspects of plant development including lateral organ morphogenesis by modulating cell proliferation and differentiation. Here, we show that the miR319-regulated class II TCP proteins, notably TCP4, suppress trichome branching in Arabidopsis leaves and inflorescence stem by direct transcriptional activation of GLABROUS INFLORESCENCE STEMS (GIS), a known negative regulator of trichome branching. The trichome branch number is increased in plants with reduced TCP activity and decreased in the gain-of-function lines of TCP4. Biochemical analyses show that TCP4 binds to the upstream regulatory region of GIS and activates its expression. Detailed genetic analyses show that GIS and TCP4 work in same pathway and GIS function is required for TCP4-mediated regulation of trichome differentiation. Taken together, these results identify a role for the class II TCP genes in trichome differentiation, thus providing a connection between organ morphogenesis and cellular differentiation. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

The enzyme toxicity and genotoxicity of chlorpyrifos and its toxic metabolite TCP to zebrafish Danio rerio.

PubMed

Wang, Jun; Wang, Jinhua; Zhu, Lusheng; Xie, Hui; Shao, Bo; Hou, Xinxin

2014-12-01

Chlorpyrifos is a broad-spectrum organophosphorus insecticide (O,O-diethyl -O-3,5,6-trichloro-2-pyridyl phosphorothioate) that is used in numerous agricultural and urban pest controls. The primary metabolite of chlorpyrifos is 3,5,6-trichloro pyridine-2-phenol (TCP). Because of its strong water solubility and mobility, this harmful metabolite exists in the environment in a large amount. Although TCP has potentially harmful effects on organisms in the environment, few studies have addressed TCP pollution. Therefore, this study was undertaken to investigate the effect of chlorpyrifos and TCP on the microsomal cytochrome P450 content in the liver, on the activity of NADPH-P450 reductase and antioxidative enzymes [catalase (CAT) and superoxide dismutase (SOD)], and on reactive oxygen species (ROS) generation and DNA damage in zebrafish. Male and female zebrafish were separated and exposed to a control solution and three concentrations of chlorpyrifos (0.01, 0.1, 1 mg L(-1)) and TCP (0.01, 0.1, 0.5 mg L(-1)), respectively, sampled after 5, 10, 15, 20 and 25 days. The results indicated that the P450 content and the NADPH-P450 reductase and antioxidative enzyme (CAT and SOD) activities could be induced by chlorpyrifos and TCP. DNA damage of zebrafish was enhanced with increasing chlorpyrifos and TCP concentrations. Meanwhile, chlorpyrifos and TCP induced a significant increase of ROS generation in the zebrafish hepatopancreas. In conclusion, this study proved that chlorpyrifos (0.01-1 mg L(-1)) and TCP (0.01-0.5 mg L(-1)) are both highly toxic to zebrafish.

Disulfide isomerase-like protein AtPDIL1–2 is a good candidate for trichlorophenol phytodetoxification

PubMed Central

Peng, Ri-He; Qiu, Jin; Tian, Yong-Sheng; Gao, Jian-jie; Han, Hong-juan; Fu, Xiao-Yan; Zhu, Bo; Xu, Jing; Wang, Bo; Li, Zhen-jun; Wang, Li-juan; Yao, Quan-Hong

2017-01-01

Trichlorophenol (TCP) is a widely used and persistent environmentally toxic compound that poses a carcinogenic risk to humans. Phytoremediation is a proficient cleanup technology for organic pollutants. In this study, we found that the disulfide isomerase-like protein AtPDIL1–2 in plants is a good candidate for enhancing 2,4,6-TCP phytoremediation. The expression of AtPDIL1-2 in Arabidopsis was induced by 2,4,6-TCP. The heterologously expressed AtPDIL1-2 in Escherichia coli exhibited both oxidase and isomerase activities as protein disulfide isomerase and improved bacteria tolerance to 2,4,6-TCP. Further research revealed that transgenic tobacco overexpressing AtPDIL1-2 was more tolerant to high concentrations of 2,4,6-TCP and removed the toxic compound at far greater rates than the control plants. To elucidate the mechanism of action of AtPDIL1-2, we investigated the chemical interaction of AtPDIL1-2 with 2,4,6-TCP for the first time. HPLC analysis implied that AtPDIL1-2 exerts a TCP-binding activity. A suitable configuration of AtPDIL1-2-TCP binding was obtained by molecular docking studies using the AutoDock program. It predicted that the TCP binding site is located in the b-b′ domain of AtPDIL1-2 and that His254 of the protein is critical for the binding interaction. These findings imply that AtPDIL1-2 can be used for TCP detoxification by the way of overexpression in plants. PMID:28059139

SDTCP: Towards Datacenter TCP Congestion Control with SDN for IoT Applications

PubMed Central

Lu, Yifei; Ling, Zhen; Zhu, Shuhong; Tang, Ling

2017-01-01

The Internet of Things (IoT) has gained popularity in recent years. Today’s IoT applications are now increasingly deployed in cloud platforms to perform Big Data analytics. In cloud data center networks (DCN), TCP incast usually happens when multiple senders simultaneously communicate with a single receiver. However, when TCP incast happens, DCN may suffer from both throughput collapse for TCP burst flows and temporary starvation for TCP background flows. In this paper, we propose a software defined network (SDN)-based TCP congestion control mechanism, referred to as SDTCP, to leverage the features, e.g., centralized control methods and the global view of the network, in order to solve the TCP incast problems. When we detect network congestion on an OpenFlow switch, our controller can select the background flows and reduce their bandwidth by adjusting the advertised window of TCP ACK packets of the corresponding background flows so as to reserve more bandwidth for burst flows. SDTCP is transparent to the end systems and can accurately decelerate the rate of background flows by leveraging the global view of the network gained via SDN. The experiments demonstrate that our SDTCP can provide high tolerance for burst flows and achieve better flow completion time for short flows. Therefore, SDTCP is an effective and scalable solution for the TCP incast problem. PMID:28075347

TCP4-dependent induction of CONSTANS transcription requires GIGANTEA in photoperiodic flowering in Arabidopsis

PubMed Central

Shim, Jae Sung; Song, Yong Hun; Laboy Cintrón, Dianne; Koyama, Tomotsugu; Ohme-Takagi, Masaru; Pruneda-Paz, Jose L.; Kay, Steve A.; MacCoss, Michael J.

2017-01-01

Photoperiod is one of the most reliable environmental cues for plants to regulate flowering timing. In Arabidopsis thaliana, CONSTANS (CO) transcription factor plays a central role in regulating photoperiodic flowering. In contrast to posttranslational regulation of CO protein, still little was known about CO transcriptional regulation. Here we show that the CINCINNATA (CIN) clade of class II TEOSINTE BRANCHED 1/ CYCLOIDEA/ PROLIFERATING CELL NUCLEAR ANTIGEN FACTOR (TCP) proteins act as CO activators. Our yeast one-hybrid analysis revealed that class II CIN-TCPs, including TCP4, bind to the CO promoter. TCP4 induces CO expression around dusk by directly associating with the CO promoter in vivo. In addition, TCP4 binds to another flowering regulator, GIGANTEA (GI), in the nucleus, and induces CO expression in a GI-dependent manner. The physical association of TCP4 with the CO promoter was reduced in the gi mutant, suggesting that GI may enhance the DNA-binding ability of TCP4. Our tandem affinity purification coupled with mass spectrometry (TAP-MS) analysis identified all class II CIN-TCPs as the components of the in vivo TCP4 complex, and the gi mutant did not alter the composition of the TCP4 complex. Taken together, our results demonstrate a novel function of CIN-TCPs as photoperiodic flowering regulators, which may contribute to coordinating plant development with flowering regulation. PMID:28628608

TCP4-dependent induction of CONSTANS transcription requires GIGANTEA in photoperiodic flowering in Arabidopsis.

PubMed

Kubota, Akane; Ito, Shogo; Shim, Jae Sung; Johnson, Richard S; Song, Yong Hun; Breton, Ghislain; Goralogia, Greg S; Kwon, Michael S; Laboy Cintrón, Dianne; Koyama, Tomotsugu; Ohme-Takagi, Masaru; Pruneda-Paz, Jose L; Kay, Steve A; MacCoss, Michael J; Imaizumi, Takato

2017-06-01

Photoperiod is one of the most reliable environmental cues for plants to regulate flowering timing. In Arabidopsis thaliana, CONSTANS (CO) transcription factor plays a central role in regulating photoperiodic flowering. In contrast to posttranslational regulation of CO protein, still little was known about CO transcriptional regulation. Here we show that the CINCINNATA (CIN) clade of class II TEOSINTE BRANCHED 1/ CYCLOIDEA/ PROLIFERATING CELL NUCLEAR ANTIGEN FACTOR (TCP) proteins act as CO activators. Our yeast one-hybrid analysis revealed that class II CIN-TCPs, including TCP4, bind to the CO promoter. TCP4 induces CO expression around dusk by directly associating with the CO promoter in vivo. In addition, TCP4 binds to another flowering regulator, GIGANTEA (GI), in the nucleus, and induces CO expression in a GI-dependent manner. The physical association of TCP4 with the CO promoter was reduced in the gi mutant, suggesting that GI may enhance the DNA-binding ability of TCP4. Our tandem affinity purification coupled with mass spectrometry (TAP-MS) analysis identified all class II CIN-TCPs as the components of the in vivo TCP4 complex, and the gi mutant did not alter the composition of the TCP4 complex. Taken together, our results demonstrate a novel function of CIN-TCPs as photoperiodic flowering regulators, which may contribute to coordinating plant development with flowering regulation.

Assessment of cassava toxicity in patients with tropical chronic pancreatitis.

PubMed

Girish, Banavara Narasimhamurthy; Rajesh, Gopalakrishna; Vaidyanathan, Kannan; Balakrishnan, Vallath

2011-01-01

There have been conflicting reports on the role of cassava ingestion in tropical pancreatitis (TCP). In this study we aimed to estimate cyanogens detoxifying enzyme rhodanese, thiocyanate and sulfur containing amino acids in cassava consumer as well as cassava non-consumer TCP patients and healthy controls and compare the same. Eighty-six TCP patients and 90 healthy controls were recruited. Serum rhodanese, thiocyanate, plasma amino acids, urinary inorganic sulfate/creatinine were measured. There was significant reduction in serum rhodanese activity in both cassava consumer- and non-consumer TCP patients as compared to controls but no significant difference between cassava consumer- and non-consumer TCP patients was observed. Serum thiocyanate was significantly lower in cassava consumer TCP patients as compared to cassava consumer controls but not significantly different from cassava non-consumer TCP patients. Plasma methionine, cysteine and urinary inorganic sulfate / creatinine ratio was significantly lower in both cassava consumer and non-consumer TCP patients as compared to controls but were comparable among cassava consumers and non-consumers. Significant reduction in rhodanese activity with concomitant decrease in sulfur containing amino acids and antioxidants such as glutathione suggests that TCP patients are at higher risk of defective detoxification of cyanogens. However there was no difference between cassava consumers and non-consumers. Low levels of sulfur amino acids may contribute to the development of pancreatitis.

Clinical Relevance of Baseline TCP in Transcatheter Aortic Valve Replacement.

PubMed

Sannino, Anna; Stoler, Robert C; Hebeler, Robert F; Szerlip, Molly; Mack, Michael J; Grayburn, Paul A

2017-10-01

To investigate the influence of baseline thrombocytopenia (TCP) on short-term and long-term outcomes after transcatheter aortic valve replacement (TAVR). A total of 732 consecutive patients with severe, symptomatic aortic stenosis undergoing TAVR from January 2012 to December 2015 were included. Primary outcomes of interest were the relationship of baseline TCP with 30-day and 1-year all-cause mortality. Secondary outcomes of interest were procedural complications and in-hospital mortality in the same subgroups. The prevalence of TCP (defined as platelet count <150 × 109/L) at baseline was 21.9%, of whom 4.0% had moderate/severe TCP (defined as platelet count <100 × 109/L). Compared to no or mild TCP, moderate/severe TCP at baseline was associated with a significantly higher 30-day mortality (23.3% vs 2.3% and 3.1%, respectively; P<.001) and 1-year mortality (40.0% vs 8.3% and 13.4%, respectively; P<.001). In Cox regression analysis, moderate/severe baseline TCP was an independent predictor of 30-day and 1-year mortality (hazard ratio [HR], 13.18; 95% confidence interval [CI], 4.49-38.64; P<.001 and HR, 5.90; 95% CI, 2.68-13.02; P<.001, respectively). In conclusion, baseline TCP is a strong predictor of mortality in TAVR patients, possibly identifying a specific subgroup of frail patients; therefore, it should be taken into account when addressing TAVR risk.

Genomewide analysis of TCP transcription factor gene family in Malus domestica.

PubMed

Xu, Ruirui; Sun, Peng; Jia, Fengjuan; Lu, Longtao; Li, Yuanyuan; Zhang, Shizhong; Huang, Jinguang

2014-12-01

Teosinte branched 1/cycloidea/proliferating cell factor 1 (TCP) proteins are a large family of transcriptional regulators in angiosperms. They are involved in various biological processes, including development and plant metabolism pathways. In this study, a total of 52 TCP genes were identified in apple (Malus domestica) genome. Bioinformatic methods were employed to predicate and analyse their relevant gene classification, gene structure, chromosome location, sequence alignment and conserved domains of MdTCP proteins. Expression analysis from microarray data showed that the expression levels of 28 and 51 MdTCP genes changed during the ripening and rootstock-scion interaction processes, respectively. The expression patterns of 12 selected MdTCP genes were analysed in different tissues and in response to abiotic stresses. All of the selected genes were detected in at least one of the tissues tested, and most of them were modulated by adverse treatments indicating that the MdTCPs were involved in various developmental and physiological processes. To the best of our knowledge, this is the first study of a genomewide analysis of apple TCP gene family. These results provide valuable information for studies on functions of the TCP transcription factor genes in apple.

Poly (γ-glutamic acid)/beta-TCP nanocomposites via in situ copolymerization: Preparation and characterization.

PubMed

Shu, Xiu-Lin; Shi, Qing-Shan; Feng, Jin; Yang, Yun-Hua; Zhou, Gang; Li, Wen-Ru

2016-07-01

A series biodegradable poly (γ-glutamic acid)/beta-tricalcium phosphate (γ-PGA/TCP) nanocomposites were prepared which were composed of poly-γ-glutamic acid polymerized in situ with β-tricalcium phosphate and physiochemically characterized as bone graft substitutes. The particle size via dynamic light scattering, the direct morphological characterization via transmission electron microscopy and field emission scanning electron microscope, which showed that γ-PGA and β-TCP were combined compactly at 80℃, and the γ-PGA/TCP nanocomposites had homogenous and nano-sized grains with narrow particle size distributions. The water uptake and retention abilities, in vitro degradation properties, cytotoxicity in the simulated medium, and protein release of these novel γ-PGA/TCP composites were investigated. Cell proliferation in composites was nearly twice than β-TCP when checked in vitro using MC3T3 cell line. We also envision the potential use of γ-PGA/TCP systems in bone growth factor or orthopedic drug delivery applications in future bone tissue engineering applications. These observations suggest that the γ-PGA/TCP are novel nanocomposites with great potential for application in the field of bone tissue engineering. © The Author(s) 2016.

Genetic and phenotypic heterogeneity in tropical calcific pancreatitis.

PubMed

Paliwal, Sumit; Bhaskar, Seema; Chandak, Giriraj R

2014-12-14

Tropical calcific pancreatitis (TCP) is a form of chronic non-alcoholic pancreatitis initially reported in the developing parts of the tropical world. The clinical phenotype of TCP has undergone marked changes since its first description in 1968. The disease is now seen in relatively older people with less severe symptoms. In addition, there are varying reports on the proportion of cases presenting with imaging abnormalities like calcification, ductal dilation, and glandular atrophy. Significant progress has also been made in understanding the etiopathology of TCP. The role of malnutrition and cassava toxicity in its pathogenesis is disproven and few studies have focused on the role of micronutrient deficiency and oxidative stress in the etiopathogenesis of TCP. Emerging evidence support an important role for genetic risk factors in TCP. Several studies have shown that, rather than mutations in trypsinogens, variants in serine protease inhibitor kazal type 1, cathepsin B, chymotrypsin C, cystic fibrosis transmembrane regulator, and carboxypeptidase A1, predict risk of TCP. These studies also provided evidence of mutational heterogeneity between TCP and chronic pancreatitis in Western populations. The current review summarizes recent advances that have implications in the understanding of the pathophysiology and thus, heterogeneity in genotype-phenotype correlations in TCP.

Comparative Efficacies of Collagen-Based 3D Printed PCL/PLGA/β-TCP Composite Block Bone Grafts and Biphasic Calcium Phosphate Bone Substitute for Bone Regeneration.

PubMed

Hwang, Kyoung-Sub; Choi, Jae-Won; Kim, Jae-Hun; Chung, Ho Yun; Jin, Songwan; Shim, Jin-Hyung; Yun, Won-Soo; Jeong, Chang-Mo; Huh, Jung-Bo

2017-04-17

The purpose of this study was to compare bone regeneration and space maintaining ability of three-dimensional (3D) printed bone grafts with conventional biphasic calcium phosphate (BCP). After mixing polycaprolactone (PCL), poly (lactic-co-glycolic acid) (PLGA), and β-tricalcium phosphate (β-TCP) in a 4:4:2 ratio, PCL/PLGA/β-TCP particulate bone grafts were fabricated using 3D printing technology. Fabricated particulate bone grafts were mixed with atelocollagen to produce collagen-based PCL/PLGA/β-TCP composite block bone grafts. After formation of calvarial defects 8 mm in diameter, PCL/PLGA/β-TCP composite block bone grafts and BCP were implanted into bone defects of 32 rats. Although PCL/PLGA/β-TCP composite block bone grafts were not superior in bone regeneration ability compared to BCP, the results showed relatively similar performance. Furthermore, PCL/PLGA/β-TCP composite block bone grafts showed better ability to maintain bone defects and to support barrier membranes than BCP. Therefore, within the limitations of this study, PCL/PLGA/β-TCP composite block bone grafts could be considered as an alternative to synthetic bone grafts available for clinical use.

Latency of TCP applications over the ATM-WAN using the GFR service category

NASA Astrophysics Data System (ADS)

Chen, Kuo-Hsien; Siliquini, John F.; Budrikis, Zigmantas

1998-10-01

The GFR service category has been proposed for data services in ATM networks. Since users are ultimately interested in data service that provide high efficiency and low latency, it is important to study the latency performance for data traffic of the GFR service category in an ATM network. Today much of the data traffic utilizes the TCP/IP protocol suite and in this paper we study through simulation the latency of TCP applications running over a wide-area ATM network utilizing the GFR service category using a realistic TCP traffic model. From this study, we find that during congestion periods the reserved bandwidth in GFR can improve the latency performance for TCP applications. However, due to TCP 'Slow Start' data segment generation dynamics, we show that a large proportion of TCP segments are discarded under network congestion even when the reserved bandwidth is equal to the average generated rate of user data. Therefore, a user experiences worse than expected latency performance when the network is congested. In this study we also examine the effects of segment size on the latency performance of TCP applications using the GFR service category.

Influence of the Thermal Conductivity of Thermally Conductive Plastics on the Thermal Distribution of an Light-Emitting Diode Headlight for Vehicles.

PubMed

Lee, Dong Kyu; Lee, Jae Min; Cho, Moon Uk; Park, Hyun Jung; Cha, Yu-Jung; Kim, Hyeong Jin; Kwak, Joon Seop

2018-09-01

This paper investigates the thermal distribution of an LED headlight for vehicles based on the thermal conductivity of thermally conductive plastics (TCP). In general, heat dissipation structures used for LED headlights are made from metallic materials. However, headlight structures made from TCP have not been investigated. The headlights made from TCP having a various thermal conductivity were fabricated by injection molding with and without a metal plate insert. The temperature characteristics were compared and analyzed using thermal simulations and measurement. The inserted metal in TCP greatly reduced the temperature at solder point, indicating that the fast heat dissipation from the high power LED package to TCP though the inserted metal is essential. The measured temperature at solder points decreased as the thermal conductivity of TCP increased, which is well matched to the simulation results. The measured temperature at the solder point was lower than 150 °C when the thermal conductivity of the TCP was 10 W/mK.

A new Grid Product of Tropical Cyclone Precipitation (TCP) for North America from 1930 to 2013

NASA Astrophysics Data System (ADS)

Zhu, L.

2015-12-01

We first developed a new method that collects daily TCP by using historical storm tracks and precipitation observation based on daily rain gauges in both U.S. and Mexico and calibrated it with satellite precipitation observation. We used a parametrized wind field to correct the possible under-estimations of precipitation in rain gauges. Grid interpolation parameters were optimized by testing different historical rain gauge densities and comparing our grid estimation of TCP and the observation from TRMM Multi-satellite Precipitation Analysis (3B42) by for the data available period from 1998 to 2013. The calibrated method was then used for the whole 94 years of TCP estimation. The preliminary result shows that the frequency of TCP events does not have significant change but the TCP intensity has significant increasing trends, especially in certain locations in North Carolina and Yucatan Peninsula in Mexico. This new long term TCP climatology can potentially assist model calibration and disaster prevention/mitigation.

TCP three-way handshake: linking developmental processes with plant immunity.

PubMed

Lopez, Jessica A; Sun, Yali; Blair, Peter B; Mukhtar, M Shahid

2015-04-01

The TCP gene family encodes plant-specific transcription factors involved in growth and development. Equally important are the interactions between TCP factors and other pathways extending far beyond development, as they have been found to regulate a variety of hormonal pathways and signaling cascades. Recent advances reveal that TCP factors are targets of pathogenic effectors and are likely to play a vital role in plant immunity. Our focus is on reviewing the involvement of TCP in known pathways and shedding light on other linkages in the nexus of plant immunity centered around TCP factors with an emphasis on the convergence of effectors, interconnected hormonal networks, utility of the circadian clock, and the potential mechanisms by which pathogen defense may occur. Copyright © 2015 Elsevier Ltd. All rights reserved.

Research on TCP/IP network communication based on Node.js

NASA Astrophysics Data System (ADS)

Huang, Jing; Cai, Lixiong

2018-04-01

In the face of big data, long connection and high synchronization, TCP/IP network communication will cause performance bottlenecks due to its blocking multi-threading service model. This paper presents a method of TCP/IP network communication protocol based on Node.js. On the basis of analyzing the characteristics of Node.js architecture and asynchronous non-blocking I/O model, the principle of its efficiency is discussed, and then compare and analyze the network communication model of TCP/IP protocol to expound the reasons why TCP/IP protocol stack is widely used in network communication. Finally, according to the large data and high concurrency in the large-scale grape growing environment monitoring process, a TCP server design based on Node.js is completed. The results show that the example runs stably and efficiently.

Structural and degradation characteristics of an innovative porous PLGA/TCP scaffold incorporated with bioactive molecular icaritin.

PubMed

Xie, Xin-Hui; Wang, Xin-Luan; Zhang, Ge; He, Yi-Xin; Wang, Xiao-Hong; Liu, Zhong; He, Kai; Peng, Jiang; Leng, Yang; Qin, Ling

2010-10-01

Phytomolecules may chemically bind to scaffold materials for medical applications. The present study used an osteoconductive porous poly(l-lactide-co-glycolide)/tricalcium phosphate (PLGA/TCP) to incorporate an exogenous phytoestrogenic molecule icaritin to form a PLGA/TCP/icaritin composite scaffold material with potential slow release of icaritin during scaffold degradation. Accordingly, the present study was designed to investigate its in vitro degradation characteristics and the release pattern of icaritin at three different doses (74 mg, 7.4 mg and 0.74 mg per 100 g PLGA/TCP, i.e. in the PLGA/TCP/icaritin-H, -M and -L groups, respectively). A PLGA/TCP/icaritin porous composite scaffold was fabricated using a computer-controlled printing machine. The PLGA/TCP/icaritin scaffolds were incubated in saline at 37 °C for 12 weeks and the pure PLGA/TCP scaffold served as a control. During the 12 weeks in vitro degradation, the scaffolds in all four groups showed changes, including a decrease in weight, volume and pore size of the composite scaffold, while there was a decrease in acidity and an increase in Ca and lactic acid concentrations in the degradation medium, especially after 7 weeks. The rate of degradation was explained by the relationship with the content of icaritin incorporated into the scaffolds. The higher the icaritin content in the scaffolds, the slower the degradation could be observed during 12 weeks. After 12 weeks, the SEM showed that the surface of the PLGA/TCP and PLGA/TCP/icaritin-L groups was relatively smooth with a gradual decrease in number and size of the micropores, while the porous morphology on the surface of the PLGA/TCP/icaritin-M and PLGA/TCP/icaritin-H groups was partly maintained, accompanied by a decrease in phosphate (P) and calcium (Ca) contents at the surface. Though the mechanical property of the PLGA/TCP/icaritin scaffold decreased after degradation, its porous structure was maintained, which was essential for cell migration and ingrowth of newly regenerated tissues in vivo. The controlled release of icaritin from the composite scaffold reached about 70% of the incorporated icaritin into the degradation medium after 12 weeks. The above findings suggested that the structural and degradation properties of the porous composite PLGA/TCP/icaritin scaffold were dependent on icaritin concentrations. This innovative composite porous scaffold material developed in the present study may be used as a good scaffold material for enhancing bone repair, especially at high concentrations of icaritin. In vivo confirmation is, however, needed to substantiate our in vitro findings.

TCP Pacing Developed

NASA Technical Reports Server (NTRS)

Ivancic, William D.

2002-01-01

Transmission control protocol (TCP) was conceived and designed to run over a variety of communication links, including wireless and high-bandwidth links. However, with recent technological advances in satellite and fiber-optic networks, researchers are reevaluating the flexibility of TCP. The TCP pacing and packet pair probing implementation may help overcome two of the major obstacles identified for efficient bandwidth utilization over communication links with large delay-bandwidth products.

Effect of a Particulate and a Putty-Like Tricalcium Phosphate-Based Bone-grafting Material on Bone Formation, Volume Stability and Osteogenic Marker Expression after Bilateral Sinus Floor Augmentation in Humans

PubMed Central

Knabe, Christine; Adel Khattab, Doaa; Kluk, Esther; Struck, Rainer; Stiller, Michael

2017-01-01

This study examines the effect of a hyaluronic acid (HyAc) containing tricalcium phosphate putty scaffold material (TCP-P) and of a particulate tricalcium phosphate (TCP-G) graft on bone formation, volume stability and osteogenic marker expression in biopsies sampled 6 months after bilateral sinus floor augmentation (SFA) in 7 patients applying a split-mouth design. 10% autogenous bone chips were added to the grafting material during surgery. The grain size of the TCP granules was 700 to 1400 µm for TCP-G and 125 to 250 µm and 500 to 700 µm (ratio 1:1) for TCP-P. Biopsies were processed for immunohistochemical analysis of resin-embedded sections. Sections were stained for collagen type I (Col I), alkaline phosphatase (ALP), osteocalcin (OC) and bone sialoprotein (BSP). Furthermore, the bone area and biomaterial area fraction were determined histomorphometrically. Cone-beam CT data recorded after SFA and 6 months later were used for calculating the graft volume at these two time points. TCP-P displayed more advantageous surgical handling properties and a significantly greater bone area fraction and smaller biomaterial area fraction. This was accompanied by significantly greater expression of Col I and BSP and in osteoblasts and osteoid and a less pronounced reduction in grafting volume with TCP-P. SFA using both types of materials resulted in formation of sufficient bone volume for facilitating stable dental implant placement with all dental implants having been in function without any complications for 6 years. Since TCP-P displayed superior surgical handling properties and greater bone formation than TCP-G, without the HyAc hydrogel matrix having any adverse effect on bone formation or graft volume stability, TCP-P can be regarded as excellent grafting material for SFA in a clinical setting. The greater bone formation observed with TCP-P may be related to the difference in grain size of the TCP granules and/or the addition of the HyAc. PMID:28758916

Synthesis and characterizations of alginate-α-tricalcium phosphate microparticle hybrid film with flexibility and high mechanical property as a biomaterial.

PubMed

Das, Dipankar; Zhang, Shengmin; Noh, Insup

2018-01-24

A biocompatible hybrid film has been fabricated using alginate (Alg), α-tricalcium phosphate (α-TCP) microparticle and calcium chloride through ionic crosslinking as a biomaterial. The 'screeding method' (like a concrete finishing process) has been employed to develop the Alg-α-TCP film. For this method, the Alg/α-TCP blend has been prepared using an ultra-sonicator and then put on a glass slide. After that, the excess volume of blend has been cut off by skidding another slide along with the surface of the blend to achieve proper grade and flatness. The mechanical strength and flexibility of the film (Alg-α-TCP) has been controlled by changing its compositions. The crosslinking phenomenon has been confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), 13 C nuclear magnetic resonance (NMR), x-ray diffraction and thermogravimetric analyses. The ATR-FTIR and 13 C NMR analysis results suggest that carboxylate groups of the alginate are ionically cross-linked with Ca 2+ ions, while the α-TCP particles reside in the network by physical interaction. The micro-fatigue test results imply high tensile strength (up to 257 MPa) and flexibility (up to 13% elongation) of the Alg-α-TCP hybrid films. The SEM analysis suggests the α-TCP particles are homogeneously distributed on the surface of Alg-α-TCP films, whereas cross-sectional images confirmed the presence of α-TCP in the cross-linked network. TGA results demonstrated that thermal stability of the hybrid film was enhanced due to ionic crosslinking and interfacial interaction between alginate and α-TCP. The incorporation of α-TCP particles diminished the swelling ratio of the hybrid film. The in vitro bone cell (MC3T3) culture and cytotoxicity tests showed that the hybrid film is biocompatible. The hybrid film releases bovine serum albumin and dimethyloxaloylglycine in a controlled way at pH 7 and 7.4, and 37 °C. Overall, the biocompatible Alg-α-TCP hybrid film with excellent mechanical strength and flexibility could be applied as an interfacial film in tissue engineering.

Relevance of the setting reaction to the injectability of tricalcium phosphate pastes.

PubMed

Montufar, E B; Maazouz, Y; Ginebra, M P

2013-04-01

The aim of the present work was to analyze the influence of the setting reaction on the injectability of tricalcium phosphate (TCP) pastes. Even if the injection was performed early after mixing powder and liquid, powder reactivity was shown to play a significant role in the injectability of TCP pastes. Significant differences were observed between the injection behavior of non-hardening β-TCP pastes and that of self-hardening α-TCP pastes. The differences were more marked at low liquid-to-powder ratios, using fine powders and injecting through thin needles. α-TCP was, in general, less injectable than β-TCP and required higher injection loads. Moreover, clogging was identified as a mechanism hindering or even preventing injectability, different and clearly distinguishable from the filter-pressing phenomenon. α-TCP pastes presented transient clogging episodes, which were not observed in β-TCP pastes with equivalent particle size distribution. Different parameters affecting powder reactivity were also shown to affect paste injectability. Thus, whereas powder calcination resulted in an increased injectability due to lower particle reactivity, the addition of setting accelerants, such as hydroxyapatite nanoparticles, tended to reduce the injectability of the TCP pastes, especially if adjoined simultaneously with a Na2HPO4 solution. Although, as a general trend, faster-setting pastes were less injectable, some exceptions to this rule were found. For example, whereas in the absence of setting accelerants fine TCP powders were more injectable than the coarse ones, in spite of their shorter setting times, this trend was inverted when setting accelerants were added, and coarse powders were more injectable than the fine ones. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Biomimetic composite coating on rapid prototyped scaffolds for bone tissue engineering.

PubMed

Arafat, M Tarik; Lam, Christopher X F; Ekaputra, Andrew K; Wong, Siew Yee; Li, Xu; Gibson, Ian

2011-02-01

The objective of this present study was to improve the functional performance of rapid prototyped scaffolds for bone tissue engineering through biomimetic composite coating. Rapid prototyped poly(ε-caprolactone)/tri-calcium phosphate (PCL/TCP) scaffolds were fabricated using the screw extrusion system (SES). The fabricated PCL/TCP scaffolds were coated with a carbonated hydroxyapatite (CHA)-gelatin composite via biomimetic co-precipitation. The structure of the prepared CHA-gelatin composite coating was studied by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Compressive mechanical testing revealed that the coating process did not have any detrimental effect on the mechanical properties of the scaffolds. The cell-scaffold interaction was studied by culturing porcine bone marrow stromal cells (BMSCs) on the scaffolds and assessing the proliferation and bone-related gene and protein expression capabilities of the cells. Confocal laser microscopy and SEM images of the cell-scaffold constructs showed a uniformly distributed cell sheet and accumulation of extracellular matrix in the interior of CHA-gelatin composite-coated PCL/TCP scaffolds. The proliferation rate of BMSCs on CHA-gelatin composite-coated PCL/TCP scaffolds was about 2.3 and 1.7 times higher than that on PCL/TCP scaffolds and CHA-coated PCL/TCP scaffolds, respectively, by day 10. Furthermore, reverse transcription polymerase chain reaction and Western blot analysis revealed that CHA-gelatin composite-coated PCL/TCP scaffolds stimulate osteogenic differentiation of BMSCs the most, compared with PCL/TCP scaffolds and CHA-coated PCL/TCP scaffolds. These results demonstrate that CHA-gelatin composite-coated rapid prototyped PCL/TCP scaffolds are promising for bone tissue engineering. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

αTCP ceramic doped with dicalcium silicate for bone regeneration applications prepared by powder metallurgy method: in vitro and in vivo studies.

PubMed

Velasquez, Pablo; Luklinska, Zofia B; Meseguer-Olmo, Luis; Mate-Sanchez de Val, Jose E; Delgado-Ruiz, Rafael A; Calvo-Guirado, Jose L; Ramirez-Fernandez, Ma P; de Aza, Piedad N

2013-07-01

This study reports on the in vitro and in vivo behavior of α-tricalcium phosphate (αTCP) and also αTCP doped with either 1.5 or 3.0 wt % of dicalcium silicate (C2 S). The ceramics were successfully prepared by powder metallurgy method combined with homogenization and heat treatment procedures. All materials were composed of a single-phase, αTCP in the case of a pure material, or solid solution of C2 S in αTCP for the doped αTCP, which were stable at room temperature. The ceramics were tested for bioactivity in simulated body fluid, cell culture medium containing adult mesenchymal stem cells of human origin, and in animals. Analytical scanning electron microscopy combined with chemical elemental analysis was used and Fourier transform infrared and conventional histology methods. The in vivo behavior of the ceramics matched the in vitro results, independently of the C2 S content in αTCP. Carbonated hydroxyapatite (CHA) layer was formed on the surface and within the inner parts of the specimens in all cases. A fully mineralized new bone growing in direct contact with the implants was found under the in vivo conditions. The bioactivity and biocompatibility of the implants increased with the C2 S content in αTCP. The C2 S doped ceramics also favoured a phase transformation of αTCP into CHA, important for full implant integration during the natural bone healing processes. αTCP ceramic doped with 3.0 wt % C2 S showed the best bioactive in vitro and in vivo properties of all the compositions and hence could be of interest in specific applications for bone restorative purposes. Copyright © 2012 Wiley Periodicals, Inc.

A physically-modified saline suppresses neuronal apoptosis, attenuates tau phosphorylation and protects memory in an animal model of Alzheimer's disease.

PubMed

Modi, Khushbu K; Jana, Arundhati; Ghosh, Supurna; Watson, Richard; Pahan, Kalipada

2014-01-01

Alzheimer's disease (AD), the leading cause of dementia in the aging population, is characterized by the presence of neuritic plaques, neurofibrillary tangles and extensive neuronal apoptosis. Neuritic plaques are mainly composed of aggregates of amyloid-β (Aβ) protein while neurofibrillary tangles are composed of the hyperphosphorylated tau protein. Despite intense investigations, no effective therapy is currently available to halt the progression of this disease. Here, we have undertaken a novel approach to attenuate apoptosis and tau phosphorylation in cultured neuronal cells and in a transgenic animal model of AD. RNS60 is a 0.9% saline solution containing oxygenated nanobubbles that is generated by subjecting normal saline to Taylor-Couette-Poiseuille (TCP) flow under elevated oxygen pressure. In our experiments, fibrillar Aβ1-42, but not the reverse peptide Aβ42-1, induced apoptosis and cell death in human SHSY5Y neuronal cells. RNS60, but not NS (normal saline), RNS10.3 (TCP-modified saline without excess oxygen) or PNS60 (saline containing excess oxygen without TCP modification), attenuated Aβ(1-42)-induced cell death. RNS60 inhibited neuronal cell death via activation of the type 1A phosphatidylinositol-3 (PI-3) kinase-Akt-BAD pathway. Furthermore, RNS60 also decreased Aβ(1-42)-induced tau phosphorylation via (PI-3 kinase-Akt)-mediated inhibition of GSK-3β. Similarly, RNS60 treatment suppressed neuronal apoptosis, attenuated Tau phosphorylation, inhibited glial activation, and reduced the burden of Aβ in the hippocampus and protected memory and learning in 5XFAD transgenic mouse model of AD. Therefore, RNS60 may be a promising pharmaceutical candidate in halting or delaying the progression of AD.

Genetic Traits of Vibrio cholerae O1 Haitian Isolates That Are Absent in Contemporary Strains from Kolkata, India

PubMed Central

Ghosh, Priyanka; Naha, Arindam; Pazhani, G. P.; Ramamurthy, T.; Mukhopadhyay, Asish K.

2014-01-01

The world's worst cholera epidemic in Haiti (2010) coerced to trace the origin and dissemination of the causative agent Vibrio cholerae O1 for proper management of cholera. Sequence analysis of the Haitian strain showed several variations in the genes encoding cholera toxin B subunit (ctxB); toxin-co-regulated pilus (tcpA), repeat in toxins (rtxA), quinolone resistance-determining region (QRDR) of gyrase A (gyrA), rstB of RS element along with the change in the number of repeat sequences at the promoter region of ctxAB. Our earlier studies showed that variant tcpA (tcpA CIRS) and ctxB (ctxB7) first appeared in Kolkata during 2003 and 2006, respectively. The present study revealed that a variant rtxA was first isolated in Kolkata during 2004 and probably formed the genetic background for the emergence of the ctxB7 allele as we were unable to detect a single strain with the combination of El Tor rtxA and ctxB7. The variant gyrA was first time detected in Kolkata during 1994. The Kolkata strains contained four heptad repeats (TTTTGAT) in their CT promoter regions whereas Haitian strains carried 5 heptad repeats. Haitian strains had 3 nucleotide deletions at the rstB gene, which is a unique feature of the classical biotype strains. But the Kolkata strains did not have such deletion mutations in the rstB. Our study demonstrated the existence of some Haitian genetic traits in Kolkata isolates along with the dissimilarities in genomic content with respect to rstB and ctxAB promoter region. Finally, we conclude that Haitian variant strain may be evolved due to sequential event in the Indian subcontinent strain with some cryptic modification in the genome. PMID:25415339

"SABER": A new software tool for radiotherapy treatment plan evaluation.

PubMed

Zhao, Bo; Joiner, Michael C; Orton, Colin G; Burmeister, Jay

2010-11-01

Both spatial and biological information are necessary in order to perform true optimization of a treatment plan and for predicting clinical outcome. The goal of this work is to develop an enhanced treatment plan evaluation tool which incorporates biological parameters and retains spatial dose information. A software system is developed which provides biological plan evaluation with a novel combination of features. It incorporates hyper-radiosensitivity using the induced-repair model and applies the new concept of dose convolution filter (DCF) to simulate dose wash-out effects due to cell migration, bystander effect, and/or tissue motion during treatment. Further, the concept of spatial DVH (sDVH) is introduced to evaluate and potentially optimize the spatial dose distribution in the target volume. Finally, generalized equivalent uniform dose is derived from both the physical dose distribution (gEUD) and the distribution of equivalent dose in 2 Gy fractions (gEUD2) and the software provides three separate models for calculation of tumor control probability (TCP), normal tissue complication probability (NTCP), and probability of uncomplicated tumor control (P+). TCP, NTCP, and P+ are provided as a function of prescribed dose and multivariable TCP, NTCP, and P+ plots are provided to illustrate the dependence on individual parameters used to calculate these quantities. Ten plans from two clinical treatment sites are selected to test the three calculation models provided by this software. By retaining both spatial and biological information about the dose distribution, the software is able to distinguish features of radiotherapy treatment plans not discernible using commercial systems. Plans that have similar DVHs may have different spatial and biological characteristics and the application of novel tools such as sDVH and DCF within the software may substantially change the apparent plan quality or predicted plan metrics such as TCP and NTCP. For the cases examined, both the calculation method and the application of DCF can change the ranking order of competing plans. The voxel-by-voxel TCP model makes it feasible to incorporate spatial variations of clonogen densities (n), radiosensitivities (SF2), and fractionation sensitivities (alpha/beta) as those data become available. The new software incorporates both spatial and biological information into the treatment planning process. The application of multiple methods for the incorporation of biological and spatial information has demonstrated that the order of application of biological models can change the order of plan ranking. Thus, the results of plan evaluation and optimization are dependent not only on the models used but also on the order in which they are applied. This software can help the planner choose more biologically optimal treatment plans and potentially predict treatment outcome more accurately.

Ridge Preservation After Tooth Extraction With Buccal Bone Plate Deficiency Using Tunnel Structured β-Tricalcium Phosphate Blocks: A 2-Month Histologic Pilot Study in Beagle Dogs.

PubMed

Ikawa, Takahiro; Akizuki, Tatsuya; Matsuura, Takanori; Hoshi, Shu; Ammar, Shujaa Addin; Kinoshita, Atsuhiro; Oda, Shigeru; Izumi, Yuichi

2016-02-01

Reduction in alveolar ridge volume is a direct consequence of tooth extraction. Tunnel β-tricalcium phosphate (β-TCP) blocks were manufactured from randomly organized tunnel-shaped β-TCP ceramic. Efficacy of these blocks compared to extraction alone for alveolar ridge preservation after tooth extraction with buccal bone deficiency was evaluated. Maxillary first premolars of six beagle dogs were extracted after removing the buccal bone, and bone defects of 4 × 4 × 5 mm (mesio-distal width × bucco-palatal width × depth) were created. Fresh extraction sockets with buccal bone defects were filled with tunnel β-TCP blocks at test sites. Two months after the operation, histologic and histometric evaluations were performed. Regarding histologic sections, coronal and middle horizontal widths of the alveolar ridge were significantly greater at test sites (3.2 ± 0.5 and 3.6 ± 0.4 mm, respectively) than at control sites (1.2 ± 0.3 and 2.0 ± 0.6 mm, respectively). The amount of woven bone was significantly greater at test sites (62.4% ± 7.9%) than at control sites (26.8% ± 5.3%), although that of connective tissue and bone marrow was significantly greater at control sites (38.1% ± 6.2% and 16.0% ± 6.9%, respectively) than at test sites (10.7% ± 5.7% and 4.1% ± 2.2%, respectively). Regarding basic multicellular units, no statistically significant difference was found between the test and control sites (0.5% ± 0.1% and 0.6% ± 0.1%, respectively). Tunnel β-TCP blocks represent an effective bone-graft material for alveolar ridge preservation in fresh extraction sockets with buccal bone defects.

The impact of PET/CT scanning on the size of target volumes, radiation exposure of organs at risk, TCP and NTCP, in the radiotherapy planning of non-small cell lung cancer.

PubMed

Vojtíšek, Radovan; Mužík, Jan; Slampa, Pavel; Budíková, Marie; Hejsek, Jaroslav; Smolák, Petr; Ferda, Jiří; Fínek, Jindřich

2014-05-01

To compare radiotherapy plans made according to CT and PET/CT and to investigate the impact of changes in target volumes on tumour control probability (TCP), normal tissue complication probability (NTCP) and the impact of PET/CT on the staging and treatment strategy. Contemporary studies have proven that PET/CT attains higher sensitivity and specificity in the diagnosis of lung cancer and also leads to higher accuracy than CT alone in the process of target volume delineation in NSCLC. Between October 2009 and March 2012, 31 patients with locally advanced NSCLC, who had been referred to radical radiotherapy were involved in our study. They all underwent planning PET/CT examination. Then we carried out two separate delineations of target volumes and two radiotherapy plans and we compared the following parameters of those plans: staging, treatment purpose, the size of GTV and PTV and the exposure of organs at risk (OAR). TCP and NTCP were also compared. PET/CT information led to a significant decrease in the sizes of target volumes, which had the impact on the radiation exposure of OARs. The reduction of target volume sizes was not reflected in the significant increase of the TCP value. We found that there is a very strong direct linear relationship between all evaluated dosimetric parameters and NTCP values of all evaluated OARs. Our study found that the use of planning PET/CT in the radiotherapy planning of NSCLC has a crucial impact on the precise determination of target volumes, more precise staging of the disease and thus also on possible changes of treatment strategy.

Bone Morphogenetic Protein-7 Enhances Degradation of Osteoinductive Bioceramic Implants in an Ectopic Model

PubMed Central

Klünter, Tim; Schulz, Peter; Deisinger, Ulrike; Diez, Claudius; Waiss, Waltraud; Kirschneck, Christian; Reichert, Torsten E.; Detsch, Rainer

2017-01-01

Background: The aim of the present study was to evaluate the degradation pattern of highly porous bioceramics as well as the bone formation in presence of bone morphogenetic protein 7 (BMP-7) in an ectopic site. Methods: Novel calcium phosphate ceramic cylinders sintered at 1,300°C with a total porosity of 92–94 vol%, 45 pores per inch, and sized 15 mm (Ø) × 5 mm were grafted on the musculus latissimus dorsi bilaterally in 10 Göttingen minipigs: group I (n = 5): hydroxyapatite (HA) versus biphasic calcium phosphate (BCP), a mixture of HA and tricalcium phosphate (TCP) in a ratio of 60/40 wt%; group II (n = 5): TCP versus BCP. A test side was supplied in situ with 250 μg BMP-7. Fluorochrome bone labeling and computed tomography were performed in vivo. Specimens were evaluated 14 weeks after surgery by environmental scanning electron microscopy, fluorescence microscopy, tartrate-resistant acid phosphatase, and pentachrome staining. Results: Bone formation was enhanced in the presence of BMP-7 in all ceramics (P = 0.001). Small spots of newly formed bone were observed in all implants in the absence of BMP-7. Degradation of HA and BCP was enhanced in the presence of BMP-7 (P = 0.001). In those ceramics, osteoclasts were observed. TCP ceramics were almost completely degraded independently of the effect of BMP-7 after 14 weeks (P = 0.76), osteoclasts were not observed. Conclusions: BMP-7 enhanced bone formation and degradation of HA and BCP ceramics via osteoclast resorption. TCP degraded via dissolution. All ceramics were osteoinductive. Novel degradable HA and BCP ceramics in the presence of BMP-7 are promising bone substitutes in the growing individual. PMID:28740783

Application of stochastic discrete event system framework for detection of induced low rate TCP attack.

PubMed

Barbhuiya, F A; Agarwal, Mayank; Purwar, Sanketh; Biswas, Santosh; Nandi, Sukumar

2015-09-01

TCP is the most widely accepted transport layer protocol. The major emphasis during the development of TCP was its functionality and efficiency. However, not much consideration was given on studying the possibility of attackers exploiting the protocol, which has lead to several attacks on TCP. This paper deals with the induced low rate TCP attack. Since the attack is relatively new, only a few schemes have been proposed to mitigate it. However, the main issues with these schemes are scalability, change in TCP header, lack of formal frameworks, etc. In this paper, we have adapted the stochastic DES framework for detecting the attack, which addresses most of these issues. We have successfully deployed and tested the proposed DES based IDS on a test bed. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Repression of cell proliferation by miR319-regulated TCP4.

PubMed

Schommer, Carla; Debernardi, Juan M; Bresso, Edgardo G; Rodriguez, Ramiro E; Palatnik, Javier F

2014-10-01

Leaf development has been extensively studied on a genetic level. However, little is known about the interplay between the developmental regulators and the cell cycle machinery--a link that ultimately affects leaf form and size. miR319 is a conserved microRNA that regulates TCP transcription factors involved in multiple developmental pathways, including leaf development and senescence, organ curvature, and hormone biosynthesis and signaling. Here, we analyze the participation of TCP4 in the control of cell proliferation. A small increase in TCP4 activity has an immediate impact on leaf cell number, by significantly reducing cell proliferation. Plants with high TCP4 levels have a strong reduction in the expression of genes known to be active in G2-M phase of the cell cycle. Part of these effects is mediated by induction of miR396, which represses Growth-Regulating Factor (GRF) transcription factors. Detailed analysis revealed TCP4 to be a direct regulator of MIR396b. However, we found that TCP4 can control cell proliferation through additional pathways, and we identified a direct connection between TCP4 and ICK1/KRP1, a gene involved in the progression of the cell cycle. Our results show that TCP4 can activate different pathways that repress cell proliferation. © The Author 2014. Published by the Molecular Plant Shanghai Editorial Office in association with Oxford University Press on behalf of CSPB and IPPE, SIBS, CAS.

Leaf expansion in Arabidopsis is controlled by a TCP-NGA regulatory module likely conserved in distantly related species.

PubMed

Ballester, Patricia; Navarrete-Gómez, Marisa; Carbonero, Pilar; Oñate-Sánchez, Luis; Ferrándiz, Cristina

2015-09-01

The NGATHA (NGA) clade of transcription factors (TFs) forms a small subfamily of four members in Arabidopsis thaliana. NGA genes act redundantly to direct the development of apical tissues in the gynoecium, where they have been shown to be essential for style and stigma specification. In addition, NGA genes have a more general role in controlling lateral organ growth. The four NGA genes in Arabidopsis are expressed in very similar domains, although little is known about the nature of their putative regulators. Here, we have identified a conserved region within the four NGA promoters that we have used as a bait to screen a yeast library, aiming to identify such NGA regulators. Three members of the TCP family of TFs, named after the founding factors TEOSINTE BRANCHED 1, CYCLOIDEA and PROLIFERATING CELL FACTOR 1 AND 2), were recovered from this screening, of which two [TCP2 and TCP3, members of the CINCINNATA (CIN) family of TCP genes (CIN-TCP) subclade] were shown to activate the NGA3 promoter in planta. We provide evidence that support that CIN-TCP genes are true regulators of NGA gene expression, and that part of the CIN-TCP role in leaf development is mediated by NGA upregulation. Moreover, we have found that this TCP-NGA regulatory interaction is likely conserved in angiosperms, including important crop species, for which the regulation of leaf development is a target for biotechnological improvement. © 2015 Scandinavian Plant Physiology Society.

Bone regeneration with osteogenic matrix cell sheet and tricalcium phosphate: An experimental study in sheep.

PubMed

Kira, Tsutomu; Akahane, Manabu; Omokawa, Shohei; Shimizu, Takamasa; Kawate, Kenji; Onishi, Tadanobu; Tanaka, Yasuhito

2017-10-18

To determine the effects of a cell sheet created from sheep bone marrow and tricalcium phosphate (TCP) on osteogenesis. Bone marrow cells were harvested from a sheep and cultured in a minimal essential medium (MEM) containing ascorbic acid phosphate (AscP) and dexamethasone (Dex). After 2 wk, the formed osteogenic matrix cell sheet was lifted from the culture dish using a scraper. Additionally, harvested bone marrow cells were cultured in MEM only as a negative control group, and in MEM with AscP, Dex, and β-glycerophosphate as a positive control group. For in vitro evaluation, we measured the alkaline phosphatase (ALP) activity and osteocalcin (OC) content in the media of the cultured cells from each group. For in vivo analysis, a porous TCP ceramic was used as a scaffold. We prepared an experimental group comprising TCP scaffolds wrapped with the osteogenic matrix cell sheets and a control group consisting of the TCP scaffold only. The constructs were implanted subcutaneously into athymic rats and the cell donor sheep, and bone formation was confirmed by histology after 4 wk. In the in vitro part, the mean ALP activity was 0.39 ± 0.03 mg/well in the negative control group, 0.67 ± 0.04 mg/well in the sheet group, and 0.65 ± 0.07 mg/well in the positive control group. The mean OC levels were 1.46 ± 0.33 ng/well in the negative control group, 3.92 ± 0.16 ng/well in the sheet group, and 4.4 ± 0.47 ng/well in the positive control group, respectively. The ALP activity and OC levels were significantly higher in the cell sheet and positive control groups than in the negative control group ( P < 0.05). There was no significant difference in ALP activity or OC levels between the cell sheet group and the positive control group ( P > 0.05). TCP constructs wrapped with cell sheets prior to implantation showed bone formation, in contrast to TCP scaffolds alone, which exhibited poor bone formation when implanted, in the subcutaneous layer both in athymic rats and in the sheep. This technique for preparing highly osteoinductive TCP may promote regeneration in large bone defects.

Controlling Blue and Red Light Emissions from Europium (Eu2+)/Manganese (Mn2+)-Codoped Beta-Tricalcium Phosphate [β-Ca3(PO4)2 (TCP)] Phosphors

NASA Astrophysics Data System (ADS)

Van, Hoang Nhu; Hoan, Bui Thi; Nguyen, Khoi Thi; Tam, Phuong Dinh; Huy, Pham Thanh; Pham, Vuong-Hung

2018-03-01

Tunable light emission from europium (Eu2+)/manganese (Mn2+)-codoped beta-tricalcium phosphate [β-Ca3(PO4)2 (TCP)] has been investigated as a function of the Mn2+ and Eu2+ concentrations and annealing temperature. Eu2+/Mn2+-doped TCP phosphor (Eu/Mn-TCP) was synthesized by coprecipitation method followed by thermal annealing at temperature up to 1100°C. The Eu2+/Mn2+-doped TCP particles have diameter of about 1 μm. The light emission from TCP is enhanced in the sample with 7.5 mol.% Mn2+ and 0.3 mol.% Eu2+ annealed in Ar + 5% H2 atmosphere at 1100°C. The blue band at 430 nm is attributed to the 4f 6 5d 1-4f 7 transition of Eu2+. The sharp peak at 660 nm is ascribed to the 4T1-6A1 transition of Mn2+ in TCP. These results suggest codoping of Eu2+/Mn2+ to TCP phosphor to obtain β-Ca3(PO4)2:Eu2+,Mn2+ phosphors with tunable luminescence, having potential applications in agricultural lighting.

Comparative phylogenomic analysis provides insights into TCP gene functions in Sorghum

PubMed Central

Francis, Aleena; Dhaka, Namrata; Bakshi, Mohit; Jung, Ki-Hong; Sharma, Manoj K.; Sharma, Rita

2016-01-01

Sorghum is a highly efficient C4 crop with potential to mitigate challenges associated with food, feed and fuel. TCP proteins are of particular interest for crop improvement programs due to their well-demonstrated roles in crop domestication and shaping plant architecture thereby, affecting agronomic traits. We identified 20 TCP genes from Sorghum. Except SbTCP8, all are either intronless or contain introns in the untranslated regions. Comparative phylogenetic analysis of Arabidopsis, rice, Brachypodium and Sorghum TCP proteins revealed two distinct classes categorized into ten sub-clades. Sub-clade F is dicot-specific, whereas A2, G1 and I1 groups only contained genes from grasses. Sub-clade B was missing in Sorghum, whereas group A1 was missing in rice indicating species-specific divergence of TCP proteins. TCP proteins of Sorghum are enriched in disorder promoting residues with class I containing higher percent disorder than class II proteins. Seven pairs of paralogous TCP genes were identified from Sorghum, five of which seem to predate Rice-Sorghum divergence. All of them have diverged in their expression. Based on the expression and orthology analysis, five Sorghum genes have been shortlisted for further investigation for their roles in regulating plant morphology. Whereas, three genes have been identified as candidates for engineering abiotic stress tolerance. PMID:27917941

Genome-Wide Identification and Analysis of TCP Transcription Factors Involved in the Formation of Leafy Head in Chinese Cabbage.

PubMed

Liu, Yan; Guan, Xiaoyu; Liu, Shengnan; Yang, Meng; Ren, Junhui; Guo, Meng; Huang, Zhihui; Zhang, Yaowei

2018-03-14

Chinese cabbage ( Brassica rapa L. ssp . pekinensis ) is a widely cultivated and economically important vegetable crop with typical leaf curvature. The TCP (Teosinte branched1, Cycloidea, Proliferating cell factor) family proteins are plant-specific transcription factors (TFs) and play important roles in many plant biological processes, especially in the regulation of leaf curvature. In this study, 39 genes encoding TCP TFs are detected on the whole genome of B. rapa. Based on the phylogenetic analysis of TCPs between Arabidopsis thaliana and Brassica rapa , TCP genes of Chinese cabbage are named from BrTCP1a to BrTCP24b . Moreover, the chromosomal location; phylogenetic relationships among B. rapa , A. thaliana , and rice; gene structures and protein conserved sequence alignment; and conserved domains are analyzed. The expression profiles of BrTCPs are analyzed in different tissues. To understand the role of Chinese cabbage TCP members in regulating the curvature of leaves, the expression patterns of all BrTCP genes are detected at three development stages essential for leafy head formation. Our results provide information on the classification and details of BrTCPs and allow us to better understand the function of TCPs involved in leaf curvature of Chinese cabbage.

Genome-Wide Identification and Analysis of TCP Transcription Factors Involved in the Formation of Leafy Head in Chinese Cabbage

PubMed Central

Liu, Yan; Guan, Xiaoyu; Liu, Shengnan; Yang, Meng; Ren, Junhui; Guo, Meng; Huang, Zhihui

2018-01-01

Chinese cabbage (Brassica rapa L. ssp. pekinensis) is a widely cultivated and economically important vegetable crop with typical leaf curvature. The TCP (Teosinte branched1, Cycloidea, Proliferating cell factor) family proteins are plant-specific transcription factors (TFs) and play important roles in many plant biological processes, especially in the regulation of leaf curvature. In this study, 39 genes encoding TCP TFs are detected on the whole genome of B. rapa. Based on the phylogenetic analysis of TCPs between Arabidopsis thaliana and Brassica rapa, TCP genes of Chinese cabbage are named from BrTCP1a to BrTCP24b. Moreover, the chromosomal location; phylogenetic relationships among B. rapa, A. thaliana, and rice; gene structures and protein conserved sequence alignment; and conserved domains are analyzed. The expression profiles of BrTCPs are analyzed in different tissues. To understand the role of Chinese cabbage TCP members in regulating the curvature of leaves, the expression patterns of all BrTCP genes are detected at three development stages essential for leafy head formation. Our results provide information on the classification and details of BrTCPs and allow us to better understand the function of TCPs involved in leaf curvature of Chinese cabbage. PMID:29538304

Mechanism of lubrication by tricresylphosphate (TCP)

NASA Technical Reports Server (NTRS)

Faut, O. D.; Buckley, D. H.

1984-01-01

The coefficient of friction was measured as a function of temperature on a pin-on-disk tribometer. Pins and disks of 440C and 52100 steels were lubricated with tricresylphosphate (TCP), 3.45 percent TCP in squalene, and pure squalene. The M-50 pins and disks were lubricated with 3.45 percent TCP in squalene and pure squalene. Experiments were conducted under limited lubrication conditions in dry ( 100 ppm H2O) air and dry ( pp H2O) nitrogen at 50 rpm (equivalent to a sliding velocity of 13 cm sec) and a constant load of 9.8 N (1 kg). Characteristic temperatures T sub r were identified for TCP on 52100 steel and for squalene on M-50 and 52100 steels, where the friction decreased because of a chemical reaction between the lubricant and the metal surface. The behavior of squalene obscured the influence of 3.45 percent TCP solute on the friction of the system. Wear volume measurements demonstrated that wear was lowest at temperatures just above T sub r. Comparing the behavior of TCP on M-50, 440C, and 52100 steels revealed that the TCP either reacted to give T sub r behavior or produced initial failure in the temperature range 223 + or - 5 C.

Comparative phylogenomic analysis provides insights into TCP gene functions in Sorghum.

PubMed

Francis, Aleena; Dhaka, Namrata; Bakshi, Mohit; Jung, Ki-Hong; Sharma, Manoj K; Sharma, Rita

2016-12-05

Sorghum is a highly efficient C4 crop with potential to mitigate challenges associated with food, feed and fuel. TCP proteins are of particular interest for crop improvement programs due to their well-demonstrated roles in crop domestication and shaping plant architecture thereby, affecting agronomic traits. We identified 20 TCP genes from Sorghum. Except SbTCP8, all are either intronless or contain introns in the untranslated regions. Comparative phylogenetic analysis of Arabidopsis, rice, Brachypodium and Sorghum TCP proteins revealed two distinct classes categorized into ten sub-clades. Sub-clade F is dicot-specific, whereas A2, G1 and I1 groups only contained genes from grasses. Sub-clade B was missing in Sorghum, whereas group A1 was missing in rice indicating species-specific divergence of TCP proteins. TCP proteins of Sorghum are enriched in disorder promoting residues with class I containing higher percent disorder than class II proteins. Seven pairs of paralogous TCP genes were identified from Sorghum, five of which seem to predate Rice-Sorghum divergence. All of them have diverged in their expression. Based on the expression and orthology analysis, five Sorghum genes have been shortlisted for further investigation for their roles in regulating plant morphology. Whereas, three genes have been identified as candidates for engineering abiotic stress tolerance.

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

Muller, L; Soldner, A; Kirk, M

Purpose: The beam range uncertainty presents a special challenge for proton therapy. Novel technologies currently under development offer strategies to reduce the range uncertainty [1,2]. This work quantifies the potential advantages that could be realized by such a reduction for dosimetrically challenging chordomas at the base of skull. Therapeutic improvement was assessed by evaluating tumor control probabilities (TCP) and normal tissue complication probabilities (NTCP). Methods: Treatment plans were made for a modulated-scanned proton delivery technique using the Eclipse treatment planning system. The prescription dose was 7920 cGy to the CTV. Three different range uncertainty scenarios were considered: 5 mm (3.5%more » of the beam range + 1 mm, representing current clinical practice, “Curr”), 2 mm (1.3%), and 1 mm (0.7%). For each of 4 patients, 3 different PTVs were defined via uniform expansion of the CTV by the value of the range uncertainty. Tumor control probability (TCP) and normal tissue complication probabilities (NTCPs) for organs-at-risk (OARs) were calculated using the Lyman-Kutcher-Burman[3] formalism and published model parameters [ref Terahara[4], quantec S10, Burman Red Journal v21 pp 123]. Our plan optimization strategy was to achieve PTV close to prescription while maintaining OAR NTCP values at or better than the Curr plan. Results: The average TCP values for the 5, 2, and 1 mm range uncertainty scenarios are 51%, 55% and 65%. The improvement in TCP for patients was between 4 and 30%, depending primarily on the proximity of the GTV to OAR. The average NTCPs for the brainstem and cord were about 4% and 1%, respectively, for all target margins. Conclusion: For base of skull chordomas, reduced target margins can substantially increase the TCP without increasing the NTCP. This work demonstrates the potential significance of a reduction in the range uncertainty for proton beams.« less

Intestinal damage, neurotoxicity and biochemical responses caused by tris (2-chloroethyl) phosphate and tricresyl phosphate on earthworm.

PubMed

Yang, Yang; Xiao, Yao; Chang, Yeqian; Cui, Yibin; Klobučar, Göran; Li, Mei

2018-08-30

Organophosphate esters (OPEs) draw growing concern about characterizing the potential risk on environmental health due to its wide usage and distribution. Two typical types of organophosphate esters (OPEs): tris (2-chloroethyl) phosphate (TCEP) and tricresyl phosphate (TCP) were selected to evaluate toxicity of OPEs to the soil organism like earthworm (Eisenia fetida). Histopathological examination (H&E), oxidative stress, DNA damage and RT-qPCR was used to identify the effects and potential mechanism of their toxicity. Hameatoxylin and eosin (H&E) demonstrated that intestinal cells suffered serious damage, and the observed up-regulation of chitinase and cathepsin L in mRNA levels confirmed it. Both TCEP and TCP significantly increased the DNA damage when the concentrations exceeded 1 mg/kg (p < 0.01), and a dose-response relationship was observed. In addition, TCEP and TCP also changed the acetylcholinesterase (AChE) activity and expression of genes associated with neurotoxic effects in earthworms even under exposure to low OPEs concentration (0.1 mg/kg). Moreover, genes associated with nicotinic acetylcholine receptors (nAChR) and carrier protein further demonstrated that highest concentration of TCEP (10 mg/kg) may have an overloading impact on the cholinergic system of E. fetida. Integrated Biological Response index (IBRv2) showed that TCEP exerted stronger toxicity than TCP under the same concentrations. We deduced that the observed intestinal damage, oxidative stress and neurotoxic effect might be the primary mechanisms of TCEP and TCP toxicity. This study provides insight into the toxicological effects of OPEs on earthworm model, and may be useful for risk assessment of OPEs on soil ecosystems. Copyright © 2018 Elsevier Inc. All rights reserved.

Factors influencing inapplicability of cosolvency-induced model on organic acid sorption onto humic substance from methanol mixture.

PubMed

Kim, Minhee; Kim, Juhee; Kim, Jeong-Gyu; Hyun, Seunghun

2015-10-01

Applicability of cosolvency model for describing the sorption of organic acids to humic substance was investigated by analyzing dataset of sorption (K m) and solubility (S m) of selected solutes (benzoic acid, 1-naphthoic acid, 2,4-dichlorophenoxyacetic acid, and 2,4,6-trichlorophenol (2,4,6-TCP)) as a function of pH(appCME) (apparent pH of liquid phase) and f c (methanol volume fractions). For all solutes, the K m decreased with f c with the K m reduction being less than the S m-based prediction. The slope of log K m-f c plot in the three organic carboxylic acids was well correlated with their cosolvency power, whereas the data of organic phenolic acid (2,4,6-TCP) was placed above the trend, indicating the different actions of functional groups. The occurrence of Ca(2+) bridge between carboxylate and negatively charged humic surface may explain this phenomenon. Normalizing the K m to the corresponding S m (α' = K m/S m) was not in unity over the pH(app)-f c range but decreased with f c, indicating a possible structural modification of sorption domain favoring extra sorption. For a given solute, the α' of neutral species was always greater than that of anionic species, showing that extra interaction will be likely at pH(app)

ACTS 118x: High Speed TCP Interoperability Testing

NASA Technical Reports Server (NTRS)

Brooks, David E.; Buffinton, Craig; Beering, Dave R.; Welch, Arun; Ivancic, William D.; Zernic, Mike; Hoder, Douglas J.

1999-01-01

With the recent explosion of the Internet and the enormous business opportunities available to communication system providers, great interest has developed in improving the efficiency of data transfer over satellite links using the Transmission Control Protocol (TCP) of the Internet Protocol (IP) suite. The NASA's ACTS experiments program initiated a series of TCP experiments to demonstrate scalability of TCP/IP and determine to what extent the protocol can be optimized over a 622 Mbps satellite link. Through partnerships with the government technology oriented labs, computer, telecommunication, and satellite industries NASA Glenn was able to: (1) promote the development of interoperable, high-performance TCP/IP implementations across multiple computing / operating platforms; (2) work with the satellite industry to answer outstanding questions regarding the use of standard protocols (TCP/IP and ATM) for the delivery of advanced data services, and for use in spacecraft architectures; and (3) conduct a series of TCP/IP interoperability tests over OC12 ATM over a satellite network in a multi-vendor environment using ACTS. The experiments' various network configurations and the results are presented.

TCP Packet Trace Analysis. M.S. Thesis

NASA Technical Reports Server (NTRS)

Shepard, Timothy J.

1991-01-01

Examination of a trace of packets collected from the network is often the only method available for diagnosing protocol performance problems in computer networks. This thesis explores the use of packet traces to diagnose performance problems of the transport protocol TCP. Unfortunately, manual examination of these traces can be so tedious that effective analysis is not possible. The primary contribution of this thesis is a graphical method of displaying the packet trace which greatly reduce, the tediousness of examining a packet trace. The graphical method is demonstrated by the examination of some packet traces of typical TCP connections. The performance of two different implementations of TCP sending data across a particular network path is compared. Traces many thousands of packets long are used to demonstrate how effectively the graphical method simplifies examination of long complicated traces. In the comparison of the two TCP implementations, the burstiness of the TCP transmitter appeared to be related to the achieved throughput. A method of quantifying this burstiness is presented and its possible relevance to understanding the performance of TCP is discussed.

Brucella TIR-like protein TcpB/Btp1 specifically targets the host adaptor protein MAL/TIRAP to promote infection.

PubMed

Li, Wenna; Ke, Yuehua; Wang, Yufei; Yang, Mingjuan; Gao, Junguang; Zhan, Shaoxia; Xinying, Du; Huang, Liuyu; Li, Wenfeng; Chen, Zeliang; Li, Juan

2016-08-26

Brucella spp. are known to avoid host immune recognition and weaken the immune response to infection. Brucella like accomplish this by employing two clever strategies, called the stealth strategy and hijacking strategy. The TIR domain-containing protein (TcpB/Btp1) of Brucella melitensis is thought to be involved in inhibiting host NF-κB activation by binding to adaptors downstream of Toll-like receptors. However, of the five TIR domain-containing adaptors conserved in mammals, whether MyD88 or MAL, even other three adaptors, are specifically targeted by TcpB has not been identified. Here, we confirmed the effect of TcpB on B.melitensis virulence in mice and found that TcpB selectively targets MAL. By using siRNA against MAL, we found that TcpB from B.melitensis is involved in intracellular survival and that MAL affects intracellular replication of B.melitensis. Our results confirm that TcpB specifically targets MAL/TIRAP to disrupt downstream signaling pathways and promote intra-host survival of Brucella spp. Copyright © 2016 Elsevier Inc. All rights reserved.

Global Connections for Lasting Impressions: Experiential Learning about TCP

NASA Astrophysics Data System (ADS)

Allison, Colin; Miller, Alan; Oliver, Iain; Sturgeon, Thomas

“Tell me and I forget, Show me and I remember, Involve me and I understand”. This paper discusses the motivation for, and design of, a learning resource which allows students to explore the Transmission Control Protocol (TCP). TCP is responsible for transporting over 80% of the traffic on the Internet - all web and e-mail for example - and in addition is the primary means of achieving Internet congestion control. TCP is therefore core to modern life. It is a protocol under constant study with a view to evolution, and it is incumbent on all ICT curricula to provide education at appropriate levels about its dynamics, strengths and weaknesses. There are no shortages of good textbooks which provide information on TCP, but these are no substitute for experiential learning in order to provide a lasting understanding. The TCP Live learning resource allows students to explore the behavior of TCP on the global Internet, and see the wide variety of conditions that the protocol has to cope with, thereby extending their viewpoint outwith the limited scope of their own institutional firewalls.

Effects of MgO modified β-TCP nanoparticles on the microstructure and properties of β-TCP/Mg-Zn-Zr composites.

PubMed

Zheng, H R; Li, Z; You, C; Liu, D B; Chen, M F

2017-03-01

The mechanical properties and corrosion resistance of magnesium alloy composites were improved by the addition of MgO surface modified tricalcium phosphate ceramic nanoparticles (m-β-TCP). Mg-3Zn-0.8Zr composites with unmodified (MZZT) and modified (MZZMT) nanoparticles were produced by high shear mixing technology. Effects of MgO m-β-TCP nanoparticles on the microstructure, mechanical properties, electrochemical corrosion properties and cytocompatibility of Mg-Zn-Zr/β-TCP composites were investigated. After hot extrusion deformation and dynamic recrystallization, the grain size of MZZMT was the half size of MZZT and the distribution of m-β-TCP particles in the matrix was more uniform than β-TCP particles. The yield tensile strength (YTS), ultimate tensile strength (UTS), and corrosion potential (Ecorr) of MZZMT were higher than MZZT; the corrosion current density (I corr ) of MZZMT was lower than MZZT. Cell proliferation of co-cultured MZZMT and MZZT composite samples were roughly the same and the cell number at each time point is higher for MZZMT than for MZZT samples.

Performance Analysis of TCP Enhancements in Satellite Data Networks

NASA Technical Reports Server (NTRS)

Broyles, Ren H.

1999-01-01

This research examines two proposed enhancements to the well-known Transport Control Protocol (TCP) in the presence of noisy communication links. The Multiple Pipes protocol is an application-level adaptation of the standard TCP protocol, where several TCP links cooperate to transfer data. The Space Communication Protocol Standard - Transport Protocol (SCPS-TP) modifies TCP to optimize performance in a satellite environment. While SCPS-TP has inherent advantages that allow it to deliver data more rapidly than Multiple Pipes, the protocol, when optimized for operation in a high-error environment, is not compatible with legacy TCP systems, and requires changes to the TCP specification. This investigation determines the level of improvement offered by SCPS-TP's Corruption Mode, which will help determine if migration to the protocol is appropriate in different environments. As the percentage of corrupted packets approaches 5 %, Multiple Pipes can take over five times longer than SCPS-TP to deliver data. At high error rates, SCPS-TP's advantage is primarily caused by Multiple Pipes' use of congestion control algorithms. The lack of congestion control, however, limits the systems in which SCPS-TP can be effectively used.

Morphometric analysis of the location and activity of cytokines in the tissue implant response.

PubMed

Butler, Kenneth R; Benghuzzi, Hamed A; Tucci, Michelle A; Puckett, Aaron

2014-01-01

The objective of this investigation was to evaluate the location and activity of cytokines in the fibrous tissue surrounding tricalcium phosphate (TCP) implants loaded with androgenic hormones. Sixteen animals in four experimental groups (n = 4/group) were implanted with one TCP implant each: Group I (control), Group II (testosterone), Group III (dihydrotestosterone), and Group IV (androstenedione). At 90 days post-implantation, the fibrous tissue surrounding the implants were evaluated following staining with antibodies to IL-1ß, IL-2, IL-6, and TNF?. Data were collected on the presence and distribution of cytokines within the fibrous tissue surrounding all four groups. IL-1ß was primarily found intercellular and associated with fibroblasts and macrophages of Groups I-III. IL-2 was present in the extracellular matrix and was sporadically found on the surface of macrophages in Groups I-III. IL-6 was found primarily concentrated in the fibroblast and collagen rich portions of the fibrous tissue matrix in Groups I-III. TNF-? was present in the extracellular matrix of the fibrous tissue of all four groups and was strongly associated with fibroblast and macrophage rich areas. The results of this study confirm activity of cytokines on target cells and indicate their actions may vary in their effect within the fibrous tissue surrounding TCP implants loaded with androgens.

Systemic candidiasis in mice. II.--Main role of polymorphonuclear leukocytes in resistance to infection.

PubMed

Hurtrel, B; Lagrange, P H; Michel, J C

1980-01-01

Cyclophosphamide (CY) increased whereas the talc embedded in a calcium phosphate gel (TCP) decreased the susceptibility of mice to systemic candidiasis estimated by measuring mean survival time and "renal infectivity" 12 h after challenge. Transfers of plasma from CY- and TCP-treated mice did not modify cnadidiasis susceptibility of recipient mice. Granulopenia and granulocytosis induced respectively by CY and TCP were significantly correlated with susceptibility or resistance to candidiasis. Nevertheless, TCP produced significant reticuloendothelial stimulation which could be also correlated with TCP protection. Reticuloendothelial stimulation with associated granulopenia in TCP-CY-treated mice gave protection against Listeria monocytogenes challenge but not against Candida albicans. Thus, blood polymorphonuclear leukocytes seem to play the main role in natural resistance of mice to candidiasis. This was corroborated after injection of immunostimulants; a good correlation was found between C. albicans resistance and the induced granulocytosis.

Protocol Support for a New Satellite-Based Airspace Communication Network

NASA Technical Reports Server (NTRS)

Shang, Yadong; Hadjitheodosiou, Michael; Baras, John

2004-01-01

We recommend suitable transport protocols for an aeronautical network supporting Internet and data services via satellite. We study the characteristics of an aeronautical satellite hybrid network and focus on the problems that cause dramatically degraded performance of the Transport Protocol. We discuss various extensions to standard TCP that alleviate some of these performance problems. Through simulation, we identify those TCP implementations that can be expected to perform well. Based on the observation that it is difficult for an end-to-end solution to solve these problems effectively, we propose a new TCP-splitting protocol, termed Aeronautical Transport Control Protocol (AeroTCP). The main idea of this protocol is to use a fixed window for flow control and one duplicated acknowledgement (ACK) for fast recovery. Our simulation results show that AeroTCP can maintain higher utilization for the satellite link than end-to-end TCP, especially in high BER environment.

Effect of atmosphere on phase transformation in plasma-sprayed hydroxyapatite coatings during heat treatment.

PubMed

Chen, J; Tong, W; Cao, Y; Feng, J; Zhang, X

1997-01-01

The purpose of this study was to evaluate the effect of atmosphere on the phase transformation in hydroxyapatite (HA) coatings during heat treatment by varying the atmosphere in the furnace pipe. Heat treatment always increased the crystallinity of HA coatings regardless of the kind of atmosphere. Water molecules in atmosphere further promoted HA recrystallization during heat treatment. In a dry atmosphere, tricalcium phosphate (TCP) and tetracalcium phosphate (TTCP) were more stable than HA, so heat treatment could not convert them into HA. However, in a humid atmosphere, heat treatment would transform TCP and TTCP into HA by hydrolytic reactions.

Osteoinductive potential of highly purified porous β-TCP in mice.

PubMed

Tsukanaka, Masako; Fujibayashi, Shunsuke; Otsuki, Bungo; Takemoto, Mitsuru; Matsuda, Shuichi

2015-03-01

Material-induced osteoinduction of calcium phosphate ceramics has been reported in specific animals. We previously reported that recruitment of tartrate-resistant acid phosphatase (TRAP)-positive cells might be one of the main factors responsible for the difference in the occurrence of material-induced osteoinduction between dogs and rats. In this study, we evaluated the osteoinductive potential of highly purified porous beta-tricalcium phosphate materials (HPP-β-TCP) with two different porosities, 75 and 60 % (Olympus Terumo Biomaterials, Tokyo, Japan), implanted into subcutaneous pockets of FVB and C57BL/6 mice. Twelve weeks after implantation, histological examination and gene expression analysis using reverse transcription-polymerase chain reaction were performed. We observed osteoinduction in half of the HPP-β-TCP materials with 60 % porosity implanted into FVB mice. This group of mice also exhibited the most TRAP-positive cells. Significantly more vessels were found in FVB mice than in C57BL/6 mice, but the greatest number of vessels was counted in implants from materials with 75 % porosity implanted into FVB mice, which did not show osteoinduction. These results indicate that recruitment of TRAP-positive cells is one factor responsible for osteoinduction caused by HPP-β-TCP materials in both FVB mice and dogs. Vessel formation seems to be necessary but appears to be less influential for osteoinduction than TRAP-positive cell recruitment.

Doped Tricalcium Phosphate Scaffolds by Thermal Decomposition of Naphthalene: Mechanical Properties and In vivo Osteogenesis in a Rabbit Femur Model

PubMed Central

Ke, Dongxu; Dernell, William; Bandyopadhyay, Amit; Bose, Susmita

2015-01-01

Tricalcium phosphate (TCP) is a bioceramic that is widely used in orthopedic and dental applications. TCP structures show excellent biocompatibility as well as biodegradability. In this study, porous β-TCP scaffolds were prepared by thermal decomposition of naphthalene. Scaffolds with 57.64 ± 3.54 % density and a maximum pore size around 100 μm were fabricated via removing 30% naphthalene at 1150°C. The compressive strength for these scaffolds was 32.85 ± 1.41 MPa. Furthermore, by mixing 1 wt % SrO and 0.5 wt % SiO2, pore interconnectivity improved, but the compressive strength decreased to 22.40 ± 2.70 MPa. However, after addition of polycaprolactone (PCL) coating layers, the compressive strength of doped scaffolds increased to 29.57 ± 3.77 MPa. Porous scaffolds were implanted in rabbit femur defects to evaluate their biological property. The addition of dopants triggered osteoinduction by enhancing osteoid formation, osteocalcin expression and bone regeneration, especially at the interface of the scaffold and host bone. This study showed processing flexibility to make interconnected porous scaffolds with different pore size and volume fraction porosity with high compressive mechanical strength and better bioactivity. Results show that SrO/SiO2 doped porous TCP scaffolds have excellent potential to be used in bone tissue engineering applications. PMID:25504889

Methacrylate-based root canal sealer containing chlorexidine and α-tricalcium phosphate.

PubMed

Collares, Fabrício Mezzomo; Leitune, Vicente Castelo Branco; Portella, Fernando Freitas; Santos, Paula Dapper; Balbinot, Gabriela de Souza; Dos Santos, Luís Alberto; Parolo, Clarissa Cavalcanti Fatturi; Samuel, Susana Maria Werner

2018-05-01

The aim of this study was to develop and to characterize a methacrylate-based root canal sealer containing chlorhexidine (CHX) and α-tricalcium phosphate (α-TCP). Experimental dual cure methacrylate-based sealer was produced containing 0, 2.5, or 5 wt% of CHX and 0, 25, or 50 wt% of α-TCP. Experimental sealers were evaluated based on flow, film thickness, radiopacity, degree of conversion (DC), degradation in water, pH and antibacterial activity. Flow ranged from 15.09 ± 0.11 to 17.47 ± 0.42 mm. All groups presented mean film thickness lower than 50 µm and had radiopacity equivalent to 3 mmAl. DC was higher than 60% for all compositions. The weight loss (WL) ranged 0.12-3.47%. The groups containing 5% of CHX presented the highest WL and the lower pH values after 28 days of water immersion. All chlorexidine-compositions exhibited antibacterial efficacy against Enterococcus faecalis on direct contact and agar diffusion tests. CHX and α-TCP addition at an experimental methacrylate-based root canal sealer influenced the physicochemical properties and provided antibacterial properties. The incorporation of CHX and α-TCP could be an alternative to antibacterial sealers with potential to improve periapical healing in endodontic treatments. © 2017 Wiley Periodicals, Inc. J Biomater Res Part B: 106B: 1439-1443, 2018. © 2017 Wiley Periodicals, Inc.

[Single cell gel electrophoresis of a magnesium alloy coated with beta-tricalcium phosphate].

PubMed

Hao, Yu-quan; Tan, Li-li; Yan, Ting-ting; Yan, Xiu-lin; Yang, Ke; Ai, Hong-jun

2009-10-01

To evaluate the genotoxicity of a magnesium alloy coated with beta-tricalcium phosphate (beta-TCP). Four groups were designed. In the first group, AZ31B magnesium alloy surface was coated with beta-TCP using chemical bath deposition, and in the second group magnesium alloy was tested. The other two groups were negative control (pure titanium) and positive control groups (0.5 mg/L bleomycin). Single cell gel electrophoresis was adopted to investigate genotoxicity of the alloy samples in different groups, and 60 cells from each group were analysed. Tail moment and tail DNA percentage were used as reliable indicators to show DNA damage in lymphocytes induced by every testing sample. Student-Newman-Keuls (SNK) test was used to compare results from 4 groups. There were no significant differences in tail moment and tail DNA percentage between magnesium alloy group [(0.52 +/- 0.12), (6.82 +/- 1.81)%] and magnesium alloy coated with beta-TCP group [(0.51 +/- 0.12), (6.89 +/- 1.93)%, P > 0.05]. Tail moment and tail DNA percentage in negative group were (0.47 +/- 0.14) and (6.29 +/- 1.64)%, and tail moment and tail DNA percentage in positive group were (5.17 +/- 1.23) and (22.09 +/- 4.51)%. No significant increase was found in DNA damage in lymphocytes induced by magnesium alloy coated with beta-TCP.

The intrinsically disordered C-terminal region of Arabidopsis thaliana TCP8 transcription factor acts both as a transactivation and self-assembly domain.

PubMed

Valsecchi, Isabel; Guittard-Crilat, Emilie; Maldiney, Régis; Habricot, Yvette; Lignon, Sabrina; Lebrun, Régine; Miginiac, Emile; Ruelland, Eric; Jeannette, Emmanuelle; Lebreton, Sandrine

2013-09-01

TCPs are plant specific transcription factors with non-canonical basic helix-loop-helix domains. While Arabidopsis thaliana has 24 TCPs involved in cell proliferation and differentiation, their mode of action has not been fully elucidated. Using bioinformatic tools, we demonstrate that TCP transcription factors belong to the intrinsically disordered proteins (IDP) family and that disorder is higher in class I TCPs than in class II TCPs. In particular, using bioinformatic and biochemical approaches, we have characterized TCP8, a class I TCP. TCP8 exhibits three intrinsically disordered regions (IDR) made of more than 50 consecutive residues, in which phosphorylable Ser residues are mainly clustered. Phosphorylation of Ser-211 that belongs to the central IDR was confirmed by mass spectrometry. Yeast two-hybrid assays also showed that the C-terminal IDR corresponds to a transactivation domain. Moreover, biochemical experiments demonstrated that TCP8 tends to oligomerize in dimers, trimers and higher-order multimers. Bimolecular fluorescence complementation (BiFC) experiments carried out on a truncated form of TCP8 lacking the C-terminal IDR indicated that it is effectively required for the pronounced self-assembly of TCP8. These data were reinforced by the prediction of a coiled coil domain in this IDR. The C-terminal IDR acts thus as an oligomerization domain and also a transactivation domain. Moreover, many Molecular Recognition Features (MoRFs) were predicted, indicating that TCP8 could interact with several partners to fulfill a fine regulation of transcription in response to various stimuli.

Structural and mechanical characterization of boron doped biphasic calcium phosphate produced by wet chemical method and subsequent thermal treatment

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

Albayrak, Onder, E-mail: albayrakonder@mersin.edu.tr

In the current study, boron doped biphasic calcium phosphate bioceramics consisting of a mixture of boron doped hydroxyapatite (BHA) and beta tricalcium phosphate (β-TCP) of varying BHA/β-TCP ratios were obtained after sintering stage. The effects of varying boron contents and different sintering temperatures on the BHA/β-TCP ratios and on the sinterability of the final products were investigated. Particle sizes and morphologies of the obtained precipitates were determined using SEM. XRD and FTIR investigation were conducted to detect the boron formation in the structure of HA and quantitative analysis was performed to determine the BHA/β-TCP ratio before and after sintering stage.more » In order to determine the sinterability of the obtained powders, pellets were prepared and sintered; the rates of densification were calculated and obtained results were correlated by SEM images. Also Vickers microhardness values of the sintered samples were determined. The experimental results verified that boron doped hydroxyapatite powders were obtained after sintering stage and the structure consists of a mixture of BHA and β-TCP. As the boron content used in the precipitation stage increases, β-TCP content of the BHA/β-TCP ratio increases but sinterability, density and microhardness deteriorate. As the sintering temperature increases, β-TCP content, density and microhardness of the samples increase and sinterability improves. - Highlights: • This is the first paper about boron doped biphasic calcium phosphate bioceramics. • Boron doping affects the structural and mechanical properties. • BHA/β-TCP ratio can be adjustable with boron content and sintering temperature.« less

ß-TCP bone substitutes in tibial plateau depression fractures.

PubMed

Rolvien, Tim; Barvencik, Florian; Klatte, Till Orla; Busse, Björn; Hahn, Michael; Rueger, Johannes Maria; Rupprecht, Martin

2017-10-01

The use of beta-tricalciumphospate (ß-TCP, Cerasorb®) ceramics as an alternative for autologous bone-grafting has been outlined previously, however with no study focusing on both clinical and histological outcomes of ß-TCP application in patients with multi-fragment tibial plateau fractures. The aim of this study was to analyze the long-term results of ß-TCP in patients with tibial plateau fractures. 52 patients were included in this study. All patients underwent open surgery with ß-TCP block or granulate application. After a mean follow-up of 36months (14-64months), the patients were reviewed. Radiography and computed-tomography were performed, while the Rasmussen score was obtained for clinical outcome. Furthermore, seven patients underwent biopsy during hardware removal, which was subsequently analyzed by histology and backscattered electron microscopy (BSEM). An excellent reduction with two millimeters or less of residual incongruity was achieved in 83% of the patients. At follow-up, no further changes occurred and no nonunions were observed. Functional outcome was good to excellent in 82%. Four patients underwent revision surgery due to reasons unrelated to the bone substitute material. Histologic analyses indicated that new bone was built around the ß-TCP-grafts, however a complete resorption of ß-TCP was not observed. ß-TCP combined with internal fixation represents an effective and safe treatment of tibial plateau depression fractures with good functional recovery. While its osteoconductivity seems to be successful, the biological degradation and replacement of ß-TCP is less pronounced in humans than previous animal studies have indicated. Copyright © 2017 Elsevier B.V. All rights reserved.

Nano-hydroxyapatite-coated metal-ceramic composite of iron-tricalcium phosphate: Improving the surface wettability, adhesion and proliferation of mesenchymal stem cells in vitro.

PubMed

Surmeneva, Maria A; Kleinhans, Claudia; Vacun, Gabriele; Kluger, Petra Juliane; Schönhaar, Veronika; Müller, Michaela; Hein, Sebastian Boris; Wittmar, Alexandra; Ulbricht, Mathias; Prymak, Oleg; Oehr, Christian; Surmenev, Roman A

2015-11-01

Thin radio-frequency magnetron sputter deposited nano-hydroxyapatite (HA) films were prepared on the surface of a Fe-tricalcium phosphate (Fe-TCP) bioceramic composite, which was obtained using a conventional powder injection moulding technique. The obtained nano-hydroxyapatite coated Fe-TCP biocomposites (nano-HA-Fe-TCP) were studied with respect to their chemical and phase composition, surface morphology, water contact angle, surface free energy and hysteresis. The deposition process resulted in a homogeneous, single-phase HA coating. The ability of the surface to support adhesion and the proliferation of human mesenchymal stem cells (hMSCs) was studied using biological short-term tests in vitro. The surface of the uncoated Fe-TCP bioceramic composite showed an initial cell attachment after 24h of seeding, but adhesion, proliferation and growth did not persist during 14 days of culture. However, the HA-Fe-TCP surfaces allowed cell adhesion, and proliferation during 14 days. The deposition of the nano-HA films on the Fe-TCP surface resulted in higher surface energy, improved hydrophilicity and biocompatibility compared with the surface of the uncoated Fe-TCP. Furthermore, it is suggested that an increase in the polar component of the surface energy was responsible for the enhanced cell adhesion and proliferation in the case of the nano-HA-Fe-TCP biocomposites. Copyright © 2015 Elsevier B.V. All rights reserved.

Electrospun Gelatin/β-TCP Composite Nanofibers Enhance Osteogenic Differentiation of BMSCs and In Vivo Bone Formation by Activating Ca (2+) -Sensing Receptor Signaling.

PubMed

Zhang, Xuehui; Meng, Song; Huang, Ying; Xu, Mingming; He, Ying; Lin, Hong; Han, Jianmin; Chai, Yuan; Wei, Yan; Deng, Xuliang

2015-01-01

Calcium phosphate- (CaP-) based composite scaffolds have been used extensively for the bone regeneration in bone tissue engineering. Previously, we developed a biomimetic composite nanofibrous membrane of gelatin/β-tricalcium phosphate (TCP) and confirmed their biological activity in vitro and bone regeneration in vivo. However, how these composite nanofibers promote the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) is unknown. Here, gelatin/β-TCP composite nanofibers were fabricated by incorporating 20 wt% β-TCP nanoparticles into electrospun gelatin nanofibers. Electron microscopy showed that the composite β-TCP nanofibers had a nonwoven structure with a porous network and a rough surface. Spectral analyses confirmed the presence and chemical stability of the β-TCP and gelatin components. Compared with pure gelatin nanofibers, gelatin/β-TCP composite nanofibers caused increased cell attachment, proliferation, alkaline phosphatase activity, and osteogenic gene expression in rat BMSCs. Interestingly, the expression level of the calcium-sensing receptor (CaSR) was significantly higher on the composite nanofibrous scaffolds than on pure gelatin. For rat calvarial critical sized defects, more extensive osteogenesis and neovascularization occurred in the composite scaffolds group compared with the gelatin group. Thus, gelatin/β-TCP composite scaffolds promote osteogenic differentiation of BMSCs in vitro and bone regeneration in vivo by activating Ca(2+)-sensing receptor signaling.

Calorimetry investigations of milled α-tricalcium phosphate (α-TCP) powders to determine the formation enthalpies of α-TCP and X-ray amorphous tricalcium phosphate.

PubMed

Hurle, Katrin; Neubauer, Juergen; Bohner, Marc; Doebelin, Nicola; Goetz-Neunhoeffer, Friedlinde

2015-09-01

One α-tricalcium phosphate (α-TCP) powder was either calcined at 500°C to obtain fully crystalline α-TCP or milled for different durations to obtain α-TCP powders containing various amounts of X-ray amorphous tricalcium phosphate (ATCP). These powders containing between 0 and 71wt.% ATCP and up to 2.0±0.1wt.% β-TCP as minor phase were then hydrated in 0.1M Na2HPO4 aqueous solution and the resulting heat flows were measured by isothermal calorimetry. Additionally, the evolution of the phase composition during hydration was determined by in situ XRD combined with the G-factor method, an external standard method which facilitates the indirect quantification of amorphous phases. Maximum ATCP hydration was reached after about 1h, while that of crystalline α-TCP hydration occurred between 4 and 11h, depending on the ATCP content. An enthalpy of formation of -4065±6kJ/mol (T=23°C) was calculated for ATCP (Ca3(PO4)2), while for crystalline α-TCP (α-Ca3(PO4)2) a value of -4113±6kJ/mol (T=23°C) was determined. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Fabrication and characterization of a biodegradable Mg-2Zn-0.5Ca/1β-TCP composite.

PubMed

Huang, Yan; Liu, Debao; Anguilano, Lorna; You, Chen; Chen, Minfang

2015-09-01

A biodegradable magnesium matrix and beta-tricalcium phosphate (β-TCP) particles reinforced composite Mg-2Zn-0.5Ca/1beta-TCP (wt.%) was fabricated for biomedical applications by the novel route of combined high shear solidification (HSS) and equal channel angular extrusion (ECAE). The as-cast composite obtained by HSS showed a fine and equiaxed grain structure with globally uniformly distributed β-TCP particles in aggregates of 2-25 μm in size. The ECAE processing at 300 °C resulted in further microstructural refinement and the improvement of β-TCP particle distribution. During ECAE, the β-TCP aggregates were broken into smaller ones or individual particles, forming a dispersion in the matrix. Such fabricated composite exhibited enhanced hardness and in vitro corrosion resistance. The enhanced hardness was attributed to both the addition of β-TCP particles and grain refinement while the development of a Ca-P rich surface layer from β-TCP during corrosion was responsible for the improvement in corrosion resistance. The composite was characterized in terms of microstructural evolution during fabrication, mechanical properties and electrochemical performance during polarization and immersion tests in a simulated body fluid. Discussions are made on the benefits of both HSS and ECAE and the mechanisms responsible for the enhanced corrosion resistance. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of amorphous phases during the hydraulic conversion of α-TCP into calcium-deficient hydroxyapatite.

PubMed

Hurle, Katrin; Neubauer, Juergen; Bohner, Marc; Doebelin, Nicola; Goetz-Neunhoeffer, Friedlinde

2014-09-01

Powders of α-tricalcium phosphate (α-TCP), which readily react with water to form calcium-deficient hydroxyapatite (CDHA), are frequently used in bone cements. As, for clinical applications, it is important to adjust the setting reaction of the cements to a reasonable reaction time, exact knowledge of the hydration mechanism is essential. It is known that prolonged milling results in partial amorphization of α-TCP powders and that dissolution of the amorphous phase significantly accelerates the hydration, but it is not clear yet when the amorphous phase reacts in comparison to the crystalline α-TCP. Therefore the aim of this study was to investigate the development of quantitative phase content of α-TCP samples during hydration. For this purpose, three α-TCP powders, containing 0, 16 and 71wt.% of amorphous phase (ATCP), were mixed with either deionized water or a 0.1M Na2HPO4 aqueous solution. The crystalline evolution of the paste was assessed quantitatively during the first 48h of hydration at 23°C by G-factor quantification. The present investigations demonstrate that ATCP reacted earlier than crystalline α-TCP. The results also suggest the formation of an X-ray amorphous phase during the hydraulic conversion formation of α-TCP into CDHA. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Physicomechanical, In Vitro and In Vivo Performance of 3D Printed Doped Tricalcium Phosphate Scaffolds for Bone Tissue Engineering and Drug Delivery

NASA Astrophysics Data System (ADS)

Tarafder, Solaiman

Although tricalcium phosphate (TCP) is widely used in bone tissue engineering, the strength degradation kinetics is not well controlled. This study focuses on the underlying mechanism of strength degradation kinetics by incorporating trace elements in TCP. The objective of this research is to modify the mechanical properties of TCP to achieve the desired degradation rate for the specific need, and improve the in vivo bioactivity for early wound healing by incorporating trace elements such as strontium (Sr2+), magnesium (Mg2+) and silicon (Si4+) as dopants. The hypothesis of this research is that the presence of different trace elements in TCP will influence its phase stability, microstructure, mechanical strength, and both in vitro and in vivo bioactivity. Direct three dimensional printing (3DP) was used to fabricate designed interconnected macroporous pure and doped TCP scaffolds. Microwave sintering as opposed to conventional sintering was also used for better densification and higher mechanical strength. A maximum compressive strength of 10.95 +/- 1.28 MPa and 12.01 +/- 1.56 MPa were achieved for pure and Sr2+-Mg2+ doped TCP scaffolds with 500 microm designed pores (˜400 microm after sintering) sintered in microwave furnace, respectively. Substitution of Mg2+ and Sr2+ into calcium (Ca2+) sites of TCP crystal lattice contributed to phase stability and controlled gradual degradation. On the other hand, Si4+ substitution into phosphorous (P5+) sites destabilized the crystal structure and accelerated degradation of TCP. Interconnected macroporous beta-TCP scaffolds facilitated in vivo guided bone tissue regeneration through infiltration of cells and extracellular matrix into the designed pores. Presence of Sr2+, Mg2+ and Si4+ into beta-TCP induced increased in vivo early bone formation and better bone remodeling through increased extracellular matrix production such as, collagen and osteocalcin, when tested in rat and rabbit distal femur model. The presence of Si4+ along with Mg 2+ induced increased new blood vessel formation. Our results exhibited that Sr2+, Mg2+ and Si4+ doped 3DP TCP scaffolds have strong potential in bone tissue engineering applications for early wound healing.

Mesoporous bioactive glass nanolayer-functionalized 3D-printed scaffolds for accelerating osteogenesis and angiogenesis

NASA Astrophysics Data System (ADS)

Zhang, Yali; Xia, Lunguo; Zhai, Dong; Shi, Mengchao; Luo, Yongxiang; Feng, Chun; Fang, Bing; Yin, Jingbo; Chang, Jiang; Wu, Chengtie

2015-11-01

The hierarchical microstructure, surface and interface of biomaterials are important factors influencing their bioactivity. Porous bioceramic scaffolds have been widely used for bone tissue engineering by optimizing their chemical composition and large-pore structure. However, the surface and interface of struts in bioceramic scaffolds are often ignored. The aim of this study is to incorporate hierarchical pores and bioactive components into the bioceramic scaffolds by constructing nanopores and bioactive elements on the struts of scaffolds and further improve their bone-forming activity. Mesoporous bioactive glass (MBG) modified β-tricalcium phosphate (MBG-β-TCP) scaffolds with a hierarchical pore structure and a functional strut surface (~100 nm of MBG nanolayer) were successfully prepared via 3D printing and spin coating. The compressive strength and apatite-mineralization ability of MBG-β-TCP scaffolds were significantly enhanced as compared to β-TCP scaffolds without the MBG nanolayer. The attachment, viability, alkaline phosphatase (ALP) activity, osteogenic gene expression (Runx2, BMP2, OPN and Col I) and protein expression (OPN, Col I, VEGF, HIF-1α) of rabbit bone marrow stromal cells (rBMSCs) as well as the attachment, viability and angiogenic gene expression (VEGF and HIF-1α) of human umbilical vein endothelial cells (HUVECs) in MBG-β-TCP scaffolds were significantly upregulated compared with conventional bioactive glass (BG)-modified β-TCP (BG-β-TCP) and pure β-TCP scaffolds. Furthermore, MBG-β-TCP scaffolds significantly enhanced the formation of new bone in vivo as compared to BG-β-TCP and β-TCP scaffolds. The results suggest that application of the MBG nanolayer to modify 3D-printed bioceramic scaffolds offers a new strategy to construct hierarchically porous scaffolds with significantly improved physicochemical and biological properties, such as mechanical properties, osteogenesis, angiogenesis and protein expression for bone tissue engineering applications, in which the incorporation of nanostructures and bioactive components into the scaffold struts synergistically play a key role in the improved bone formation.

Evidence of the direct involvement of the substrate TCP radical in functional switching from oxyferrous O2 carrier to ferric peroxidase in the dual-function hemoglobin/dehaloperoxidase from Amphitrite ornata.

PubMed

Sun, Shengfang; Sono, Masanori; Du, Jing; Dawson, John H

2014-08-05

The coelomic O2-binding hemoglobin dehaloperoxidase (DHP) from the sea worm Amphitrite ornata is a dual-function heme protein that also possesses a peroxidase activity. Two different starting oxidation states are required for reversible O2 binding (ferrous) and peroxidase (ferric) activity, bringing into question how DHP manages the two functions. In our previous study, the copresence of substrate 2,4,6-trichlorophenol (TCP) and H2O2 was found to be essential for the conversion of oxy-DHP to enzymatically active ferric DHP. On the basis of that study, a functional switching mechanism involving substrate radicals (TCP(•)) was proposed. To further support this mechanism, herein we report details of our investigations into the H2O2-mediated conversion of oxy-DHP to the ferric or ferryl ([TCP] < [H2O2]) state triggered by both biologically relevant [TCP and 4-bromophenol (4-BP)] and nonrelevant (ferrocyanide) compounds. At <50 μM H2O2, all of these conversion reactions are completely inhibited by ferric heme ligands (KCN and imidazole), indicating the involvement of ferric DHP. Furthermore, the spin-trapping reagent 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) effectively inhibits the TCP/4-BP (but not ferrocyanide)-triggered conversion of oxy-DHP to ferric DHP. These results and O2 concentration-dependent conversion rates observed in this study demonstrate that substrate TCP triggers the conversion of oxy-DHP to a peroxidase by TCP(•) oxidation of the deoxyferrous state. TCP(•) is progressively generated, by increasingly produced amounts of ferric DHP, upon H2O2 oxidation of TCP catalyzed initially by trace amounts of ferric enzyme present in the oxy-DHP sample. The data presented herein further address the mechanism of how the halophenolic substrate triggers the conversion of hemoglobin DHP into a peroxidase.

SU-F-T-681: Does the Biophysical Modeling for Immunological Aspects in Radiotherapy Precisely Predict Tumor and Normal Tissue Responses?

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

Oita, M; Nakata, K; Sasaki, M

2016-06-15

Purpose: Recent advances in immunotherapy make possible to combine with radiotherapy. The aim of this study was to assess the TCP/NTCP model with immunological aspects including stochastic distribution as intercellular uncertainties. Methods: In the clinical treatment planning system (Eclipse ver.11.0, Varian medical systems, US), biological parameters such as α/β, D50, γ, n, m, TD50 including repair parameters (bi-exponential repair) can be set as any given values to calculate the TCP/NTCP. Using a prostate cancer patient data with VMAT commissioned as a 6-MV photon beam of Novalis-Tx (BrainLab, US) in clinical use, the fraction schedule were hypothesized as 70–78Gy/35–39fr, 72–81Gy/40–45fr, 52.5–66Gy/16–22fr,more » 35–40Gy/5fr of 5–7 fractions in a week. By use of stochastic biological model applying for Gaussian distribution, the effects of the TCP/NTCP variation of repair parameters of the immune system as well as the intercellular uncertainty of tumor and normal tissues have been evaluated. Results: As respect to the difference of the α/β, the changes of the TCP/NTCP were increased in hypo-fraction regimens. The difference between the values of n and m affect the variation of the NTCP with the fraction schedules, independently. The elongation of repair half-time (long) increased the TCP/NTCP twice or much higher in the case of hypo-fraction scheme. For tumor, the repopulation parameters such as Tpot and Tstart, which is immunologically working to the tumor, improved TCP. Conclusion: Compared to default fixed value, which has affected by the probability of cell death and cure, hypo-fractionation schemes seemed to have advantages for the variations of the values of m. The possibility of an increase of the α/β or TD50 and repair parameters in tumor and normal tissue by immunological aspects were highly expected. For more precise prediction, treatment planning systems should be incorporated the complicated biological optimization in clinical practice combined with basic experiments data.« less

[Experimental study of the effect of new bone formation on new type artificial bone composed of bioactive ceramics].

PubMed

Zhu, Minghua; Zeng, Yi; Sun, Tao; Peng, Qiang

2005-03-15

To investigate the osteogenic potential of four kinds of new bioactive ceramics combined with bovine bone morphogenetic proteins (BMP) and to explore the feasibility of using compounds as bone substitute material. Ninety-six rats were divided into 4 groups (24 in each group). BMP was combined with hydroxyapatite (HA), tricalcium phosphate (TCP), fluoridated-HA (FHA), and collagen-HA(CHA) respectively. The left thighs of the rats implanted with HA/BMP, TCP/BMP, FHA/BMP, and CHA/BMP were used as experimental groups. The right thighs of the rats implanted with HA, TCP, CHA, and decalcified dentin matrix (DDM) were used as control groups. The rats were sacrificed 1, 3, 5 and 7 weeks after implantation and bone induction was estimated by alkaline phosphatase (ALP), phosphorus (P), and total protein (TP) measurement. The histological observation and electronic microscope scanning of the implants were also made. The cartilage growth in the 4 experimental groups and the control group implanted with DDM was observed 1 week after operation and fibrous connective tissues were observed in the other 3 control groups. 3 weeks after implantation, lamellar bone with bone marrow and positive reaction in ALP stain were observed in the 4 experimental groups. No bone formation or positive reaction in ALP stain were observed in the control groups. The amount of ALP activity, P value, and new bone formation in the experimental groups were higher than those in the control group(P < 0.05). The amount of ALP activity, P value, and new bone formation in TCP/BMP group were higher than those in HA/BMP, CHA/BMP and FHA/BMP groups (P < 0.05). There was no significant difference in TP between the BMP treatment group and the control groups. From 5th to 7th week, new bone formation, histochemistry evaluation, and the level of ALP, P, TP value were as high as those in the 3rd week. New composite artificial bone of TCP/BMP, HA/BMP, CHA/BMP, and FHA/BMP all prove to be effective, but TCP/BMP is the most effective so that it is the most suitable biomaterial replacement of tissue.

Determination of ortho-cresyl phosphate isomers of tricresyl phosphate used in aircraft turbine engine oils by gas chromatography and mass spectrometry.

PubMed

De Nola, G; Kibby, J; Mazurek, W

2008-07-25

Tricresyl phosphate (TCP) is used as an anti-wear additive in aircraft turbine engine oil. Concerns about its toxicity are largely based on the tri-o-cresyl phosphate isomer content. However, the presence of other and more toxic isomers has been previously suggested. In this work, the structural isomers of TCP have been determined by two methods (experimental and semi-theoretical). First, the TCP isomers were separated by gas chromatography (GC) and identified by mass spectrometry (MS). Second, after base cleavage of TCP, GC was used to quantify the cresol precursors. These results were used to calculate the TCP isomer distribution based on the assumption of a statistical distribution of the TCP isomers. The results from the two determinations showed reasonable agreement for three of the four oils studied. The o-cresyl isomers were found to be present almost exclusively as the more toxic mono-o-cresyl isomers in the concentration range 13-150 mg/L. The ability to analyse for the mono-o-cresyl isomers allows the toxicity of TCP to be based on the latter isomers rather than on the less toxic tri-o-cresyl phosphate isomer.

Aerobic secondary utilization of a non-growth and inhibitory substrate 2,4,6-trichlorophenol by Sphingopyxis chilensis S37 and sphingopyxis-like strain S32.

PubMed

Aranda, Carlos; Godoy, Félix; Becerra, José; Barra, Ricardo; Martínez, Miguel

2003-08-01

This paper reports 2,4,6-trichlorophenol (246TCP) degradation by Sphingopyxis chilensis S37 and Sphingopyxis chilensis-like strain S32, which were unable to use 246TCP as the sole carbon and energy source. In R2A broth, the strains degraded 246TCP up to 0.5 mM. Results with mixtures of different 246TCP and glucose concentrations in mineral salt media demonstrated dependence on glucose to allow bacterial growth and degradation of 246TCP. Strain S32 degraded halophenol up to 0.2 mM when 5.33 mM glucose was simultaneously added, while strain S37 degraded the compound up to 0.1 mM when 1.33 mM glucose was added. These 246TCP concentrations were lethal for inocula in absence of glucose. Stoichiometric releases of chloride and analysis by HPLC, GC-ECD and GC-MS indicated 246TCP mineralisation by both strains. To our knowledge, this is the first report of bacteria able to mineralize a chlorophenol as a non-growth and inhibitory substrate. The concept of secondary utilization instead of cometabolism is proposed for this activity.

Network Analysis with SiLK

DTIC Science & Technology

2015-01-06

Carnegie Mellon University rwcut Default Display By default • sIP , sPort • dIP, dPort • protocol • packets, bytes • flags • sTime, eTime, duration...TCP/IP SOCKET IP address: 10.0.0.1 L4 protocol : TCP High-numbered ephemeral port # TCP/IP SOCKET IP address: 203.0.113.1 L4 protocol : TCP Low-numbered...Fields found to be useful in analysis: • source address, destination address • source port, destination port (Internet Control Message Protocol

Nitrate foraging by Arabidopsis roots is mediated by the transcription factor TCP20 through the systemic signaling pathway

PubMed Central

Guan, Peizhu; Wang, Rongchen; Nacry, Philippe; Breton, Ghislain; Kay, Steve A.; Pruneda-Paz, Jose L.; Davani, Ariea; Crawford, Nigel M.

2014-01-01

To compete for nutrients in diverse soil microenvironments, plants proliferate lateral roots preferentially in nutrient-rich zones. For nitrate, root foraging involves local and systemic signaling; however, little is known about the genes that function in the systemic signaling pathway. By using nitrate enhancer DNA to screen a library of Arabidopsis transcription factors in the yeast one-hybrid system, the transcription factor gene TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR1-20 (TCP20) was identified. TCP20, which belongs to an ancient, plant-specific gene family that regulates shoot, flower, and embryo development, was implicated in nitrate signaling by its ability to bind DNA in more than 100 nitrate-regulated genes. Analysis of insertion mutants of TCP20 showed that they had normal primary and lateral root growth on homogenous nitrate media but were impaired in preferential lateral root growth (root foraging) on heterogeneous media in split-root plates. Inhibition of preferential lateral root growth was still evident in the mutants even when ammonium was uniformly present in the media, indicating that the TCP20 response was to nitrate. Comparison of tcp20 mutants with those of nlp7 mutants, which are defective in local control of root growth but not in the root-foraging response, indicated that TCP20 function is independent of and distinct from NLP7 function. Further analysis showed that tcp20 mutants lack systemic control of root growth regardless of the local nitrate concentrations. These results indicate that TCP20 plays a key role in the systemic signaling pathway that directs nitrate foraging by Arabidopsis roots. PMID:25288754

Effect of zinc oxide on flexural and physical properties of PMMA composites

NASA Astrophysics Data System (ADS)

Hamad, Wan Nur Fadilla Wan; Abdullah, Abdul Manaf; Mohamad, Dasmawati

2016-12-01

Polymethylmethacrylate (PMMA) is the most widely accepted material in maxillofacial implants due to its superior advantages. The material used for craniofacial implant should have good mechanical and antibacterial properties to withstand forces and eliminate infection. A study was conducted to prepare PMMA incorporated with β-tricalcium phosphate (β -TCP) filler and zinc oxide as an antibacterial agent at different compositions and investigate the flexural properties of the produced PMMA/β- TCP/ZnOcomposites. Pure PMMA as control,15 % β -TCP filled, 15% β -TCPwith 2.5% ZnO filled as well as15% β -TCPwith5% ZnOfilled PMMA were prepared. PMMA were mixed together with β -TCP and zinc oxide manually according to the percentages specified until it has reached the homogeneous state. Flexural specimens were prepared by casting the paste in silicone mould which has been fabricated using 3D printed flexural template. The number of samples was n=7 for each composition. Statistical analysis of One Way ANOVA was employed to compare the flexural properties of each samples. Flexural strength of pure PMMA,15 % β -TCP filled, 15% β -TCP with 2.5% ZnO filled as well as 15% β -TCP with 5% ZnO filled PMMA were 60.79, 46.75, 38.72 and 41.49 MPa respectively. The addition of either β- TCP or β- TCP with ZnO decreased the flexural properties and it showed significant differences as compared to pure PMMA (p<0.05).5% ZnO filled PMMA showed higher flexural properties as compared to 2.5% ZnO filled PMMA, however the differences were found not significant(p>0.05).

ACTS 118x Final Report High-Speed TCP Interoperability Testing

NASA Technical Reports Server (NTRS)

Ivancic, William D.; Zernic, Mike; Hoder, Douglas J.; Brooks, David E.; Beering, Dave R.; Welch, Arun

1999-01-01

With the recent explosion of the Internet and the enormous business opportunities available to communication system providers, great interest has developed in improving the efficiency of data transfer using the Transmission Control Protocol (TCP) of the Internet Protocol (IP) suite. The satellite system providers are interested in solving TCP efficiency problems associated with long delays and error-prone links. Similarly, the terrestrial community is interested in solving TCP problems over high-bandwidth links. Whereas the wireless community is interested in improving TCP performance over bandwidth constrained, error-prone links. NASA realized that solutions had already been proposed for most of the problems associated with efficient data transfer over large bandwidth-delay links (which include satellite links). The solutions are detailed in various Internet Engineering Task Force (IETF) Request for Comments (RFCs). Unfortunately, most of these solutions had not been tested at high-speed (155+ Mbps). Therefore, the NASA's ACTS experiments program initiated a series of TCP experiments to demonstrate scalability of TCP/IP and determine how far the protocol can be optimized over a 622 Mbps satellite link. These experiments were known as the 118i and 118j experiments. During the 118i and 118j experiments, NASA worked closely with SUN Microsystems and FORE Systems to improve the operating system, TCP stacks. and network interface cards and drivers. We were able to obtain instantaneous data throughput rates of greater than 520 Mbps and average throughput rates of 470 Mbps using TCP over Asynchronous Transfer Mode (ATM) over a 622 Mbps Synchronous Optical Network (SONET) OC12 link. Following the success of these experiments and the successful government/industry collaboration, a new series of experiments. the 118x experiments. were developed.

Fabrication of individual alginate-TCP scaffolds for bone tissue engineering by means of powder printing.

PubMed

Castilho, Miguel; Rodrigues, Jorge; Pires, Inês; Gouveia, Barbara; Pereira, Manuel; Moseke, Claus; Groll, Jürgen; Ewald, Andrea; Vorndran, Elke

2015-01-06

The development of polymer-calcium phosphate composite scaffolds with tailored architectures and properties has great potential for bone regeneration. Herein, we aimed to improve the functional performance of brittle ceramic scaffolds by developing a promising biopolymer-ceramic network. For this purpose, two strategies, namely, direct printing of a powder composition consisting of a 60:40 mixture of α/β-tricalcium phosphate (TCP) powder and alginate powder or vacuum infiltration of printed TCP scaffolds with an alginate solution, were tracked. Results of structural characterization revealed that the scaffolds printed with 2.5 wt% alginate-modified TCP powders presented a uniformly distributed and interfusing alginate TCP network. Mechanical results indicated a significant increase in strength, energy to failure and reliability of powder-modified scaffolds with an alginate content in the educts of 2.5 wt% when compared to pure TCP, as well as to TCP scaffolds containing 5 wt% or 7.5 wt% in the educts, in both dry and wet states. Culture of human osteoblast cells on these scaffolds also demonstrated a great improvement of cell proliferation and cell viability. While in the case of powder-mixed alginate TCP scaffolds, isolated alginate gels were formed between the calcium phosphate crystals, the vacuum-infiltration strategy resulted in the covering of the surface and internal pores of the TCP scaffold with a thin alginate film. Furthermore, the prediction of the scaffolds' critical fracture conditions under more complex stress states by the applied Mohr fracture criterion confirmed the potential of the powder-modified scaffolds with 2.5 wt% alginate in the educts as structural biomaterial for bone tissue engineering.

Maxillary Sinus Lift with Beta-Tricalcium Phosphate (β-TCP) in Edentulous Patients: A Nanotomographic and Raman Study.

PubMed

Pascaretti-Grizon, Florence; Guillaume, Bernard; Terranova, Lisa; Arbez, Baptiste; Libouban, Hélène; Chappard, Daniel

2017-09-01

Sinus lift elevation restores bone mass at the maxilla in edentulate patients before the placement of dental implants. It consists of opening the lateral side of the sinus and grafting beta-tricalcium phosphate granules (β-TCP) under the olfactory membrane. Bone biopsies were obtained in five patients after 60 weeks. They were embedded undecalcified in poly(methyl methacrylate) (pMMA); blocks were analyzed by nanocomputed tomography (nanoCT); specific areas were studied by Raman microspectroscopy. Remnants of β-TCP were osseointegrated and covered with mineralized bone; osteoid tissue was also filling the inner porosity. Macrophages having engulfed numerous β-TCP grains were observed in marrow spaces. β-TCP was identified by nanoCT as osseointegrated particles and as granules in the cytoplasm of macrophages. Raman microspectroscopy permitted to compare the spectra of β-TCP and bone in different areas. The ratio of the ~820 cm -1 band of pMMA (-CH 2 groups) on the ν1 phosphate band at 960 cm -1 reflected tissue hydration because water was substituted by MMA during histological processing. In bone, the ratio of the ~960 cm -1 phosphate to the amide 1 band and the ratio ν2 phosphate band by the 1240-1250 amide III band reflect the mineralization degree. Specific bands of β-TCP were found in osseointegrated β-TCP granules and in the grains phagocytized by the macrophages. The hydration degree was maximal for β-TCP phagocytized by macrophages. Raman microspectroscopy associated with nanoCT is a powerful tool in the analysis of the biomaterial degradation and osseointegration.

The diagnostic performance of recombinant Trypanosoma cruzi ribosomal P2beta protein is influenced by its expression system.

PubMed

Marcipar, Iván S; Olivares, María Laura; Robles, Lucía; Dekanty, Andrés; Marcipar, Alberto; Silber, Ariel M

2004-03-01

In the present work, we have determined the effect of expression vectors and their corresponding host bacteria on the antigenic performance of Trypanosoma cruzi P2beta (TcP2beta) full-length recombinant protein. The gene encoding the TcP2beta ribosomal protein was cloned in pMAL-c2 and pET-32a vectors that allow the expression of high levels of soluble fusion proteins. A panel of 32 positive and 32 negative sera was assayed with the purified proteins expressed using pMal-c2 (TcP2beta-MBP) and pET-32a (TcP2beta-TRX) vectors and with MBP and TRX purified from pMAL-c2 and pET-32a vectors, respectively. The antigenic behavior of each TcP2beta recombinant protein differed in the diagnostic performance in terms of DI(+) (93.7 for TcP2beta-MBP vs 100% for TcP2beta-TRX), in DI(-) (90.5 for TcP2beta-MBP vs 100% for TcP2beta-TRX) and in cross-reaction with negative sera. To determine if the higher reactivity of expressed pMAL-c2 protein was due to folding during protein expression or to a steric effect related to the protein adsorption at the titration plate, the reactivity of sera against soluble proteins was assessed by ELISA inhibition assays. As each soluble protein preserved its level of reactivity, we concluded that differences in reactivity were due to intrinsic characteristics of the proteins and not to differences in patterns of adsorption to the plates.

Engineering biomimetic periosteum with β-TCP scaffolds to promote bone formation in calvarial defects of rats.

PubMed

Zhang, Dan; Gao, Peng; Li, Qin; Li, Jinda; Li, Xiaojuan; Liu, Xiaoning; Kang, Yunqing; Ren, Liling

2017-06-05

There is a critical need for the management of large bone defects. The purpose of this study was to engineer a biomimetic periosteum and to combine this with a macroporous β-tricalcium phosphate (β-TCP) scaffold for bone tissue regeneration. Rat bone marrow-derived mesenchymal stem cells (rBMSCs) were harvested and cultured in different culture media to form undifferentiated rBMSC sheets (undifferentiated medium (UM)) and osteogenic cell sheets (osteogenic medium (OM)). Simultaneously, rBMSCs were differentiated to induced endothelial-like cells (iECs), and the iECs were further cultured on a UM to form a vascularized cell sheet. At the same time, flow cytometry was used to detect the conversion rates of rBMSCs to iECs. The pre-vascularized cell sheet (iECs/UM) and the osteogenic cell sheet (OM) were stacked together to form a biomimetic periosteum with two distinct layers, which mimicked the fibrous layer and cambium layer of native periosteum. The biomimetic periostea were wrapped onto porous β-TCP scaffolds (BP/β-TCP) and implanted in the calvarial bone defects of rats. As controls, autologous periostea with β-TCP (AP/β-TCP) and β-TCP alone were implanted in the calvarial defects of rats, with a no implantation group as another control. At 2, 4, and 8 weeks post-surgery, implants were retrieved and X-ray, microcomputed tomography (micro-CT), histology, and immunohistochemistry staining analyses were performed. Flow cytometry results showed that rBMSCs were partially differentiated into iECs with a 35.1% conversion rate in terms of CD31. There were still 20.97% rBMSCs expressing CD90. Scanning electron microscopy (SEM) results indicated that cells from the wrapped cell sheet on the β-TCP scaffold apparently migrated into the pores of the β-TCP scaffold. The histology and immunohistochemistry staining results from in vivo implantation indicated that the BP/β-TCP and AP/β-TCP groups promoted the formation of blood vessels and new bone tissues in the bone defects more than the other two control groups. In addition, micro-CT showed that more new bone tissue formed in the BP/β-TCP and AP/β-TCP groups than the other groups. Inducing rBMSCs to iECs could be a good strategy to obtain an endothelial cell source for prevascularization. Our findings indicate that the biomimetic periosteum with porous β-TCP scaffold has a similar ability to promote osteogenesis and angiogenesis in vivo compared to the autologous periosteum. This function could result from the double layers of biomimetic periosteum. The prevascularized cell sheet served a mimetic fibrous layer and the osteogenic cell sheet served a cambium layer of native periosteum. The biomimetic periosteum with a porous ceramic scaffold provides a new promising method for bone healing.

Quick Vegas: Improving Performance of TCP Vegas for High Bandwidth-Delay Product Networks

NASA Astrophysics Data System (ADS)

Chan, Yi-Cheng; Lin, Chia-Liang; Ho, Cheng-Yuan

An important issue in designing a TCP congestion control algorithm is that it should allow the protocol to quickly adjust the end-to-end communication rate to the bandwidth on the bottleneck link. However, the TCP congestion control may function poorly in high bandwidth-delay product networks because of its slow response with large congestion windows. In this paper, we propose an enhanced version of TCP Vegas called Quick Vegas, in which we present an efficient congestion window control algorithm for a TCP source. Our algorithm improves the slow-start and congestion avoidance techniques of original Vegas. Simulation results show that Quick Vegas significantly improves the performance of connections as well as remaining fair when the bandwidth-delay product increases.

Clinical assessment of bone quality of human extraction sockets after conversion with growth factors.

PubMed

Ntounis, Athanasios; Geurs, Nico; Vassilopoulos, Philip; Reddy, Michael

2015-01-01

The study was conducted to evaluate the effect of mineralized freeze-dried bone allograft (FDBA), alone or in combination with growth factors in extraction sockets, on subjective assessment of bone quality during implant placement. Forty-one patients whose treatment plan involved extraction of anterior or premolar teeth were randomized into four groups: Group 1, collagen plug (control); Group 2, FDBA/β-tricalcium phosphate (β-TCP)/collagen plug; Group 3, FDBA/β-TCP/platelet-rich plasma (PRP)/collagen plug; Group 4, FDBA/β-TCP/recombinant human platelet-derived growth factor BB (rhPDGF-BB)/collagen plug. After 8 weeks of healing, implants were placed. The clinicians assessed bone quality according to the Misch classification. A benchtop calibration exercise test was conducted to evaluate agreement and accuracy of operators in recognizing different bone qualities. Differences were analyzed using one-way analysis of variance (ANOVA) or chi-square tests for continuous and categorical data. Pairwise comparisons were tested using least squares means (LS means). Spearman correlation coefficients were used to evaluate the relationship of bone growth with potential confounders. P < .05 was considered statistically significant. A simple (not weighted) kappa statistic was used to assess the agreement between raters. To assess accuracy in identifying bone quality, a chi-square test was used to compare the percent correct for each rater. The benchtop calibration exercise test demonstrated agreement among clinicians (0.75 and 0.92 between raters 1 and 2 and raters 1 and 3, respectively). Raters were more likely to identify the correct bone quality (P > .05). Inclusion of bone grafting is associated with a shift from D4 quality to D3 quality bone. Inclusion of PRP in bone grafting eliminates the incidence of D4 bone, establishing D3 and D2 quality bone as prevalent (56% vs. 42%, respectively). Inclusion of rhPDGF-BB and β-TCP in combination with the bone grafting has the same effect, although D2 quality is less prevalent. When compared to sockets grafted with FDBA/β-TCP/collagen plug alone, the sockets with growth factors demonstrated fewer residual bone graft particles. (1) Inclusion of bone grafting enhanced bone quality as assessed during implant placement. (2) Overall inclusion of PRP and rhPDGF-BB enhanced subjective bone quality, eliminating incidence of D4 quality in human extraction sockets. (3) The use of PRP or rhPDGF-BB may enhance healing within extraction sockets and decrease the healing time prior to dental implant placement.

Comprehensive analysis of TCP transcription factors and their expression during cotton (Gossypium arboreum) fiber early development

PubMed Central

Ma, Jun; Liu, Fang; Wang, Qinglian; Wang, Kunbo; Jones, Don C.; Zhang, Baohong

2016-01-01

TCP proteins are plant-specific transcription factors implicated to perform a variety of physiological functions during plant growth and development. In the current study, we performed for the first time the comprehensive analysis of TCP gene family in a diploid cotton species, Gossypium arboreum, including phylogenetic analysis, chromosome location, gene duplication status, gene structure and conserved motif analysis, as well as expression profiles in fiber at different developmental stages. Our results showed that G. arboreum contains 36 TCP genes, distributing across all of the thirteen chromosomes. GaTCPs within the same subclade of the phylogenetic tree shared similar exon/intron organization and motif composition. In addition, both segmental duplication and whole-genome duplication contributed significantly to the expansion of GaTCPs. Many these TCP transcription factor genes are specifically expressed in cotton fiber during different developmental stages, including cotton fiber initiation and early development. This suggests that TCP genes may play important roles in cotton fiber development. PMID:26857372

Regulated expression of a novel TCP domain transcription factor indicates an involvement in the control of meristem activation processes in Solanum tuberosum.

PubMed

Faivre-Rampant, Odile; Bryan, Glenn J; Roberts, Alison G; Milbourne, Daniel; Viola, Roberto; Taylor, Mark A

2004-04-01

In this study, the aim was to determine whether TCP transcription factors are implicated in meristem activation in potato (Solanum tuberosum). By searching a database of potato EST sequences, with a sequence characteristically conserved in TCP domains, a potato tcp gene was identified. A BAC clone containing the tcp sequence was isolated and the genomic sequence was determined. Using a CAPS marker assay, the potato tcp gene (sttcp1) was mapped to chromosome 8. In dormant buds, relatively high levels of sttcp1-specific transcript were detected by in situ hybridization. By contrast, in sprouting buds, no expression of the sttcp1 could be detected. Furthermore, an inverse relationship between axillary bud size and the steady-state level of the sstcp1 transcript was demonstrated. In non-growing buds exhibiting correlative inhibition, sttcpI-specific transcript levels were also relatively high, but rapidly decreased when apical dominance was removed by excision of the apical bud.

Comprehensive analysis of TCP transcription factors and their expression during cotton (Gossypium arboreum) fiber early development.

PubMed

Ma, Jun; Liu, Fang; Wang, Qinglian; Wang, Kunbo; Jones, Don C; Zhang, Baohong

2016-02-09

TCP proteins are plant-specific transcription factors implicated to perform a variety of physiological functions during plant growth and development. In the current study, we performed for the first time the comprehensive analysis of TCP gene family in a diploid cotton species, Gossypium arboreum, including phylogenetic analysis, chromosome location, gene duplication status, gene structure and conserved motif analysis, as well as expression profiles in fiber at different developmental stages. Our results showed that G. arboreum contains 36 TCP genes, distributing across all of the thirteen chromosomes. GaTCPs within the same subclade of the phylogenetic tree shared similar exon/intron organization and motif composition. In addition, both segmental duplication and whole-genome duplication contributed significantly to the expansion of GaTCPs. Many these TCP transcription factor genes are specifically expressed in cotton fiber during different developmental stages, including cotton fiber initiation and early development. This suggests that TCP genes may play important roles in cotton fiber development.

SU-C-BRE-02: BED Vs. Local Control: Radiobiological Effect of Tumor Volume in Monte Carlo (MC) Lung SBRT Planning

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

Pokhrel, D; Badkul, R; Jiang, H

2014-06-15

Purpose: SBRT with hypofractionated dose schemata has emerged a compelling treatment modality for medically inoperable early stage lung cancer patients. It requires more accurate dose calculation and treatment delivery technique. This report presents the relationship between tumor control probability(TCP) and size-adjusted biological effective dose(sBED) of tumor volume for MC lung SBRT patients. Methods: Fifteen patients who were treated with MC-based lung SBRT to 50Gy in 5 fractions to PTVV100%=95% were studied. ITVs were delineated on MIP images of 4DCT-scans. PTVs diameter(ITV+5mm margins) ranged from 2.7–4.9cm (mean 3.7cm). Plans were generated using non-coplanar conformal arcs/beams using iPlan XVMC algorithm (BrainLABiPlan ver.4.1.2)more » for Novalis-TX with HD-MLCs and 6MVSRS(1000MU/min) mode, following RTOG-0813 dosimetric guidelines. To understand the known uncertainties of conventional heterogeneities-corrected/uncorrected pencil beam (PBhete/ PB-homo) algorithms, dose distributions were re-calculated with PBhete/ PB-homo using same beam configurations, MLCs and monitor units. Biologically effective dose(BED10) was computed using LQ-model with α/β=10Gy for meanPTV and meanITV. BED10-c*L, gave size-adjusted BED(sBED), where c=10Gy/cm and L=PTV diameter in centimeter. The TCP model was adopted from Ohri et al.(IJROBP, 2012): TCP = exp[sBEDTCD50]/ k /(1.0 + exp[sBED-TCD50]/k), where k=31Gy corresponding to TCD50=0Gy; and more realistic MC-based TCP was computed for PTV(V99%). Results: Mean PTV PB-hete TCP value was 6% higher, but, mean PTV PB-homo TCP value was 4% lower compared to mean PTV MC TCP. Mean ITV PB-hete/PB-homo TCP values were comparable (within ±3.0%) to mean ITV MC TCP. The mean PTV(V99%)had BED10=90.9±3.7%(median=92.2%),sBED=54.1±8.2%(median=53.5%) corresponding to mean MC TCP value of 84.8±3.3%(median=84.9%) at 2- year local control. Conclusion: The TCP model which incorporates BED10 and tumor diameter indicates that radiobiological effect of target volume and dose calculation algorithm significantly affects TCP for lung SBRT patients. Dose calculation using MC-based algorithm is more realistic with tissue heterogeneities and is routinely performed in our clinic. Patients will be followed up to determine whether TCP prediction correlate clinical outcomes.« less

A comparison of fresh and used aircraft oil for the identification of toxic substances linked to aerotoxic syndrome.

PubMed

Megson, David; Ortiz, Xavier; Jobst, Karl J; Reiner, Eric J; Mulder, Michel F A; Balouet, Jean-Christophe

2016-09-01

Fresh and used aircraft engine lubricants (Mobil Jet Oil II) were analysed using a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FTICRMS) and comprehensive two dimensional gas chromatography with high resolution time of flight mass spectrometry (GCxGC-HRTOFMS). The composition of the fresh oil was established, with special focus to its tricresyl phosphate (TCP) content as this has formed the focus for most investigations into aerotoxic syndrome. The results showed that only four TCP isomers were present at detectable levels in the fresh oil: mmm-TCP, mmp-TCP, ppm-TCP and ppp-TCP. The results indicate that the formulation of Mobile Jet Oil II does not contain the more toxic ortho substituted TCP isomers at concentrations above 0.0005%. The temperatures of jet engines during operation are greater than 200 °C which creates the potential to alter the composition of the original oil and create other toxic compounds. The results show there may be a significant risk from alkylated cresyl phosphates, which were identified in the used oils at concentrations calculated in the range of 0.13-0.69%. w/w. Several xylenyl and ethylphenyl phosphates have been shown to exhibit a similar toxicity to ortho substituted TCP isomers which makes there discovery in used oil significant. These compounds should be included in future aircraft air quality studies and when assessing the risks and causes of aerotoxic syndrome. Copyright © 2016 Elsevier Ltd. All rights reserved.

Degradation of 1,2,3-trichloropropane (TCP): hydrolysis, elimination, and reduction by iron and zinc.

PubMed

Sarathy, Vaishnavi; Salter, Alexandra J; Nurmi, James T; O'Brien Johnson, Graham; Johnson, Richard L; Tratnyek, Paul G

2010-01-15

1,2,3-Trichloropropane (TCP) is an emerging contaminant because of increased recognition of its occurrence in groundwater, potential carcinogenicity, and resistance to natural attenuation. The physical and chemical properties of TCP make it difficult to remediate, with all conventional options being relatively slow or inefficient. Treatments that result in alkaline conditions (e.g., permeable reactive barriers containing zerovalent iron) favor base-catalyzed hydrolysis of TCP, but high temperature (e.g., conditions of in situ thermal remediation) is necessary for this reaction to be significant. Common reductants (sulfide, ferrous iron adsorbed to iron oxides, and most forms of construction-grade or nano-Fe(0)) produce insignificant rates of reductive dechlorination of TCP. Quantifiable rates of TCP reduction were obtained with several types of activated nano-Fe(0), but the surface area normalized rate contants (k(SA)) for these reactions were lower than is generally considered useful for in situ remediation applications (10(-4) L m(-2) h(-1)). Much faster rates of degradation of TCP were obtained with granular Zn(0), (k(SA) = 10(-3) - 10(-2) L m(-2) h(-1)) and potentially problematic dechlorination intermediates (1,2- or 1,3-dichloropropane, 3-chloro-1-propene) were not detected. The advantages of Zn(0) over Fe(0) are somewhat peculiar to TCP and may suggest a practical application for Zn(0) even though it has not found favor for remediation of contamination with other chlorinated solvents.

Osteogenesis and angiogenesis properties of dental pulp cell on novel injectable tricalcium phosphate cement by silica doped.

PubMed

Su, Ying-Fang; Lin, Chi-Chang; Huang, Tsui-Hsien; Chou, Ming-Yung; Yang, Jaw-Ji; Shie, Ming-You

2014-09-01

β-Tricalcium phosphate (β-TCP) is an osteoconductive material in clinical. In this study, we have doped silica (Si) into β-TCP and enhanced its bioactive and osteostimulative properties. To check its effectiveness, a series of Si-doped with different ratios were prepared to make new bioactive and biodegradable biocomposites for bone repair. Formation of the diametral tensile strength, ions released and weight loss of cements was considered after immersion. In addition, we also examined the behavior of human dental pulp cells (hDPCs) cultured on Si-doped β-TCP cements. The results showed that setting time and injectability of the Si-doped β-TCP cements were decreased as the Si content was increased. At the end of the immersion point, weight losses of 30.1%, 36.9%, 48.1%, and 55.3% were observed for the cement doping 0%, 10%, 20%, and 30% Si into β-TCP cements, respectively. In vitro cell experiments show that the Si-rich cements promote human dental pulp cell (hDPC) proliferation and differentiation. However, when the Si-doped in the cement is more than 20%, the amount of cells and osteogenesis protein of hDPCs was stimulated by Si released from Si-doped β-TCP cements. The degradation of β-TCP and osteogenesis of Si gives a strong reason to believe that these Si-doped β-TCP cements may prove to be promising bone repair materials. Copyright © 2014 Elsevier B.V. All rights reserved.

3D printed scaffolds of calcium silicate-doped β-TCP synergize with co-cultured endothelial and stromal cells to promote vascularization and bone formation.

PubMed

Deng, Yuan; Jiang, Chuan; Li, Cuidi; Li, Tao; Peng, Mingzheng; Wang, Jinwu; Dai, Kerong

2017-07-17

Synthetic bone scaffolds have potential application in repairing large bone defects, however, inefficient vascularization after implantation remains the major issue of graft failure. Herein, porous β-tricalcium phosphate (β-TCP) scaffolds with calcium silicate (CS) were 3D printed, and pre-seeded with co-cultured human umbilical cord vein endothelial cells (HUVECs) and human bone marrow stromal cells (hBMSCs) to construct tissue engineering scaffolds with accelerated vascularization and better bone formation. Results showed that in vitro β-TCP scaffolds doped with 5% CS (5%CS/β-TCP) were biocompatible, and stimulated angiogenesis and osteogenesis. The results also showed that 5%CS/β-TCP scaffolds not only stimulated co-cultured cells angiogenesis on Matrigel, but also stimulated co-cultured cells to form microcapillary-like structures on scaffolds, and promoted migration of BMSCs by stimulating co-cultured cells to secrete PDGF-BB and CXCL12 into the surrounding environment. Moreover, 5%CS/β-TCP scaffolds enhanced vascularization and osteoinduction in comparison with β-TCP, and synergized with co-cultured cells to further increase early vessel formation, which was accompanied by earlier and better ectopic bone formation when implanted subcutaneously in nude mice. Thus, our findings suggest that porous 5%CS/β-TCP scaffolds seeded with co-cultured cells provide new strategy for accelerating tissue engineering scaffolds vascularization and osteogenesis, and show potential as treatment for large bone defects.

Synthesis and photoluminescence properties of a cyan-emitting phosphor Ca3(PO4)2:Eu2+ for white light-emitting diodes

NASA Astrophysics Data System (ADS)

Zhou, Wenli; Han, Jin; Zhang, Xuejie; Qiu, Zhongxian; Xie, Qingji; Liang, Hongbin; Lian, Shixun; Wang, Jing

2015-01-01

In this paper, a cyan-emitting phosphor Ca3(PO4)2:Eu2+ (TCP:Eu2+) was synthesized and evaluated as a candidate for white light emitting diodes (WLEDs). This phosphor shows strong and broad absorption in 250-450 nm region, but the emission spectrum is prominent at around 480 nm. The emission intensity of the TCP:Eu2+ was found to be 60% and 82% of that of the commercial BaMgAl10O17:Eu2+ (BAM) under excitation at 340 nm and 370 nm, respectively. Upon excitation at 370 nm, the absolute internal and external quantum efficiencies of the Ca3(PO4)2:1.5%Eu2+ are 60% and 42%, respectively. Moreover, a white LED lamp was fabricated by coating TCP:Eu2+ with a blue-emitting BAM and a red-emitting CaAlSiN3:Eu2+ on a near-ultraviolet (375 nm) LED chip, driven by a 350 mA forward bias current, and it produces an intense white light with a color rendering index of 75.

Improving TCP Performance over Mobile Satellite Channels: The ACKPrime Approach

NASA Technical Reports Server (NTRS)

Scott, Keith; Czetty, Stephen

1998-01-01

Various issues associated with "Improving TCP Performance over Mobile Satellite Channels: The ACKPrime Approach" are presented in viewgraph form. Specific topics include: 1) TCP over mobile satellite links; 2) ways of breaking the control loop at the groundstation; 3) ACK implementation; and 4) ACK performance.

Estimating Bottleneck Bandwidth using TCP

NASA Technical Reports Server (NTRS)

Allman, Mark

1998-01-01

Various issues associated with estimating bottleneck bandwidth using TCP are presented in viewgraph form. Specific topics include: 1) Why TCP is wanted to estimate the bottleneck bandwidth; 2) Setting ssthresh to an appropriate value to reduce loss; 3) Possible packet-pair solutions; and 4) Preliminary results: ACTS and the Internet.

A Lewinian Perspective on Taking Conflict Personally: Revision, Refinement, and Validation of the Instrument.

ERIC Educational Resources Information Center

Hample, Dale; Dallinger, Judith M.

1995-01-01

Describes theoretical connections among field theory, defensiveness, attributions, and taking conflict personally (TCP). Revises the original version of a multidimensional TCP scale, measuring six TCP subscales: direct personalization, persecution feelings, stress reaction, positive relational effects, negative relational effects, and like/dislike…

DETERMINATION OF 3,5,6-TRICHLORO-2-PYRIDINOL (TCP) BY ELISA

EPA Science Inventory

A sensitive, competitive enzyme-linked immunosorbent assay (ELISA) for 3,5,6-trichloro-2pyridinol (TCP) has been developed to quantitate parts per billion (ppb) amounts of the analyte in urine. TCP is a major metabolite and environmental degradation product of the insecticide c...

β-TCP porous pellets as an orthopaedic drug delivery system: ibuprofen/carrier physicochemical interactions

NASA Astrophysics Data System (ADS)

Baradari, Hiba; Damia, Chantal; Dutreih-Colas, Maggy; Champion, Eric; Chulia, Dominique; Viana, Marylène

2011-10-01

Calcium phosphate bone substitute materials can be loaded with active substances for in situ, targeted drug administration. In this study, porous β-TCP pellets were investigated as an anti-inflammatory drug carrier. Porous β-TCP pellets were impregnated with an ethanolic solution of ibuprofen. The effects of contact time and concentration of ibuprofen solution on drug adsorption were studied. The ibuprofen adsorption equilibrium time was found to be one hour. The adsorption isotherms fitted to the Freundlich model, suggesting that the interaction between ibuprofen and β-TCP is weak. The physicochemical characterizations of loaded pellets confirmed that the reversible physisorption of ibuprofen on β-TCP pellets is due to Van der Waals forces, and this property was associated with the 100% ibuprofen release.

Toll/Interleukin-1 Receptor Domain Derived from TcpC (TIR-TcpC) Ameliorates Experimental Autoimmune Arthritis by Down-modulating Th17 Cell Response*

PubMed Central

Pasi, Shweta; Kant, Ravi; Surolia, Avadhesha

2016-01-01

Evasion through immunomodulation is one of the several strategies adopted by pathogens to prolong their survival within the host. One such pathogen, Escherichia coli CFT073, utilizes an immunomodulatory protein, TcpC, to combat the host's innate immune defense. TcpC abrogates the function of MyD88 in macrophages, thus perturbing all the signaling processes that involve this adaptor protein. Although central to various signaling pathways initiated by IL-1, IL-18, and toll-like receptors, the precise contribution of MyD88 to the development of autoimmunity, particularly rheumatoid arthritis, still needs extensive exploration. Herein, by using the toll/interleukin-1 receptor (TIR) domain homologous C-terminal motif of TcpC, i.e. TIR-TcpC, we found MyD88 to be critical for the induction and progression of rheumatoid arthritis through its pivotal role in the development of Th17 cells, the subset of CD4+ T-cells widely implicated in various autoimmune disorders. The TIR-TcpC mediated inhibition of signaling through MyD88, and subsequent amelioration of experimental autoimmune arthritis was observed to be an outcome of perturbations in the NFκB-RORγt (RAR-related orphan receptor γt) axis. PMID:27022030

Analysis of the TCP genes expressed in the inflorescence of the orchid Orchis italica

PubMed Central

De Paolo, Sofia; Gaudio, Luciano; Aceto, Serena

2015-01-01

TCP proteins are plant-specific transcription factors involved in many different processes. Because of their involvement in a large number of developmental pathways, their roles have been investigated in various plant species. However, there are almost no studies of this transcription factor family in orchids. Based on the available transcriptome of the inflorescence of the orchid Orchis italica, in the present study we identified 12 transcripts encoding TCP proteins. The phylogenetic analysis showed that they belong to different TCP classes (I and II) and groups (PCF, CIN and CYC/TB1), and that they display a number of conserved motifs when compared with the TCPs of Arabidopsis and Oryza. The presence of a specific cleavage site for the microRNA miRNA319, an important post-transcriptional regulator of several TCP genes in other species, was demonstrated for one transcript of O. italica, and the analysis of the expression pattern of the TCP transcripts in different inflorescence organs and in leaf tissue suggests that some TCP transcripts of O. italica exert their role only in specific tissues, while others may play multiple roles in different tissues. In addition, the evolutionary analysis showed a general purifying selection acting on the coding region of these transcripts. PMID:26531864

Analysis of the TCP genes expressed in the inflorescence of the orchid Orchis italica.

PubMed

De Paolo, Sofia; Gaudio, Luciano; Aceto, Serena

2015-11-04

TCP proteins are plant-specific transcription factors involved in many different processes. Because of their involvement in a large number of developmental pathways, their roles have been investigated in various plant species. However, there are almost no studies of this transcription factor family in orchids. Based on the available transcriptome of the inflorescence of the orchid Orchis italica, in the present study we identified 12 transcripts encoding TCP proteins. The phylogenetic analysis showed that they belong to different TCP classes (I and II) and groups (PCF, CIN and CYC/TB1), and that they display a number of conserved motifs when compared with the TCPs of Arabidopsis and Oryza. The presence of a specific cleavage site for the microRNA miRNA319, an important post-transcriptional regulator of several TCP genes in other species, was demonstrated for one transcript of O. italica, and the analysis of the expression pattern of the TCP transcripts in different inflorescence organs and in leaf tissue suggests that some TCP transcripts of O. italica exert their role only in specific tissues, while others may play multiple roles in different tissues. In addition, the evolutionary analysis showed a general purifying selection acting on the coding region of these transcripts.

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

Vardoyan, G.; Rao, Nageswara S; Towlsey, D.

In recent years, the computer networking community has seen a steady growth in bandwidth-delay products (BDPs). Several TCP variants were created to combat the shortcomings of legacy TCP when it comes to operation in high-BDP environments. These variants, among which are CUBIC, STCP, and H-TCP, have been extensively studied in some empirical contexts, and some analytical models exist for CUBIC and STCP. However, since these studies have been conducted, BDPs have risen even more, and new bulk data transfer tools have emerged that utilize multiple parallel TCP streams. In view of these new developments, it is imperative to revisit themore » question: Which congestion control algorithms are best adapted to current networking environments? In order to help resolve this question, we contribute the following: (i) using first principles, we develop a general throughput-prediction framework that takes into account buffer sizes and maximum window constraints; (ii) we validate the models using measurements and achieve low prediction errors; (iii) we note differences in TCP dynamics between two experimental configurations and find one of them to be significantly more deterministic than the other; we also find that CUBIC and H-TCP outperform STCP, especially when multiple streams are used; and (iv) we present preliminary results for modelling multiple TCP streams for CUBIC and STCP.« less

Examination of Diverse Toxin-Coregulated Pilus-Positive Vibrio cholerae Strains Fails To Demonstrate Evidence for Vibrio Pathogenicity Island Phage

PubMed Central

Faruque, Shah M.; Zhu, Jun; Asadulghani; Kamruzzaman, M.; Mekalanos, John J.

2003-01-01

The major virulence factors of toxigenic Vibrio cholerae are cholera toxin, which is encoded by a lysogenic filamentous bacteriophage (CTXΦ), and toxin-coregulated pilus (TCP), an essential colonization factor that is also the receptor for CTXΦ. The genes involved in the biosynthesis of TCP reside in a pathogenicity island, which has been reported to correspond to the genome of another filamentous phage (designated VPIΦ) and to encode functions necessary for the production of infectious VPIΦ particles. We examined 46 V. cholerae strains having diverse origins and carrying different genetic variants of the TCP island for the production of the VPIΦ and CTXΦ in different culture conditions, including induction of prophages with mitomycin C and UV irradiation. Although 9 of 10 V. cholerae O139 strains and 12 of 15 toxigenic El Tor strains tested produced extracellular CTXΦ, none of the 46 TCP-positive strains produced detectable VPIΦ in repeated assays, which detected as few as 10 particles of a control CTX phage per ml. These results contradict the previous report regarding VPIΦ-mediated horizontal transfer of the TCP genes and suggest that the TCP island is unable to support the production of phage particles. Further studies are necessary to understand the mechanism of horizontal transfer of the TCP island. PMID:12761075

Teriparatide promotes healing of critical size femur defect through accelerating angiogenesis and degradation of β-TCP in OVX osteoporotic rat model.

PubMed

Xie, Zhongjie; Weng, Sheji; Li, Hang; Yu, Xia; Lu, Shanshan; Huang, Kate; Wu, Zongyi; Bai, Bingli; Boodhun, Viraj; Yang, Lei

2017-12-01

Accumulating evidence suggests that early angiogenesis has an important effect on the healing of injury. Teriparatide (PTH) is extensively applied for its potent anabolic activity on bone, while little is known about its angiogenic ability which may facilitate new bone formation. In this study, we tested the angiogenic ability of PTH and its effect on degradation of β-tricalcium phosphate (β-TCP) in an ovariectomized (OVX) rat distal femoral metaphysis model. After successful establishment of the OVX model was confirmed, a critical size defect was drilled into each distal femur of the OVX rats. Afterwards all animals were randomly divided into three groups: control group, group β-TCP and group β-TCP+PTH, then rats of group β-TCP+PTH were injected Teriparatide (30 μg/kg) subcutaneous every other day. Four weeks after femur surgery, five specimens from each group were used for Microfil perfusion to reveal blood vessels in the bone defect. The residual rats were harvested for micro-computed tomography, histological analysis and immunochemistry. The results showed Teriparatide facilitated neovascularization, degradation of β-TCP and new bone formation in combination with β-TCP, which may be relevant to neovascularization in an early phase. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Development of bioactive porous α-TCP/HAp beads for bone tissue engineering.

PubMed

Asaoka, Teruo; Ohtake, Shoji; Furukawa, Katsuko S; Tamura, Akito; Ushida, Takashi

2013-11-01

Porous beads of bioactive ceramics such as hydroxyapatite (HAp) and tribasic calcium phosphate (TCP) are considered a promising scaffold for cultivating bone cells. To realize this, α-TCP/HAp functionally graded porous beads are fabricated with two main purposes: to maintain the function of the scaffold with sufficient strength up to the growth of new bone, and is absorbed completely after the growth. HAp is a bioactive material that has both high strength and strong tissue-adhesive properties, but is not readily absorbed by the human body. On the contrary, α-TCP is highly bioabsorbable, resulting in a scaffold that is absorbed before it is completely replaced by bone. In this study, we produced porous, bead-shaped carriers as scaffolds for osteoblast culture. To control the solubility in vivo, the fabricated beads contained α-TCP at the center and HAp at the surface. Cell adaptability of these beads for bone tissue engineering was confirmed in vitro. It was found that α-TCP/HAp bead carriers exhibit low toxicity in the initial stages of cell seeding and cell adhesion. The presence of HAp in the composite bead form effectively increased ALP activity. In conclusion, it is suggested that these newly developed α-TCP/HAp beads are a promising tool for bone tissue engineering. Copyright © 2013 Wiley Periodicals, Inc.

Compact Modbus TCP/IP protocol for data acquisition systems based on limited hardware resources

NASA Astrophysics Data System (ADS)

Bai, Q.; Jin, B.; Wang, D.; Wang, Y.; Liu, X.

2018-04-01

The Modbus TCP/IP has been a standard industry communication protocol and widely utilized for establishing sensor-cloud platforms on the Internet. However, numerous existing data acquisition systems built on traditional single-chip microcontrollers without sufficient resources cannot support it, because the complete Modbus TCP/IP protocol always works dependent on a full operating system which occupies abundant hardware resources. Hence, a compact Modbus TCP/IP protocol is proposed in this work to make it run efficiently and stably even on a resource-limited hardware platform. Firstly, the Modbus TCP/IP protocol stack is analyzed and the refined protocol suite is rebuilt by streamlining the typical TCP/IP suite. Then, specific implementation of every hierarchical layer is respectively presented in detail according to the protocol structure. Besides, the compact protocol is implemented in a traditional microprocessor to validate the feasibility of the scheme. Finally, the performance of the proposed scenario is assessed. The experimental results demonstrate that message packets match the frame format of Modbus TCP/IP protocol and the average bandwidth reaches to 1.15 Mbps. The compact protocol operates stably even based on a traditional microcontroller with only 4-kB RAM and 12-MHz system clock, and no communication congestion or frequent packet loss occurs.

Material Characterization of Microsphere-Based Scaffolds with Encapsulated Raw Materials

PubMed Central

Sridharan, BanuPriya; Mohan, Neethu; Berkland, Cory J.; Detamore, Michael S.

2016-01-01

“Raw materials,” or materials capable of serving both as building blocks and as signals, which are often but not always natural materials, are taking center stage in biomaterials for contemporary regenerative medicine. In osteochondral tissue engineering, a field leveraging the underlying bone to facilitate cartilage regeneration, common raw materials include chondroitin sulfate (CS) for cartilage and β-tricalcium phosphate (TCP) for bone. Building on our previous work with gradient scaffolds based on microspheres, here we delved deeper into the characterization of individual components. In the current study, the release of CS and TCP from poly(D,L-lactic-co-glycolic acid) (PLGA) microsphere-based scaffolds was evaluated over a time period of 4 weeks. Raw material encapsulated groups were compared to ‘blank’ groups and evaluated for surface topology, molecular weight, and mechanical performance as a function of time. The CS group may have led to increased surface porosity, and the addition of CS improved the mechanical performance of the scaffold. The finding that CS was completely released into the surrounding media by 4 weeks has a significant impact on future in vivo studies, given rapid bioavailability. The addition of TCP seemed to contribute to the rough external appearance of the scaffold. The current study provides an introduction to degradation patterns of homogenous raw material encapsulated scaffolds, providing characterization data to advance the field of microsphere-based scaffolds in tissue engineering. PMID:27040236

A Transcriptome Atlas of Physcomitrella patens Provides Insights into the Evolution and Development of Land Plants.

PubMed

Ortiz-Ramírez, Carlos; Hernandez-Coronado, Marcela; Thamm, Anna; Catarino, Bruno; Wang, Mingyi; Dolan, Liam; Feijó, José A; Becker, Jörg D

2016-02-01

Identifying the genetic mechanisms that underpin the evolution of new organ and tissue systems is an aim of evolutionary developmental biology. Comparative functional genetic studies between angiosperms and bryophytes can define those genetic changes that were responsible for developmental innovations. Here, we report the generation of a transcriptome atlas covering most phases in the life cycle of the model bryophyte Physcomitrella patens, including detailed sporophyte developmental progression. We identified a comprehensive set of sporophyte-specific transcription factors, and found that many of these genes have homologs in angiosperms that function in developmental processes such as flowering and shoot branching. Deletion of the PpTCP5 transcription factor results in development of supernumerary sporangia attached to a single seta, suggesting that it negatively regulates branching in the moss sporophyte. Given that TCP genes repress branching in angiosperms, we suggest that this activity is ancient. Finally, comparison of P. patens and Arabidopsis thaliana transcriptomes led us to the identification of a conserved core of transcription factors expressed in tip-growing cells. We identified modifications in the expression patterns of these genes that could account for developmental differences between P. patens tip-growing cells and A. thaliana pollen tubes and root hairs. Copyright © 2016 The Author. Published by Elsevier Inc. All rights reserved.

Novel Radiobiological Gamma Index for Evaluation of 3-Dimensional Predicted Dose Distribution

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

Sumida, Iori, E-mail: sumida@radonc.med.osaka-u.ac.jp; Yamaguchi, Hajime; Kizaki, Hisao

2015-07-15

Purpose: To propose a gamma index-based dose evaluation index that integrates the radiobiological parameters of tumor control (TCP) and normal tissue complication probabilities (NTCP). Methods and Materials: Fifteen prostate and head and neck (H&N) cancer patients received intensity modulated radiation therapy. Before treatment, patient-specific quality assurance was conducted via beam-by-beam analysis, and beam-specific dose error distributions were generated. The predicted 3-dimensional (3D) dose distribution was calculated by back-projection of relative dose error distribution per beam. A 3D gamma analysis of different organs (prostate: clinical [CTV] and planned target volumes [PTV], rectum, bladder, femoral heads; H&N: gross tumor volume [GTV], CTV,more » spinal cord, brain stem, both parotids) was performed using predicted and planned dose distributions under 2%/2 mm tolerance and physical gamma passing rate was calculated. TCP and NTCP values were calculated for voxels with physical gamma indices (PGI) >1. We propose a new radiobiological gamma index (RGI) to quantify the radiobiological effects of TCP and NTCP and calculate radiobiological gamma passing rates. Results: The mean RGI gamma passing rates for prostate cases were significantly different compared with those of PGI (P<.03–.001). The mean RGI gamma passing rates for H&N cases (except for GTV) were significantly different compared with those of PGI (P<.001). Differences in gamma passing rates between PGI and RGI were due to dose differences between the planned and predicted dose distributions. Radiobiological gamma distribution was visualized to identify areas where the dose was radiobiologically important. Conclusions: RGI was proposed to integrate radiobiological effects into PGI. This index would assist physicians and medical physicists not only in physical evaluations of treatment delivery accuracy, but also in clinical evaluations of predicted dose distribution.« less

Microporous pure beta-tricalcium phosphate implants for press-fit fixation of anterior cruciate ligament grafts: strength and healing in a sheep model.

PubMed

Mayr, Hermann O; Dietrich, Markwart; Fraedrich, Franz; Hube, Robert; Nerlich, Andreas; von Eisenhart-Rothe, Rüdiger; Hein, Werner; Bernstein, Anke

2009-09-01

A sheep study was conducted to test a press-fit technique using microporous pure beta-tricalcium phosphate (beta-TCP) dowels for fixation of the anterior cruciate ligament (ACL) graft. Microporous (5 mum) cylindrical plugs of beta-TCP (diameter, 7 mm; length, 25 mm) with interconnecting pores were used. The material featured a novel configuration of structure and surface geometry. Implants were tested by use of press-fit fixation of ACL grafts with and without bone blocks in 42 sheep over a period of 24 weeks. Biomechanical, radiologic, histologic, and immunohistochemical evaluations were performed. In load-to-failure tests at 6, 12, and 24 weeks after surgery, the intra-articular graft always failed, not the fixation. Grafts showed bony fixation in the tunnel at 6 weeks and primary healing at the junction of the tunnel and joint after 24 weeks. Tricalcium phosphate was resorbed and simultaneously replaced by bone. Remodeling was still incomplete at 24 weeks. In the sheep model microporous beta-TCP implants used with press-fit fixation of ACL grafts permit early functional rehabilitation. After 6 weeks, the graft is fixed by woven bone or bony integration. Implanted microporous tricalcium phosphate is resorbed and replaced by bone. In a sheep model we showed that primary healing of ACL grafts with resorption and bony replacement of the fixating implant can be achieved by means of press-fit fixation with pure beta-TCP.

Tissue-engineered bone constructed in a bioreactor for repairing critical-sized bone defects in sheep.

PubMed

Li, Deqiang; Li, Ming; Liu, Peilai; Zhang, Yuankai; Lu, Jianxi; Li, Jianmin

2014-11-01

Repair of bone defects, particularly critical-sized bone defects, is a considerable challenge in orthopaedics. Tissue-engineered bones provide an effective approach. However, previous studies mainly focused on the repair of bone defects in small animals. For better clinical application, repairing critical-sized bone defects in large animals must be studied. This study investigated the effect of a tissue-engineered bone for repairing critical-sized bone defect in sheep. A tissue-engineered bone was constructed by culturing bone marrow mesenchymal-stem-cell-derived osteoblast cells seeded in a porous β-tricalcium phosphate ceramic (β-TCP) scaffold in a perfusion bioreactor. A critical-sized bone defect in sheep was repaired with the tissue-engineered bone. At the eighth and 16th week after the implantation of the tissue-engineered bone, X-ray examination and histological analysis were performed to evaluate the defect. The bone defect with only the β-TCP scaffold served as the control. X-ray showed that the bone defect was successfully repaired 16 weeks after implantation of the tissue-engineered bone; histological sections showed that a sufficient volume of new bones formed in β-TCP 16 weeks after implantation. Eight and 16 weeks after implantation, the volume of new bones that formed in the tissue-engineered bone group was more than that in the β-TCP scaffold group (P < 0.05). Tissue-engineered bone improved osteogenesis in vivo and enhanced the ability to repair critical-sized bone defects in large animals.

Tumor control probability reduction in gated radiotherapy of non-small cell lung cancers: a feasibility study.

PubMed

Siochi, R Alfredo; Kim, Yusung; Bhatia, Sudershan

2014-10-16

We studied the feasibility of evaluating tumor control probability (TCP) reductions for tumor motion beyond planned gated radiotherapy margins. Tumor motion was determined from cone-beam CT projections acquired for patient setup, intrafraction respiratory traces, and 4D CTs for five non-small cell lung cancer (NSCLC) patients treated with gated radiotherapy. Tumors were subdivided into 1 mm sections whose positions and doses were determined for each beam-on time point. (The dose calculation model was verified with motion phantom measurements.) The calculated dose distributions were used to generate the treatment TCPs for each patient. The plan TCPs were calculated from the treatment planning dose distributions. The treatment TCPs were compared to the plan TCPs for various models and parameters. Calculated doses matched phantom measurements within 0.3% for up to 3 cm of motion. TCP reductions for excess motion greater than 5mm ranged from 1.7% to 11.9%, depending on model parameters, and were as high as 48.6% for model parameters that simulated an individual patient. Repeating the worst case motion for all fractions increased TCP reductions by a factor of 2 to 3, while hypofractionation decreased these reductions by as much as a factor of 3. Treatment motion exceeding gating margins by more than 5 mm can lead to considerable TCP reductions. Appropriate margins for excess motion are recommended, unless applying daily tumor motion verification and adjusting thegating window.

Implantation of Tetrapod-Shaped Granular Artificial Bones or β-Tricalcium Phosphate Granules in a Canine Large Bone-Defect Model

PubMed Central

CHOI, Sungjin; LIU, I-Li; YAMAMOTO, Kenichi; HONNAMI, Muneki; SAKAI, Takamasa; OHBA, Shinsuke; ECHIGO, Ryosuke; SUZUKI, Shigeki; NISHIMURA, Ryouhei; CHUNG, Ung-il; SASAKI, Nobuo; MOCHIZUKI, Manabu

2013-01-01

ABSTRACT We investigated biodegradability and new bone formation after implantation of tetrapod-shaped granular artificial bone (Tetrabone®) or β-tricalcium phosphate granules (β-TCP) in experimental critical-size defects in dogs, which were created through medial and lateral femoral condyles. The defect was packed with Tetrabone® (Tetrabone group) or β-TCP (β-TCP group) or received no implant (control group). Computed tomography (CT) was performed at 0, 4 and 8 weeks after implantation. Micro-CT and histological analysis were conducted to measure the non-osseous tissue rate and the area and distribution of new bone tissue in the defect at 8 weeks after implantation. On CT, β-TCP was gradually resorbed, while Tetrabone® showed minimal resorption at 8 weeks after implantation. On micro-CT, non-osseous tissue rate of the control group was significantly higher compared with the β-TCP and Tetrabone groups (P<0.01), and that of the β-TCP group was significantly higher compared with the Tetrabone group (P<0.05). On histology, area of new bone tissue of the β-TCP group was significantly greater than those of the Tetrabone and control groups (P<0.05), and new bone distribution of the Tetrabone group was significantly greater than those of the β-TCP and control groups (P<0.05). These results indicate differences in biodegradability and connectivity of intergranule pore structure between study samples. In conclusion, Tetrabone® may be superior for the repair of large bone defects in dogs. PMID:24161964

Implantation of tetrapod-shaped granular artificial bones or β-tricalcium phosphate granules in a canine large bone-defect model.

PubMed

Choi, Sungjin; Liu, I-Li; Yamamoto, Kenichi; Honnami, Muneki; Sakai, Takamasa; Ohba, Shinsuke; Echigo, Ryosuke; Suzuki, Shigeki; Nishimura, Ryouhei; Chung, Ung-Il; Sasaki, Nobuo; Mochizuki, Manabu

2014-03-01

We investigated biodegradability and new bone formation after implantation of tetrapod-shaped granular artificial bone (Tetrabone®) or β-tricalcium phosphate granules (β-TCP) in experimental critical-size defects in dogs, which were created through medial and lateral femoral condyles. The defect was packed with Tetrabone® (Tetrabone group) or β-TCP (β-TCP group) or received no implant (control group). Computed tomography (CT) was performed at 0, 4 and 8 weeks after implantation. Micro-CT and histological analysis were conducted to measure the non-osseous tissue rate and the area and distribution of new bone tissue in the defect at 8 weeks after implantation. On CT, β-TCP was gradually resorbed, while Tetrabone® showed minimal resorption at 8 weeks after implantation. On micro-CT, non-osseous tissue rate of the control group was significantly higher compared with the β-TCP and Tetrabone groups (P<0.01), and that of the β-TCP group was significantly higher compared with the Tetrabone group (P<0.05). On histology, area of new bone tissue of the β-TCP group was significantly greater than those of the Tetrabone and control groups (P<0.05), and new bone distribution of the Tetrabone group was significantly greater than those of the β-TCP and control groups (P<0.05). These results indicate differences in biodegradability and connectivity of intergranule pore structure between study samples. In conclusion, Tetrabone® may be superior for the repair of large bone defects in dogs.

Engineering Vascularized Bone Grafts by Integrating a Biomimetic Periosteum and β-TCP Scaffold

PubMed Central

2015-01-01

Treatment of large bone defects using synthetic scaffolds remain a challenge mainly due to insufficient vascularization. This study is to engineer a vascularized bone graft by integrating a vascularized biomimetic cell-sheet-engineered periosteum (CSEP) and a biodegradable macroporous beta-tricalcium phosphate (β-TCP) scaffold. We first cultured human mesenchymal stem cells (hMSCs) to form cell sheet and human umbilical vascular endothelial cells (HUVECs) were then seeded on the undifferentiated hMSCs sheet to form vascularized cell sheet for mimicking the fibrous layer of native periosteum. A mineralized hMSCs sheet was cultured to mimic the cambium layer of native periosteum. This mineralized hMSCs sheet was first wrapped onto a cylindrical β-TCP scaffold followed by wrapping the vascularized HUVEC/hMSC sheet, thus generating a biomimetic CSEP on the β-TCP scaffold. A nonperiosteum structural cell sheets-covered β-TCP and plain β-TCP were used as controls. In vitro studies indicate that the undifferentiated hMSCs sheet facilitated HUVECs to form rich capillary-like networks. In vivo studies indicate that the biomimetic CSEP enhanced angiogenesis and functional anastomosis between the in vitro preformed human capillary networks and the mouse host vasculature. MicroCT analysis and osteocalcin staining show that the biomimetic CSEP/β-TCP graft formed more bone matrix compared to the other groups. These results suggest that the CSEP that mimics the cellular components and spatial configuration of periosteum plays a critical role in vascularization and osteogenesis. Our studies suggest that a biomimetic periosteum-covered β-TCP graft is a promising approach for bone regeneration. PMID:24858072

The Live Attenuated Cholera Vaccine CVD 103-HgR Primes Responses to the Toxin-Coregulated Pilus Antigen TcpA in Subjects Challenged with Wild-Type Vibrio cholerae.

PubMed

Mayo-Smith, Leslie M; Simon, Jakub K; Chen, Wilbur H; Haney, Douglas; Lock, Michael; Lyon, Caroline E; Calderwood, Stephen B; Kirkpatrick, Beth D; Cohen, Mitchell; Levine, Myron M; Gurwith, Marc; Harris, Jason B

2017-01-01

One potential advantage of live attenuated bacterial vaccines is the ability to stimulate responses to antigens which are only expressed during the course of infection. To determine whether the live attenuated cholera vaccine CVD 103-HgR (Vaxchora) results in antibody responses to the in vivo-induced toxin-coregulated pilus antigen TcpA, we measured IgA and IgG responses to Vibrio cholerae O1 El Tor TcpA in a subset of participants in a recently reported experimental challenge study. Participants were challenged with V. cholerae O1 El Tor Inaba N16961 either 10 days or 90 days after receiving the vaccine or a placebo. Neither vaccination nor experimental infection with V. cholerae alone resulted in a robust TcpA IgG or IgA response, but each did elicit a strong response to cholera toxin. However, compared to placebo recipients, vaccinees had a marked increase in IgG TcpA antibodies following the 90-day challenge, suggesting that vaccination with CVD 103-HgR resulted in priming for a subsequent response to TcpA. No such difference between vaccine and placebo recipients was observed for volunteers challenged 10 days after vaccination, indicating that this was insufficient time for vaccine-induced priming of the TcpA response. The priming of the response to TcpA and potentially other antigens expressed in vivo by attenuated V. cholerae may have relevance to the maintenance of immunity in areas where cholera is endemic. Copyright © 2017 American Society for Microbiology.

Effects of hypoxia-ischemia and MK-801 treatment on the binding of a phencyclidine analogue in the developing rat brain

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

Silverstein, F.S.; McDonald, J.W. III; Bommarito, M.

1990-02-01

The phencyclidine analogue ({sup 3}H)(1-(2-thienyl)cyclohexyl)piperidine ({sup 3}H-TCP) binds to the ion channel associated with the N-methyl-D-aspartate receptor channel complex. In vitro autoradiography indicates that the distribution of {sup 3}H-TCP binding in brain closely parallels that of ({sup 3}H)glutamate binding to the N-methyl-D-aspartate receptor. In nine 7-day-old rats, an acute focal hypoxic-ischemic insult produced by unilateral carotid artery ligation and subsequent exposure to 8% oxygen acutely reduced {sup 3}H-TCP binding ipsilateral to the ligation by 30% in the CA1, by 27% in the CA3, by 26% in the dentate gyrus, and by 17% in the striatum compared with values from themore » contralateral hemisphere. In 10 littermates that received 1 mg/kg of the neuroprotective noncompetitive N-methyl-D-aspartate antagonist MK-801 immediately before hypoxic exposure, the regional distribution of {sup 3}H-TCP binding in hypoxic-ischemic brain was relatively preserved and there were no interhemispheric asymmetries in {sup 3}H-TCP binding densities. In addition, in three unoperated rats decapitated 24 hours after MK-801 treatment, {sup 3}H-TCP binding was reduced by 15-35%; similar bilateral suppression of {sup 3}H-TCP binding was detected in MK-801-treated ligates. Our data indicate that {sup 3}H-TCP autoradiography can be used to assay the efficacy of neuroprotective agents in this experimental model of perinatal stroke.« less

Bioactive and biodegradable silica biomaterial for bone regeneration.

PubMed

Wang, Shunfeng; Wang, Xiaohong; Draenert, Florian G; Albert, Olga; Schröder, Heinz C; Mailänder, Volker; Mitov, Gergo; Müller, Werner E G

2014-10-01

Biosilica, a biocompatible, natural inorganic polymer that is formed by an enzymatic, silicatein-mediated reaction in siliceous sponges to build up their inorganic skeleton, has been shown to be morphogenetically active and to induce mineralization of human osteoblast-like cells (SaOS-2) in vitro. In the present study, we prepared beads (microspheres) by encapsulation of β-tricalcium phosphate [β-TCP], either alone (control) or supplemented with silica or silicatein, into the biodegradable copolymer poly(d,l-lactide-co-glycolide) [PLGA]. Under the conditions used, ≈5% β-TCP, ≈9% silica, and 0.32μg/mg of silicatein were entrapped into the PLGA microspheres (diameter≈800μm). Determination of the biocompatibility of the β-TCP microspheres, supplemented with silica or silicatein, revealed no toxicity in the MTT based cell viability assay using SaOS-2 cells. The adherence of SaOS-2 cells to the surface of silica-containing microspheres was higher than for microspheres, containing only β-TCP. In addition, the silica-containing β-TCP microspheres and even more pronounced, a 1:1 mixture of microspheres containing β-TCP and silica, and β-TCP and silicatein, were found to strongly enhance the mineral deposition by SaOS-2 cells. Using these microspheres, first animal experiments with silica/biosilica were performed in female, adult New Zealand White rabbits to study the effect of the inorganic polymer on bone regeneration in vivo. The microspheres were implanted into 5mm thick holes, drilled into the femur of the animals, applying a bilateral comparison study design (3 test groups with 4-8 animals each). The control implant on one of the two hind legs contained microspheres with only β-TCP, while the test implant on the corresponding leg consisted either of microspheres containing β-TCP and silica, or a 1:1 mixture of microspheres, supplemented with β-TCP and silica, and β-TCP and silicatein. The results revealed that tissue/bone sections of silica containing implants and implants, composed of a 1:1 mixture of silica-containing microspheres and silicatein-containing microspheres, show an enhanced regeneration of bone tissue around the microspheres, compared to the control implants containing only β-TCP. The formation of new bone induced by the microspheres is also evident from measurements of the stiffness/reduced Young's modulus of the regenerated bone tissue. The reduced Young's modulus of the regenerating bone tissue around the implants was markedly higher for the silica-containing microspheres (1.1MPa), and even more for the 1:1 mixture of the silica- and silicatein-containing microspheres (1.4MPa), compared to the β-TCP microsphere controls (0.4MPa). We propose that based on their morphogenetic activity on bone-forming cells in vitro and the results of the animal experiments presented here, silica/biosilica-based scaffolds are promising materials for bone repair/regeneration. Copyright © 2014 Elsevier Inc. All rights reserved.

TCF7L2 gene polymorphisms do not predict susceptibility to diabetes in tropical calcific pancreatitis but may interact with SPINK1 and CTSB mutations in predicting diabetes.

PubMed

Mahurkar, Swapna; Bhaskar, Seema; Reddy, D Nageshwar; Prakash, Swami; Rao, G Venkat; Singh, Shivaram Prasad; Thomas, Varghese; Chandak, Giriraj Ratan

2008-08-16

Tropical calcific pancreatitis (TCP) is a type of chronic pancreatitis unique to developing countries in tropical regions and one of its important features is invariable progression to diabetes, a condition called fibro-calculous pancreatic diabetes (FCPD), but the nature of diabetes in TCP is controversial. We analysed the recently reported type 2 diabetes (T2D) associated polymorphisms in the TCF7L2 gene using a case-control approach, under the hypothesis that TCF7L2 variants should show similar association if diabetes in FCPD is similar to T2D. We also investigated the interaction between the TCF7L2 variants and N34S SPINK1 and L26V CTSB mutations, since they are strong predictors of risk for TCP. Two polymorphisms rs7903146 and rs12255372 in the TCF7L2 gene were analyzed by direct sequencing in 478 well-characterized TCP patients and 661 healthy controls of Dravidian and Indo-European ethnicities. Their association with TCP with diabetes (FCPD) and without diabetes was tested in both populations independently using chi-square test. Finally, a meta analysis was performed on all the cases and controls for assessing the overall significance irrespective of ethnicity. We dichotomized the whole cohort based on the presence or absence of N34S SPINK1 and L26V CTSB mutations and further subdivided them into TCP and FCPD patients and compared the distribution of TCF7L2 variants between them. The allelic and genotypic frequencies for both TCF7L2 polymorphisms, did not differ significantly between TCP patients and controls belonging to either of the ethnic groups or taken together. No statistically significant association of the SNPs was observed with TCP or FCPD or between carriers and non-carriers of N34S SPINK1 and L26V CTSB mutations. The minor allele frequency for rs7903146 was different between TCP and FCPD patients carrying the N34S SPINK1 variant but did not reach statistical significance (OR = 1.59, 95% CI = 0.93-2.70, P = 0.09), while, TCF7L2variant showed a statistically significant association between TCP and FCPD patients carrying the 26V allele (OR = 1.69, 95% CI = 1.11-2.56, P = 0.013). Type 2 diabetes associated TCF7L2 variants are not associated with diabetes in TCP. Since, TCF7L2 is a major susceptibility gene for T2D, it may be hypothesized that the diabetes in TCP patients may not be similar to T2D. Our data also suggests that co-existence of TCF7L2 variants and the SPINK1 and CTSB mutations, that predict susceptibility to exocrine damage, may interact to determine the onset of diabetes in TCP patients.

Testing Cadmium-Free Coatings

DTIC Science & Technology

2011-08-30

Chromium (Cr6+) None Zinc Cr6+ None Zinc Trivalent Chromium Process (TCP) Enseal C22 Zinc Nickel TCP Enseal C22 High Purity Al TCP Enseal C22 Zn-rich two...Secretary of Defense Directive • “Approve the use of alternatives [to hexavalent chromium (Cr6+)] where they can perform adequately for the intended

Polymer powder processing of cryomilled polycaprolactone for solvent-free generation of homogeneous bioactive tissue engineering scaffolds.

PubMed

Lim, Jing; Chong, Mark Seow Khoon; Chan, Jerry Kok Yen; Teoh, Swee-Hin

2014-06-25

Synthetic polymers used in tissue engineering require functionalization with bioactive molecules to elicit specific physiological reactions. These additives must be homogeneously dispersed in order to achieve enhanced composite mechanical performance and uniform cellular response. This work demonstrates the use of a solvent-free powder processing technique to form osteoinductive scaffolds from cryomilled polycaprolactone (PCL) and tricalcium phosphate (TCP). Cryomilling is performed to achieve micrometer-sized distribution of PCL and reduce melt viscosity, thus improving TCP distribution and improving structural integrity. A breakthrough is achieved in the successful fabrication of 70 weight percentage of TCP into a continuous film structure. Following compaction and melting, PCL/TCP composite scaffolds are found to display uniform distribution of TCP throughout the PCL matrix regardless of composition. Homogeneous spatial distribution is also achieved in fabricated 3D scaffolds. When seeded onto powder-processed PCL/TCP films, mesenchymal stem cells are found to undergo robust and uniform osteogenic differentiation, indicating the potential application of this approach to biofunctionalize scaffolds for tissue engineering applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Changes of Field Incurred Chlorpyrifos and Its Toxic Metabolite Residues in Rice during Food Processing from-RAC-to-Consumption

PubMed Central

Zhang, Zhiyong; Jiang, Wayne W.; Jian, Qiu; Song, Wencheng; Zheng, Zuntao; Wang, Donglan; Liu, Xianjin

2015-01-01

The objectives of this study were to determine the effects of food processing on field incurred residues levels of chlorpyrifos and its metabolite 3,5,6-Trichloro-2-pyridinol (TCP) in rice. The chlorpyrifos and TCP were found to be 1.27 and 0.093 mg kg-1 in straw and 0.41 and 0.073 mg kg-1 in grain, respectively. It is observed that the sunlight for 2 hours does not decrease the chlorpyrifos and TCP residues in grain significantly. Their residues in rice were reduced by up to 50% by hulling. The cooking reduced the chlorpyrifos and TCP in rice to undetectable level (below 0.01 mg kg-1). Processing factors (PFs) of chlorpyrifos and TCP residues in rice during food processing were similar. Various factors have impacts on the fates of chlorpyrifos and TCP residues and the important steps to reduce their residues in rice were hulling and cooking. The results can contribute to assure the consumer of a safe wholesome food supply. PMID:25608031

The heterologous expression of a chrysanthemum TCP-P transcription factor CmTCP14 suppresses organ size and delays senescence in Arabidopsis thaliana.

PubMed

Zhang, Ting; Qu, Yixin; Wang, Haibin; Wang, Jingjing; Song, Aiping; Hu, Yueheng; Chen, Sumei; Jiang, Jiafu; Chen, Fadi

2017-06-01

TCP transcription factors are important for plant growth and development, but their activity in chrysanthemum (Chrysanthemum morifolium) has not been thoroughly explored. Here, a chrysanthemum TCP-P sequence, which encodes a protein harboring the conserved basic helix-loop-helix (bHLH) motif, was shown to be related phylogenetically to the Arabidopsis thaliana gene AtTCP14. A yeast-one hybrid assay showed that the encoding protein had no transcriptional activation ability, and a localization experiment indicated that it was localized in the nucleus. Transcription profiling established that the gene was most active in the stem and leaf. Its heterologous expression in A. thaliana down-regulated certain cell cycle-related genes, reduced the size of various organs and increased the chlorophyll and carotenoid contents of the leaf which led to delayed senescence and a prolonged flowering period. Moreover, by screening the cDNA library of chrysanthemum, we found that the CmTCP14 can interact with CmFTL2 and some CmDELLAs. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

LWD-TCP complex activates the morning gene CCA1 in Arabidopsis.

PubMed

Wu, Jing-Fen; Tsai, Huang-Lung; Joanito, Ignasius; Wu, Yi-Chen; Chang, Chin-Wen; Li, Yi-Hang; Wang, Ying; Hong, Jong Chan; Chu, Jhih-Wei; Hsu, Chao-Ping; Wu, Shu-Hsing

2016-10-13

A double-negative feedback loop formed by the morning genes CIRCADIAN CLOCK ASSOCIATED1 (CCA1)/LATE ELONGATED HYPOCOTYL (LHY) and the evening gene TIMING OF CAB EXPRESSION1 (TOC1) contributes to regulation of the circadian clock in Arabidopsis. A 24-h circadian cycle starts with the peak expression of CCA1 at dawn. Although CCA1 is targeted by multiple transcriptional repressors, including PSEUDO-RESPONSE REGULATOR9 (PRR9), PRR7, PRR5 and CCA1 HIKING EXPEDITION (CHE), activators of CCA1 remain elusive. Here we use mathematical modelling to infer a co-activator role for LIGHT-REGULATED WD1 (LWD1) in CCA1 expression. We show that the TEOSINTE BRANCHED 1-CYCLOIDEA-PCF20 (TCP20) and TCP22 proteins act as LWD-interacting transcriptional activators. The concomitant binding of LWD1 and TCP20/TCP22 to the TCP-binding site in the CCA1 promoter activates CCA1. Our study reveals activators of the morning gene CCA1 and provides an action mechanism that ensures elevated expression of CCA1 at dawn to sustain a robust clock.

LWD–TCP complex activates the morning gene CCA1 in Arabidopsis

PubMed Central

Wu, Jing-Fen; Tsai, Huang-Lung; Joanito, Ignasius; Wu, Yi-Chen; Chang, Chin-Wen; Li, Yi-Hang; Wang, Ying; Hong, Jong Chan; Chu, Jhih-Wei; Hsu, Chao-Ping; Wu, Shu-Hsing

2016-01-01

A double-negative feedback loop formed by the morning genes CIRCADIAN CLOCK ASSOCIATED1 (CCA1)/LATE ELONGATED HYPOCOTYL (LHY) and the evening gene TIMING OF CAB EXPRESSION1 (TOC1) contributes to regulation of the circadian clock in Arabidopsis. A 24-h circadian cycle starts with the peak expression of CCA1 at dawn. Although CCA1 is targeted by multiple transcriptional repressors, including PSEUDO-RESPONSE REGULATOR9 (PRR9), PRR7, PRR5 and CCA1 HIKING EXPEDITION (CHE), activators of CCA1 remain elusive. Here we use mathematical modelling to infer a co-activator role for LIGHT-REGULATED WD1 (LWD1) in CCA1 expression. We show that the TEOSINTE BRANCHED 1-CYCLOIDEA-PCF20 (TCP20) and TCP22 proteins act as LWD-interacting transcriptional activators. The concomitant binding of LWD1 and TCP20/TCP22 to the TCP-binding site in the CCA1 promoter activates CCA1. Our study reveals activators of the morning gene CCA1 and provides an action mechanism that ensures elevated expression of CCA1 at dawn to sustain a robust clock. PMID:27734958

Strength and fracture mechanism of iron reinforced tricalcium phosphate cermet fabricated by spark plasma sintering.

PubMed

Tkachenko, Serhii; Horynová, Miroslava; Casas-Luna, Mariano; Diaz-de-la-Torre, Sebastian; Dvořák, Karel; Celko, Ladislav; Kaiser, Jozef; Montufar, Edgar B

2018-05-01

The present work studies the microstructure and mechanical performance of tricalcium phosphate (TCP) based cermet toughened by iron particles. A novelty arises by the employment of spark plasma sintering for fabrication of the cermet. Results showed partial transformation of initial alpha TCP matrix to beta phase and the absence of oxidation of iron particles, as well as a lack of chemical reaction between TCP and iron components during sintering. The values of compressive and tensile strength of TCP/Fe cermet were 3.2 and 2.5 times, respectively, greater than those of monolithic TCP. Fracture analysis revealed the simultaneous action of crack-bridging and crack-deflection microstructural toughening mechanisms under compression. In contrast, under tension the reinforcing mechanism was only crack-bridging, being the reason for smaller increment of strength. Elastic properties of the cermet better matched values reported for human cortical bone. Thereby the new TCP/Fe cermet has potential for eventual use as a material for bone fractures fixation under load-bearing conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Basic research and clinical application of beta-tricalcium phosphate (β-TCP).

PubMed

Tanaka, T; Komaki, H; Chazono, M; Kitasato, S; Kakuta, A; Akiyama, S; Marumo, K

2017-09-01

The mechanism of bone substitute resorption involves two processes: solution-mediated and cell-mediated disintegration. In our previous animal studies, the main resorption process of beta-tricalcium phosphate (β-TCP) was considered to be cell-mediated disintegration by TRAP-positive cells. Thus, osteoclast-mediated resorption of β-TCP is important for enabling bone formation. We also report the results of treatment with β-TCP graft in patients since 1989. Two to three weeks after implantation, resorption of β-TCP occurred from the periphery, and then continued toward the center over time. Complete or nearly complete bone healing was achieved in most cases within a few years and was dependent upon the amount of implanted material, the patient's age, and the type of bone (cortical or cancellous). We have previously reported that an injectable complex of β-TCP granules and collagen supplemented with rhFGF-2 enabled cortical bone regeneration of rabbit tibiae. Based on the experimental results, we applied this technique to the patients with femoral and humeral fractures in elderly patients, and obtained bone union. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

High time for a roll call: gene duplication and phylogenetic relationships of TCP-like genes in monocots

PubMed Central

Mondragón-Palomino, Mariana; Trontin, Charlotte

2011-01-01

Background and Aims The TCP family is an ancient group of plant developmental transcription factors that regulate cell division in vegetative and reproductive structures and are essential in the establishment of flower zygomorphy. In-depth research on eudicot TCPs has documented their evolutionary and developmental role. This has not happened to the same extent in monocots, although zygomorphy has been critical for the diversification of Orchidaceae and Poaceae, the largest families of this group. Investigating the evolution and function of TCP-like genes in a wider group of monocots requires a detailed phylogenetic analysis of all available sequence information and a system that facilitates comparing genetic and functional information. Methods The phylogenetic relationships of TCP-like genes in monocots were investigated by analysing sequences from the genomes of Zea mays, Brachypodium distachyon, Oryza sativa and Sorghum bicolor, as well as EST data from several other monocot species. Key Results All available monocot TCP-like sequences are associated in 20 major groups with an average identity ≥64 % and most correspond to well-supported clades of the phylogeny. Their sequence motifs and relationships of orthology were documented and it was found that 67 % of the TCP-like genes of Sorghum, Oryza, Zea and Brachypodium are in microsyntenic regions. This analysis suggests that two rounds of whole genome duplication drove the expansion of TCP-like genes in these species. Conclusions A system of classification is proposed where putative or recognized monocot TCP-like genes are assigned to a specific clade of PCF-, CIN- or CYC/tb1-like genes. Specific biases in sequence data of this family that must be tackled when studying its molecular evolution and phylogeny are documented. Finally, the significant retention of duplicated TCP genes from Zea mays is considered in the context of balanced gene drive. PMID:21444336

Applying a Hypoxia-Incorporating TCP Model to Experimental Data on Rat Sarcoma

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

Ruggieri, Ruggero, E-mail: ruggieri.ruggero@gmail.com; Stavreva, Nadejda; Naccarato, Stefania

2012-08-01

Purpose: To verify whether a tumor control probability (TCP) model which mechanistically incorporates acute and chronic hypoxia is able to describe animal in vivo dose-response data, exhibiting tumor reoxygenation. Methods and Materials: The investigated TCP model accounts for tumor repopulation, reoxygenation of chronic hypoxia, and fluctuating oxygenation of acute hypoxia. Using the maximum likelihood method, the model is fitted to Fischer-Moulder data on Wag/Rij rats, inoculated with rat rhabdomyosarcoma BA1112, and irradiated in vivo using different fractionation schemes. This data set is chosen because two of the experimental dose-response curves exhibit an inverse dose behavior, which is interpreted as duemore » to reoxygenation. The tested TCP model is complex, and therefore, in vivo cell survival data on the same BA1112 cell line from Reinhold were added to Fischer-Moulder data and fitted simultaneously with a corresponding cell survival function. Results: The obtained fit to the combined Fischer-Moulder-Reinhold data was statistically acceptable. The best-fit values of the model parameters for which information exists were in the range of published values. The cell survival curves of well-oxygenated and hypoxic cells, computed using the best-fit values of the radiosensitivities and the initial number of clonogens, were in good agreement with the corresponding in vitro and in situ experiments of Reinhold. The best-fit values of most of the hypoxia-related parameters were used to recompute the TCP for non-small cell lung cancer patients as a function of the number of fractions, TCP(n). Conclusions: The investigated TCP model adequately describes animal in vivo data exhibiting tumor reoxygenation. The TCP(n) curve computed for non-small cell lung cancer patients with the best-fit values of most of the hypoxia-related parameters confirms previously obtained abrupt reduction in TCP for n < 10, thus warning against the adoption of severely hypofractionated schedules.« less

The effectiveness of the controlled release of simvastatin from β-TCP macrosphere in the treatment of OVX mice.

PubMed

Chou, Joshua; Ito, Tomoko; Otsuka, Makoto; Ben-Nissan, Besim; Milthorpe, Bruce

2016-03-01

Simvastatin, a cholesterol treatment drug, has been shown to stimulate bone regeneration. As such, there has been an increase interest in the development of suitable materials and systems for the delivery of simvastatin. Without the appropriate dosage of simvastatin, the therapeutic effects on bone growth will be significantly reduced. Furthermore, similar to many pharmaceutical compounds, at high concentration simvastatin can cause various adverse side-effects. Given the associated side-effects with the usage of simvastatin, the development of suitable controlled drug release system is pertinent. Calcium phosphate in particularly beta-tricalcium phosphate (β-TCP) has been extensively studied and used as a carrier material for drug delivery system. In this study, Foraminifera exoskeletons were used as calcium carbonate precursor materials, which were hydrothermally converted to β-TCP as a carrier material for simvastatin. Natural marine exoskeletons posses interconnected and uniformly porous network capable of improving drug loading and release rate. To prolong the release of simvastatin, an apatite coating was made around the β-TCP sample and in vitro release studies in simulated body fluid (SBF) showed a significant decrease in release rate. Osteoporotic mice were used to examine the compare therapeutic effectiveness of β-TCP, β-TCP with simvastatin, apatite-coated β-TCP with simvastatin and direct injection of simvastatin near the right femur of the mice. Localized and systemic effect were compared with the femur of the non-implanted side (left) and showed that β-TCP with or without simvastatin was able to induce significant bone formation over 6 weeks. Mechanical analysis showed that apatite-coated β-TCP with simvastatin produced significantly stronger bones compared with other experimental groups. This study shows that natural exoskeletons with the appropriate structure can be successfully used as a drug delivery system for simvastatin and can its release can be prolonged with an apatite coating to significantly promote relevant bone formation. Copyright © 2013 John Wiley & Sons, Ltd.

Osteointegration of PLGA implants with nanostructured or microsized β-TCP particles in a minipig model.

PubMed

Kulkova, Julia; Moritz, Niko; Suokas, Esa O; Strandberg, Niko; Leino, Kari A; Laitio, Timo T; Aro, Hannu T

2014-12-01

Bioresorbable suture anchors and interference screws have certain benefits over equivalent titanium-alloy implants. However, there is a need for compositional improvement of currently used bioresorbable implants. We hypothesized that implants made of poly(l-lactide-co-glycolide) (PLGA) compounded with nanostructured particles of beta-tricalcium phosphate (β-TCP) would induce stronger osteointegration than implants made of PLGA compounded with microsized β-TCP particles. The experimental nanostructured self-reinforced PLGA (85L:15G)/β-TCP composite was made by high-energy ball-milling. Self-reinforced microsized PLGA (95L:5G)/β-TCP composite was prepared by melt-compounding. The composites were characterized by gas chromatography, Ubbelohde viscometry, scanning electron microscopy, laser diffractometry, and standard mechanical tests. Four groups of implants were prepared for the controlled laboratory study employing a minipig animal model. Implants in the first two groups were prepared from nanostructured and microsized PLGA/β-TCP composites respectively. Microroughened titanium-alloy (Ti6Al4V) implants served as positive intra-animal control, and pure PLGA implants as negative control. Cone-shaped implants were inserted in a random order unilaterally in the anterior cortex of the femoral shaft. Eight weeks after surgery, the mechanical strength of osteointegration of the implants was measured by a push-out test. The quality of new bone surrounding the implant was assessed by microcomputed tomography and histology. Implants made of nanostructured PLGA/β-TCP composite did not show improved mechanical osteointegration compared with the implants made of microsized PLGA/β-TCP composite. In the intra-animal comparison, the push-out force of two PLGA/β-TCP composites was 35-60% of that obtained with Ti6Al4V implants. The implant materials did not result in distinct differences in quality of new bone surrounding the implant. Copyright © 2014 Elsevier Ltd. All rights reserved.

Study and Simulation of Enhancements for TCP (Transmission Control Protocol) Performance Over Noisy, High-Latency Links

NASA Technical Reports Server (NTRS)

Shepard, Timothy J.; Partridge, Craig; Coulter, Robert

1997-01-01

The designers of the TCP/IP protocol suite explicitly included support of satellites in their design goals. The goal of the Internet Project was to design a protocol which could be layered over different networking technologies to allow them to be concatenated into an internet. The results of this project included two protocols, IP and TCP. IP is the protocol used by all elements in the network and it defines the standard packet format for IP datagrams. TCP is the end-to-end transport protocol commonly used between end systems on the Internet to derive a reliable bi-directional byte-pipe service from the underlying unreliable IP datagram service. Satellite links are explicitly mentioned in Vint Cerf's 2-page article which appeared in 1980 in CCR [2] to introduce the specifications for IP and TCP. In the past fifteen years, TCP has been demonstrated to work over many differing networking technologies, including over paths including satellites links. So if satellite links were in the minds of the designers from the beginning, what is the problem? The problem is that the performance of TCP has in some cases been disappointing. A goal of the authors of the original specification of TCP was to specify only enough behavior to ensure interoperability. The specification left a number of important decisions, in particular how much data is to be sent when, to the implementor. This was deliberately' done. By leaving performance-related decisions to the implementor, this would allow the protocol TCP to be tuned and adapted to different networks and situations in the future without the need to revise the specification of the protocol, or break interoperability. Interoperability would continue while future implementations would be allowed flexibility to adapt to needs which could not be anticipated at the time of the original protocol design.

Baghdadite ceramics modulate the cross talk between human adipose stem cells and osteoblasts for bone regeneration.

PubMed

Lu, Zufu; Wang, Guocheng; Roohani-Esfahani, Iman; Dunstan, Colin R; Zreiqat, Hala

2014-03-01

Understanding interactions among the three elements (cells, scaffolds, and bioactive factors) is critical for successful tissue engineering. This study was aimed to investigate how scaffolds would affect osteogenic gene expression in human adipose tissue-derived stem cells (ASCs) or human primary osteoblasts (HOBs), and their cross talk. Either ASCs or HOBs were seeded on Baghdadite (Ca3ZrSi2O9) and hydroxyapatite/tricalcium phosphate (HA/TCP) scaffolds, and osteogenic gene expression was assessed. To further evaluate how substrate affected HOB and ASC cross talk, an indirect co-culture system with semipermeable inserts placed on the culture plate was set up to co-culture ASCs or HOBs, which were grown in monolayer or seeded on Baghdadite or HA/TCP scaffolds, and osteogenic differentiation of the cells was assessed. We found that Baghdadite scaffolds induced a significantly greater increase in RUNX2, osteopontin, bone sialoprotein, and osteocalcin gene expression in HOBs in comparison to HA/TCP scaffolds; Baghdadite scaffolds also significantly induced RUNX2 and osteopontin, but not bone sialoprotein and osteocalcin gene expression in ASCs. In the co-culture system, the HOBs on Baghdadite scaffolds more markedly promoted osteogenic gene expression in ASCs compared to HOBs in monolayer or the HOBs on HA/TCP scaffolds. In addition, the ASCs seeded on Baghdadite scaffolds more markedly promoted osteogenic gene expression in HOBs than did the ASCs on HA/TCP scaffolds. BMP-2 expression in ASCs or HOBs was increased when they were seeded on Baghdadite scaffolds, and adding Noggin into the co-culture medium largely abrogated Baghdadite scaffold-modulated ASC-HOB cross talk. In summary, Baghdadite scaffolds not only promote the osteogenic differentiation of HOBs or ASCs but also modulate the cross talk between ASCs and HOBs, in part via increasing BMP2 expression, thereby promoting their osteogenic differentiation.

Regulation and Biological Significance of Formation of Osteoclasts and Foreign Body Giant Cells in an Extraskeletal Implantation Model

PubMed Central

Ahmed, Gazi Jased; Tatsukawa, Eri; Morishita, Kota; Shibata, Yasuaki; Suehiro, Fumio; Kamitakahara, Masanobu; Yokoi, Taishi; Koji, Takehiko; Umeda, Masahiro; Nishimura, Masahiro; Ikeda, Tohru

2016-01-01

The implantation of biomaterials induces a granulomatous reaction accompanied by foreign body giant cells (FBGCs). The characterization of multinucleated giant cells (MNGCs) around bone substitutes implanted in bone defects is more complicated because of healing with bone admixed with residual bone substitutes and their hybrid, and the appearance of two kinds of MNGCs, osteoclasts and FBGCs. Furthermore, the clinical significance of osteoclasts and FBGCs in the healing of implanted regions remains unclear. The aim of the present study was to characterize MNGCs around bone substitutes using an extraskeletal implantation model and evaluate the clinical significance of osteoclasts and FBGCs. Beta-tricalcium phosphate (β-TCP) granules were implanted into rat subcutaneous tissue with or without bone marrow mesenchymal cells (BMMCs), which include osteogenic progenitor cells. We also compared the biological significance of plasma and purified fibrin, which were used as binders for implants. Twelve weeks after implantation, osteogenesis was only detected in specimens implanted with BMMCs. The expression of two typical osteoclast markers, tartrate-resistant acid phosphatase (TRAP) and cathepsin-K (CTSK), was analyzed, and TRAP-positive and CTSK-positive osteoclasts were only detected beside bone. In contrast, most of the MNGCs in specimens without the implantation of BMMCs were FBGCs that were negative for TRAP, whereas the degradation of β-TCP was detected. In the region implanted with β-TCP granules with plasma, FBGCs tested positive for CTSK, and when β-TCP granules were implanted with purified fibrin, FBGCs tested negative for CTSK. These results showed that osteogenesis was essential to osteoclastogenesis, two kinds of FBGCs, CTSK-positive and CTSK-negative, were induced, and the expression of CTSK was plasma-dependent. In addition, the implantation of BMMCs was suggested to contribute to osteogenesis and the replacement of implanted β-TCP granules to bone. PMID:27462135

Analysis of Malicious Traffic in Modbus/TCP Communications

NASA Astrophysics Data System (ADS)

Kobayashi, Tiago H.; Batista, Aguinaldo B.; Medeiros, João Paulo S.; Filho, José Macedo F.; Brito, Agostinho M.; Pires, Paulo S. Motta

This paper presents the results of our analysis about the influence of Information Technology (IT) malicious traffic on an IP-based automation environment. We utilized a traffic generator, called MACE (Malicious trAffic Composition Environment), to inject malicious traffic in a Modbus/TCP communication system and a sniffer to capture and analyze network traffic. The realized tests show that malicious traffic represents a serious risk to critical information infrastructures. We show that this kind of traffic can increase latency of Modbus/TCP communication and that, in some cases, can put Modbus/TCP devices out of communication.

Study on different characteristics of doped tri calcium phosphate at different sintering temperatures

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

Samanta, Sujan Krishna, E-mail: itssujan@rediffmail.com; Chanda, Abhijit, E-mail: abhijitchanda.biomed@gmail.com

2016-04-13

Pure β-tricalcium phosphate (β-TCP), Zn-doped (3wt %) β-TCP and Mg- doped (3wt %) β-TCP samples were prepared by using a wet chemical precipitation synthesis technique, followed by calcination at 800 °C in air. The developed materials were subjected to sintering at different temperatures. Density and porosity were compared. The X-ray diffractometry (XRD) and Fourier-transformed infrared (FTIR) spectrometer were used to examine the changes in crystalline phases and presence of functional groups of TCP ceramics. The scanning electron microscopy (SEM) was used to study the pore formation, pore size, grain size.

Collagenous matrix supported by a 3D-printed scaffold for osteogenic differentiation of dental pulp cells.

PubMed

Fahimipour, Farahnaz; Dashtimoghadam, Erfan; Rasoulianboroujeni, Morteza; Yazdimamaghani, Mostafa; Khoshroo, Kimia; Tahriri, Mohammadreza; Yadegari, Amir; Gonzalez, Jose A; Vashaee, Daryoosh; Lobner, Douglas C; Jafarzadeh Kashi, Tahereh S; Tayebi, Lobat

2018-02-01

A systematic characterization of hybrid scaffolds, fabricated based on combinatorial additive manufacturing technique and freeze-drying method, is presented as a new platform for osteoblastic differentiation of dental pulp cells (DPCs). The scaffolds were consisted of a collagenous matrix embedded in a 3D-printed beta-tricalcium phosphate (β-TCP) as the mineral phase. The developed construct design was intended to achieve mechanical robustness owing to 3D-printed β-TCP scaffold, and biologically active 3D cell culture matrix pertaining to the Collagen extracellular matrix. The β-TCP precursor formulations were investigated for their flow-ability at various temperatures, which optimized for fabrication of 3D printed scaffolds with interconnected porosity. The hybrid constructs were characterized by 3D laser scanning microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and compressive strength testing. The in vitro characterization of scaffolds revealed that the hybrid β-TCP/Collagen constructs offer superior DPCs proliferation and alkaline phosphatase (ALP) activity compared to the 3D-printed β-TCP scaffold over three weeks. Moreover, it was found that the incorporation of TCP into the Collagen matrix improves the ALP activity. The presented results converge to suggest the developed 3D-printed β-TCP/Collagen hybrid constructs as a new platform for osteoblastic differentiation of DPCs for craniomaxillofacial bone regeneration. Copyright © 2017. Published by Elsevier Ltd.

Soybean TCP transcription factors: Evolution, classification, protein interaction and stress and hormone responsiveness.

PubMed

Feng, Zhi-Juan; Xu, Sheng-Chun; Liu, Na; Zhang, Gu-Wen; Hu, Qi-Zan; Gong, Ya-Ming

2018-06-01

TEOSINTE-BRANCHED1/CYCLOIDEA/PCF (TCP) transcription factors, a family of plant-specific proteins, play crucial roles in plant growth and development and stress response. However, systematical information is unknown regarding the TCP gene family in soybean. In the present study, a total of 54 GmTCPs were identified in soybean, which were grouped into 11 groups with the typical TCP conserved domains. Phylogenetic relationship, protein motif and gene structure analyses distinguished the GmTCPs into two homology classes: Class I and Class II. Class II was then differentiated into two subclasses: CIN and CYC/TB1. Unique cis-element number and composition existed in the promoter regions which might be involved in the gene transcriptional regulation of different GmTCPs. Tissue expression analysis demonstrated the diverse spatiotemporal expression profiles of GmTCPs. Furthermore, the interaction protein of one previously functionally unknown TCP protein-GmTCP8 was investigated. Yeast two-hybrid assay showed the interaction between GmTCP8 and an abscisic acid receptor (GmPYL10). QRT-PCR assays indicated the distinct expression profiles of GmTCPs in response to abiotic stresses (heat, drought and salt) and stress-related signals (abscisic acid, brassinolide, salicylicacid and methyl jasmonate). These results will facilitate to uncover the possible roles of GmTCPs under abiotic stress and hormone signal responses in soybean. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

In Vitro and In Vivo Dentinogenic Efficacy of Human Dental Pulp-Derived Cells Induced by Demineralized Dentin Matrix and HA-TCP

PubMed Central

Kang, Kyung-Jung; Lee, Min Suk; Moon, Chan-Woong; Lee, Jae-Hoon

2017-01-01

Human dental pulp cells have been known to have the stem cell features such as self-renewal and multipotency. These cells are differentiated into hard tissue by addition of proper cytokines and biomaterials. Hydroxyapatite-tricalcium phosphates (HA-TCPs) are essential components of hard tissue and generally used as a biocompatible material in tissue engineering of bone. Demineralized dentin matrix (DDM) has been reported to increase efficiency of bone induction. We compared the efficiencies of osteogenic differentiation and in vivo bone formation of HA-TCP and DDM on human dental pulp stem cells (hDPSCs). DDM contains inorganic components as with HA-TCP, and organic components such as collagen type-1. Due to these components, osteoinduction potential of DDM on hDPSCs was remarkably higher than that of HA-TCP. However, the efficiencies of in vivo bone formation are similar in HA-TCP and DDM. Although osteogenic gene expression and bone formation in immunocompromised nude mice were similar levels in both cases, dentinogenic gene expression level was slightly higher in DDM transplantation than in HA-TCP. All these results suggested that in vivo osteogenic potentials in hDPSCs are induced with both HA-TCP and DDM by osteoconduction and osteoinduction, respectively. In addition, transplantation of hDPSCs/DDM might be more effective for differentiation into dentin. PMID:28761445

High porous titanium scaffolds showed higher compatibility than lower porous beta-tricalcium phosphate scaffolds for regulating human osteoblast and osteoclast differentiation.

PubMed

Hirota, Makoto; Hayakawa, Tohru; Shima, Takaki; Ametani, Akihiro; Tohnai, Iwai

2015-04-01

We compared osteoblast and osteoclast differentiation when using beta-tricalcium phosphate (βTCP) and titanium scaffolds by investigating human mesenchymal stem cells (hMSCs) and osteoclast progenitor cell activities. hMSCs were cultured for 7, 14, and 21days on titanium scaffolds with 60%, 73%, and 87% porosity and on βTCP scaffolds with 60% and 75% porosity. Human osteoclast progenitor cells were cultured with osteoblast for 14 and 21days on 87% titanium and 75% βTCP scaffolds. Viable cell numbers with 60% and 73% titanium were higher than with 87% titanium and βTCP scaffolds (P<0.05). An 87% titanium scaffold resulted in the highest osteocalcin production with calcification on day 14 (P<0.01) in titanium scaffolds. All titanium scaffolds resulted in higher osteocalcin production on days 7 and 14 compared to βTCP scaffolds (P<0.01). Osteoblasts cultured on 87% titanium scaffolds suppressed osteoclast differentiation on day 7 but enhanced osteoclast differentiation on day 14 compared to 75% βTCP scaffolds (P<0.01). These findings concluded that high porosity titanium scaffolds could enhance progression of hMSC/osteoblast differentiation and regulated osteoclast differentiation cooperating with osteoblast differentiation for calcification as compared with lower porous βTCP. Copyright © 2015 Elsevier B.V. All rights reserved.

In Vitro and In Vivo Dentinogenic Efficacy of Human Dental Pulp-Derived Cells Induced by Demineralized Dentin Matrix and HA-TCP.

PubMed

Kang, Kyung-Jung; Lee, Min Suk; Moon, Chan-Woong; Lee, Jae-Hoon; Yang, Hee Seok; Jang, Young-Joo

2017-01-01

Human dental pulp cells have been known to have the stem cell features such as self-renewal and multipotency. These cells are differentiated into hard tissue by addition of proper cytokines and biomaterials. Hydroxyapatite-tricalcium phosphates (HA-TCPs) are essential components of hard tissue and generally used as a biocompatible material in tissue engineering of bone. Demineralized dentin matrix (DDM) has been reported to increase efficiency of bone induction. We compared the efficiencies of osteogenic differentiation and in vivo bone formation of HA-TCP and DDM on human dental pulp stem cells (hDPSCs). DDM contains inorganic components as with HA-TCP, and organic components such as collagen type-1. Due to these components, osteoinduction potential of DDM on hDPSCs was remarkably higher than that of HA-TCP. However, the efficiencies of in vivo bone formation are similar in HA-TCP and DDM. Although osteogenic gene expression and bone formation in immunocompromised nude mice were similar levels in both cases, dentinogenic gene expression level was slightly higher in DDM transplantation than in HA-TCP. All these results suggested that in vivo osteogenic potentials in hDPSCs are induced with both HA-TCP and DDM by osteoconduction and osteoinduction, respectively. In addition, transplantation of hDPSCs/DDM might be more effective for differentiation into dentin.

Bioremediation of soils co-contaminated with heavy metals and 2,4,5-trichlorophenol by fruiting body of Clitocybe maxima.

PubMed

Liu, Hongying; Guo, Shanshan; Jiao, Kai; Hou, Junjun; Xie, Han; Xu, Heng

2015-08-30

Pot experiments were performed to investigate the single effect of 2,4,5-trichlorophenol (TCP) or heavy metals (Cu, Cd, Cu+Cd) and the combined effects of metals-TCP on the growth of Clitocybe maxima together with the accumulation of heavy metals as well as dissipation of TCP. Results showed a negative effect of contaminations on fruiting time and biomass of the mushroom. TCP decreased significantly in soils accounting for 70.66-96.24% of the initial extractable concentration in planted soil and 66.47-91.42% in unplanted soil, which showed that the dissipation of TCP was enhanced with mushroom planting. Higher biological activities (bacterial counts, soil respiration and laccase activity) were detected in planted soils relative to unplanted controls, and the enhanced dissipation of TCP in planted soils might be derived from the increased biological activities. The metals accumulation in mushroom increased with the augment of metal load, and the proportion of acetic acid (HOAc) extractable metal in soils with C. maxima was larger than that in unplanted soils, which may be an explanation of metal uptake by C. maxima. These results suggested that the presence of C. maxima was effective in promoting the bioremediation of soil contaminated with heavy metals and TCP. Copyright © 2015 Elsevier B.V. All rights reserved.

Trend Analyses of Major Contributions in "The Counseling Psychologist" Cited From 1986 to 1996: Impact and Implications.

ERIC Educational Resources Information Center

Flores, Lisa Y.; Rooney, S. Craig; Heppner, P. Paul; Browne, LaVonne Douglas; Wei, Mei-Fen

1999-01-01

This study commemorates the 30th anniversary of "The Counseling Psychologist" (TCP). Analyzes trends in the professional citations of the Major Contribution articles from the inception of TCP in 1969 through 1995. Results and implications are discussed with regard to professional issues, "TCP," and future research. (GCP)

78 FR 46368 - Certain Dimmable Compact Fluorescent Lamps and Products Containing Same; Termination of an...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-31

...; Zhejiang Qiang Ling Electronic Co. Ltd. of Zhenjiang, China (collectively, ``TCP''); U Lighting America Inc... of the '318 patent have been asserted against TCP. On February 27, 2013, the ALJ issued his final... domestic industry requirement of section 337. The ALJ also found that respondent TCP's accused products do...

Continued Development of Internet Protocols under the IBM OS/MVS Operating System

DTIC Science & Technology

1985-01-25

developed a prototype TCP/IP implementation for an IBM MVS host under a previous DARPA contract’ as part of the Internet research effort on the design of...participated in the DARPA Internet research program which led to the present TCP and IP protocols. Development of a prototype implementation of TCP/IP

Inhibition of osteolysis after local administration of osthole in a TCP particles-induced osteolysis model.

PubMed

Lv, Shumin; Zhang, Yun; Yan, Ming; Mao, Hongjiao; Pan, Cailing; Gan, Mingxiao; Fan, Jiawen; Wang, Guoxia

2016-07-01

Wear debris-induced osteolysis and aseptic loosening are the most frequent late complications of total joint arthroplasty leading to revision of the prosthesis. However, no effective measures for the prevention and treatment of particles-induced osteolysis currently exist. Here, we investigated the efficacy of local administration of osthole on tricalcium phosphate (TCP) particles-induced osteolysis in a murine calvarial model. TCP particles were implanted over the calvaria of ICR mice, and established TCP particles-induced osteolysis model. On days one, four, seven, ten and thirteen post-surgery, osthole (10 mg/kg) or phosphate buffer saline (PBS) were subcutaneously injected into the calvaria of TCP particles-implanted or sham-operated mice. Two weeks later, blood, the periosteum and the calvaria were collected and processed for bone turnover markers, pro-inflammatory cytokine, histomorphometric and molecular analysis. Osthole (10 mg/kg) markedly prevented TCP particles-induced osteoclastogenesis and bone resorption in a mouse calvarial model. Osthole also inhibited the decrease of serum osteocalcin level and calvarial alkaline phosphatase (ALP) activity, and prevented the increase in the activity of tartrate resistant acid phosphatase (TRAP) and cathepsin K in the mouse calvaria. Furthermore, osthole obviously reduced the release of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) into the periosteum. Western blotting demonstrated TCP particles caused a remarkable endoplasmic reticulum (ER) stress response in the mouse calvaria, which was obviously blocked by osthole treatment. These results suggest that local administration of osthole inhibits TCP particles-induced osteolysis in the mouse calvarial in vivo, which may be mediated by inhibition of the ER stress signaling pathway, and it will be developed as a new drug in the prevention and treatment of destructive diseases caused by prosthetic wear particles.

Combining Phylogenetic and Syntenic Analyses for Understanding the Evolution of TCP ECE Genes in Eudicots

PubMed Central

Citerne, Hélène L.; Le Guilloux, Martine; Sannier, Julie; Nadot, Sophie; Damerval, Catherine

2013-01-01

TCP ECE genes encode transcription factors which have received much attention for their repeated recruitment in the control of floral symmetry in core eudicots, and more recently in monocots. Major duplications of TCP ECE genes have been described in core eudicots, but the evolutionary history of this gene family is unknown in basal eudicots. Reconstructing the phylogeny of ECE genes in basal eudicots will help set a framework for understanding the functional evolution of these genes. TCP ECE genes were sequenced in all major lineages of basal eudicots and Gunnera which belongs to the sister clade to all other core eudicots. We show that in these lineages they have a complex evolutionary history with repeated duplications. We estimate the timing of the two major duplications already identified in the core eudicots within a timeframe before the divergence of Gunnera and after the divergence of Proteales. We also use a synteny-based approach to examine the extent to which the expansion of TCP ECE genes in diverse eudicot lineages may be due to genome-wide duplications. The three major core-eudicot specific clades share a number of collinear genes, and their common evolutionary history may have originated at the γ event. Genomic comparisons in Arabidopsis thaliana and Solanum lycopersicum highlight their separate polyploid origin, with syntenic fragments with and without TCP ECE genes showing differential gene loss and genomic rearrangements. Comparison between recently available genomes from two basal eudicots Aquilegia coerulea and Nelumbo nucifera suggests that the two TCP ECE paralogs in these species are also derived from large-scale duplications. TCP ECE loci from basal eudicots share many features with the three main core eudicot loci, and allow us to infer the makeup of the ancestral eudicot locus. PMID:24019982

Suppression of Virulence of Toxigenic Vibrio cholerae by Anethole through the Cyclic AMP (cAMP)-cAMP Receptor Protein Signaling System

PubMed Central

Zahid, M. Shamim Hasan; Awasthi, Sharda Prasad; Asakura, Masahiro; Chatterjee, Shruti; Hinenoya, Atsushi; Faruque, Shah M.; Yamasaki, Shinji

2015-01-01

Use of natural compounds as antivirulence drugs could be an alternative therapeutic approach to modify the outcome of bacterial infections, particularly in view of growing resistance to available antimicrobials. Here, we show that sub-bactericidal concentration of anethole, a component of sweet fennel seed, could suppress virulence potential in O1 El Tor biotype strains of toxigenic Vibrio cholerae, the causative agent of the ongoing 7th cholera pandemic. The expression of cholera toxin (CT) and toxin coregulated pilus (TCP), the major virulence factors of V. cholerae, is controlled through a regulatory cascade involving activation of ToxT with synergistic coupling interaction of ToxR/ToxS with TcpP/TcpH. We present evidence that anethole inhibits in vitro expression of CT and TCP in a toxT-dependent but toxR/toxS-independent manner and through repression of tcpP/tcpH, by using bead-ELISA, western blotting and quantitative real-time RT-PCR assays. The cyclic AMP (cAMP)-cAMP receptor protein (CRP) is a well-studied global signaling system in bacterial pathogens, and this complex is known to suppress expression of tcpP/tcpH in V. cholerae. We find that anethole influences the virulence regulatory cascade by over-expressing cyaA and crp genes. Moreover, suppression of toxigenic V. cholerae-mediated fluid accumulation in ligated ileum of rabbit by anethole demonstrates its potentiality as an antivirulence drug candidate against the diseases caused by toxigenic V. cholerae. Taken altogether, these results revealing a mechanism of virulence inhibition in V. cholerae by the natural compound anethole, may have relevance in designing antivirulence compounds, particularly against multiple antibiotic resistant bacterial pathogens. PMID:26361388

Suppression of Virulence of Toxigenic Vibrio cholerae by Anethole through the Cyclic AMP (cAMP)-cAMP Receptor Protein Signaling System.

PubMed

Zahid, M Shamim Hasan; Awasthi, Sharda Prasad; Asakura, Masahiro; Chatterjee, Shruti; Hinenoya, Atsushi; Faruque, Shah M; Yamasaki, Shinji

2015-01-01

Use of natural compounds as antivirulence drugs could be an alternative therapeutic approach to modify the outcome of bacterial infections, particularly in view of growing resistance to available antimicrobials. Here, we show that sub-bactericidal concentration of anethole, a component of sweet fennel seed, could suppress virulence potential in O1 El Tor biotype strains of toxigenic Vibrio cholerae, the causative agent of the ongoing 7th cholera pandemic. The expression of cholera toxin (CT) and toxin coregulated pilus (TCP), the major virulence factors of V. cholerae, is controlled through a regulatory cascade involving activation of ToxT with synergistic coupling interaction of ToxR/ToxS with TcpP/TcpH. We present evidence that anethole inhibits in vitro expression of CT and TCP in a toxT-dependent but toxR/toxS-independent manner and through repression of tcpP/tcpH, by using bead-ELISA, western blotting and quantitative real-time RT-PCR assays. The cyclic AMP (cAMP)-cAMP receptor protein (CRP) is a well-studied global signaling system in bacterial pathogens, and this complex is known to suppress expression of tcpP/tcpH in V. cholerae. We find that anethole influences the virulence regulatory cascade by over-expressing cyaA and crp genes. Moreover, suppression of toxigenic V. cholerae-mediated fluid accumulation in ligated ileum of rabbit by anethole demonstrates its potentiality as an antivirulence drug candidate against the diseases caused by toxigenic V. cholerae. Taken altogether, these results revealing a mechanism of virulence inhibition in V. cholerae by the natural compound anethole, may have relevance in designing antivirulence compounds, particularly against multiple antibiotic resistant bacterial pathogens.

Transient transcriptional activation of the Vibrio cholerae El Tor virulence regulator toxT in response to culture conditions.

PubMed

Medrano, A I; DiRita, V J; Castillo, G; Sanchez, J

1999-05-01

Vibrio cholerae El Tor require special in vitro culture conditions, consisting of an initial static growth period followed by shift to shaking (AKI conditions), for expression of cholera toxin (CT) and toxin coregulated pili (TCP). ToxT, a regulator whose initial transcription depends on the ToxR regulator, positively modulates expression of CT and TCP. To help understand control of CT and TCP in El Tor vibrios, we monitored ctxAB and ToxR-dependent toxT transcription by time course primer extension assays. AKI conditions stimulated CT synthesis with an absence of ctxAB transcription during static growth followed by induction upon shaking. ToxR-dependent toxT transcription was induced at the end of the static growth period but was transient, stopping shortly after shaking was initiated but, interestingly, also if the static phase was prolonged. Immunoblot assays showed that ToxR protein levels were not coincidentally transient, implying a protein on/off switch mechanism for ToxR. Despite the transient activation by ToxR, transcription of ctxAB was maintained during shaking. This finding suggested continued toxT expression, possibly through relay transcription from another promoter. The 12.6-kb distant upstream tcpA promoter responsible for expression of the TCP operon has been proposed to provide an alternate toxT message by readthrough transcription. Activation of the tcpA promoter is supported by increased expression of TcpA protein during the shaking phase of the culture. Readthrough transcription of toxT from tcpA would be compatible with reverse transcription-PCR evidence for a toxT mRNA at times when ToxR-dependent transcription was no longer detectable by primer extension.

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

Balderson, Michael, E-mail: michael.balderson@rmp.uhn.ca; Brown, Derek; Johnson, Patricia

The purpose of this work was to compare static gantry intensity-modulated radiation therapy (IMRT) with volume-modulated arc therapy (VMAT) in terms of tumor control probability (TCP) under scenarios involving large geometric misses, i.e., those beyond what are accounted for when margin expansion is determined. Using a planning approach typical for these treatments, a linear-quadratic–based model for TCP was used to compare mean TCP values for a population of patients who experiences a geometric miss (i.e., systematic and random shifts of the clinical target volume within the planning target dose distribution). A Monte Carlo approach was used to account for themore » different biological sensitivities of a population of patients. Interestingly, for errors consisting of coplanar systematic target volume offsets and three-dimensional random offsets, static gantry IMRT appears to offer an advantage over VMAT in that larger shift errors are tolerated for the same mean TCP. For example, under the conditions simulated, erroneous systematic shifts of 15 mm directly between or directly into static gantry IMRT fields result in mean TCP values between 96% and 98%, whereas the same errors on VMAT plans result in mean TCP values between 45% and 74%. Random geometric shifts of the target volume were characterized using normal distributions in each Cartesian dimension. When the standard deviations were doubled from those values assumed in the derivation of the treatment margins, our model showed a 7% drop in mean TCP for the static gantry IMRT plans but a 20% drop in TCP for the VMAT plans. Although adding a margin for error to a clinical target volume is perhaps the best approach to account for expected geometric misses, this work suggests that static gantry IMRT may offer a treatment that is more tolerant to geometric miss errors than VMAT.« less

Genome-Wide Identification of TCP Family Transcription Factors in Medicago truncatula Reveals Significant Roles of miR319-Targeted TCPs in Nodule Development

PubMed Central

Wang, Hongfeng; Wang, Hongwei; Liu, Rong; Xu, Yiteng; Lu, Zhichao; Zhou, Chuanen

2018-01-01

TCP proteins, the plant-specific transcription factors, are involved in the regulation of multiple aspects of plant development among different species, such as leaf development, branching, and flower symmetry. However, thus far, the roles of TCPs in legume, especially in nodulation are still not clear. In this study, a genome-wide analysis of TCP genes was carried out to discover their evolution and function in Medicago truncatula. In total, 21 MtTCPs were identified and classified into class I and class II, and the class II MtTCPs were further divided into two subclasses, CIN and CYC/TB1. The expression profiles of MtTCPs are dramatically different. The universal expression of class I MtTCPs was detected in all organs. However, the MtTCPs in CIN subclass were highly expressed in leaf and most of the members in CYC/TB1 subclass were highly expressed in flower. Such organ-specific expression patterns of MtTCPs suggest their different roles in plant development. In addition, most MtTCPs were down-regulated during the nodule development, except for the putative MtmiR319 targets, MtTCP3, MtTCP4, and MtTCP10A. Overexpression of MtmiR319A significantly reduced the expression level of MtTCP3/4/10A/10B and resulted in the decreased nodule number, indicating the important roles of MtmiR319-targeted MtTCPs in nodulation. Taken together, this study systematically analyzes the MtTCP gene family at a genome-wide level and their possible functions in nodulation, which lay the basis for further explorations of MtmiR319/MtTCPs module in association with nodule development in M. truncatula.

SrO- and MgO-doped microwave sintered 3D printed tricalcium phosphate scaffolds: mechanical properties and in vivo osteogenesis in a rabbit model.

PubMed

Tarafder, Solaiman; Dernell, William S; Bandyopadhyay, Amit; Bose, Susmita

2015-04-01

The presence of interconnected macro pores allows guided tissue regeneration in tissue engineering scaffolds. However, highly porous scaffolds suffer from having poor mechanical strength. Previously, we showed that microwave sintering could successfully be used to improve mechanical strength of macro porous tricalcium phosphate (TCP) scaffolds. This study reports the presence of SrO and MgO as dopants in TCP scaffolds improves mechanical and in vivo biological performance. We have used direct three dimensional printing (3DP) technology for scaffold fabrication. These 3DP scaffolds possessed multiscale porosity, that is, 3D interconnected designed macro pores along with intrinsic micro pores. A significant increase in mechanical strength, between 37 and 41%, was achieved due to SrO and MgO doping in TCP as compared with pure TCP. Maximum compressive strengths of 9.38 ± 1.86 MPa and 12.01 ± 1.56 MPa were achieved by conventional and microwave sintering, respectively, for SrO-MgO-doped 3DP scaffolds with 500 μm designed pores. Histomorphological and histomorphometric analysis revealed a significantly higher osteoid, bone and haversian canal formation induced by the presence of SrO and MgO dopants in 3DP TCP as compared with pure TCP scaffolds when tested in rabbit femoral condyle defect model. Increased osteon and thus enhanced network of blood vessel formation, and osteocalcin expression were observed in the doped TCP scaffolds. Our results show that these 3DP SrO-MgO-doped TCP scaffolds have the potential for early wound healing through accelerated osteogenesis and vasculogenesis. © 2014 Wiley Periodicals, Inc.

Enhanced bone regeneration composite scaffolds of PLLA/β-TCP matrix grafted with gelatin and HAp.

PubMed

Wang, Jie-Lin; Chen, Qian; Du, Bei-Bei; Cao, Lu; Lin, Hong; Fan, Zhong-Yong; Dong, Jian

2018-06-01

The composite polylactide PLLA/β-TCP scaffolds were fabricated by solution casting and were coated with gelatin/hydroxyapatite (Gel/HAp) to improve the biological properties of the composite scaffolds. The Gel/HAp mixture was prepared using an in situ reaction, and a grafting-coating method was used to increase the efficiency of coating the PLLA/β-TCP matrix with Gel/HAp. First, free amino groups were introduced by 1,6-hexanediamine to aminolyze the PLLA/β-TCP matrix surface. Second, glutaraldehyde was coupled to Gel/HAp as a crosslinking agent. The structure and properties of Gel/HAp-modified PLLA/β-TCP films were characterized by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and water contact angle measurements (WCA). The experimental results show that 23 wt% HAp was uniformly dispersed in the gelatin coating by in situ synthesis. The Gel/HAp composite coating was successfully immobilized on the aminolyzed PLLA/β-TCP surface via a chemical grafting method, which promoted a lower degradation rate and was more hydrophilic than a physical grafting method. The Gel/HAp composite coating adhered tightly and homogeneously to the hydrophobic PLLA/β-TCP surface. Moreover, mouse embryo osteoblast precursor (MC3T3-E1) cells grown on the scaffolds were behaviorally and morphologically characterized. The results indicated that the Gel/HAp composite coating was favorable for the attachment and proliferation of preosteoblasts and that Gel/HAp-NH-PLLA/β-TCP would be a candidate scaffold for bone repair. Copyright © 2018 Elsevier B.V. All rights reserved.

Bioresorbable β-TCP-FeAg nanocomposites for load bearing bone implants: High pressure processing, properties and cell compatibility.

PubMed

Swain, S K; Gotman, I; Unger, R; Gutmanas, E Y

2017-09-01

In this paper, the processing and properties of iron-toughened bioresorbable β-tricalcium phosphate (β-TCP) nanocomposites are reported. β-TCP is chemically similar to bone mineral and thus a good candidate material for bioresorbable bone healing devices; however intrinsic brittleness and low bending strength make it unsuitable for use in load-bearing sites. Near fully dense β-TCP-matrix nanocomposites containing 30vol% Fe, with and without addition of silver, were produced employing high energy attrition milling of powders followed by high pressure consolidation/cold sintering at 2.5GPa. In order to increase pure iron's corrosion rate, 10 to 30vol% silver were added to the metal phase. The degradation behavior of the developed composite materials was studied by immersion in Ringer's and saline solutions for up to 1month. The mechanical properties, before and after immersion, were tested in compression and bending. All the compositions exhibited high mechanical strength, the strength in bending being several fold higher than that of polymer toughened β-TCP-30PLA nanocomposites prepared by the similar procedure of attrition milling and cold sintering, and of pure high-temperature sintered β-TCP. Partial substitution of iron with silver led to an increase in both strength and ductility. Furthermore, the galvanic action of silver particles dispersed in the iron phase significantly accelerated in vitro degradation of β-TCP-30(Fe-Ag) nanocomposites. After 1month immersion, the composites retained about 50% of their initial bending strength. In cell culture experiments, β-TCP-27Fe3Ag nanocomposites exhibited no signs of cytotoxicity towards human osteoblasts suggesting that they can be used as an implant material. Copyright © 2017 Elsevier B.V. All rights reserved.

Upregulation of cell proliferation via Shc and ERK1/2 MAPK signaling in SaOS-2 osteoblasts grown on magnesium alloy surface coating with tricalcium phosphate.

PubMed

Jiang, Tianlong; Guo, Lei; Ni, Shenghui; Zhao, Yuyan

2015-04-01

Magnesium (Mg) alloys have been demonstrated to be viable orthopedic implants because of mechanical and biocompatible properties similar to natural bone. In order to improve its osteogenic properties, a porous β-tricalcium phosphate (β-TCP) was coated on the Mg-3AI-1Zn alloy by alkali-heat treatment technique. The human bone-derived cells (SaOS-2) were cultured on (β-TCP)-Mg-3AI-1Zn in vitro, and the osteoblast response, the morphology and the elements on this alloy surface were investigated. Also, the regulation of key intracellular signalling proteins was investigated in the SaOS-2 cells cultured on alloy surface. The results from scanning electron microscope and immunofluorescence staining demonstrated that (β-TCP)-Mg-3AI-1Zn induced significant osteogenesis. SaOS-2 cell proliferation was improved by β-TCP coating. Moreover, the (β-TCP)-Mg-3AI-1Zn surface induced activation of key intracellular signalling proteins in SaOS-2 cells. We observed an enhanced activation of Src homology and collagen (Shc), a common point of integration between bone morphogenetic protein 2, and the Ras/mitogen-activated protein kinase (MAPK) pathway. ERK1/2 MAP kinase activation was also upregulated, suggesting a role in mediating osteoblastic cell interactions with biomaterials. The signalling pathway involving c-fos (member of the activated protein-1) was also shown to be upregulated in osteoblasts cultured on the (β-TCP)-Mg-3AI-1Zn. These results suggest that β-TCP coating may contribute to successful osteoblast function on Mg alloy surface. (β-TCP)-Mg-3AI-1Zn may upregulate cell proliferation via Shc and ERK1/2 MAPK signaling in SaOS-2 osteoblasts grown on Mg alloy surface.

Evolutionary Telemetry and Command Processor (TCP) architecture

NASA Technical Reports Server (NTRS)

Schneider, John R.

1992-01-01

A low cost, modular, high performance, and compact Telemetry and Command Processor (TCP) is being built as the foundation of command and data handling subsystems for the next generation of satellites. The TCP product line will support command and telemetry requirements for small to large spacecraft and from low to high rate data transmission. It is compatible with the latest TDRSS, STDN and SGLS transponders and provides CCSDS protocol communications in addition to standard TDM formats. Its high performance computer provides computing resources for hosted flight software. Layered and modular software provides common services using standardized interfaces to applications thereby enhancing software re-use, transportability, and interoperability. The TCP architecture is based on existing standards, distributed networking, distributed and open system computing, and packet technology. The first TCP application is planned for the 94 SDIO SPAS 3 mission. The architecture enhances rapid tailoring of functions thereby reducing costs and schedules developed for individual spacecraft missions.

Assessment and quantification of patient set-up errors in nasopharyngeal cancer patients and their biological and dosimetric impact in terms of generalized equivalent uniform dose (gEUD), tumour control probability (TCP) and normal tissue complication probability (NTCP).

PubMed

Boughalia, A; Marcie, S; Fellah, M; Chami, S; Mekki, F

2015-06-01

The aim of this study is to assess and quantify patients' set-up errors using an electronic portal imaging device and to evaluate their dosimetric and biological impact in terms of generalized equivalent uniform dose (gEUD) on predictive models, such as the tumour control probability (TCP) and the normal tissue complication probability (NTCP). 20 patients treated for nasopharyngeal cancer were enrolled in the radiotherapy-oncology department of HCA. Systematic and random errors were quantified. The dosimetric and biological impact of these set-up errors on the target volume and the organ at risk (OARs) coverage were assessed using calculation of dose-volume histogram, gEUD, TCP and NTCP. For this purpose, an in-house software was developed and used. The standard deviations (1SDs) of the systematic set-up and random set-up errors were calculated for the lateral and subclavicular fields and gave the following results: ∑ = 0.63 ± (0.42) mm and σ = 3.75 ± (0.79) mm, respectively. Thus a planning organ at risk volume (PRV) margin of 3 mm was defined around the OARs, and a 5-mm margin used around the clinical target volume. The gEUD, TCP and NTCP calculations obtained with and without set-up errors have shown increased values for tumour, where ΔgEUD (tumour) = 1.94% Gy (p = 0.00721) and ΔTCP = 2.03%. The toxicity of OARs was quantified using gEUD and NTCP. The values of ΔgEUD (OARs) vary from 0.78% to 5.95% in the case of the brainstem and the optic chiasm, respectively. The corresponding ΔNTCP varies from 0.15% to 0.53%, respectively. The quantification of set-up errors has a dosimetric and biological impact on the tumour and on the OARs. The developed in-house software using the concept of gEUD, TCP and NTCP biological models has been successfully used in this study. It can be used also to optimize the treatment plan established for our patients. The gEUD, TCP and NTCP may be more suitable tools to assess the treatment plans before treating the patients.

EVALUATION OF IMMUNOASSAY METHODS FOR DETERMINATION OF 3,5,6-TRICHLORO-2-PYRIDINOL IN MULTIPLE SAMPLE MEDIA

EPA Science Inventory

Two enzyme-linked immunosorbent assay (ELISA) methods were evaluated for the determination of 3,5,6-trichloro-2-pyridinol (3,5,6-TCP) in multiple sample media (dust, soil, food, and urine). The dust and soil samples were analyzed by the RaPID (TM) commercial immunoassay testing ...

Effect of surface condition on the formation of solid lubricating films at high temperatures

NASA Technical Reports Server (NTRS)

Hanyaloglu, Bengi; Graham, E. E.

1992-01-01

Solid films were produced on active metal or ceramic surfaces using lubricants (such as tricresyl phosphate) delivered as a vapor at high temperatures, and the lubricity of these deposits under different dynamic wear conditions was investigated. A method is described for chemically activating ceramic surfaces resulting in a surface that could promote the formation of lubricating polymeric derivative of TCP. Experiments were carried out to evaluate the wear characteristics of unlubricated cast iron and of Sialon ceramic at 25 and 280 C, and lubricated with a vapor of TCP at 280 C. It is shown that continuous vapor phase lubrication of chemically treated Sialon reduced its coefficient of friction from 0.7 to less than 0.1.

Synthesis, structural properties and thermal stability of Mn-doped hydroxyapatite

NASA Astrophysics Data System (ADS)

Paluszkiewicz, Czesława; Ślósarczyk, Anna; Pijocha, Dawid; Sitarz, Maciej; Bućko, Mirosław; Zima, Aneta; Chróścicka, Anna; Lewandowska-Szumieł, Małgorzata

2010-07-01

Hydroxyapatite (HA) - Ca 10(PO 4) 6(OH) 2 is a basic inorganic model component of hard biological tissues, such as bones and teeth. The significant property of HA is its ability to exchange Ca 2+ ions, which influences crystallinity, physico-chemical and biological properties of modified hydroxyapatite materials. In this work, FTIR, Raman spectroscopy, XRD, SEM and EDS techniques were used to determine thermal stability, chemical and phase composition of Mn containing hydroxyapatite (MnHA). Described methods confirmed thermal decomposition and phase transformation of MnHA to αTCP, βTCP and formation of Mn 3O 4 depending on sintering temperature and manganese content. In vitro biological evaluation of Mn-modified HA ceramics was also performed using human osteoblast cells.

Tutorial Community Report. Progress Report, August 1971-July 1972.

ERIC Educational Resources Information Center

COP Bulletin, 1972

1972-01-01

The Tutorial Community Project (TCP) is a seven-year effort (1968-1975) designed to establish a model elementary school in the Los Angeles City School System. This document reports the project's accomplishments at Wilshire Crest and Dublin Avenue schools during the first year of the TCP. The main thrust of TCP is to develop a model, self-renewing,…

Bandwidth Management in Resource Constrained Networks

DTIC Science & Technology

2012-03-01

Postgraduate School OSI Open Systems Interconnection QoS Quality of Service TCP Transmission Control Protocol/Internet Protocol TCP/IP Transmission...filtering. B. NORMAL TCP/IP COMMUNICATIONS The Internet is a “complex network WAN that connects LANs and clients around the globe” (Dean, 2009...of the Open Systems Interconnection ( OSI ) model allowing them to route traffic based on MAC address (Kurose & Ross, 2009). While switching

76 FR 41315 - Self-Regulatory Organizations; BATS Exchange, Inc.; Notice of Filing and Immediate Effectiveness...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-13

... Change The Exchange proposes to amend BATS Rule 11.22 to extend the availability of its TCP FAST PITCH... extend the availability of its TCP FAST PITCH data feed for one additional month to allow recipients of... to decommission the TCP FAST PITCH data feed effective July 1, 2011, but is proposing to extend this...

Immunohistochemical response in rats of beta-tricalcium phosphate (TCP) with or without BMP-2 in the production of collagen matrix critical defects.

PubMed

Luvizuto, Eloá Rodrigues; de Oliveira, Júlio César Silva; Gomes-Ferreira, Pedro Henrique Silva; Pereira, Cassiano Costa Silva; Faverani, Leonardo Perez; Antoniali, Cristina; Okamoto, Roberta

2017-04-01

This study aimed to assess the biological response of BMP-2 (bone morphogenetic protein-2) in supplementation with β-tricalcium phosphate (TCP) as a carrier in the bone healing of surgical defects in rats' calvaria. A critical-size defect (5mm in diameter) was filled with β-TCP alone or added with that plus 5mg of BMP-2 at 5, 15, and 30 postoperative days. Histomorphometric and immunohistochemical (osteocalcin, collagen type I, and metalloproteinase-9) analysis was performed to assess the features of bone healing. Histological behavior and collagen type I labeling showed increased formation of the collagen matrix, leading to a higher percentage of newly formed bone and biomaterial for tissue and more total mineralization of pure TCP when compared to the other groups. The supplementation with BMP-2 promoted faster TCP remodeling; however, there was no statistically significant difference for the bone formed in both groups (P>0.05). Collagen-matrix formation and new bone formation reached maximum levels when the defects were filled with pure TCP, even exceeding the levels from BMP-2 supplementation. Copyright © 2017 Elsevier GmbH. All rights reserved.

Genome-wide Identification of TCP Family Transcription Factors from Populus euphratica and Their Involvement in Leaf Shape Regulation

PubMed Central

Ma, Xiaodong; Ma, Jianchao; Fan, Di; Li, Chaofeng; Jiang, Yuanzhong; Luo, Keming

2016-01-01

Higher plants have been shown to experience a juvenile vegetative phase, an adult vegetative phase, and a reproductive phase during its postembryonic development and distinct lateral organ morphologies have been observed at the different development stages. Populus euphratica, commonly known as a desert poplar, has developed heteromorphic leaves during its development. The TCP family genes encode a group of plant-specific transcription factors involved in several aspects of plant development. In particular, TCPs have been shown to influence leaf size and shape in many herbaceous plants. However, whether these functions are conserved in woody plants remains unknown. In the present study, we carried out genome-wide identification of TCP genes in P. euphratica and P. trichocarpa, and 33 and 36 genes encoding putative TCP proteins were found, respectively. Phylogenetic analysis of the poplar TCPs together with Arabidopsis TCPs indicated a biased expansion of the TCP gene family via segmental duplications. In addition, our results have also shown a correlation between different expression patterns of several P. euphratica TCP genes and leaf shape variations, indicating their involvement in the regulation of leaf shape development. PMID:27605130

Effect of Water-Glass Coating on HA and HA-TCP Samples for MSCs Adhesion, Proliferation, and Differentiation.

PubMed

Bajpai, Indu; Kim, Duk Yeon; Kyong-Jin, Jung; Song, In-Hwan; Kim, Sukyoung

2016-01-01

Ca-P and silicon based materials have become very popular as bone tissue engineering materials. In this study, water-glass (also known as sodium silicate glass) was coated on sintered hydroxyapatite (HA) and HA-TCP (TCP stands for tricalcium phosphate) samples and subsequently heat-treated at 600°C for 2 hrs. X-rays diffraction showed the presence of β- and α-TCP phases along with HA in the HA-TCP samples. Samples without coating, with water-glass coating, and heat-treated after water-glass coating were used to observe the adhesion and proliferation response of bone marrow derived-mesenchymal stem cells (MSCs). Cell culture was carried out for 4 hrs, 1 day, and 7 days. Interestingly, all samples showed similar response for cell adhesion and proliferation up to 7-day culture but fibronectin, E-cadherin, and osteogenic differentiation related genes (osteocalcin and osteopontin) were significantly induced in heat-treated water-glass coated HA-TCP samples. A water-glass coating on Ca-P samples was not found to influence the cell proliferation response significantly but activated some extracellular matrix genes and induced osteogenic differentiation in the MSCs.

Datamining approaches for modeling tumor control probability.

PubMed

Naqa, Issam El; Deasy, Joseph O; Mu, Yi; Huang, Ellen; Hope, Andrew J; Lindsay, Patricia E; Apte, Aditya; Alaly, James; Bradley, Jeffrey D

2010-11-01

Tumor control probability (TCP) to radiotherapy is determined by complex interactions between tumor biology, tumor microenvironment, radiation dosimetry, and patient-related variables. The complexity of these heterogeneous variable interactions constitutes a challenge for building predictive models for routine clinical practice. We describe a datamining framework that can unravel the higher order relationships among dosimetric dose-volume prognostic variables, interrogate various radiobiological processes, and generalize to unseen data before when applied prospectively. Several datamining approaches are discussed that include dose-volume metrics, equivalent uniform dose, mechanistic Poisson model, and model building methods using statistical regression and machine learning techniques. Institutional datasets of non-small cell lung cancer (NSCLC) patients are used to demonstrate these methods. The performance of the different methods was evaluated using bivariate Spearman rank correlations (rs). Over-fitting was controlled via resampling methods. Using a dataset of 56 patients with primary NCSLC tumors and 23 candidate variables, we estimated GTV volume and V75 to be the best model parameters for predicting TCP using statistical resampling and a logistic model. Using these variables, the support vector machine (SVM) kernel method provided superior performance for TCP prediction with an rs=0.68 on leave-one-out testing compared to logistic regression (rs=0.4), Poisson-based TCP (rs=0.33), and cell kill equivalent uniform dose model (rs=0.17). The prediction of treatment response can be improved by utilizing datamining approaches, which are able to unravel important non-linear complex interactions among model variables and have the capacity to predict on unseen data for prospective clinical applications.

In the linear quadratic model, the Poisson approximation and the Zaider-Minerbo formula agree on the ranking of tumor control probabilities, up to a critical cell birth rate.

PubMed

Ballhausen, Hendrik; Belka, Claus

2017-03-01

To provide a rule for the agreement or disagreement of the Poisson approximation (PA) and the Zaider-Minerbo formula (ZM) on the ranking of treatment alternatives in terms of tumor control probability (TCP) in the linear quadratic model. A general criterion involving a critical cell birth rate was formally derived. For demonstration, the criterion was applied to a distinct radiobiological model of fast growing head and neck tumors and a respective range of 22 conventional and nonconventional head and neck schedules. There is a critical cell birth rate b crit below which PA and ZM agree on which one out of two alternative treatment schemes with single-cell survival curves S'(t) and S''(t) offers better TCP: [Formula: see text] For cell birth rates b above this critical cell birth rate, PA and ZM disagree if and only if b >b crit > 0. In case of the exemplary head and neck schedules, out of 231 possible combinations, only 16 or 7% were found where PA and ZM disagreed. In all 231 cases the prediction of the criterion was numerically confirmed, and cell birth rates at crossovers between schedules matched the calculated critical cell birth rates. TCP estimated by PA and ZM almost never numerically coincide. Still, in many cases both formulas at least agree about which one out of two alternative fractionation schemes offers better TCP. In case of fast growing tumors featuring a high cell birth rate, however, ZM may suggest a re-evaluation of treatment options.

Radiobiological and treatment planning study of a simultaneously integrated boost for canine nasal tumors using helical tomotherapy.

PubMed

Gutíerrez, Alonso N; Deveau, Michael; Forrest, Lisa J; Tomé, Wolfgang A; Mackie, Thomas R

2007-01-01

Feasibility of delivering a simultaneously integrated boost to canine nasal tumors using helical tomotherapy to improve tumor control probability (TCP) via an increase in total biological equivalent uniform dose (EUD) was evaluated. Eight dogs with varying size nasal tumors (5.8-110.9 cc) were replanned to 42 Gy to the nasal cavity and integrated dose boosts to gross disease of 45.2, 48.3, and 51.3 Gy in 10 fractions. EUD values were calculated for tumors and mean normalized total doses (NTD(mean)) for organs at risk (OAR). Normal Tissue Complication Probability (NTCP) values were obtained for OARs, and estimated TCP values were computed using a logistic dose-response model and based on deliverable EUD boost doses. Significant increases in estimated TCP to 54%, 74%, and 86% can be achieved with 10%, 23%, and 37% mean relative EUD boosts to the gross disease, respectively. NTCP values for blindness of either eye and for brain necrosis were < 0.01% for all boosts. Values for cataract development were 31%, 42%, and 46% for studied boost schemas, respectively. Average NTD(mean) to eyes and brain for mean EUD boosts were 10.2, 11.3, and 12.1 Gy3, and 7.5, 7.2, and 7.9 Gy2, respectively. Using helical tomotherapy, simultaneously integrated dose boosts can be delivered to increase the estimated TCP at 1-year without significantly increasing the NTD(mean) to eyes and brain. Delivery of these treatments in a prospective trial may allow quantification of a dose-response relationship in canine nasal tumors.

Degradation and silicon excretion of the calcium silicate bioactive ceramics during bone regeneration using rabbit femur defect model.

PubMed

Lin, Kaili; Liu, Yong; Huang, Hai; Chen, Lei; Wang, Zhen; Chang, Jiang

2015-06-01

The investigation of the bone regeneration ability, degradation and excretion of the grafts is critical for development and application of the newly developed biomaterials. Herein, the in vivo bone-regeneration, biodegradation and silicon (Si) excretion of the new type calcium silicate (CaSiO3, CS) bioactive ceramics were investigated using rabbit femur defect model, and the results were compared with the traditional β-tricalcium phosphate [β-Ca3(PO4)2, β-TCP] bioceramics. After implantation of the scaffolds in rabbit femur defects for 4, 8 and 12 weeks, the bone regenerative capacity and degradation were evaluated by histomorphometric analysis. While urine and some organs such as kidney, liver, lung and spleen were resected for chemical analysis to determine the excretion of the ionic products from CS implants. The histomorphometric analysis showed that the bioresorption rate of CS was similar to that of β-TCP in femur defect model, while the CS grafts could significantly stimulate bone formation capacity as compared with β-TCP bioceramics (P < 0.05). The chemical analysis results showed that Si concentration in urinary of the CS group was apparently higher than that in control group of β-TCP. However, no significant increase of the Si excretion was found in the organs including kidney, which suggests that the resorbed Si element is harmlessly excreted in soluble form via the urine. The present studies show that the CS ceramics can be used as safe, bioactive and biodegradable materials for hard tissue repair and tissue engineering applications.

Negative Ion Chemical Ionization Mass Spectrometry for the Analysis of 3,5,6-trichloro-2-pyridinol in Saliva of Rats Exposed to Chlorpyrifos

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

Campbell, James A.; Timchalk, Chuck; Kousba, Ahmed A.

2005-05-01

Organophosphorus (OP) insecticides (e.g. chlorpyrifos) are widely used in a variety of applications, and the potential exists for significant occupational and environmental exposures. They have been associated with more occupational poisoning cases than any other class of insecticides. One of the best approaches for accurately assessing human dosimetry and determining risk from both occupational and environmental exposure is biomonitoring. Biological matrices such as blood and urine have been routinely used for biomonitoring; however, other matrices such as saliva represent a simple and readily obtainable fluid. As a result, saliva has been suggested as an alternative biological matrix for the evaluationmore » of a broad range of biomarkers such as environmental contaminants, drugs of abuse, hormones, chemotherapeutics, heavy metals, and pesticides. Chlorpyrifos (CPF), and its major metabolite, 3,5,6-trichloro-2-pyridinol (TCP), have been quantified in urine and blood as a biomarker for exposure to OP insecticides. The purpose of this study was to develop an analytical approach for detecting and quantitating the levels of TCP in saliva obtained from rats exposed to CPF and to evaluate the potential of saliva as a non-invasive biomonitoring matrix. Adult male rats were administered CPF, and blood and saliva were humanely collected for analysis of TCP and CPF. TCP was detected and quantitated in saliva using negative ion chemical ionization mass spectrometry with selected ion monitoring. Initial results indicate that saliva may be potentially utilized as a non-invasive biomonitoring matrix to determine exposure to organophosphate insecticides.« less

A Vision-Based Self-Calibration Method for Robotic Visual Inspection Systems

PubMed Central

Yin, Shibin; Ren, Yongjie; Zhu, Jigui; Yang, Shourui; Ye, Shenghua

2013-01-01

A vision-based robot self-calibration method is proposed in this paper to evaluate the kinematic parameter errors of a robot using a visual sensor mounted on its end-effector. This approach could be performed in the industrial field without external, expensive apparatus or an elaborate setup. A robot Tool Center Point (TCP) is defined in the structural model of a line-structured laser sensor, and aligned to a reference point fixed in the robot workspace. A mathematical model is established to formulate the misalignment errors with kinematic parameter errors and TCP position errors. Based on the fixed point constraints, the kinematic parameter errors and TCP position errors are identified with an iterative algorithm. Compared to the conventional methods, this proposed method eliminates the need for a robot-based-frame and hand-to-eye calibrations, shortens the error propagation chain, and makes the calibration process more accurate and convenient. A validation experiment is performed on an ABB IRB2400 robot. An optimal configuration on the number and distribution of fixed points in the robot workspace is obtained based on the experimental results. Comparative experiments reveal that there is a significant improvement of the measuring accuracy of the robotic visual inspection system. PMID:24300597

The Arabidopsis RING-Type E3 Ligase TEAR1 Controls Leaf Development by Targeting the TIE1 Transcriptional Repressor for Degradation[OPEN

PubMed Central

Zhang, Jinzhe; Wei, Baoye; Yuan, Rongrong; Yu, Hao

2017-01-01

The developmental plasticity of leaf size and shape is important for leaf function and plant survival. However, the mechanisms by which plants form diverse leaves in response to environmental conditions are not well understood. Here, we identified TIE1-ASSOCIATED RING-TYPE E3 LIGASE1 (TEAR1) and found that it regulates leaf development by promoting the degradation of TCP INTERACTOR-CONTAINING EAR MOTIF PROTEIN1 (TIE1), an important repressor of CINCINNATA (CIN)-like TEOSINTE BRANCHED1/CYCLOIDEA/PCF (TCP) transcription factors, which are key for leaf development. TEAR1 contains a typical C3H2C3-type RING domain and has E3 ligase activity. We show that TEAR1 interacts with the TCP repressor TIE1, which is ubiquitinated in vivo and degraded by the 26S proteasome system. We demonstrate that TEAR1 is colocalized with TIE1 in nuclei and negatively regulates TIE1 protein levels. Overexpression of TEAR1 rescued leaf defects caused by TIE1 overexpression, whereas disruption of TEAR1 resulted in leaf phenotypes resembling those caused by TIE1 overexpression or TCP dysfunction. Deficiency in TEAR partially rescued the leaf defects of TCP4 overexpression line and enhanced the wavy leaf phenotypes of jaw-5D. We propose that TEAR1 positively regulates CIN-like TCP activity to promote leaf development by mediating the degradation of the TCP repressor TIE1. PMID:28100709

The effect of Tricresyl-Phosphate (TCP) as an additive on wear of Iron (Fe)

NASA Technical Reports Server (NTRS)

Ghose, Hiren M.; Ferrante, John; Honecy, Frank C.

1987-01-01

The effect of tricresyl phosphate (TCP) as an antiwear additive in lubricant trimethyol propane triheptanoate (TMPTH) was investigated. The objective was to examine step loading wear by use of surface analysis, wetting, and chemical bonding changes in the lubricant. The investigation consisted of steploading wear studies by a pin or disk tribometer, the effects on wear related to wetting by contact angle and surface tension measurements of various liquid systems, the chemical bonding changes between lubricant and TCP chromatographic analysis, and by determining the reaction between the TCP and metal surfaces through wear scar analysis by Auger emission spectroscopy (AES). The steploading curve for the base fluid alone shows rapid increase of wear rate with load. The steploading curve for the base fluid in presence of 4.25 percent by volume TCP under dry air purge has shown a great reduction of wear rate with all loads studied. It has also been found that the addition of 4.25 percent by volume TCP plus 0.33 percent by volume water to the base lubricant under N2 purge also greatly reduces the wear rate with all loads studied. AES surface analysis reveals a phosphate type wear resistant film, which greatly increases load-bearing capacity, formed on the iron disk. Preliminary chromatographic studies suggest that this film forms either because of ester oxidation or TCP degradation. Wetting studies show direct correlation between the spreading coefficient and the wear rate.

Mechanism of lubrication by tricresylphosphate (TCP)

NASA Technical Reports Server (NTRS)

Faut, O. D.; Wheeler, D. R.

1983-01-01

A pin-on-disk tribometer equipped with an induction heater was used to study the coefficient of friction as a function of temperature for tricresylphosphate (TCP) on continuous vacuum melted (CVM) M-50 tool steel when the TCP was present in a liquid reservoir (bulk lubrication), and when it was applied as a liquid layer directly to the disk (limited lubrication). Under limited lubrication conditions, experiments were performed in dry ( 100 ppm H2O) air, dry ( 20 ppm H2O) nitrogen, dry nitrogen with the disks heated to 700 C then cooled to room temperature before the TCP was applied and the measurements made (preheated disks), and moist nitrogen using preheated disks. When the coefficient of friction was plotted as a function of the disk temperature, the friction decreased at a characteristic temperature, T sub r whose observed values were 265 C for bulk lubrication conditions in dry air, 225 C for limited lubrication conditions in dry air, and 215 C for limited lubrication conditions in dry nitrogen. No decrease in friction was observed with preheated disks; instead a sharp failure temperature was observed at 218 C, which was taken as the temperature about which the behavior of TCP should be judged, X-ray photoelectron spectroscopy confirmed the presence of phosphate on the surface of the iron pins used in the tribometer under TCP lubrication. Depth profile studies support the idea that a chemical reaction occurs between the TCP and the metal surface at T sub r.

Dosimetric effects of patient rotational setup errors on prostate IMRT treatments

NASA Astrophysics Data System (ADS)

Fu, Weihua; Yang, Yong; Li, Xiang; Heron, Dwight E.; Saiful Huq, M.; Yue, Ning J.

2006-10-01

The purpose of this work is to determine dose delivery errors that could result from systematic rotational setup errors (ΔΦ) for prostate cancer patients treated with three-phase sequential boost IMRT. In order to implement this, different rotational setup errors around three Cartesian axes were simulated for five prostate patients and dosimetric indices, such as dose-volume histogram (DVH), tumour control probability (TCP), normal tissue complication probability (NTCP) and equivalent uniform dose (EUD), were employed to evaluate the corresponding dosimetric influences. Rotational setup errors were simulated by adjusting the gantry, collimator and horizontal couch angles of treatment beams and the dosimetric effects were evaluated by recomputing the dose distributions in the treatment planning system. Our results indicated that, for prostate cancer treatment with the three-phase sequential boost IMRT technique, the rotational setup errors do not have significant dosimetric impacts on the cumulative plan. Even in the worst-case scenario with ΔΦ = 3°, the prostate EUD varied within 1.5% and TCP decreased about 1%. For seminal vesicle, slightly larger influences were observed. However, EUD and TCP changes were still within 2%. The influence on sensitive structures, such as rectum and bladder, is also negligible. This study demonstrates that the rotational setup error degrades the dosimetric coverage of target volume in prostate cancer treatment to a certain degree. However, the degradation was not significant for the three-phase sequential boost prostate IMRT technique and for the margin sizes used in our institution.

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

Kang, S; Suh, T; Chung, J

Purpose: The purpose of this study is to evaluate the dosimetric and radiobiological impact of Acuros XB (AXB) and Anisotropic Analytic Algorithm (AAA) dose calculation algorithms on prostate stereotactic body radiation therapy plans with both conventional flattened (FF) and flattening-filter free (FFF) modes. Methods: For thirteen patients with prostate cancer, SBRT planning was performed using 10-MV photon beam with FF and FFF modes. The total dose prescribed to the PTV was 42.7 Gy in 7 fractions. All plans were initially calculated using AAA algorithm in Eclipse treatment planning system (11.0.34), and then were re-calculated using AXB with the same MUsmore » and MLC files. The four types of plans for different algorithms and beam energies were compared in terms of homogeneity and conformity. To evaluate the radiobiological impact, the tumor control probability (TCP) and normal tissue complication probability (NTCP) calculations were performed. Results: For PTV, both calculation algorithms and beam modes lead to comparable homogeneity and conformity. However, the averaged TCP values in AXB plans were always lower than in AAA plans with an average difference of 5.3% and 6.1% for 10-MV FFF and FF beam, respectively. In addition, the averaged NTCP values for organs at risk (OARs) were comparable. Conclusion: This study showed that prostate SBRT plan were comparable dosimetric results with different dose calculation algorithms as well as delivery beam modes. For biological results, even though NTCP values for both calculation algorithms and beam modes were similar, AXB plans produced slightly lower TCP compared to the AAA plans.« less

A Technique for Presenting a Deceptive Dynamic Network Topology

DTIC Science & Technology

2013-03-01

Comment RIP Routing Information Protocol SNOS Systemic Network Obfuscation System SSH Secure Shell TCP Transmission Control Protocol TTL time to live...because it sacrifices elements available in Transmission Control Protocol ( TCP ) such as ordered delivery of packets, delivery confirmation and duplication...avoidance [4]. Of note, some traceroute implementations use TCP packets since they are able to pass through firewalls which are typically configured

Clean Metal Finishing Alternatives

DTIC Science & Technology

2006-05-01

Cr, must heat treat for hardness 4 4 Trivalent chrome Trivalent plating chemistry Varying success, some must be brush plate 3 3 Alloy plating...metals. Hard coating deposition unproven. 3 N/A Weld coating Electrospark Deposition/ Alloying (ESD/ ESA) Microarc welding Localized repair of non...Alternatives to chromate conversion coatings Al TriChrome Pretreatment (TCP)* – AnoChem TCP, Aluminescent, TCP-HF Trivalent Cr3+ conversion with Zr

SU-D-16A-04: Accuracy of Treatment Plan TCP and NTCP Values as Determined Via Treatment Course Delivery Simulations

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

Siebers, J; Xu, H; Gordon, J

2014-06-01

Purpose: To to determine if tumor control probability (TCP) and normal tissue control probability (NTCP) values computed on the treatment planning image are representative of TCP/NTCP distributions resulting from probable positioning variations encountered during external-beam radiotherapy. Methods: We compare TCP/NTCP as typically computed on the planning PTV/OARs with distributions of those parameters computed for CTV/OARs via treatment delivery simulations which include the effect of patient organ deformations for a group of 19 prostate IMRT pseudocases. Planning objectives specified 78 Gy to PTV1=prostate CTV+5 mm margin, 66 Gy to PTV2=seminal vesicles+8 mm margin, and multiple bladder/rectum OAR objectives to achieve typicalmore » clinical OAR sparing. TCP were computed using the Poisson Model while NTCPs used the Lyman-Kutcher-Bruman model. For each patient, 1000 30-fraction virtual treatment courses were simulated with each fractional pseudo- time-oftreatment anatomy sampled from a principle component analysis patient deformation model. Dose for each virtual treatment-course was determined via deformable summation of dose from the individual fractions. CTVTCP/ OAR-NTCP values were computed for each treatment course, statistically analyzed, and compared with the planning PTV-TCP/OARNTCP values. Results: Mean TCP from the simulations differed by <1% from planned TCP for 18/19 patients; 1/19 differed by 1.7%. Mean bladder NTCP differed from the planned NTCP by >5% for 12/19 patients and >10% for 4/19 patients. Similarly, mean rectum NTCP differed by >5% for 12/19 patients, >10% for 4/19 patients. Both mean bladder and mean rectum NTCP differed by >5% for 10/19 patients and by >10% for 2/19 patients. For several patients, planned NTCP was less than the minimum or more than the maximum from the treatment course simulations. Conclusion: Treatment course simulations yield TCP values that are similar to planned values, while OAR NTCPs differ significantly, indicating the need for probabilistic methods or PRVs for OAR risk assessment. Presenting author receives support from Philips Medical Systems.« less

[Biological evaluation of three-dimensional printed co-poly lactic acid/glycolic acid/tri-calcium phosphate scaffold for bone reconstruction].

PubMed

Li, S Y; Zhou, M; Lai, Y X; Geng, Y M; Cao, S S; Chen, X M

2016-11-09

Objective: To biologically evaluate the three-dimensional(3D) printed co-poly lactic acid/glycolic acid/tri-calcium phosphate(PLGA/TCP) scaffold which could be used for repairing oral and maxillofacial bone defects, and to provide experimental evidence for its further research and clinical application. Methods: PLGA/TCP scaffolds were fabricated using low temperature rapid prototyping technique. Micro-CT and scanning electron microscope(SEM) were used to characterize the surface morphology. MC3T3-E1 cells were seeded onto the scaffold and stained with the rhodamine phalloidin and calcein acetomethoxy. After that, confocal laser scanning microscope was exploited to observe the features and viability of the cells. Moreover, the cells were co-cultured with the extract of PLGA/TCP and complete medium, respectively. The proliferation capability of the cells was assessed by the cell counting kit-8 (CCK-8) on the 1st, 2nd, and 3rd day. The PLGA/TCP scaffolds incorporated with recombinant human bone morphogenetic protein-2(rhBMP-2) of 0, 30, 60 μg(i.e. blank control group, low-dose group and high-dose group) were implanted into the latissimus dorsi muscle of the rats, and 6 weeks later, the samples were harvested to estimate the volume and pattern of new bone. Results: The 3D printed PLGA/TCP scaffold possessed a regular and well-defined porous stereo-structure with porosity of (73±3)%. Micro-CT and SEM showed that pore size were (379±32) and (453±29) μm respectively, and distance between layers were (452± 24) and (415±25) μm, and cylinder diameter were (342±24) and (350±28) μm. It also exhibited excellent cell adhesion and growth ability on the exterior and inner surface through rhodamine phalloidin and calcein acetomethoxy staining. The CCK-8 test demonstrated that the absorbance value of extract group on the 1st and 2nd day(0.51±0.08 and 0.63±0.09) were significantly higher than those in the blank control group(0.39± 0.05 and 0.53±0.05)( P< 0.05), while there was no significant difference between the extract group(0.67±0.06) and the blank control group(0.68±0.04)( P> 0.05) on the 3rd day. For in vivo test, there was obvious ectopic new bone formation on the PLGA/TCP scaffold incorporated with rhBMP-2, and this was demonstrated using the histological examination and micro-CT. The bone formation in the low-dose group was similar to the shape of the pre-implanted 3D printed scaffold, while much diversity was revealed in the high-dose group duo to over osteogenesis which was validated by the examinations of gross observation, histology and micro-CT. Conclusions: Customized PLGA/TCP scaffolds can be manufactured by 3D printing technique. The scaffold showed an excellent biocompatibility and ectopic osteogenesis when incorporated with rhBMP-2. However, further research is needed to validate it ' s effect on repairment of the oral and maxillofacial bone defects.

Evaluation of biofilm formation using milk in a flow cell model and microarray characterization of Staphylococcus aureus strains from bovine mastitis.

PubMed

Snel, G G M; Malvisi, M; Pilla, R; Piccinini, R

2014-12-05

It was hypothesized that biofilm could play an important role in the establishment of chronic Staphylococcus aureus bovine mastitis. The in vitro evaluation of biofilm formation can be performed either in closed/static or in flow-based systems. Efforts have been made to characterize the biofilm-forming ability of S. aureus mastitis isolates, however most authors used static systems and matrices other than UHT milk. It is not clear whether such results could be extrapolated to the mammary gland environment. Therefore, the present study aimed to investigate the biofilm-forming ability of S. aureus strains from subclinical bovine mastitis using the static method and a flow-based one. One hundred and twelve strains were tested by the classic tissue culture plate assay (TCP) and 30 out of them were also tested by a dynamic semi-quantitative assay using commercial UHT milk as culture medium (Milk Flow Culture, MFC) or Tryptic Soy Broth as control medium (TS Flow Culture, TSFC). Only 6 (20%) strains formed biofilm in milk under flow conditions, while 36.6% were considered biofilm-producers in TCP, and 93.3% produced biofilm in TSFC. No agreement was found between TCP, MFC and TSFC results. The association between strain genetic profile, determined by microarray, and biofilm-forming ability in milk was evaluated. Biofilm formation in MFC was significantly associated with the presence of those genes commonly found in bovine-associated strains, assigned to clonal complexes typically detected in mastitis. Based on our results, biofilm-forming potential of bovine strains should be critically analysed and tested applying conditions similar to mammary environment. Copyright © 2014 Elsevier B.V. All rights reserved.

FastLane: Agile Drop Notification for Datacenter Networks

DTIC Science & Technology

2013-10-23

interactivity dead- lines mean that networks are increasingly evaluated on high percentile completion times of these short flows. Achieving consistent flow...triggering retransmissions based on out-of-order delivery. We evaluate FastLane in a number of scenarios, us- ing both testbed experiments and simulations...Results from our evaluation demonstrate that FastLane improves the 99.9th percentile completion time of short flows by up to 75% compared to TCP

Hexavalent Chromium Free Coatings Projects for Aerospace Applications

DTIC Science & Technology

2012-08-01

1-Evaluate trivalent chromium pretreatment (TCP) for use on aluminum  2-Evaluate three hexavalent chrome free alternatives to DoD-P-15328 wash...UNCLASSIFIED UNCLASSIFIED Hexavalent Chromium Free Coatings Projects for Aerospace Applications Report Documentation Page Form...COVERED 00-00-2012 to 00-00-2012 4. TITLE AND SUBTITLE Hexavalent Chromium Free Coatings Projects for Aerospace Applications 5a. CONTRACT NUMBER

Measuring infrastructure: A key step in program evaluation and planning

PubMed Central

Schmitt, Carol L.; Glasgow, LaShawn; Lavinghouze, S. Rene; Rieker, Patricia P.; Fulmer, Erika; McAleer, Kelly; Rogers, Todd

2016-01-01

State tobacco prevention and control programs (TCPs) require a fully functioning infrastructure to respond effectively to the Surgeon General’s call for accelerating the national reduction in tobacco use. The literature describes common elements of infrastructure; however, a lack of valid and reliable measures has made it difficult for program planners to monitor relevant infrastructure indicators and address observed deficiencies, or for evaluators to determine the association among infrastructure, program efforts, and program outcomes. The Component Model of Infrastructure (CMI) is a comprehensive, evidence-based framework that facilitates TCP program planning efforts to develop and maintain their infrastructure. Measures of CMI components were needed to evaluate the model’s utility and predictive capability for assessing infrastructure. This paper describes the development of CMI measures and results of a pilot test with nine state TCP managers. Pilot test findings indicate that the tool has good face validity and is clear and easy to follow. The CMI tool yields data that can enhance public health efforts in a funding-constrained environment and provides insight into program sustainability. Ultimately, the CMI measurement tool could facilitate better evaluation and program planning across public health programs. PMID:27037655

Measuring infrastructure: A key step in program evaluation and planning.

PubMed

Schmitt, Carol L; Glasgow, LaShawn; Lavinghouze, S Rene; Rieker, Patricia P; Fulmer, Erika; McAleer, Kelly; Rogers, Todd

2016-06-01

State tobacco prevention and control programs (TCPs) require a fully functioning infrastructure to respond effectively to the Surgeon General's call for accelerating the national reduction in tobacco use. The literature describes common elements of infrastructure; however, a lack of valid and reliable measures has made it difficult for program planners to monitor relevant infrastructure indicators and address observed deficiencies, or for evaluators to determine the association among infrastructure, program efforts, and program outcomes. The Component Model of Infrastructure (CMI) is a comprehensive, evidence-based framework that facilitates TCP program planning efforts to develop and maintain their infrastructure. Measures of CMI components were needed to evaluate the model's utility and predictive capability for assessing infrastructure. This paper describes the development of CMI measures and results of a pilot test with nine state TCP managers. Pilot test findings indicate that the tool has good face validity and is clear and easy to follow. The CMI tool yields data that can enhance public health efforts in a funding-constrained environment and provides insight into program sustainability. Ultimately, the CMI measurement tool could facilitate better evaluation and program planning across public health programs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Degradation kinetics of chlorpyrifos and 3,5,6-trichloro-2-pyridinol (TCP) by fungal communities.

PubMed

Maya, K; Upadhyay, S N; Singh, R S; Dubey, Suresh K

2012-12-01

Fungal isolates obtained from soil were used for degrading chlorpyrifos (CP) and TCP. The percentage degradation ranged from 69.4 to 89.8 for CP and 62.2 to 92.6 for TCP after one week. The values of K(s) and V(max) were different for different isolates. The K(s) ranged from 66.66 to 169.5mg/L and V(max) from 6.56 to 40.4 mg/L/d for CP and from 53.19 to 163.9 mg/L and 3.41 to 40.40 mg/L/d, respectively, for TCP. Fungal community showed high affinity for both CP and TCP. The genetic relatedness of isolate F1 to Aspergillus sp., F2 and F3 to Penicillium sp., F4 to Eurotium sp. and F5 to Emericella sp. were confirmed. The degradation potential was in the order: F1>F2=F3>F4>F5. Copyright © 2012 Elsevier Ltd. All rights reserved.

JPARSS: A Java Parallel Network Package for Grid Computing

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

Chen, Jie; Akers, Walter; Chen, Ying

2002-03-01

The emergence of high speed wide area networks makes grid computinga reality. However grid applications that need reliable data transfer still have difficulties to achieve optimal TCP performance due to network tuning of TCP window size to improve bandwidth and to reduce latency on a high speed wide area network. This paper presents a Java package called JPARSS (Java Parallel Secure Stream (Socket)) that divides data into partitions that are sent over several parallel Java streams simultaneously and allows Java or Web applications to achieve optimal TCP performance in a grid environment without the necessity of tuning TCP window size.more » This package enables single sign-on, certificate delegation and secure or plain-text data transfer using several security components based on X.509 certificate and SSL. Several experiments will be presented to show that using Java parallelstreams is more effective than tuning TCP window size. In addition a simple architecture using Web services« less

Data Transfer Efficiency Over Satellite Circuits Using a Multi-Socket Extension to the File Transfer Protocol (FTP)

NASA Technical Reports Server (NTRS)

Allman, Mark; Ostermann, Shawn; Kruse, Hans

1996-01-01

In several experiments using NASA's Advanced Communications Technology Satellite (ACTS), investigators have reported disappointing throughput using the transmission control protocol/Internet protocol (TCP/IP) protocol suite over 1.536Mbit/sec (T1) satellite circuits. A detailed analysis of file transfer protocol (FTP) file transfers reveals that both the TCP window size and the TCP 'slow starter' algorithm contribute to the observed limits in throughput. In this paper we summarize the experimental and and theoretical analysis of the throughput limit imposed by TCP on the satellite circuit. We then discuss in detail the implementation of a multi-socket FTP, XFTP client and server. XFTP has been tested using the ACTS system. Finally, we discuss a preliminary set of tests on a link with non-zero bit error rates. XFTP shows promising performance under these conditions, suggesting the possibility that a multi-socket application may be less effected by bit errors than a single, large-window TCP connection.

Scalability Analysis and Use of Compression at the Goddard DAAC and End-to-End MODIS Transfers

NASA Technical Reports Server (NTRS)

Menasce, Daniel A.

1998-01-01

The goal of this task is to analyze the performance of single and multiple FTP transfer between SCF's and the Goddard DAAC. We developed an analytic model to compute the performance of FTP sessions as a function of various key parameters, implemented the model as a program called FTP Analyzer, and carried out validations with real data obtained by running single and multiple FTP transfer between GSFC and the Miami SCF. The input parameters to the model include the mix to FTP sessions (scenario), and for each FTP session, the file size. The network parameters include the round trip time, packet loss rate, the limiting bandwidth of the network connecting the SCF to a DAAC, TCP's basic timeout, TCP's Maximum Segment Size, and TCP's Maximum Receiver's Window Size. The modeling approach used consisted of modeling TCP's overall throughput, computing TCP's delay per FTP transfer, and then solving a queuing network model that includes the FTP clients and servers.

Pseudomonas syringae Type III Effector HopBB1 Promotes Host Transcriptional Repressor Degradation to Regulate Phytohormone Responses and Virulence.

PubMed

Yang, Li; Teixeira, Paulo José Pereira Lima; Biswas, Surojit; Finkel, Omri M; He, Yijian; Salas-Gonzalez, Isai; English, Marie E; Epple, Petra; Mieczkowski, Piotr; Dangl, Jeffery L

2017-02-08

Independently evolved pathogen effectors from three branches of life (ascomycete, eubacteria, and oomycete) converge onto the Arabidopsis TCP14 transcription factor to manipulate host defense. However, the mechanistic basis for defense control via TCP14 regulation is unknown. We demonstrate that TCP14 regulates the plant immune system by transcriptionally repressing a subset of the jasmonic acid (JA) hormone signaling outputs. A previously unstudied Pseudomonas syringae (Psy) type III effector, HopBB1, interacts with TCP14 and targets it to the SCF COI1 degradation complex by connecting it to the JA signaling repressor JAZ3. Consequently, HopBB1 de-represses the TCP14-regulated subset of JA response genes and promotes pathogen virulence. Thus, HopBB1 fine-tunes host phytohormone crosstalk by precisely manipulating part of the JA regulon to avoid pleiotropic host responses while promoting pathogen proliferation. Copyright © 2017 Elsevier Inc. All rights reserved.

"Fabrication of arbitrarily shaped carbonate apatite foam based on the interlocking process of dicalcium hydrogen phosphate dihydrate".

PubMed

Sugiura, Yuki; Tsuru, Kanji; Ishikawa, Kunio

2017-08-01

Carbonate apatite (CO 3 Ap) foam with an interconnected porous structure is highly attractive as a scaffold for bone replacement. In this study, arbitrarily shaped CO 3 Ap foam was formed from α-tricalcium phosphate (α-TCP) foam granules via a two-step process involving treatment with acidic calcium phosphate solution followed by hydrothermal treatment with NaHCO 3 . The treatment with acidic calcium phosphate solution, which is key to fabricating arbitrarily shaped CO 3 Ap foam, enables dicalcium hydrogen phosphate dihydrate (DCPD) crystals to form on the α-TCP foam granules. The generated DCPD crystals cause the α-TCP granules to interlock with each other, inducing an α-TCP/DCPD foam. The interlocking structure containing DCPD crystals can survive hydrothermal treatment with NaHCO 3 . The arbitrarily shaped CO 3 Ap foam was fabricated from the α-TCP/DCPD foam via hydrothermal treatment at 200 °C for 24 h in the presence of a large amount of NaHCO 3 .

Anion-π interaction in metal-organic networks formed by metal halides and tetracyanopyrazine

NASA Astrophysics Data System (ADS)

Rosokha, Sergiy V.; Kumar, Amar

2017-06-01

Co-crystallization of tetracyanopyrazine, TCP, with the tetraalkylammonium salts of linear [CuBr2]-, planar [PtCl4]2- or [Pt2Br6]2-, or octahedral [PtBr6]2- complexes resulted in formation of the alternating [MlXn]m-/TCP stacks separated by the Alk4N+ cations. These hybrid stacks showed multiple short contacts between halide ligands of the [MlXn]m- complexes and carbon atoms of the TCP acceptor indicating strong anion-π bonding between these species. It confirmed that the anion-π interaction is sufficiently strong to bring together such disparate components as ionic metal complexes and neutral aromatic molecules regardless of the geometry of the coordination compound. Structural features of the solid-state stacks and [MlXn]m-·TCP dyads resulted from the quantum-mechanical computations suggests that the molecular-orbital (weakly-covalent) component play an important role in association of the [MlXn]m- complexes with the TCP acceptor.

Biopolymers/poly(ε-caprolactone)/polyethylenimine functionalized nano-hydroxyapatite hybrid cryogel: Synthesis, characterization and application in gene delivery.

PubMed

Simionescu, Bogdan C; Drobota, Mioara; Timpu, Daniel; Vasiliu, Tudor; Constantinescu, Cristina Ana; Rebleanu, Daniela; Calin, Manuela; David, Geta

2017-12-01

Nano-hydroxyapatite (nHAp), surface functionalized with linear polyethylenimine (LPEI), was used for the preparation of biocomposites in combination with biopolymers and poly(ε-caprolactone) (PCL), by cryogelation technique, to yield biomimetic scaffolds with controlled interconnected macroporosity, mechanical stability, and predictable degradation behavior. The structural characteristics, swelling and degradation behavior of hydroxyapatite and hydroxyapatite/β-tricalcium phosphate (β-TCP) filled matrices were investigated as compared to the corresponding naked polymer 3D system. It was found that the homogeneity and cohesivity of the composite are significantly dependent on the size and amount of the included inorganic particles, which are thus determining the structural parameters. Surface modification with LPEI and nanodimensions favored the nHAp integration in the organic matrix, with preferential location along protein fibers, while β-TCP microparticles induced an increased disorder in the hybrid system. The biocomposite including nHAp only was further investigated targeting biomedical uses, and proved to be non-cytotoxic and capable of acting as gene-activated matrix (GAM). It allowed sustained delivery over time (until 22days) of embedded PEI 25 -pDNA polyplexes at high levels of transgene expression, while insuring a decrease in cytotoxicity as compared to polyplexes alone. Experimental data recommend such biocomposite as an attractive material for regenerative medicine. Copyright © 2017 Elsevier B.V. All rights reserved.

Fixing Two BSD TCP Bugs

NASA Technical Reports Server (NTRS)

Allman, Mark

1997-01-01

This note outlines two bugs found in the BSD 4.4 Lite TCP implementation, as well as the implications of these bugs and possible ways to correct them. The first problem encountered in this particular TCP implementation is the use of a 2 segment initial congestion window, rather than the standard 1 segment initial window. The second problem is that the receiver delays ACKs in violation of the delayed ACK rules,

3D Powder Printed Bioglass and β-Tricalcium Phosphate Bone Scaffolds.

PubMed

Seidenstuecker, Michael; Kerr, Laura; Bernstein, Anke; Mayr, Hermann O; Suedkamp, Norbert P; Gadow, Rainer; Krieg, Peter; Hernandez Latorre, Sergio; Thomann, Ralf; Syrowatka, Frank; Esslinger, Steffen

2017-12-22

The use of both bioglass (BG) and β tricalcium phosphate (β-TCP) for bone replacement applications has been studied extensively due to the materials' high biocompatibility and ability to resorb when implanted in the body. 3D printing has been explored as a fast and versatile technique for the fabrication of porous bone scaffolds. This project investigates the effects of using different combinations of a composite BG and β-TCP powder for 3D printing of porous bone scaffolds. Porous 3D powder printed bone scaffolds of BG, β-TCP, 50/50 BG/β-TCP and 70/30 BG/β-TCP compositions were subject to a variety of characterization and biocompatibility tests. The porosity characteristics, surface roughness, mechanical strength, viability for cell proliferation, material cytotoxicity and in vitro bioactivity were assessed. The results show that the scaffolds can support osteoblast-like MG-63 cells growth both on the surface of and within the scaffold material and do not show alarming cytotoxicity; the porosity and surface characteristics of the scaffolds are appropriate. Of the two tested composite materials, the 70/30 BG/β-TCP scaffold proved to be superior in terms of biocompatibility and mechanical strength. The mechanical strength of the scaffolds makes them unsuitable for load bearing applications. However, they can be useful for other applications such as bone fillers.

Can reduction of uncertainties in cervix cancer brachytherapy potentially improve clinical outcome?

PubMed

Nesvacil, Nicole; Tanderup, Kari; Lindegaard, Jacob C; Pötter, Richard; Kirisits, Christian

2016-09-01

The aim of this study was to quantify the impact of different types and magnitudes of dosimetric uncertainties in cervix cancer brachytherapy (BT) on tumour control probability (TCP) and normal tissue complication probability (NTCP) curves. A dose-response simulation study was based on systematic and random dose uncertainties and TCP/NTCP models for CTV and rectum. Large patient cohorts were simulated assuming different levels of dosimetric uncertainties. TCP and NTCP were computed, based on the planned doses, the simulated dose uncertainty, and an underlying TCP/NTCP model. Systematic uncertainties of 3-20% and random uncertainties with a 5-30% standard deviation per BT fraction were analysed. Systematic dose uncertainties of 5% lead to a 1% decrease/increase of TCP/NTCP, while random uncertainties of 10% had negligible impact on the dose-response curve at clinically relevant dose levels for target and OAR. Random OAR dose uncertainties of 30% resulted in an NTCP increase of 3-4% for planned doses of 70-80Gy EQD2. TCP is robust to dosimetric uncertainties when dose prescription is in the more flat region of the dose-response curve at doses >75Gy. For OARs, improved clinical outcome is expected by reduction of uncertainties via sophisticated dose delivery and treatment verification. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

A novel immunochromatographic electrochemical biosensor for highly sensitive and selective detection of trichloropyridinol, a biomarker of exposure to chlorpyrifos.

PubMed

Wang, Limin; Lu, Donglai; Wang, Jun; Du, Dan; Zou, Zhexiang; Wang, Hua; Smith, Jordan N; Timchalk, Charles; Liu, Fengquan; Lin, Yuehe

2011-02-15

We present a novel portable immunochromatographic electrochemical biosensor (IEB) for simple, rapid, and sensitive biomonitoring of trichloropyridinol (TCP), a metabolite biomarker of exposure to organophosphorus insecticides. Our new approach takes the advantage of immunochromatographic test strip for a rapid competitive immunoreaction and a disposable screen-printed carbon electrode for a rapid and sensitive electrochemical analysis of captured HRP labeling. Several key experimental parameters (e.g. immunoreaction time, the amount of HRP labeled TCP, concentration of the substrate for electrochemical measurements, and the blocking agents for the nitrocellulose membrane) were optimized to achieve a high sensitivity, selectivity and stability. Under optimal conditions, the IEB has demonstrated a wide linear range (0.1-100 ng/ml) with a detection limit as low as 0.1 ng/ml TCP. Furthermore, the IEB has been successfully applied for biomonitoring of TCP in the rat plasma samples with in vivo exposure to organophosphorus insecticides like Chlorpyrifos-oxon (CPF-oxon). The IEB thus opens up new pathways for designing a simple, rapid, clinically accurate, and quantitative tool for TCP detection, as well as holds a great promise for in-field screening of metabolite biomarkers, e.g., TCP, for humans exposed to organophosphorus insecticides. Copyright © 2010 Elsevier B.V. All rights reserved.

Mechanism of enhanced conversion of 1,2,3-trichloropropane by mutant haloalkane dehalogenase revealed by molecular modeling

NASA Astrophysics Data System (ADS)

Banáš, Pavel; Otyepka, Michal; Jeřábek, Petr; Petřek, Martin; Damborský, Jiří

2006-06-01

1,2,3-Trichloropropane (TCP) is a highly toxic, recalcitrant byproduct of epichlorohydrin manufacture. Haloalkane dehalogenase (DhaA) from Rhodococcus sp. hydrolyses the carbon-halogen bond in various halogenated compounds including TCP, but with low efficiency ( k cat/ K m = 36 s-1 M-1). A Cys176Tyr-DhaA mutant with a threefold higher catalytic efficiency for TCP dehalogenation has been previously obtained by error-prone PCR. We have used molecular simulations and quantum mechanical calculations to elucidate the molecular mechanisms involved in the improved catalysis of the mutant, and enantioselectivity of DhaA toward TCP. The Cys176Tyr mutation modifies the protein access and export routes. Substitution of the Cys residue by the bulkier Tyr narrows the upper tunnel, making the second tunnel "slot" the preferred route. TCP can adopt two major orientations in the DhaA enzyme, in one of which the halide-stabilizing residue Asn41 forms a hydrogen bond with the terminal halogen atom of the TCP molecule, while in the other it bonds with the central halogen atom. The differences in these binding patterns explain the preferential formation of the ( R)- over the ( S)-enantiomer of 2,3-dichloropropane-1-ol in the reaction catalyzed by the enzyme.

Transcription factor AtTCP14 regulates embryonic growth potential during seed germination in Arabidopsis thaliana.

PubMed

Tatematsu, Kiyoshi; Nakabayashi, Kazumi; Kamiya, Yuji; Nambara, Eiji

2008-01-01

To understand the molecular mechanisms underlying regulation of seed germination, we searched enriched cis elements in the upstream regions of Arabidopsis genes whose transcript levels increased during seed germination. Using available published microarray data, we found that two cis elements, Up1 or Up2, which regulate outgrowth of Arabidopsis axillary shoots, were significantly over-represented. Classification of Up1- and Up2-containing genes by gene ontology revealed that protein synthesis-related genes, especially ribosomal protein genes, were highly over-represented. Expression analysis using a reporter gene driven by a synthetic promoter regulated by these elements showed that the Up1 is necessary and sufficient for germination-associated gene induction, whereas Up2 acts as an enhancer of Up1. Up1-mediated gene expression was suppressed by treatments that blocked germination. Up1 is almost identical to the site II motif, which is the predicted target of TCP transcription factors. Of 24 AtTCP genes, AtTCP14, which showed the highest transcript level just prior to germination, was functionally characterized to test its involvement in the regulation of seed germination. Transposon-tagged lines for AtTCP14 showed delayed germination. In addition, germination of attcp14 mutants exhibited hypersensitivity to exogenously applied abscisic acid and paclobutrazol, an inhibitor of gibberellin biosynthesis. AtTCP14 was predominantly expressed in the vascular tissues of the embryo, and affected gene expression in radicles in a non-cell-autonomous manner. Taken together, these results indicate that AtTCP14 regulates the activation of embryonic growth potential in Arabidopsis seeds.

Anorganic bovine-derived hydroxyapatite vs β-tricalcium phosphate in sinus augmentation: a comparative histomorphometric study.

PubMed

Kurkcu, Mehmet; Benlidayi, M Emre; Cam, Burcu; Sertdemir, Yasar

2012-09-01

The choice of augmentation material is a crucial factor in sinus augmentation surgery. Bovine-derived hydroxyapatite (BHA) and beta-tricalcium phosphate (β-TCP) have been used successfully in sinus augmentation procedures. Choosing one of these materials for sinus augmentation is still controversial. The aim of this clinical study was to compare the biological performance of the new BHA graft material and the well-known synthetic β-TCP material in the sinus augmentation procedure. The study consisted of 23 patients (12 male and 11 female) who were either edentulous or partially edentulous in the posterior maxilla and required implant placement. A total of 23 two-step sinus-grafting procedures were performed. BHA was used in 13 patients, and β-TCP was used in 10 patients. After an average of 6.5 months of healing, bone biopsies were taken from the grafted areas. Undecalcified sections were prepared for histomorphometric analysis. The mean new bone formation was 30.13% ± 3.45% in the BHA group and 21.09% ± 2.86% in the β-TCP group (P = .001). The mean percentage of residual graft particle area was 31.88% ± 6.05% and 34.05% ± 3.01% for the BHA group and β-TCP group, respectively (P = .047). The mean percentage of soft-tissue area was 37.99% ± 5.92% in the BHA group and 44.86% ± 4.28% in the β-TCP group (P = .011). Both graft materials demonstrated successful biocompatibility and osteoconductivity in the sinus augmentation procedure. However, BHA appears to be more efficient in osteoconduction when compared with β-TCP.

Effect of Casein Phosphopeptide-Amorphous Calcium Phosphate and Three Calcium Phosphate on Enamel Microhardness.

PubMed

Haghgou, En Hr; Haghgoo, Roza; Roholahi, Mohamad R; Ghorbani, Zahra

2017-07-01

This study aims to investigate the effect of casein phos-phopeptide-amorphous calcium phosphate and three calcium phosphate (CPP-ACP and TCP) on increasing the microhardness of human enamel after induction of erosion. A total of 26 healthy human-impacted third molar teeth were chosen, and their hardness measured using a microhardness testing machine. The samples were immersed in Coca Cola (pH = 4.7) for 8 minutes. Then, micro-hardness was measured again, and these samples were randomly divided into four groups (two control groups and two experimental groups). (1) Negative control group: Artificial saliva was used for 10 minutes, (2) positive control group: Fluoride gel was used for 10 minutes, (3) β-TCP group: TCP was used for 10 minutes, (4) CCP-ACP group: CCP-ACP was used for 10 minutes. The final microhardness of those samples was measured, and the changes in microhardness of teeth within group and between groups were analyzed using the paired and analysis of variance tests respectively. Results were considered statistically significant at a level of p < 0.05. No significant difference was observed in microhard-ness between CPP-ACP group and TCP group (p = 0.368) during the time microhardness significantly dropped after soaking in soda. Casein phosphopeptide-amorphous calcium phosphate and TCP increased the microhardness of teeth. The increase in hardness in the TCP group was higher than in the CPP-ACP group, but this difference was not significant (p = 0.36). Casein phosphopeptide-amorphous calcium phosphate and TCP can affect the remineralization of erosive lesions.

Biocompatibility and biodegradation studies of PCL/β-TCP bone tissue scaffold fabricated by structural porogen method.

PubMed

Lu, Lin; Zhang, Qingwei; Wootton, David; Chiou, Richard; Li, Dichen; Lu, Bingheng; Lelkes, Peter; Zhou, Jack

2012-09-01

Three-dimensional printer (3DP) (Z-Corp) is a solid freeform fabrication system capable of generating sub-millimeter physical features required for tissue engineering scaffolds. By using plaster composite materials, 3DP can fabricate a universal porogen which can be injected with a wide range of high melting temperature biomaterials. Here we report results toward the manufacture of either pure polycaprolactone (PCL) or homogeneous composites of 90/10 or 80/20 (w/w) PCL/beta-tricalcium phosphate (β-TCP) by injection molding into plaster composite porogens fabricated by 3DP. The resolution of printed plaster porogens and produced scaffolds was studied by scanning electron microscopy. Cytotoxicity test on scaffold extracts and biocompatibility test on the scaffolds as a matrix supporting murine osteoblast (7F2) and endothelial hybridoma (EAhy 926) cells growth for up to 4 days showed that the porogens removal process had only negligible effects on cell proliferation. The biodegradation tests of pure PCL and PCL/β-TCP composites were performed in DMEM with 10 % (v/v) FBS for up to 6 weeks. The PCL/β-TCP composites show faster degradation rate than that of pure PCL due to the addition of β-TCP, and the strength of 80/20 PCL/β-TCP composite is still suitable for human cancellous bone healing support after 6 weeks degradation. Combining precisely controlled porogen fabrication structure, good biocompatibility, and suitable mechanical properties after biodegradation, PCL/β-TCP scaffolds fabricated by 3DP porogen method provide essential capability for bone tissue engineering.

Effects of ß-TCP scaffolds on neurogenic and osteogenic differentiation of human embryonic stem cells.

PubMed

Arpornmaeklong, Premjit; Pressler, Michael J

2018-01-01

Extracellular matrix (ECM) and adhesion molecules play crucial roles in regulating growth and differentiation of stem cells. The current study aimed to investigate the effects of beta-tricalcium phosphate (ß-TCP) scaffolds on differentiation and expression of ECM and adhesion molecules of human embryonic stem cells (hESCs). Undifferentiated hESCs were seeded on ß-TCP scaffolds and cell culture plates and cultured in growth and osteogenic medium for 21 days. Scanning electron microscopy (SEM) displayed adhesion and growth of hESCs on the porous ß-TCP scaffolds. Histological analysis, immunohistochemical staining and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) demonstrated that the scaffolds supported growth and differentiation of hESCs. Expression levels of neural crest related genes (AP2a, FoxD3, HNK1, P75, Sox1, Sox10) and osteoblast-related genes (Runx2, SPP1 and BGLA) on the scaffolds in osteogenic medium were significantly higher than on the scaffolds in growth and cell culture plates in osteogenic medium, respectively (p<0.05). Polymerase chain reaction array experiments demonstrated increased expression of ECM and adhesion molecule-related genes on the scaffolds. In conclusion, osteoconductive scaffolds such as ß-TCP scaffolds promoted differentiation of hESCs, particularly expression of genes related to neural crest stem cell and osteoblastic differentiations. Beta-TCP scaffolds could be an alternative cell culture substrate for neural crest and osteogenic differentiation of hESCs. Optimization of culture medium may be necessary to enhance lineage restriction of hESCs on the ß-TCP scaffolds. Copyright © 2017 Elsevier GmbH. All rights reserved.

Under conditions of large geometric miss, tumor control probability can be higher for static gantry intensity-modulated radiation therapy compared to volume-modulated arc therapy for prostate cancer.

PubMed

Balderson, Michael; Brown, Derek; Johnson, Patricia; Kirkby, Charles

2016-01-01

The purpose of this work was to compare static gantry intensity-modulated radiation therapy (IMRT) with volume-modulated arc therapy (VMAT) in terms of tumor control probability (TCP) under scenarios involving large geometric misses, i.e., those beyond what are accounted for when margin expansion is determined. Using a planning approach typical for these treatments, a linear-quadratic-based model for TCP was used to compare mean TCP values for a population of patients who experiences a geometric miss (i.e., systematic and random shifts of the clinical target volume within the planning target dose distribution). A Monte Carlo approach was used to account for the different biological sensitivities of a population of patients. Interestingly, for errors consisting of coplanar systematic target volume offsets and three-dimensional random offsets, static gantry IMRT appears to offer an advantage over VMAT in that larger shift errors are tolerated for the same mean TCP. For example, under the conditions simulated, erroneous systematic shifts of 15mm directly between or directly into static gantry IMRT fields result in mean TCP values between 96% and 98%, whereas the same errors on VMAT plans result in mean TCP values between 45% and 74%. Random geometric shifts of the target volume were characterized using normal distributions in each Cartesian dimension. When the standard deviations were doubled from those values assumed in the derivation of the treatment margins, our model showed a 7% drop in mean TCP for the static gantry IMRT plans but a 20% drop in TCP for the VMAT plans. Although adding a margin for error to a clinical target volume is perhaps the best approach to account for expected geometric misses, this work suggests that static gantry IMRT may offer a treatment that is more tolerant to geometric miss errors than VMAT. Copyright © 2016 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

SU-E-T-352: Why Is the Survival Rate Low in Oropharyngeal Squamous Cell Carcinoma?

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

Huang, Z; Feng, Y; Rasmussen, K

2014-06-01

Purpose: Tumors are composed of a large number of clonogens that have the capability of indefinite reproduction. Even when there is complete clinical or radiographic regression of the gross tumor mass after treatment, tumor recurrence can occur if the clonogens are not completely eradicated by radiotherapy. This study was to investigate the colonogen number and its association with the tumor control probability (TCP) in oropharyngeal squamous cell carcinoma (OSCCA). Methods: A literature search was conducted to collect clinical information of patients with OSCCA, including the prescription dose, tumor volume and survival rate. The linear-quadratic (LQ) model was incorporated into TCPmore » model for clinical data analysis. The total dose ranged from 60 to 70 Gy and tumor volume ranged from 10 to 50 cc. The TCP was calculated for each group according to tumor size and dose. The least χ{sup 2} method was used to fit the TCP calculation to clinical data while other LQ model parameters (α, β) were adopted from the literature, due to the limited patient data. Results: A total of 190 patients with T2–T4 OSCCA were included. The association with HPV was not available for all the patients. The 3-year survival rate was about 82% for T2 squamous cell carcinoma and 40% for advanced tumors. Fitting the TCP model to the survival data, the average clonogen number was 1.56×10{sup 12}. For the prescription dose of 70 Gy, the calculated TCP ranged from 40% to 90% when the tumor volume varied from 10 to 50 cc. Conclusion: Our data suggests variation between the clonogen number and TCP in OSCCA. Tumors with larger colonogen number tend to have lower TCP and therefore dose escalation above 70 Gy may be indicated in order to improve the TCP and survival rate. Our result will require future confirmation with a large number of patients.« less

High prevalence of known and unknown pulmonary diseases in patients with claudication during exercise oximetry: A retrospective analysis.

PubMed

Colas-Ribas, Christophe; Signolet, Isabelle; Henni, Samir; Feuillloy, Mathieu; Gagnadoux, Frédéric; Abraham, Pierre

2016-10-01

The prevalence of pulmonary disease in patients with peripheral artery disease (PAD) has not been extensively studied. Recent evidence has shown that ∼20% of the patients have an atypical chest transcutaneous oxygen pressure (TcpO2) pattern during exercise, which suggests walking-induced hypoxemia. The main objectives of this study were to: (1) describe in a retrospective way the characteristics of the patients suffering from claudication, who attended a treadmill testing in our laboratory, (2) assess the prevalence of known or unknown pulmonary disease. The second aim of this study was to evaluate the impact of the therapeutic interventions on the walking capacities, after treatment, of the eventually detected pulmonary disorders.We retrospectively analyzed 1482 exercise TcpO2 test results. Patients that had no history of pulmonary disease, but either reported severe dyspnea or showed atypical profiles on their chest exercise-TcpO2, were advised to refer to the department of pneumology for additional investigations.In addition to the 166 patients with a history of pulmonary disease, 158 patients were suspected of unknown pulmonary disease from the result of their TcpO2 test. Many patients (n = 99/158, 62.7%) did not attend a pulmonologist visit. A pulmonary disease was established in 55 (93.2%) of the other 59 patients. Obstructive sleep apnea syndrome (OSAS) was the one and only diagnosis retained in 42/59 patients (71.2%). Among the 47 patients who had a second evaluation of their walking capacity on treadmill, 38 had treatment of the pulmonary disease found, vascular surgery treatment or a severe restricted diet, 9 had no treatment. Only the "treated" group showed a significant improvement in the maximal walking distance on treadmill between the 2 evaluations, 313 ± 251 m to 433 ± 317 m (P = 0.03).This retrospective pilot study underlines the high prevalence of both known and unknown pulmonary disease in patients whose primary complaint was lower limb claudication. Systematic screening and treatment of pulmonary disease in patients with claudication might be justified, to improve walking ability of such patients and possibly reduce or delay the requirement for revascularization. Prospective studies are required to confirm these preliminary results.

Evolving Tale of TCPs: New Paradigms and Old Lacunae

PubMed Central

Dhaka, Namrata; Bhardwaj, Vasudha; Sharma, Manoj K.; Sharma, Rita

2017-01-01

Teosinte Branched1/Cycloidea/Proliferating cell factors (TCP) genes are key mediators of genetic innovations underlying morphological novelties, stress adaptation, and evolution of immune response in plants. They have a remarkable ability to integrate and translate diverse endogenous, and environmental signals with high fidelity. Compilation of studies, aimed at elucidating the mechanism of TCP functions, shows that it takes an amalgamation and interplay of several different factors, regulatory processes and pathways, instead of individual components, to achieve the incredible functional diversity and specificity, demonstrated by TCP proteins. Through this minireview, we provide a brief description of key structural features and molecular components, known so far, that operate this conglomerate, and highlight the important conceptual challenges and lacunae in TCP research. PMID:28421104

Evolving Tale of TCPs: New Paradigms and Old Lacunae.

PubMed

Dhaka, Namrata; Bhardwaj, Vasudha; Sharma, Manoj K; Sharma, Rita

2017-01-01

Teosinte Branched1/Cycloidea/Proliferating cell factors (TCP) genes are key mediators of genetic innovations underlying morphological novelties, stress adaptation, and evolution of immune response in plants. They have a remarkable ability to integrate and translate diverse endogenous, and environmental signals with high fidelity. Compilation of studies, aimed at elucidating the mechanism of TCP functions, shows that it takes an amalgamation and interplay of several different factors, regulatory processes and pathways, instead of individual components, to achieve the incredible functional diversity and specificity, demonstrated by TCP proteins. Through this minireview, we provide a brief description of key structural features and molecular components, known so far, that operate this conglomerate, and highlight the important conceptual challenges and lacunae in TCP research.

Spectroscopic Confirmation of TCP J07134590-2112330 as a Galactic Classical Nova in Canis Major

NASA Astrophysics Data System (ADS)

Strader, Jay; Chomiuk, Laura; Bahramian, Arash; Swihart, Sam

2018-03-01

TCP J07134590-2112330 was discovered by Yuji Nakamura on 2018 March 24.5 UT as a 12 mag optical transient. We obtained spectroscopic observations of TCP J07134590-2112330 with the Goodman spectrograph on the 4-m SOAR telescope on 2018 Mar 25.1 UT, with a low-resolution spectrum (R 1200) covering 3850-7850 A. The spectrum indicates that TCP J07134590-2112330 is a young classical nova, with strong hydrogen Balmer emission lines and additional strong lines of [O I] and Fe II. The Balmer lines show P Cygni profiles; the FWHM of the H alpha emission component is 1250 km/s, and the absorption trough extends to -2000 km/s.

Research and realization of key technology in HILS interactive system

NASA Astrophysics Data System (ADS)

Liu, Che; Lu, Huiming; Wang, Fankai

2018-03-01

This paper designed HILS (Hardware In the Loop Simulation) interactive system based on xPC platform . Through the interface between C++ and MATLAB engine, establish the seamless data connection between Simulink and interactive system, complete data interaction between system and Simulink, realize the function development of model configuration, parameter modification and off line simulation. We establish the data communication between host and target machine through TCP/IP protocol to realize the model download and real-time simulation. Use database to store simulation data, implement real-time simulation monitoring and simulation data management. Realize system function integration by Qt graphic interface library and dynamic link library. At last, take the typical control system as an example to verify the feasibility of HILS interactive system.

TU-A-BRD-01: Outcomes of Hypofractionated Treatments - Initial Results of the WGSBRT

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

Li, X; Lee, P; Ohri, N

2014-06-15

Stereotactic Body Radiation Therapy (SBRT) has emerged in recent decades as a treatment paradigm that is becoming increasingly important in clinical practice. Clinical outcomes data are rapidly accumulating. Although published relations between outcomes and dose distributions are still sparse, the field has progressed to the point where evidence-based normal tissue dose-volume constraints, prescription strategies, and Tumor Control Probability (TCP) and Normal Tissue Complication Probability (NTCP) models can be developed. The Working Group on SBRT (WGSBRT), under the Biological Effects Subcommittee of AAPM, is a group of physicists and physicians working in the area of SBRT. It is currently performing criticalmore » literature reviews to extract and synthesize usable data and to develop guidelines and models to aid with safe and effective treatment. The group is investigating clinically relevant findings from SBRT in six anatomical regions: Cranial, Head and Neck, Thoracic, Abdominal, Pelvic, and Spinal. In this session of AAPM 2014, interim results are presented on TCP for lung and liver, NTCP for thoracic organs, and radiobiological foundations:• Lung TCP: Detailed modeling of TCP data from 118 published studies on early stage lung SBRT investigates dose response and hypothesized mechanisms to explain the improved outcomes of SBRT. This is presented from the perspective of a physicist, a physician, and a radiobiologist.• Liver TCP: For primary and metastatic liver tumors, individual patient data were extracted from published reports to examine the effects of biologically effective dose on local control.• Thoracic NTCP: Clinically significant SBRT toxicity of lung, rib / chest wall and other structures are evaluated and compared among published clinical data, in terms of risk, risk factors, and safe practice.• Improving the clinical utility of published toxicity reports from SBRT and Hypofractionated treatments. What do we want, and how do we get it? Methods and problems of synthesizing data from published reports. Learning Objectives: Common SBRT fractionation schemes and current evidence for efficacy. Evidence for normal tissue tolerances in hypofractionated treatments. Clinically relevant radiobiological effects at large fraction sizes.« less

Adapting radiotherapy to hypoxic tumours

NASA Astrophysics Data System (ADS)

Malinen, Eirik; Søvik, Åste; Hristov, Dimitre; Bruland, Øyvind S.; Rune Olsen, Dag

2006-10-01

In the current work, the concepts of biologically adapted radiotherapy of hypoxic tumours in a framework encompassing functional tumour imaging, tumour control predictions, inverse treatment planning and intensity modulated radiotherapy (IMRT) were presented. Dynamic contrast enhanced magnetic resonance imaging (DCEMRI) of a spontaneous sarcoma in the nasal region of a dog was employed. The tracer concentration in the tumour was assumed related to the oxygen tension and compared to Eppendorf histograph measurements. Based on the pO2-related images derived from the MR analysis, the tumour was divided into four compartments by a segmentation procedure. DICOM structure sets for IMRT planning could be derived thereof. In order to display the possible advantages of non-uniform tumour doses, dose redistribution among the four tumour compartments was introduced. The dose redistribution was constrained by keeping the average dose to the tumour equal to a conventional target dose. The compartmental doses yielding optimum tumour control probability (TCP) were used as input in an inverse planning system, where the planning basis was the pO2-related tumour images from the MR analysis. Uniform (conventional) and non-uniform IMRT plans were scored both physically and biologically. The consequences of random and systematic errors in the compartmental images were evaluated. The normalized frequency distributions of the tracer concentration and the pO2 Eppendorf measurements were not significantly different. 28% of the tumour had, according to the MR analysis, pO2 values of less than 5 mm Hg. The optimum TCP following a non-uniform dose prescription was about four times higher than that following a uniform dose prescription. The non-uniform IMRT dose distribution resulting from the inverse planning gave a three times higher TCP than that of the uniform distribution. The TCP and the dose-based plan quality depended on IMRT parameters defined in the inverse planning procedure (fields and step-and-shoot intensity levels). Simulated random and systematic errors in the pO2-related images reduced the TCP for the non-uniform dose prescription. In conclusion, improved tumour control of hypoxic tumours by dose redistribution may be expected following hypoxia imaging, tumour control predictions, inverse treatment planning and IMRT.

Radiobiological Impact of Planning Techniques for Prostate Cancer in Terms of Tumor Control Probability and Normal Tissue Complication Probability

PubMed Central

Rana, S; Cheng, CY

2014-01-01

Background: The radiobiological models describe the effects of the radiation treatment on cancer and healthy cells, and the radiobiological effects are generally characterized by the tumor control probability (TCP) and normal tissue complication probability (NTCP). Aim: The purpose of this study was to assess the radiobiological impact of RapidArc planning techniques for prostate cancer in terms of TCP and normal NTCP. Subjects and Methods: A computed tomography data set of ten cases involving low-risk prostate cancer was selected for this retrospective study. For each case, two RapidArc plans were created in Eclipse treatment planning system. The double arc (DA) plan was created using two full arcs and the single arc (SA) plan was created using one full arc. All treatment plans were calculated with anisotropic analytical algorithm. Radiobiological modeling response evaluation was performed by calculating Niemierko's equivalent uniform dose (EUD)-based Tumor TCP and NTCP values. Results: For prostate tumor, the average EUD in the SA plans was slightly higher than in the DA plans (78.10 Gy vs. 77.77 Gy; P = 0.01), but the average TCP was comparable (98.3% vs. 98.3%; P = 0.01). In comparison to the DA plans, the SA plans produced higher average EUD to bladder (40.71 Gy vs. 40.46 Gy; P = 0.03) and femoral heads (10.39 Gy vs. 9.40 Gy; P = 0.03), whereas both techniques produced NTCP well below 0.1% for bladder (P = 0.14) and femoral heads (P = 0.26). In contrast, the SA plans produced higher average NTCP compared to the DA plans (2.2% vs. 1.9%; P = 0.01). Furthermore, the EUD to rectum was slightly higher in the SA plans (62.88 Gy vs. 62.22 Gy; P = 0.01). Conclusion: The SA and DA techniques produced similar TCP for low-risk prostate cancer. The NTCP for femoral heads and bladder was comparable in the SA and DA plans; however, the SA technique resulted in higher NTCP for rectum in comparison with the DA technique. PMID:24761232