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Sample records for direct rubisco fixation

  1. Prospects for improving CO2 fixation in C3-crops through understanding C4-Rubisco biogenesis and catalytic diversity.

    Sharwood, Robert E; Ghannoum, Oula; Whitney, Spencer M

    2016-06-01

    By operating a CO2 concentrating mechanism, C4-photosynthesis offers highly successful solutions to remedy the inefficiency of the CO2-fixing enzyme Rubisco. C4-plant Rubisco has characteristically evolved faster carboxylation rates with low CO2 affinity. Owing to high CO2 concentrations in bundle sheath chloroplasts, faster Rubisco enhances resource use efficiency in C4 plants by reducing the energy and carbon costs associated with photorespiration and lowering the nitrogen investment in Rubisco. Here, we show that C4-Rubisco from some NADP-ME species, such as maize, are also of potential benefit to C3-photosynthesis under current and future atmospheric CO2 pressures. Realizing this bioengineering endeavour necessitates improved understanding of the biogenesis requirements and catalytic variability of C4-Rubisco, as well as the development of transformation capabilities to engineer Rubisco in a wider variety of food and fibre crops. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Role of the Rubisco Small Subunit

    Spreitzer, Robert Joseph [Univ. of Nebraska, Lincoln, NE (United States)

    2016-11-05

    Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes the rate-limiting step of CO2 fixation in photosynthesis. However, it is a slow enzyme, and O2 competes with CO2 at the active site. Oxygenation initiates the photorespiratory pathway, which also results in the loss of CO2. If carboxylation could be increased or oxygenation decreased, an increase in net CO2 fixation would be realized. Because Rubisco provides the primary means by which carbon enters all life on earth, there is much interest in engineering Rubisco to increase the production of food and renewable energy. Rubisco is located in the chloroplasts of plants, and it is comprised of two subunits. Much is known about the chloroplast-gene-encoded large subunit (rbcL gene), which contains the active site, but much less is known about the role of the nuclear-gene-encoded small subunit in Rubisco function (rbcS gene). Both subunits are coded by multiple genes in plants, which makes genetic engineering difficult. In the eukaryotic, green alga Chlamydomonas reinhardtii, it has been possible to eliminate all the Rubisco genes. These Rubisco-less mutants can be maintained by providing acetate as an alternative carbon source. In this project, focus has been placed on determining whether the small subunit might be a better genetic-engineering target for improving Rubisco. Analysis of a variable-loop structure (βA-βB loop) of the small subunit by genetic selection, directed mutagenesis, and construction of chimeras has shown that the small subunit can influence CO2/O2 specificity. X-ray crystal structures of engineered chimeric-loop enzymes have indicated that additional residues and regions of the small subunit may also contribute to Rubisco function. Structural dynamics of the small-subunit carboxyl terminus was also investigated. Alanine-scanning mutagenesis of the most-conserved small-subunit residues has identified a

  3. An improved PCR method for direct identification of Porphyra (Bangiales, Rhodophyta) using conchocelis based on a RUBISCO intergenic spacer

    Wang, Chao; Dong, Dong; Wang, Guangce; Zhang, Baoyu; Peng, Guang; Xu, Pu; Tang, Xiaorong

    2009-09-01

    An improved method of PCR in which the small segment of conchocelis is amplified directly without DNA extraction was used to amplify a RUBISCO intergenic spacer DNA fragment from nine species of red algal genus Porphyra (Bangiales, Rhodophyta), including Porphyra yezoensis (Jiangsu, China), P. haitanensis (Fujian, China), P. oligospermatangia (Qingdao, China), P. katadai (Qingdao, China), P. tenera (Qingdao, China), P. suborboculata (Fujian, China), P. pseudolinearis (Kogendo, Korea), P. linearis (Devon, England), and P. fallax (Seattle, USA). Standard PCR and the method developed here were both conducted using primers specific for the RUBISCO spacer region, after which the two PCR products were sequenced. The sequencing data of the amplicons obtained using both methods were identical, suggesting that the improved PCR method was functional. These findings indicate that the method developed here may be useful for the rapid identification of species of Porphyra in a germplasm bank. In addition, a phylogenetic tree was constructed using the RUBISCO spacer and partial rbcS sequence, and the results were in concordant with possible alternative phylogenies based on traditional morphological taxonomic characteristics, indicating that the RUBISCO spacer is a useful region for phylogenetic studies.

  4. Contribution of carbon fixed by Rubisco and PEPC to phloem export in the Crassulacean acid metabolism plant Kalanchoe daigremontiana.

    Wild, Birgit; Wanek, Wolfgang; Postl, Wolfgang; Richter, Andreas

    2010-03-01

    Crassulacean acid metabolism (CAM) plants exhibit a complex interplay between CO(2) fixation by phosphoenolpyruvate carboxylase (PEPC) and ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco), and carbon demand for CAM maintenance and growth. This study investigated the flux of carbon from PEPC and direct Rubisco fixation to different leaf carbon pools and to phloem sap over the diurnal cycle. Concentrations and carbon isotope compositions of starch, soluble sugars, and organic acids were determined in leaves and phloem exudates of Kalanchoë daigremontiana Hamet et Perr., and related to CO(2) fixation by PEPC and Rubisco. Three types of leaf carbon pools could be distinguished. (i) Starch and malate pools were dominant and showed a pattern of reciprocal mobilization and accumulation (85/54 and 13/48 mg C g(-1) DW, respective, at the beginning/end of phase I). The carbon isotope composition of these pools was compatible with predominant PEPC fixation (delta(13)C values of -13 and -11 per thousand for starch and malate compared to -11 per thousand of PEPC fixed carbon). (ii) Isotopic composition (-17 per thousand and -14 per thousand) and concentration of glucose and fructose (2 and 3 mg C g(-1) DW, respectively) were not affected by diurnal metabolism, suggesting a low turnover. (iii) Sucrose (1-3 mg C g(-1) DW), in contrast, exhibited large diurnal changes in delta(13)C values (from -17 per thousand in the evening to -12 per thousand in the morning), which were not matched by net changes in sucrose concentration. This suggests a high sucrose turnover, fed by nocturnal starch degradation and direct Rubisco fixation during the day. A detailed dissection of the carbon fixation and mobilization pattern in K. daigremontiana revealed that direct fixation of Rubisco during the light accounted for 30% of phloem sucrose, but only 15% of fixed carbon, indicating that carbon from direct Rubisco fixation was preferentially used for leaf export.

  5. Surveying the expanding prokaryotic Rubisco multiverse.

    Liu, Di; Ramya, Ramaswamy Chettiyan Seetharaman; Mueller-Cajar, Oliver

    2017-09-01

    The universal, but catalytically modest, CO2-fixing enzyme Rubisco is currently experiencing intense interest by researchers aiming to enhance crop photosynthesis. These efforts are mostly focused on the highly conserved hexadecameric enzyme found in land plants. In comparison, prokaryotic organisms harbor a far greater diversity in Rubisco forms. Recent work towards improving our appreciation of microbial Rubisco properties and harnessing their potential is surveyed. New structural models are providing informative glimpses into catalytic subtleties and diverse oligomeric states. Ongoing characterization is informing us about the conservation of constraints, such as sugar phosphate inhibition and the associated dependence on Rubisco activase helper proteins. Prokaryotic Rubiscos operate under a far wider range of metabolic contexts than the photosynthetic function of higher plant enzymes. Relaxed selection pressures may have resulted in the exploration of a larger volume of sequence space than permitted in organisms performing oxygenic photosynthesis. To tap into the potential of microbial Rubiscos, in vivo selection systems are being used to discover functional metagenomic Rubiscos. Various directed evolution systems to optimize their function have been developed. It is anticipated that this approach will provide access to biotechnologically valuable enzymes that cannot be encountered in the higher plant Rubisco space. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. Molecular Evolution of the Substrate Specificity of Chloroplastic Aldolases/Rubisco Lysine Methyltransferases in Plants.

    Ma, Sheng; Martin-Laffon, Jacqueline; Mininno, Morgane; Gigarel, Océane; Brugière, Sabine; Bastien, Olivier; Tardif, Marianne; Ravanel, Stéphane; Alban, Claude

    2016-04-04

    Rubisco and fructose-1,6-bisphosphate aldolases (FBAs) are involved in CO2 fixation in chloroplasts. Both enzymes are trimethylated at a specific lysine residue by the chloroplastic protein methyltransferase LSMT. Genes coding LSMT are present in all plant genomes but the methylation status of the substrates varies in a species-specific manner. For example, chloroplastic FBAs are naturally trimethylated in both Pisum sativum and Arabidopsis thaliana, whereas the Rubisco large subunit is trimethylated only in the former species. The in vivo methylation status of aldolases and Rubisco matches the catalytic properties of AtLSMT and PsLSMT, which are able to trimethylate FBAs or FBAs and Rubisco, respectively. Here, we created chimera and site-directed mutants of monofunctional AtLSMT and bifunctional PsLSMT to identify the molecular determinants responsible for substrate specificity. Our results indicate that the His-Ala/Pro-Trp triad located in the central part of LSMT enzymes is the key motif to confer the capacity to trimethylate Rubisco. Two of the critical residues are located on a surface loop outside the methyltransferase catalytic site. We observed a strict correlation between the presence of the triad motif and the in vivo methylation status of Rubisco. The distribution of the motif into a phylogenetic tree further suggests that the ancestral function of LSMT was FBA trimethylation. In a recent event during higher plant evolution, this function evolved in ancestors of Fabaceae, Cucurbitaceae, and Rosaceae to include Rubisco as an additional substrate to the archetypal enzyme. Our study provides insight into mechanisms by which SET-domain protein methyltransferases evolve new substrate specificity. Copyright © 2016 The Author. Published by Elsevier Inc. All rights reserved.

  7. Rubisco Activases: AAA+ Chaperones Adapted to Enzyme Repair.

    Bhat, Javaid Y; Thieulin-Pardo, Gabriel; Hartl, F Ulrich; Hayer-Hartl, Manajit

    2017-01-01

    Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), the key enzyme of the Calvin-Benson-Bassham cycle of photosynthesis, requires conformational repair by Rubisco activase for efficient function. Rubisco mediates the fixation of atmospheric CO 2 by catalyzing the carboxylation of the five-carbon sugar ribulose-1,5-bisphosphate (RuBP). It is a remarkably inefficient enzyme, and efforts to increase crop yields by bioengineering Rubisco remain unsuccessful. This is due in part to the complex cellular machinery required for Rubisco biogenesis and metabolic maintenance. To function, Rubisco must undergo an activation process that involves carboxylation of an active site lysine by a non-substrate CO 2 molecule and binding of a Mg 2+ ion. Premature binding of the substrate RuBP results in an inactive enzyme. Moreover, Rubisco can also be inhibited by a range of sugar phosphates, some of which are "misfire" products of its multistep catalytic reaction. The release of the inhibitory sugar molecule is mediated by the AAA+ protein Rubisco activase (Rca), which couples hydrolysis of ATP to the structural remodeling of Rubisco. Rca enzymes are found in the vast majority of photosynthetic organisms, from bacteria to higher plants. They share a canonical AAA+ domain architecture and form six-membered ring complexes but are diverse in sequence and mechanism, suggesting their convergent evolution. In this review, we discuss recent advances in understanding the structure and function of this important group of client-specific AAA+ proteins.

  8. Engineering chloroplasts to improve Rubisco catalysis: prospects for translating improvements into food and fiber crops.

    Sharwood, Robert E

    2017-01-01

    494 I. 495 II. 496 III. 496 IV. 499 V. 499 VI. 501 VII. 501 VIII. 502 IX. 505 X. 506 507 References 507 SUMMARY: The uncertainty of future climate change is placing pressure on cropping systems to continue to provide stable increases in productive yields. To mitigate future climates and the increasing threats against global food security, new solutions to manipulate photosynthesis are required. This review explores the current efforts available to improve carbon assimilation within plant chloroplasts by engineering Rubisco, which catalyzes the rate-limiting step of CO 2 fixation. Fixation of CO 2 and subsequent cycling of 3-phosphoglycerate through the Calvin cycle provides the necessary carbohydrate building blocks for maintaining plant growth and yield, but has to compete with Rubisco oxygenation, which results in photorespiration that is energetically wasteful for plants. Engineering improvements in Rubisco is a complex challenge and requires an understanding of chloroplast gene regulatory pathways, and the intricate nature of Rubisco catalysis and biogenesis, to transplant more efficient forms of Rubisco into crops. In recent times, major advances in Rubisco engineering have been achieved through improvement of our knowledge of Rubisco synthesis and assembly, and identifying amino acid catalytic switches in the L-subunit responsible for improvements in catalysis. Improving the capacity of CO 2 fixation in crops such as rice will require further advances in chloroplast bioengineering and Rubisco biogenesis. © 2016 The Author. New Phytologist © 2016 New Phytologist Trust.

  9. Direct lexical control of eye movements in reading: Evidence from a survival analysis of fixation durations

    Reingold, Eyal M.; Reichle, Erik D.; Glaholt, Mackenzie G.; Sheridan, Heather

    2013-01-01

    Participants’ eye movements were monitored in an experiment that manipulated the frequency of target words (high vs. low) as well as their availability for parafoveal processing during fixations on the pre-target word (valid vs. invalid preview). The influence of the word-frequency by preview validity manipulation on the distributions of first fixation duration was examined by using ex-Gaussian fitting as well as a novel survival analysis technique which provided precise estimates of the timing of the first discernible influence of word frequency on first fixation duration. Using this technique, we found a significant influence of word frequency on fixation duration in normal reading (valid preview) as early as 145 ms from the start of fixation. We also demonstrated an equally rapid non-lexical influence on first fixation duration as a function of initial landing position (location) on target words. The time-course of frequency effects, but not location effects was strongly influenced by preview validity, demonstrating the crucial role of parafoveal processing in enabling direct lexical control of reading fixation times. Implications for models of eye-movement control are discussed. PMID:22542804

  10. A function-based screen for seeking RubisCO active clones from metagenomes: novel enzymes influencing RubisCO activity.

    Böhnke, Stefanie; Perner, Mirjam

    2015-03-01

    Ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) is a key enzyme of the Calvin cycle, which is responsible for most of Earth's primary production. Although research on RubisCO genes and enzymes in plants, cyanobacteria and bacteria has been ongoing for years, still little is understood about its regulation and activation in bacteria. Even more so, hardly any information exists about the function of metagenomic RubisCOs and the role of the enzymes encoded on the flanking DNA owing to the lack of available function-based screens for seeking active RubisCOs from the environment. Here we present the first solely activity-based approach for identifying RubisCO active fosmid clones from a metagenomic library. We constructed a metagenomic library from hydrothermal vent fluids and screened 1056 fosmid clones. Twelve clones exhibited RubisCO activity and the metagenomic fragments resembled genes from Thiomicrospira crunogena. One of these clones was further analyzed. It contained a 35.2 kb metagenomic insert carrying the RubisCO gene cluster and flanking DNA regions. Knockouts of twelve genes and two intergenic regions on this metagenomic fragment demonstrated that the RubisCO activity was significantly impaired and was attributed to deletions in genes encoding putative transcriptional regulators and those believed to be vital for RubisCO activation. Our new technique revealed a novel link between a poorly characterized gene and RubisCO activity. This screen opens the door to directly investigating RubisCO genes and respective enzymes from environmental samples.

  11. Exploiting transplastomically modified Rubisco to rapidly measure natural diversity in its carbon isotope discrimination using tuneable diode laser spectroscopy.

    von Caemmerer, Susanne; Tazoe, Youshi; Evans, John R; Whitney, Spencer M

    2014-07-01

    Carbon isotope discrimination (Δ) during C3 photosynthesis is dominated by the fractionation occurring during CO2-fixation by the enzyme Rubisco. While knowing the fractionation by enzymes is pivotal to fully understanding plant carbon metabolism, little is known about variation in the discrimination factor of Rubisco (b) as it is difficult to measure using existing in vitro methodologies. Tuneable diode laser absorption spectroscopy has improved the ability to make rapid measurements of Δ concurrently with photosynthetic gas exchange. This study used this technique to estimate b in vivo in five tobacco (Nicotiana tabacum L. cv Petit Havana [N,N]) genotypes expressing alternative Rubisco isoforms. For transplastomic tobacco producing Rhodospirillum rubrum Rubisco b was 23.8±0.7‰, while Rubisco containing the large subunit Leu-335-Val mutation had a b-value of 13.9±0.7‰. These values were significantly less than that for Rubisco from wild-type tobacco (b=29‰), a C3 species. Transplastomic tobacco producing chimeric Rubisco comprising tobacco Rubisco small subunits and the catalytic large subunits from either the C4 species Flaveria bidentis or the C3-C4 species Flaveria floridana had b-values of 27.8±0.8 and 28.6±0.6‰, respectively. These values were not significantly different from tobacco Rubisco. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  12. Differential expression of rubisco in sporophytes and gametophytes of some marine macroalgae.

    Chao Wang

    2011-01-01

    Full Text Available Rubisco (ribulose-1, 5-bisphosphate carboxylase/oxygenase, a key enzyme of photosynthetic CO(2 fixation, is one of the most abundant proteins in both higher plants and algae. In this study, the differential expression of Rubisco in sporophytes and gametophytes of four seaweed species--Porphyra yezoensis, P. haitanensis, Bangia fuscopurpurea (Rhodophyte and Laminaria japonica (Phaeophyceae--was studied in terms of the levels of transcription, translation and enzyme activity. Results indicated that both the Rubisco content and the initial carboxylase activity were notably higher in algal gametophytes than in the sporophytes, which suggested that the Rubisco content and the initial carboxylase activity were related to the ploidy of the generations of the four algal species.

  13. A short history of RubisCO: the rise and fall (?) of Nature's predominant CO2 fixing enzyme.

    Erb, Tobias J; Zarzycki, Jan

    2018-02-01

    Ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) is arguably one of the most abundant proteins in the biosphere and a key enzyme in the global carbon cycle. Although RubisCO has been intensively studied, its evolutionary origins and rise as Nature's most dominant carbon dioxide (CO 2 )-fixing enzyme still remain in the dark. In this review we will bring together biochemical, structural, physiological, microbiological, as well as phylogenetic data to speculate on the evolutionary roots of the CO 2 -fixation reaction of RubisCO, the emergence of RubisCO-based autotrophic CO 2 -fixation in the context of the Calvin-Benson-Bassham cycle, and the further evolution of RubisCO into the 'RubisCOsome', a complex of various proteins assembling and interacting with the enzyme to improve its operational capacity (functionality) under different biological and environmental conditions. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Highly conserved small subunit residues influence rubisco large subunit catalysis.

    Genkov, Todor; Spreitzer, Robert J

    2009-10-30

    The chloroplast enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes the rate-limiting step of photosynthetic CO(2) fixation. With a deeper understanding of its structure-function relationships and competitive inhibition by O(2), it may be possible to engineer an increase in agricultural productivity and renewable energy. The chloroplast-encoded large subunits form the active site, but the nuclear-encoded small subunits can also influence catalytic efficiency and CO(2)/O(2) specificity. To further define the role of the small subunit in Rubisco function, the 10 most conserved residues in all small subunits were substituted with alanine by transformation of a Chlamydomonas reinhardtii mutant that lacks the small subunit gene family. All the mutant strains were able to grow photosynthetically, indicating that none of the residues is essential for function. Three of the substitutions have little or no effect (S16A, P19A, and E92A), one primarily affects holoenzyme stability (L18A), and the remainder affect catalysis with or without some level of associated structural instability (Y32A, E43A, W73A, L78A, P79A, and F81A). Y32A and E43A cause decreases in CO(2)/O(2) specificity. Based on the x-ray crystal structure of Chlamydomonas Rubisco, all but one (Glu-92) of the conserved residues are in contact with large subunits and cluster near the amino- or carboxyl-terminal ends of large subunit alpha-helix 8, which is a structural element of the alpha/beta-barrel active site. Small subunit residues Glu-43 and Trp-73 identify a possible structural connection between active site alpha-helix 8 and the highly variable small subunit loop between beta-strands A and B, which can also influence Rubisco CO(2)/O(2) specificity.

  15. Comparison of inoculant and indigenous rhizobial dinitrogen fixation in cowpeas by direct nitrogen-15 analyses

    ElHassan, G.A.; Focht, D.D.

    1986-01-01

    Soil that contained 15 N enriched organic matter (0.461 % 15 N) was used to determine competitiveness of six strains at different logarithmic inoculum densities against indigenous rhizobia and against a previous surviving inoculant (strain P132). Analyses of N content of plant tissues by direct 15 N technique showed that cowpeas (Vigna unguiculata L. Walp.) were capable of deriving 60 to 98% of shoot N from N 2 fixation. The two fast-growing strains (176A26 and 176A28) were poorer competitors and fixed less N 2 compared to the other slow-growing strains. Inoculum density had no effect upon yield response of cowpeas, but inoculation with strains P132, 401, and 22A1 effected greater seed yield, shoot dry matter, total N, and percentage of N derived from fixation (86-98%) than other strains and the uninoculated control (60-73%). By contrast, N 2 fixation and yield parameters in inoculated cowpeas were not significantly different from inoculated controls that contained residual P132 from a previous inoculum study. The higher hydrogen uptake (Hup) efficiency of nodules containing residual P132 (98 ± 2%) facilitated presumptive identification of P132 (100% ± 0 Hup efficiency axenically) as the surviving and infecting inoculant strain since nodules infected by indigenous rhizobia had lower Hup efficiencies (88 ± 2%)

  16. Internal Fixation of Complicated Acetabular Fractures Directed by Preoperative Surgery with 3D Printing Models.

    Liu, Zhao-Jie; Jia, Jian; Zhang, Yin-Guang; Tian, Wei; Jin, Xin; Hu, Yong-Cheng

    2017-05-01

    The purpose of this article is to evaluate the efficacy and feasibility of preoperative surgery with 3D printing-assisted internal fixation of complicated acetabular fractures. A retrospective case review was performed for the above surgical procedure. A 23-year-old man was confirmed by radiological examination to have fractures of multiple ribs, with hemopneumothorax and communicated fractures of the left acetabulum. According to the Letounel and Judet classification, T-shaped fracture involving posterior wall was diagnosed. A 3D printing pelvic model was established using CT digital imaging and communications in medicine (DICOM) data preoperatively, with which surgical procedures were simulated in preoperative surgery to confirm the sequence of the reduction and fixation as well as the position and length of the implants. Open reduction with internal fixation (ORIF) of the acetabular fracture using modified ilioinguinal and Kocher-Langenbeck approaches was performed 25 days after injury. Plates that had been pre-bent in the preoperative surgery were positioned and screws were tightened in the directions determined in the preoperative planning following satisfactory reduction. The duration of the operation was 170 min and blood loss was 900 mL. Postoperative X-rays showed that anatomical reduction of the acetabulum was achieved and the hip joint was congruous. The position and length of the implants were not different when compared with those in preoperative surgery on 3D printing models. We believe that preoperative surgery using 3D printing models is beneficial for confirming the reduction and fixation sequence, determining the reduction quality, shortening the operative time, minimizing preoperative difficulties, and predicting the prognosis for complicated fractures of acetabulam. © 2017 Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.

  17. Coevolution of amino acid residues in the key photosynthetic enzyme Rubisco

    Kapralov Maxim V

    2011-09-01

    Full Text Available Abstract Background One of the key forces shaping proteins is coevolution of amino acid residues. Knowing which residues coevolve in a particular protein may facilitate our understanding of protein evolution, structure and function, and help to identify substitutions that may lead to desired changes in enzyme kinetics. Rubisco, the most abundant enzyme in biosphere, plays an essential role in the process of carbon fixation through photosynthesis, thus facilitating life on Earth. This makes Rubisco an important model system for studying the dynamics of protein fitness optimization on the evolutionary landscape. In this study we investigated the selective and coevolutionary forces acting on large subunit of land plants Rubisco using Markov models of codon substitution and clustering approaches applied to amino acid substitution histories. Results We found that both selection and coevolution shape Rubisco, and that positively selected and coevolving residues have their specifically favored amino acid composition and pairing preference. The mapping of these residues on the known Rubisco tertiary structures showed that the coevolving residues tend to be in closer proximity with each other compared to the background, while positively selected residues tend to be further away from each other. This study also reveals that the residues under positive selection or coevolutionary force are located within functionally important regions and that some residues are targets of both positive selection and coevolution at the same time. Conclusion Our results demonstrate that coevolution of residues is common in Rubisco of land plants and that there is an overlap between coevolving and positively selected residues. Knowledge of which Rubisco residues are coevolving and positively selected could be used for further work on structural modeling and identification of substitutions that may be changed in order to improve efficiency of this important enzyme in crops.

  18. Large centric diatoms allocate more cellular nitrogen to photosynthesis to counter slower RUBISCO turnover rates

    Yaping eWu

    2014-12-01

    Full Text Available Diatoms contribute ~40% of primary production in the modern ocean and encompass the largest cell size range of any phytoplankton group. Diatom cell size influences their nutrient uptake, photosynthetic light capture, carbon export efficiency, and growth responses to increasing pCO2. We therefore examined nitrogen resource allocations to the key protein complexes mediating photosynthesis across six marine centric diatoms, spanning 5 orders of magnitude in cell volume, under past, current and predicted future pCO2 levels, in balanced growth under nitrogen repletion. Membrane bound photosynthetic protein concentrations declined with cell volume in parallel with cellular concentrations of total protein, total nitrogen and chlorophyll. Larger diatom species, however, allocated a greater fraction (by 3.5 fold of their total cellular nitrogen to the soluble RUBISCO carbon fixation complex than did smaller species. Carbon assimilation per unit of RUBISCO large subunit (C RbcL-1 s-1 decreased with cell volume, from ~8 to ~2 C RbcL-1 s-1 from the smallest to the largest cells. Whilst a higher allocation of cellular nitrogen to RUBISCO in larger cells increases the burden upon their nitrogen metabolism, the higher RUBISCO allocation buffers their lower achieved RUBISCO turnover rate to enable larger diatoms to maintain carbon assimilation rates per total protein comparable to small diatoms. Individual species responded to increased pCO2, but cell size effects outweigh pCO2 responses across the diatom species size range examined. In large diatoms a higher nitrogen cost for RUBISCO exacerbates the higher nitrogen requirements associated with light absorption, so the metabolic cost to maintain photosynthesis is a cell size-dependent trait.

  19. Structure of Arabidopsis thaliana Rubisco activase.

    Hasse, Dirk; Larsson, Anna M; Andersson, Inger

    2015-04-01

    The CO2-fixing enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is inactivated by the formation of dead-end complexes with inhibitory sugar phosphates. In plants and green algae, the ATP-dependent motor protein Rubisco activase restores catalytic competence by facilitating conformational changes in Rubisco that promote the release of the inhibitory compounds from the active site. Here, the crystal structure of Rubisco activase from Arabidopsis thaliana is presented at 2.9 Å resolution. The structure reveals an AAA+ two-domain structure. More than 100 residues in the protein were not visible in the electron-density map owing to conformational disorder, but were verified to be present in the crystal by mass spectrometry. Two sulfate ions were found in the structure. One was bound in the loop formed by the Walker A motif at the interface of the domains. A second sulfate ion was bound at the N-terminal end of the first helix of the C-terminal domain. The protein packs in a helical fashion in the crystal, as observed previously for Rubisco activase, but differences in the helical pitch indicate flexibility in the packing of the protein.

  20. Transgenic tobacco plants with improved cyanobacterial Rubisco expression but no extra assembly factors grow at near wild-type rates if provided with elevated CO2.

    Occhialini, Alessandro; Lin, Myat T; Andralojc, P John; Hanson, Maureen R; Parry, Martin A J

    2016-01-01

    Introducing a carbon-concentrating mechanism and a faster Rubisco enzyme from cyanobacteria into higher plant chloroplasts may improve photosynthetic performance by increasing the rate of CO2 fixation while decreasing losses caused by photorespiration. We previously demonstrated that tobacco plants grow photoautotrophically using Rubisco from Synechococcus elongatus, although the plants exhibited considerably slower growth than wild-type and required supplementary CO2 . Because of concerns that vascular plant assembly factors may not be adequate for assembly of a cyanobacterial Rubisco, prior transgenic plants included the cyanobacterial chaperone RbcX or the carboxysomal protein CcmM35. Here we show that neither RbcX nor CcmM35 is needed for assembly of active cyanobacterial Rubisco. Furthermore, by altering the gene regulatory sequences on the Rubisco transgenes, cyanobacterial Rubisco expression was enhanced and the transgenic plants grew at near wild-type growth rates, although still requiring elevated CO2 . We performed detailed kinetic characterization of the enzymes produced with and without the RbcX and CcmM35 cyanobacterial proteins. These transgenic plants exhibit photosynthetic characteristics that confirm the predicted benefits of introduction of non-native forms of Rubisco with higher carboxylation rate constants in vascular plants and the potential nitrogen-use efficiency that may be achieved provided that adequate CO2 is available near the enzyme. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

  1. Rubisco - jeden z mnoha enzymů

    Kalina, J.; Urban, Otmar; Bukovská, R.

    2006-01-01

    Roč. 100, - (2006), s. 700-700 ISSN 0009-2770. [58. sjezd Asociací chemických společností. 04.09.2006-08.09.2006, Ústí nad Labem] R&D Projects: GA MŽP SM/640/18/03; GA ČR(CZ) GA522/06/0930 Keywords : photosynthesis * Rubisco * spectrophotometry Subject RIV: BO - Biophysics

  2. Intrascleral IOL Fixation.

    Jacob, Soosan

    2017-01-01

    Intrascleral sutureless intraocular lens (IOL) fixation utilizes direct haptic fixation within the sclera in eyes with deficient capsular support. This has advantages of long-term stability, good control of tilt and decentration, and lesser pseudophakodonesis. This review summarizes various techniques for intrascleral haptic fixation, results, complications, adaptations in special situations, modifications of the technique, combination surgeries, and intrascleral capsular bag fixation techniques (glued capsular hook). Copyright 2017 Asia-Pacific Academy of Ophthalmology.

  3. Single-molecule diffusometry reveals the nucleotide-dependent oligomerization pathways of Nicotiana tabacum Rubisco activase

    Wang, Quan; Serban, Andrew J.; Wachter, Rebekka M.; Moerner, W. E.

    2018-03-01

    Oligomerization plays an important role in the function of many proteins, but a quantitative picture of the oligomer distribution has been difficult to obtain using existing techniques. Here we describe a method that combines sub-stoichiometric labeling and recently developed single-molecule diffusometry to measure the size distribution of oligomers under equilibrium conditions in solution, one molecule at a time. We use this technique to characterize the oligomerization behavior of Nicotiana tabacum (Nt) Rubisco activase (Nt-Rca), a chaperone-like AAA-plus ATPase essential in regulating carbon fixation during photosynthesis. We directly observed monomers, dimers, and a tetramer/hexamer mixture and extracted their fractional abundance as a function of protein concentration. We show that the oligomerization pathway of Nt-Rca is nucleotide dependent: ATPγS binding strongly promotes tetramer/hexamer formation from dimers and results in a preferred tetramer/hexamer population for concentrations in the 1-10 μM range. Furthermore, we directly observed dynamic assembly and disassembly processes of single complexes in real time and from there estimated the rate of subunit exchange to be ˜0.1 s-1 with ATPγS. On the other hand, ADP binding destabilizes Rca complexes by enhancing the rate of subunit exchange by >2 fold. These observations provide a quantitative starting point to elucidate the structure-function relations of Nt-Rca complexes. We envision the method to fill a critical gap in defining and quantifying protein assembly pathways in the small-oligomer regime.

  4. In Vitro Characterization of Thermostable CAM Rubisco Activase Reveals a Rubisco Interacting Surface Loop1[OPEN

    Shivhare, Devendra

    2017-01-01

    To maintain metabolic flux through the Calvin-Benson-Bassham cycle in higher plants, dead-end inhibited complexes of Rubisco must constantly be engaged and remodeled by the molecular chaperone Rubisco activase (Rca). In C3 plants, the thermolability of Rca is responsible for the deactivation of Rubisco and reduction of photosynthesis at moderately elevated temperatures. We reasoned that crassulacean acid metabolism (CAM) plants must possess thermostable Rca to support Calvin-Benson-Bassham cycle flux during the day when stomata are closed. A comparative biochemical characterization of rice (Oryza sativa) and Agave tequilana Rca isoforms demonstrated that the CAM Rca isoforms are approximately10°C more thermostable than the C3 isoforms. Agave Rca also possessed a much higher in vitro biochemical activity, even at low assay temperatures. Mixtures of rice and agave Rca form functional hetero-oligomers in vitro, but only the rice isoforms denature at nonpermissive temperatures. The high thermostability and activity of agave Rca mapped to the N-terminal 244 residues. A Glu-217-Gln amino acid substitution was found to confer high Rca activity to rice Rca. Further mutational analysis suggested that Glu-217 restricts the flexibility of the α4-β4 surface loop that interacts with Rubisco via Lys-216. CAM plants thus promise to be a source of highly functional, thermostable Rca candidates for thermal fortification of crop photosynthesis. Careful characterization of their properties will likely reveal further protein-protein interaction motifs to enrich our mechanistic model of Rca function. PMID:28546437

  5. Advantages of Direct Insertion of a Straight Probe Without a Guide Tube During Anterior Odontoid Screw Fixation of Odontoid Fractures.

    Park, Jin Hoon; Kang, Dong-Ho; Lee, Moon Kyu; Yoo, Byoungwoo; Jung, Sang Ku; Hwang, Soo-Hyun; Kim, Jeoung Hee; Oh, Sunkyu; Lee, Eun Jung; Jeon, Sang Ryong; Roh, Sung Woo; Rhim, Seung Chul

    2016-05-01

    A retrospective cohort study. The aim of this study was to compare the anterior odontoid screw fixation (AOSF) with a guide tube or with a straight probe. AOSF associates with several complications, including malpositioning, fixation loss, and screw breakage. Screw pull-out from the C2 body is the most common complication. All consecutive patients with type II or rostral shallow type III odontoid fractures who underwent AOSFs during the study period were enrolled retrospectively. The guide-tube AOSF method followed the standard published method except C3 body and C2-3 disc annulus rimming was omitted to prevent disc injury; instead, the guide tube was anchored at the anterior inferior C2 vertebra corner. After 2 screw pull-outs, the guide-tube cohort was analyzed to identify the cause of instrument failure. Thereafter, the straight-probe method was developed. A guide tube was not used. A small pilot hole was made on the most anterior side of the inferior endplate, followed by insertion of a 2.5 mm straight probe through the C2 body. Non-union and instrument failure rates and screw-direction angles of the guide-tube and straight-probe groups were recorded. The guide-tube group (n = 13) had 2 screw pull-outs and 1 non-union. The straight-probe group (n = 8) had no complications and significantly larger screw-direction angles than the guide-tube group (60.5 ± 4.63 vs. 54.8 ± 3.82 degrees; P = 0.047). Straight-probe AOSF yielded larger direction angles without injuring bone and disc. Complications were absent. The procedure was easier than guide-tube AOSF and assured sufficient engagement, even in horizontal fracture orientation cases. 3.

  6. In Vitro Characterization of Thermostable CAM Rubisco Activase Reveals a Rubisco Interacting Surface Loop.

    Shivhare, Devendra; Mueller-Cajar, Oliver

    2017-07-01

    To maintain metabolic flux through the Calvin-Benson-Bassham cycle in higher plants, dead-end inhibited complexes of Rubisco must constantly be engaged and remodeled by the molecular chaperone Rubisco activase (Rca). In C3 plants, the thermolability of Rca is responsible for the deactivation of Rubisco and reduction of photosynthesis at moderately elevated temperatures. We reasoned that crassulacean acid metabolism (CAM) plants must possess thermostable Rca to support Calvin-Benson-Bassham cycle flux during the day when stomata are closed. A comparative biochemical characterization of rice ( Oryza sativa ) and Agave tequilana Rca isoforms demonstrated that the CAM Rca isoforms are approximately10°C more thermostable than the C3 isoforms. Agave Rca also possessed a much higher in vitro biochemical activity, even at low assay temperatures. Mixtures of rice and agave Rca form functional hetero-oligomers in vitro, but only the rice isoforms denature at nonpermissive temperatures. The high thermostability and activity of agave Rca mapped to the N-terminal 244 residues. A Glu-217-Gln amino acid substitution was found to confer high Rca activity to rice Rca Further mutational analysis suggested that Glu-217 restricts the flexibility of the α4-β4 surface loop that interacts with Rubisco via Lys-216. CAM plants thus promise to be a source of highly functional, thermostable Rca candidates for thermal fortification of crop photosynthesis. Careful characterization of their properties will likely reveal further protein-protein interaction motifs to enrich our mechanistic model of Rca function. © 2017 American Society of Plant Biologists. All Rights Reserved.

  7. Dinitrogen fixation by legume shade trees and direct transfer of fixed N to associated cacao in a tropical agroforestry system.

    Nygren, Pekka; Leblanc, Humberto A

    2015-02-01

    Natural abundance of (15)N (δ (15)N) was determined in bulk soil, rhizospheric soil and vegetation in an organically managed cacao (Theobroma cacao L.) plantation with Inga edulis Mart. legume trees (inga) as the principal shade for studying the nitrogen (N) cycle in the system. Cacao without contact with legumes in an adjacent plantation was used as the reference for N2 fixation and direct N transfer calculations. Bulk and rhizospheric soils contained 72 and 20%, respectively, of whole- system N. No vegetation effect on δ (15)N in rhizospheric soil was detected, probably due to the high native soil N pool. Fine roots of the cacaos associated with inga contained ∼35% of N fixed from the atmosphere (Nf) out of the total N. Leaves of all species had significantly higher δ (15)N than fine roots. Twenty percent of system Nf was found in cacao suggesting direct N transfer from inga via a common mycelial network of mycorrhizal fungi or recycling of N-rich root exudates of inga. Inga had accumulated 98 kg [Nf] ha(-1) during the 14-year history of the plantation. The conservative estimate of current N2 fixation rate was 41 kg [Nf] ha(-1) year(-1) based on inga biomass only and 50 kg [Nf] ha(-1) year(-1) based on inga and associated trees. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. The single-process biochemical reaction of Rubisco: a unified theory and model with the effects of irradiance, CO₂ and rate-limiting step on the kinetics of C₃ and C₄ photosynthesis from gas exchange.

    Farazdaghi, Hadi

    2011-02-01

    night, it leads to progressively negative daily CO₂ fixation with no possibility of oxygenic life on the planet. The Rubisco-limited theory at low CO₂ also contradicts all experimental evidence for low substrate reactions, and for all known enzymes, Rubisco included. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  9. Rubisco activity and gene expression of tropical tree species under ...

    Young

    2013-05-15

    May 15, 2013 ... Proteomics analysis associated with gene expression of plants reveal .... Consequently, Rubisco enzyme plays a role in assi- milating into ... technique for examining gene expression encoded at the. mRNA level .... Ammonia.

  10. Rubisco mutants of Chlamydomonas reinhardtii enhance photosynthetic hydrogen production.

    Pinto, T S; Malcata, F X; Arrabaça, J D; Silva, J M; Spreitzer, R J; Esquível, M G

    2013-06-01

    Molecular hydrogen (H2) is an ideal fuel characterized by high enthalpy change and lack of greenhouse effects. This biofuel can be released by microalgae via reduction of protons to molecular hydrogen catalyzed by hydrogenases. The main competitor for the reducing power required by the hydrogenases is the Calvin cycle, and rubisco plays a key role therein. Engineered Chlamydomonas with reduced rubisco levels, activity and stability was used as the basis of this research effort aimed at increasing hydrogen production. Biochemical monitoring in such metabolically engineered mutant cells proceeded in Tris/acetate/phosphate culture medium with S-depletion or repletion, both under hypoxia. Photosynthetic activity, maximum photochemical efficiency, chlorophyll and protein levels were all measured. In addition, expression of rubisco, hydrogenase, D1 and Lhcb were investigated, and H2 was quantified. At the beginning of the experiments, rubisco increased followed by intense degradation. Lhcb proteins exhibited monomeric isoforms during the first 24 to 48 h, and D1 displayed sensitivity under S-depletion. Rubisco mutants exhibited a significant decrease in O2 evolution compared with the control. Although the S-depleted medium was much more suitable than its complete counterpart for H2 production, hydrogen release was observed also in sealed S-repleted cultures of rubisco mutated cells under low-moderate light conditions. In particular, the rubisco mutant Y67A accounted for 10-15-fold higher hydrogen production than the wild type under the same conditions and also displayed divergent metabolic parameters. These results indicate that rubisco is a promising target for improving hydrogen production rates in engineered microalgae.

  11. Mechanism of Enzyme Repair by the AAA+ Chaperone Rubisco Activase.

    Bhat, Javaid Y; Miličić, Goran; Thieulin-Pardo, Gabriel; Bracher, Andreas; Maxwell, Andrew; Ciniawsky, Susanne; Mueller-Cajar, Oliver; Engen, John R; Hartl, F Ulrich; Wendler, Petra; Hayer-Hartl, Manajit

    2017-09-07

    How AAA+ chaperones conformationally remodel specific target proteins in an ATP-dependent manner is not well understood. Here, we investigated the mechanism of the AAA+ protein Rubisco activase (Rca) in metabolic repair of the photosynthetic enzyme Rubisco, a complex of eight large (RbcL) and eight small (RbcS) subunits containing eight catalytic sites. Rubisco is prone to inhibition by tight-binding sugar phosphates, whose removal is catalyzed by Rca. We engineered a stable Rca hexamer ring and analyzed its functional interaction with Rubisco. Hydrogen/deuterium exchange and chemical crosslinking showed that Rca structurally destabilizes elements of the Rubisco active site with remarkable selectivity. Cryo-electron microscopy revealed that Rca docks onto Rubisco over one active site at a time, positioning the C-terminal strand of RbcL, which stabilizes the catalytic center, for access to the Rca hexamer pore. The pulling force of Rca is fine-tuned to avoid global destabilization and allow for precise enzyme repair. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Electron microscopy of the complexes of ribulose-1,5-bisphosphate carboxylase (Rubisco) and Rubisco subunit-binding protein from pea leaves

    Tsuprun, V.L.; Boekema, E.J.; Samsonidze, T.G.; Pushkin, A.V.

    1991-01-01

    The structure of ribulose-1,5-bisphosphate carboxylase (Rubisco) subunit-binding protein and its interaction with pea leaf chloroplast Rubisco were studied by electron microscopy and image analysis. Electron-microscopic evidence for the association of Rubisco subunit-binding protein, consisting of

  13. The plastid casein kinase 2 phosphorylates Rubisco activase at the Thr-78 site but is not essential for regulation of Rubisco activation state

    Rubisco activase (RCA) is essential for the activation of Rubisco, the carboxylating enzyme of photosynthesis. In Arabidopsis, RCA is encoded by a single gene (At2g39730) that is alternatively spliced to form a large alpha-RCA and small beta-RCA isoform. The activity of Rubisco is controlled in res...

  14. Direct and indirect costs of dinitrogen fixation in Crocosphaera watsonii WH8501 and possible implications for the nitrogen cycle

    Tobias eGroßkopf

    2012-07-01

    Full Text Available The recent detection of heterotrophic nitrogen (N2 fixation in deep waters of the southern Californian and Peruvian OMZ questions our current understanding of marine N2 fixation as a process confined to oligotrophic surface waters of the oceans. In experiments with Crocosphaera watsonii WH8501, a marine unicellular diazotrophic (N2-fixing cyanobacterium, we demonstrated that the presence of high nitrate concentrations (up to 800 µM had no inhibitory effect on growth and N2 fixation over a period of two weeks. In contrast, the environmental oxygen concentration significantly influenced rates of N2 fixation and respiration, as well as carbon and nitrogen cellular content of C. watsonii over a 24 hour period. Cells grown under lowered oxygen atmosphere (5% had a higher nitrogenase activity and respired less carbon during the dark cycle than under normal oxygen atmosphere (20%. Respiratory oxygen drawdown during the dark period could be fully explained (104% by energetic needs due to basal metabolism and N2 fixation at low oxygen, while at normal oxygen these two processes could only account for 40% of the measured respiration rate. Our results revealed that under normal oxygen concentration most of the energetic costs during N2 fixation (~60% are not derived from the process of N2 fixation per se but rather from the indirect costs incurred for the removal of intracellular oxygen or by the reversal of oxidative damage (e.g. nitrogenase de novo synthesis. Theoretical calculations suggest a slight energetic advantage of N2 fixation relative to assimilatory nitrate uptake for heterotrophic and phototrophic growth, when oxygen supply is in balance with the oxygen requirement for cellular respiration (i.e. energy generation for basal metabolism and N2 fixation. Taken together our results imply the existence of a niche for diazotrophic organisms inside oxygen minimum zones, which are predicted to further expand in the future ocean.

  15. Material Evaluation of an Elastomer, Epoxy and Lightweight Concrete Rail Attachment System for Direct Fixation Light Rail Applications

    Swarner, Benjamin R.

    Sound Transit plans to extend its current light rail system, which runs along the I-5 corridor in Seattle, Washington, across the I-90 Homer Hadley floating bridge as part of a project to connect the major city centers in the region. But, no light rail has ever crossed a floating bridge due to several unique engineering challenges. One of these challenges is attaching the rails to the existing bridge deck without drilling into the bridge pontoons. This research program was developed to test and analyze a direct fixation method that uses lightweight concrete plinths and an elastomer-epoxy system to attach the rails to the bridge deck. The elastomer used was a two-part, pourable elastomer with cork particles intermixed to alter the mechanical properties of the material. A lightweight concrete mixture was analyzed for use in the plinths, and system tests investigated the system response under tensile, compressive and shear loading. The shear response of the system was examined further under varying loading conditions including different surface preparations, elastomer thicknesses, strain-rates and after freeze-thaw conditioning. Experimental data was examined for trends based on these parameters to best characterize the system, and the elastomer was evaluated in the context of modern elastomer research.

  16. Regulation of carbon dioxide fixation in facultatively autotrophic bacteria. A phisiological and genetical study.

    Meijer, Wilhelmus Gerhardus

    1990-01-01

    Autotrophic bactcria are capable of CO2 fixation via the Calvin cycle, emplofng energy derived from the oxidation of anorganic substrates (e.g. Hz), simple organic substrates (one-carbon compounds, e.g. methanol, formate), or from light. Ribulose-1,5-bisphospbate carboxylase/oxygenase (RuBisC/O),

  17. Modes of carbon fixation in an arsenic and CO2-rich shallow hydrothermal ecosystem

    Callac, Nolwenn; Posth, Nicole R.; Rattray, Jayne E.

    2017-01-01

    for autotrophic carbon fixation used in the Calvin-Benson-Bassham (CBB) and reverse tricaboxylic acid (rTCA) cycles. Both forms of RuBisCO, together with ATP citrate lyase genes in the rTCA cycle, increase with distance from the active hydrothermal centres and decrease with sediment depth. Clustering of Ru...

  18. Large variation in the Rubisco kinetics of diatoms reveals diversity among their carbon-concentrating mechanisms

    Young, Jodi N.; Heureux, Ana M.C.; Sharwood, Robert E.; Rickaby, Rosalind E.M.; Morel, François M.M.; Whitney, Spencer M.

    2016-01-01

    While marine phytoplankton rival plants in their contribution to global primary productivity, our understanding of their photosynthesis remains rudimentary. In particular, the kinetic diversity of the CO2-fixing enzyme, Rubisco, in phytoplankton remains unknown. Here we quantify the maximum rates of carboxylation (k cat c), oxygenation (k cat o), Michaelis constants (K m) for CO2 (K C) and O2 (K O), and specificity for CO2 over O2 (SC/O) for Form I Rubisco from 11 diatom species. Diatom Rubisco shows greater variation in K C (23–68 µM), SC/O (57–116mol mol−1), and K O (413–2032 µM) relative to plant and algal Rubisco. The broad range of K C values mostly exceed those of C4 plant Rubisco, suggesting that the strength of the carbon-concentrating mechanism (CCM) in diatoms is more diverse, and more effective than previously predicted. The measured k cat c for each diatom Rubisco showed less variation (2.1–3.7s−1), thus averting the canonical trade-off typically observed between K C and k cat c for plant Form I Rubisco. Uniquely, a negative relationship between K C and cellular Rubisco content was found, suggesting variation among diatom species in how they allocate their limited cellular resources between Rubisco synthesis and their CCM. The activation status of Rubisco in each diatom was low, indicating a requirement for Rubisco activase. This work highlights the need to better understand the correlative natural diversity between the Rubisco kinetics and CCM of diatoms and the underpinning mechanistic differences in catalytic chemistry among the Form I Rubisco superfamily. PMID:27129950

  19. Improved analysis of C4 and C3 photosynthesis via refined in vitro assays of their carbon fixation biochemistry

    Sharwood, Robert E.; Sonawane, Balasaheb V.; Ghannoum, Oula; Whitney, Spencer M.

    2016-01-01

    Plants operating C3 and C4 photosynthetic pathways exhibit differences in leaf anatomy and photosynthetic carbon fixation biochemistry. Fully understanding this underpinning biochemical variation is requisite to identifying solutions for improving photosynthetic efficiency and growth. Here we refine assay methods for accurately measuring the carboxylase and decarboxylase activities in C3 and C4 plant soluble protein. We show that differences in plant extract preparation and assay conditions are required to measure NADP-malic enzyme and phosphoenolpyruvate carboxylase (pH 8, Mg2+, 22 °C) and phosphoenolpyruvate carboxykinase (pH 7, >2mM Mn2+, no Mg2+) maximal activities accurately. We validate how the omission of MgCl2 during leaf protein extraction, lengthy (>1min) centrifugation times, and the use of non-pure ribulose-1,5-bisphosphate (RuBP) significantly underestimate Rubisco activation status. We show how Rubisco activation status varies with leaf ontogeny and is generally lower in mature C4 monocot leaves (45–60% activation) relative to C3 monocots (55–90% activation). Consistent with their >3-fold lower Rubisco contents, full Rubisco activation in soluble protein from C4 leaves (<5min) was faster than in C3 plant samples (<10min), with addition of Rubisco activase not required for full activation. We conclude that Rubisco inactivation in illuminated leaves primarily stems from RuBP binding to non-carbamylated enzyme, a state readily reversible by dilution during cellular protein extraction. PMID:27122573

  20. Rubisco catalytic properties of wild and domesticated relatives provide scope for improving wheat photosynthesis.

    Prins, Anneke; Orr, Douglas J; Andralojc, P John; Reynolds, Matthew P; Carmo-Silva, Elizabete; Parry, Martin A J

    2016-03-01

    Rubisco is a major target for improving crop photosynthesis and yield, yet natural diversity in catalytic properties of this enzyme is poorly understood. Rubisco from 25 genotypes of the Triticeae tribe, including wild relatives of bread wheat (Triticum aestivum), were surveyed to identify superior enzymes for improving photosynthesis in this crop. In vitro Rubisco carboxylation velocity (V c), Michaelis-Menten constants for CO2 (K c) and O2 (K o) and specificity factor (S c/o) were measured at 25 and 35 °C. V c and K c correlated positively, while V c and S c/o were inversely related. Rubisco large subunit genes (rbcL) were sequenced, and predicted corresponding amino acid differences analysed in relation to the corresponding catalytic properties. The effect of replacing native wheat Rubisco with counterparts from closely related species was analysed by modelling the response of photosynthesis to varying CO2 concentrations. The model predicted that two Rubisco enzymes would increase photosynthetic performance at 25 °C while only one of these also increased photosynthesis at 35 °C. Thus, under otherwise identical conditions, catalytic variation in the Rubiscos analysed is predicted to improve photosynthetic rates at physiological CO2 concentrations. Naturally occurring Rubiscos with superior properties amongst the Triticeae tribe can be exploited to improve wheat photosynthesis and crop productivity. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  1. Nitric oxide overcomes Cd and Cu toxicity in in vitro-grown tobacco plants through increasing contents and activities of rubisco and rubisco activase.

    Khairy, Alaaldin Idris H; Oh, Mi Jeong; Lee, Seung Min; Kim, Da Som; Roh, Kwang Soo

    2016-06-01

    Toxic heavy metals such as cadmium (Cd) and copper (Cu) are global problems that are a growing threat to the environment. Despite some heavy metals are required for plant growth and development, others are considered toxic elements and do not play any known physiological role in plant cells. Elevated doses of Cd or Cu cause toxicity in plants and generate damages due to the stress condition and eventually cause a significant reduction in quantity and quality of crop plants. The nitric oxide (NO) donor sodium nitroprusside (SNP) is reported to alleviate the toxicity of some heavy metals like Cd and Cu. In the current study, the role of NO in alleviating stresses of Cd and Cu was investigated in in vitro -grown tobacco ( Nicotiana tabacum ) Based on plant growth, total chlorophyll contents, contents and activities of rubisco and rubisco activase. According to the results of this study, the growth and total chlorophyll contents of Cd/Cu stressed plants were hugely decreased in the absence of SNP, while the supplementation of SNP resulted in a significant increase of both fresh weight and total chlorophyll contents. Remarkable reductions of Rubisco and rubisco activase contents and activities were observed in Cd and Cu-induced plants. SNP supplementation showed the highest contents and activities of rubisco and rubisco activase compared to the control and Cu/Cd-stressed plants. Taken together, our findings suggest that SNP could play a protective role in regulation of plant responses to abiotic stresses such as Cd and Cu by enhancing Rubisco and Rubisco activase.

  2. The differential response of photosynthesis to high temperature for a boreal and temperate Populus species relates to differences in Rubisco activation and Rubisco activase properties.

    Hozain, Moh'd I; Salvucci, Michael E; Fokar, Mohamed; Holaday, A Scott

    2010-01-01

    Significant inhibition of photosynthesis occurs at temperatures only a few degrees (Rubisco and correlated with a higher ATPase activity of Rubisco activase. The temperature response of minimal chlorophyll a fluorescence for darkened leaves was similar for both species and was not consistent with a thylakoid lipid phase change contributing to the decline in A in the range of 30-40 degrees C. Taken together, these data support the idea that the differences in the temperature response of A for the two Populus species could be attributed to the differences in the response of Rubisco activation and ultimately to the thermal properties of Rubisco activase. That the primary sequence of Rubisco activase differed between the species, especially in regions associated with ATPase activity and Rubisco recognition, indicates that the genotypic differences in Rubisco activase might underlie the differences in the heat sensitivity of Rubisco activase and photosynthesis at moderately high temperatures.

  3. Characterization of Rubisco activase from thermally contrasting genotypes of Acer rubrum (Aceraceae).

    Weston, David J; Bauerle, William L; Swire-Clark, Ginger A; Moore, Brandon D; Baird, Wm Vance

    2007-06-01

    The lability of Rubisco activase function is thought to have a major role in the decline of leaf photosynthesis under moderate heat (RCA1 and RCA2 proteins increased modestly in FL plants under warmer temperature, while only RCA2 protein increased in MN plants. Rubisco large subunit (RbsL) protein abundance was relatively unaffected in either genotype by temperature. These results support the idea that Rubisco activase, particularly the ratio of Rubisco activase to Rubisco, may play a role in the photosynthetic heat acclimation in A. rubrum and may have adaptive significance. This mechanism alone is not likely to entirely explain the thermotolerance in the FL genotype, and future research on adaptive mechanisms to high temperatures should consider activase function in a multipathway framework.

  4. From chemolithoautotrophs to electrolithoautotrophs: CO2 fixation by Fe(II)-oxidizing bacteria coupled with direct uptake of electrons from solid electron sources.

    Ishii, Takumi; Kawaichi, Satoshi; Nakagawa, Hirotaka; Hashimoto, Kazuhito; Nakamura, Ryuhei

    2015-01-01

    At deep-sea vent systems, hydrothermal emissions rich in reductive chemicals replace solar energy as fuels to support microbial carbon assimilation. Until recently, all the microbial components at vent systems have been assumed to be fostered by the primary production of chemolithoautotrophs; however, both the laboratory and on-site studies demonstrated electrical current generation at vent systems and have suggested that a portion of microbial carbon assimilation is stimulated by the direct uptake of electrons from electrically conductive minerals. Here we show that chemolithoautotrophic Fe(II)-oxidizing bacterium, Acidithiobacillus ferrooxidans, switches the electron source for carbon assimilation from diffusible Fe(2+) ions to an electrode under the condition that electrical current is the only source of energy and electrons. Site-specific marking of a cytochrome aa3 complex (aa3 complex) and a cytochrome bc1 complex (bc1 complex) in viable cells demonstrated that the electrons taken directly from an electrode are used for O2 reduction via a down-hill pathway, which generates proton motive force that is used for pushing the electrons to NAD(+) through a bc1 complex. Activation of carbon dioxide fixation by a direct electron uptake was also confirmed by the clear potential dependency of cell growth. These results reveal a previously unknown bioenergetic versatility of Fe(II)-oxidizing bacteria to use solid electron sources and will help with understanding carbon assimilation of microbial components living in electronically conductive chimney habitats.

  5. Strain-stress analysis of lower limb with applied fixator

    Mrázek M.

    2010-07-01

    Full Text Available This paper compares physiological state of tibia before and after application of an external fixator. The fixator systems’ models but also model of tibia are loaded in the direction of body axis. The paper is focused on the examination of differences in stiffness before and after the application of fixation. Two types of axial external fixators are compared. Both fixators differ in their construction. The first fixator is two-frame and fixation rods are used for fixing the bone tissue (variant I. The second one is fixed into tibia with screws (variant II. We have found out that the two-frame external fixator has much bigger stiffness during limb fixation than the fixator with one body. Much higher deformations compared to physiological state of tibia occur in the variant II.

  6. Comparison of spectrophotometric and radioisotopic methods for the assay of Rubisco in ozone-treated plants

    Reid, C.D.; Tissue, D.T.; Fiscus, E.L.; Strain, B.R.

    1997-01-01

    Radioisotopic and spectrophotometric assays for ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) initial and final activities and Rubisco content were compared in plants chronically exposed to ozone (O 3 ) in a greenhouse and the field. In a greenhouse experiment, Glycine max was treated in exposure chambers with either charcoal-filtered air (CF air) or 100 nl O 3 l -1 for 6 h daily during vegetative growth. Samples were collected after 7 days of exposure. In a field experiment, G. max was treated in open-top chambers with either CF air or non-filtered air with O 3 added at 1.5 times ambient O 3 for 12 h daily. Average daily O 3 concentrations were 21 and 92 nl l -1 in the CF and O 3 treatments, respectively. Samples were collected during vegetative and reproductive growth. Both assays generally yielded comparable Rubisco initial and final activities for greenhouse-grown plants regardless of the O 3 treatment. However for field-grown plants, Rubisco initial and final activities average 15 and 23% lower when assayed by the spectrophotometric rather than the radioisotopic method. For Rubisco content estimated by the spectrophotometric method, lower values for the regression of Rubisco activity vs concentration of carboxyarabinitol-1.5-bisphosphate were observed in O 3- than in CF-treated plants. Both assays yielded comparable Rubisco contents in the greenhouse and in the field although the variation was larger with the spectrophotometric method in field-grown plants. Growth conditions, field vs greenhouse, were more critical to the spectrophotometric assay performance than the O 3 treatments for measurement of Rubisco activity and content. (au) 40 refs

  7. [Regulation of alternative CO[sub 2] fixation pathways in procaryotic and eucaryotic photosynthetic organisms

    1992-01-01

    The major goal of this project is to determine how microorganisms regulate the assimilation of CO[sup 2] via pathways alternative to the usual Calvin reductive pentose phosphate scheme. In particular, we are interest in the molecular basis for switches in CO[sub 2] metabolic paths. Several earlier studies had indicated that purple nonsulfur photosynthetic bacteria assimilate significant amounts of CO[sub 2] via alternative non-Calvin routes. We have deleted the gene that encodes. RubisCo (ribulose bisphosphate carboxylase/oxygenase) in both the Rhodobacter sphaeroids and Rhodospirillum rubrum. The R. sphaeroides RubisCO deletion strain (strain 16) could not grow under photoheterotrophic conditions with malate as electron donor and CO[sub 2] as the electron acceptor; however the R. rub RubisCO deletion strain (strain I-19) could. Over the past year we have sought to physiologically characterize strain 16PHC. We found that, 16PHC exhibited rates of whole-cell CO[sub 2] fixation which were significantly higher than strain 16. Strain 16PHC could not grow photolithoautotrophically in a CO[sub 2] atmosphere; however, CO[sub 2] fixation catalyzed by photoheterotrophically grown 16PHC was repressed by the addition of DMSO. Likewise, we found that cells initially grown in the presence of DMSO could induce the CO[sub 2] fixation system when DMSO was removed. Thus, these results suggested that both PHC and I-19 could be used to study alternative CO[sub 2] fixation reactions and their significance in R. sphaexoides and R. rubrum.

  8. CSF coccidioides complement fixation

    ... this page: //medlineplus.gov/ency/article/003526.htm CSF coccidioides complement fixation test To use the sharing features on this page, please enable JavaScript. CSF coccidioides complement fixation is a test that checks ...

  9. Early motion and directed exercise (EMADE) versus usual care post ankle fracture fixation: study protocol for a pragmatic randomised controlled trial.

    Matthews, Paul A; Scammell, Brigitte E; Ali, Arfan; Coughlin, Timothy; Nightingale, Jessica; Khan, Tanvir; Ollivere, Ben J

    2018-05-31

    Following surgical fixation of ankle fractures, the traditional management has included immobilisation for 6 weeks in a below-knee cast. However, this can lead to disuse atrophy of the affected leg and joint stiffness. While early rehabilitation from 2 weeks post surgery is viewed as safe, controversy remains regarding its benefits. We will compare the effectiveness of early motion and directed exercise (EMADE) ankle rehabilitation, against usual care, i.e. 6 weeks' immobilisation in a below-knee cast. We have designed a pragmatic randomised controlled trial (p-RCT) to compare the EMADE intervention against usual care. We will recruit 144 independently living adult participants, absent of tissue-healing comorbidities, who have undergone surgical stabilisation of isolated Weber B ankle fractures. The EMADE intervention consists of a non-weight-bearing progressive home exercise programme, complemented with manual therapy and education. Usual care consists of immobilisation in a non-weight-bearing below-knee cast. The intervention period is between week 2 and week 6 post surgery. The primary outcome is the Olerud and Molander Ankle Score (OMAS) patient-reported outcome measure (PROM) at 12 weeks post surgery. Secondary PROMs include the EQ-5D-5 L questionnaire, return to work and return to driving, with objective outcomes including ankle range of motion. Analysis will be on an intention-to-treat basis. An economic evaluation will be included. The EMADE intervention is a package of care designed to address the detrimental effects of disuse atrophy and joint stiffness. An advantage of the OMAS is the potential of meta-analysis with other designs. Within the economic evaluation, the cost-utility analysis, may be used by commissioners, while the use of patient-relevant outcomes, such as return to work and driving, will ensure that the study remains pertinent to patients and their families. As it is being conducted in the clinical environment, this p-RCT has high external

  10. Direct repair surgery with screw fixation for young patients with lumbar spondylolysis: patient-reported outcomes and fusion rate in a prospective interventional study.

    Lee, Gun Woo; Lee, Sun-Mi; Suh, Bo-Gun

    2015-02-15

    Prospective interventional study. To thoroughly investigate the therapeutic outcomes of direct repair (DR) for young patients with lumbar spondylolysis. DR surgery with screw fixation for a pars defect of lumbar spondylolysis is considered a notable surgical option. However, prior studies do not provide clear information on the significance of DR and its outcomes in young patients with lumbar spondylolysis because most previous studies in this area were conducted with spondylolysis patients of all ages and with low-quality study designs that were retrospective in design and had a small sample size and short follow-up time. A total of 47 young patients with lumbar spine spondylolysis who were surgically treated with DR surgery and followed up for 1 year after surgery were enrolled in this study. The primary outcome was degree of pain assessed by visual analogue scale, which separately recorded pain intensity and pain frequency. Secondary outcomes included (1) patient satisfaction, (2) clinical outcomes based on Oswestry Disability Index score and a 12-item short form health survey, (3) fusion rate of pars defect based on computed tomographic scans, and (4) surgery-related complications. The degree of lower back pain (intensity and frequency) significantly improved at final follow-up compared with preoperative level. However, 6 patients (13%) had no significant improvement, and pain frequency tended to worsen 6 months after the operation. Only 25 patients (53%) were satisfied with DR surgery. One-year postoperative clinical outcomes (Oswestry Disability Index and 12-item short form health survey) significantly improved compared with preoperative levels, but the 2 scores also tended to decrease after 6 months. The union rate of the pars defect was 55% (26/47). There was no significant difference in clinical outcomes between fusion group and nonunion group of the pars defect at the final follow-up. Two patients (4%) experienced surgery-related complications. The

  11. A compendium of temperature responses of Rubisco kinetic traits: variability among and within photosynthetic groups and impacts on photosynthesis modeling

    Galmés, Jeroni; Hermida-Carrera, Carmen; Laanisto, Lauri; Niinemets, Ülo

    2016-01-01

    The present study provides a synthesis of the in vitro and in vivo temperature responses of Rubisco Michaelis–Menten constants for CO2 (Kc) and O2 (Ko), specificity factor (Sc,o) and maximum carboxylase turnover rate (kcatc) for 49 species from all the main photosynthetic kingdoms of life. Novel correction routines were developed for in vitro data to remove the effects of study-to-study differences in Rubisco assays. The compilation revealed differences in the energy of activation (∆Ha) of Rubisco kinetics between higher plants and other photosynthetic groups, although photosynthetic bacteria and algae were under-represented and very few species have been investigated so far. Within plants, the variation in Rubisco temperature responses was related to species’ climate and photosynthetic mechanism, with differences in ∆Ha for kcatc among C3 plants from cool and warm environments, and in ∆Ha for kcatc and Kc among C3 and C4 plants. A negative correlation was observed among ∆Ha for Sc/o and species’ growth temperature for all data pooled, supporting the convergent adjustment of the temperature sensitivity of Rubisco kinetics to species’ thermal history. Simulations of the influence of varying temperature dependences of Rubisco kinetics on Rubisco-limited photosynthesis suggested improved photosynthetic performance of C3 plants from cool habitats at lower temperatures, and C3 plants from warm habitats at higher temperatures, especially at higher CO2 concentration. Thus, variation in Rubisco kinetics for different groups of photosynthetic organisms might need consideration to improve prediction of photosynthesis in future climates. Comparisons between in vitro and in vivo data revealed common trends, but also highlighted a large variability among both types of Rubisco kinetics currently used to simulate photosynthesis, emphasizing the need for more experimental work to fill in the gaps in Rubisco datasets and improve scaling from enzyme kinetics to

  12. Carboxysomal carbonic anhydrases: Structure and role in microbial CO2 fixation

    Cannon, Gordon C.; Heinhorst, Sabine; Kerfeld, Cheryl A.

    2010-06-23

    Cyanobacteria and some chemoautotrophic bacteria are able to grow in environments with limiting CO2 concentrations by employing a CO2-concentrating mechanism (CCM) that allows them to accumulate inorganic carbon in their cytoplasm to concentrations several orders of magnitude higher than that on the outside. The final step of this process takes place in polyhedral protein microcompartments known as carboxysomes, which contain the majority of the CO2-fixing enzyme, RubisCO. The efficiency of CO2 fixation by the sequestered RubisCO is enhanced by co-localization with a specialized carbonic anhydrase that catalyzes dehydration of the cytoplasmic bicarbonate and ensures saturation of RubisCO with its substrate, CO2. There are two genetically distinct carboxysome types that differ in their protein composition and in the carbonic anhydrase(s) they employ. Here we review the existing information concerning the genomics, structure and enzymology of these uniquely adapted carbonic anhydrases, which are of fundamental importance in the global carbon cycle.

  13. The impact of elevated CO2 concentration on the Rubisco activity

    Hrstka, M.; Urban, Otmar; Nečesaná, P.

    2002-01-01

    Roč. 96, - (2002), s. 121-123 ISSN 0009-2770. [2nd Meeting of Chemistry and Life . Brno, 10.10.2002-11.10.2002] Institutional research plan: CEZ:AV0Z6087904 Keywords : elevated CO2 * Norway spruce * Rubisco Subject RIV: ED - Physiology Impact factor: 0.336, year: 2002

  14. [Regulation of alternative CO{sub 2} fixation pathways in procaryotic and eucaryotic photosynthetic organisms]. Progress report

    1992-12-31

    The major goal of this project is to determine how microorganisms regulate the assimilation of CO{sup 2} via pathways alternative to the usual Calvin reductive pentose phosphate scheme. In particular, we are interest in the molecular basis for switches in CO{sub 2} metabolic paths. Several earlier studies had indicated that purple nonsulfur photosynthetic bacteria assimilate significant amounts of CO{sub 2} via alternative non-Calvin routes. We have deleted the gene that encodes. RubisCo (ribulose bisphosphate carboxylase/oxygenase) in both the Rhodobacter sphaeroids and Rhodospirillum rubrum. The R. sphaeroides RubisCO deletion strain (strain 16) could not grow under photoheterotrophic conditions with malate as electron donor and CO{sub 2} as the electron acceptor; however the R. rub RubisCO deletion strain (strain I-19) could. Over the past year we have sought to physiologically characterize strain 16PHC. We found that, 16PHC exhibited rates of whole-cell CO{sub 2} fixation which were significantly higher than strain 16. Strain 16PHC could not grow photolithoautotrophically in a CO{sub 2} atmosphere; however, CO{sub 2} fixation catalyzed by photoheterotrophically grown 16PHC was repressed by the addition of DMSO. Likewise, we found that cells initially grown in the presence of DMSO could induce the CO{sub 2} fixation system when DMSO was removed. Thus, these results suggested that both PHC and I-19 could be used to study alternative CO{sub 2} fixation reactions and their significance in R. sphaexoides and R. rubrum.

  15. Genes and pathways for CO2 fixation in the obligate, chemolithoautotrophic acidophile, Acidithiobacillus ferrooxidans, Carbon fixation in A. ferrooxidans

    Esparza Mario

    2010-08-01

    Full Text Available Abstract Background Acidithiobacillus ferrooxidans is chemolithoautotrophic γ-proteobacterium that thrives at extremely low pH (pH 1-2. Although a substantial amount of information is available regarding CO2 uptake and fixation in a variety of facultative autotrophs, less is known about the processes in obligate autotrophs, especially those living in extremely acidic conditions, prompting the present study. Results Four gene clusters (termed cbb1-4 in the A. ferrooxidans genome are predicted to encode enzymes and structural proteins involved in carbon assimilation via the Calvin-Benson-Bassham (CBB cycle including form I of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO, EC 4.1.1.39 and the CO2-concentrating carboxysomes. RT-PCR experiments demonstrated that each gene cluster is a single transcriptional unit and thus is an operon. Operon cbb1 is divergently transcribed from a gene, cbbR, encoding the LysR-type transcriptional regulator CbbR that has been shown in many organisms to regulate the expression of RubisCO genes. Sigma70-like -10 and -35 promoter boxes and potential CbbR-binding sites (T-N11-A/TNA-N7TNA were predicted in the upstream regions of the four operons. Electrophoretic mobility shift assays (EMSAs confirmed that purified CbbR is able to bind to the upstream regions of the cbb1, cbb2 and cbb3 operons, demonstrating that the predicted CbbR-binding sites are functional in vitro. However, CbbR failed to bind the upstream region of the cbb4 operon that contains cbbP, encoding phosphoribulokinase (EC 2.7.1.19. Thus, other factors not present in the assay may be required for binding or the region lacks a functional CbbR-binding site. The cbb3 operon contains genes predicted to encode anthranilate synthase components I and II, catalyzing the formation of anthranilate and pyruvate from chorismate. This suggests a novel regulatory connection between CO2 fixation and tryptophan biosynthesis. The presence of a form II RubisCO

  16. Guide to radiation fixatives

    Tawil, J.J.; Bold, F.C.

    1983-11-01

    This report identifies and then characterizes a variety of substances available in the market place for potential effectiveness as a fixative on radiologically contaminated surfaces. The substances include both generic chemicals and proprietary products. In selecting a fixative for a particular application, several attributes of the fixative may be relevant to the choice. These attributes include: toxicity, durability, and cleanliness and removability. In addition to the attributes of the fixative, one should also take into account certain characteristics of the site to be treated. These characteristics relate to climate, nature of the surface, use to which the treated surface will be put, subsequent cleanup operations, and type of neighboring surfaces. Finally, costs and potential environmental effects may influence the decision. A variety of fixatives are evaluated with respect to these various attributes and summarized in a reference table

  17. Ozone impact on vegetation: phenolic metabolism modification and oxidative alteration of Rubisco in Phaseolus vulgaris L; Impact de l'ozone sur le vegetal: modification du metabolisme phenolique et alteration de la Rubisco chez Phaseolus vulgaris L.

    Kanoun, M.

    2002-04-15

    In order to characterize and quantify, in semi-natural situation, the incidence of atmospheric pollution on some physiological and metabolic functions in plants, the aim of our work was to identify sub-cellular impact markers, in bean (Phaseolus vulgaris L.), able to characterize a chronic and realistic ozone pollution climate. Two criteria were chosen: the foliar phenolic metabolism and the Rubisco, the key enzyme of photosynthesis. Using Open Top Chambers system, we demonstrated that, according to concentration, exposure kinetic and leaf type, ozone could induce amount variations of some constitutive soluble phenolic and the synthesis of new phenolic (iso-flavonoids). In some cases, these disturbances were observed jointly with foliar injuries and/or biomass reduction. Concurrently, this chronic and moderate ozone exposure could also induce carbonyl formation in amino acid residues constitutive of Rubisco small subunit (Rubisco-SSU) and a reduction in the amount of the native Rubisco. The amount of a constitutive kaempferol glucuronide and the ozone-induced oxidative alteration of Rubisco-SSU were selected and tested for the construction of dose-response relationships. Whatever the marker, the linear model was able to describe the relation. For the phenolic response, several exposure indexes were tested. According to their mode of calculation, these exposure forms emphasize more or less the contribution of high ozone concentrations. If, for Rubisco oxidation, the use of the exposure index AOT40 seems relevant, in the case of the phenolic marker, the choice of the right index is leaf type dependant. (author)

  18. Seasonal changes of Rubisco content and activity in Fagus sylvatica and Picea abies affected by elevated CO2 concentration

    Hrstka, M.; Urban, Otmar; Babák, L.

    2012-01-01

    Roč. 66, č. 9 (2012), s. 836-841 ISSN 0366-6352 R&D Projects: GA AV ČR IAA600870701; GA MŠk(CZ) LM2010007; GA MŠk(CZ) ED1.1.00/02.0073 Institutional research plan: CEZ:AV0Z60870520 Keywords : Rubisco content * Rubisco activity * seasonal changes * elevated CO2 concentrations * Fagus sylvatica * Picea abies Subject RIV: EH - Ecology, Behaviour Impact factor: 0.879, year: 2012

  19. [Complications of open reduction and internal fixation versus external fixation for unstable distal radius fractures: a meta-analysis].

    Yang, Z; Yuan, Z Z; Ma, J X; Ma, X L

    2016-12-20

    Objective: To make a systematic assessment of the complications of open reduction and internal fixation versus external fixation for unstable distal radius fractures. Method: A computer-based online search of PubMed, ScienceDirect, EMBASE, BIOSIS, Springer and Cochrane Library were performed.The randomized and controlled trials of open reduction and internal fixation versus external fixation for unstable distal radius fractures were collected.The included trials were screened out strictly based on the criterion of inclusion and exclusion.The quality of included trials was evaluated.RevMan 5.0 was used for data analysis. Result: A total of 17 studies involving 1 402 patients were included.There were 687 patients with open reduction and internal fixation and 715 with external fixation.The results of Meta-analysis indicated that there were statistically significant differences with regard to the postoperatively total complications, infection, malunion, tendon rupture ( I 2 =8%, RR =0.77(95% CI 0.65-0.91, Z =3.10, P 0.05). Conclusion: Postoperative complications are present in both open reduction and internal fixation and external fixation.Compared with external fixation, open reduction and internal fixation is lower in total complications postoperatively, infection and malunion, but external fixation has lower tendon rupture incidence.

  20. Variable Nitrogen Fixation in Wild Populus.

    Sharon L Doty

    Full Text Available The microbiome of plants is diverse, and like that of animals, is important for overall health and nutrient acquisition. In legumes and actinorhizal plants, a portion of essential nitrogen (N is obtained through symbiosis with nodule-inhabiting, N2-fixing microorganisms. However, a variety of non-nodulating plant species can also thrive in natural, low-N settings. Some of these species may rely on endophytes, microorganisms that live within plants, to fix N2 gas into usable forms. Here we report the first direct evidence of N2 fixation in the early successional wild tree, Populus trichocarpa, a non-leguminous tree, from its native riparian habitat. In order to measure N2 fixation, surface-sterilized cuttings of wild poplar were assayed using both 15N2 incorporation and the commonly used acetylene reduction assay. The 15N label was incorporated at high levels in a subset of cuttings, suggesting a high level of N-fixation. Similarly, acetylene was reduced to ethylene in some samples. The microbiota of the cuttings was highly variable, both in numbers of cultured bacteria and in genetic diversity. Our results indicated that associative N2-fixation occurred within wild poplar and that a non-uniformity in the distribution of endophytic bacteria may explain the variability in N-fixation activity. These results point to the need for molecular studies to decipher the required microbial consortia and conditions for effective endophytic N2-fixation in trees.

  1. Amino Acids Sequence Based in Silico Analysis of RuBisCO (Ribulose-1,5 Bisphosphate Carboxylase Oxygenase Proteins in Some Carthamus L. ssp.

    Emre SEVİNDİK

    2017-06-01

    Full Text Available RuBisCO is an important enzyme for plants to photosynthesize and balance carbon dioxide in the atmosphere. This study aimed to perform sequence, physicochemical, phylogenetic and 3D (three-dimensional comparative analyses of RuBisCO proteins in the Carthamus ssp. using various bioinformatics tools. The sequence lengths of the RuBisCO proteins were between 166 and 477 amino acids, with an average length of 411.8 amino acids. Their molecular weights (Mw ranged from 18711.47 to 52843.09 Da; the most acidic and basic protein sequences were detected in C. tinctorius (pI = 5.99 and in C. tenuis (pI = 6.92, respectively. The extinction coefficients of RuBisCO proteins at 280 nm ranged from 17,670 to 69,830 M-1 cm-1, the instability index (II values for RuBisCO proteins ranged from 33.31 to 39.39, while the GRAVY values of RuBisCO proteins ranged from -0.313 to -0.250. The most abundant amino acid in the RuBisCO protein was Gly (9.7%, while the least amino acid ratio was Trp (1.6 %. The putative phosphorylation sites of RuBisCO proteins were determined by NetPhos 2.0. Phylogenetic analysis revealed that RuBisCO proteins formed two main clades. A RAMPAGE analysis revealed that 96.3%-97.6% of residues were located in the favoured region of RuBisCO proteins. To predict the three dimensional (3D structure of the RuBisCO proteins PyMOL was used. The results of the current study provide insights into fundamental characteristic of RuBisCO proteins in Carthamus ssp.

  2. Direct repair of defects in lumbar spondylolysis with a new pedicle screw hook fixation: clinical, functional and Ct-assessed study

    Troussel, Serge

    2007-01-01

    Spondylolysis is a common entity, a minority of people affected by this disease need medical care, and only a few require surgery. Reconstruction of the pars interarticularis is an interesting alternative to segmental fusion; this technique has the advantage of preserving segmental motion. Most authors report good results for young patients without intervertebral disk or facet degenerative changes. Moreover Louis also showed good to excellent results with his technique carried out among people who presented a satisfactory disk height (equal to two thirds of normal height). This could extend the number of patients for whom pars interarticularis repair could be proposed. In this study, the limit of reconstruction was set at grade 3of the Pfirrmann’s classification. The fixation of the isthmus was done with a new kind of pedicle screw hook system. This stable and strong device is easy to use, allows an anatomic pars interarticularis reconstruction of spondylolysis and avoids a postoperative bracing. Twenty-three patients were assessed in this study, the mean age at operation was 34 (range 16–52 years) and the average follow-up was for 59 months (range 6–113 months). Eight patients showed moderate degenerative disk disease before the surgery and 12 patients had a grade 1 spondylolisthesis. The visual analogical scale, the Oswestry disability index (ODI) and the modified Prolo score were used for assessment of pain and clinical outcome before and after surgery. The results were from “excellent” to “good” for twenty patients (87%) and “fair” for three of them (13%). The consolidation of the isthmus was assessed at the end of the study (CT-scan); the fusion rate was observed in 91%. Among patients aged less than 30 years results are from “good”, to “excellent” in all cases and consolidation was always observed. All of them showed normal disc signal before the surgery. In the group aged more than 30 years, the results varied from

  3. Flexible fixation and fracture healing

    Schmal, Hagen; Strohm, Peter C; Jaeger, Martin

    2011-01-01

    , noncomminuted fractures. External fixation uses external bars for stabilization, whereas internal fixation is realized by subcutaneous placement of locking plates. Both of these "biologic" osteosynthesis methods allow a minimally invasive approach and do not compromise fracture hematoma and periosteal blood...

  4. Sacroiliac Screw Fixation

    E.W. van den Bosch

    2003-01-01

    textabstractThe aim of this thesis is to evaluate three major aspects of the use of sacroiliac screws in patients with unstable pelvic ring fractures: the optimal technique for sacroiliac screw fixation, the reliability of peroperative fluoroscopy and the late results. We focused on the questions

  5. Customizable rigid head fixation for infants: technical note.

    Udayakumaran, Suhas; Onyia, Chiazor U

    2016-01-01

    The need and advantages of rigid fixation of the head in cranial surgeries are well documented (Berryhill et al., Otolaryngol Head Neck Surg 121:269-273, 1999). Head fixation for neurosurgical procedures in infants and in early years has been a challenge and is fraught with risk. Despite the fact that pediatric pins are designed, rigid head fixation involving direct application of pins to the head of infants and slightly older children is still generally not safe (Agrawal and Steinbok, Childs Nerv Syst 22:1473-1474, 2006). Yet, there are some surgeries in which some form of rigid fixation is required (Agrawal and Steinbok, Childs Nerv Syst 22:1473-1474, 2006). We describe a simple technique to achieve rigid fixation of the head in infants for neurosurgical procedures. This involves applying a head band made of Plaster of Paris (POP) around the head and then applying the fixation pins of the fixation frame directly on to the POP. We have used this technique of head fixation successfully for infants with no complications.

  6. Effect of season, needle age and elevated CO2concentration on photosynthesis and Rubisco acclimation in Picea abies

    Urban, Otmar; Hrstka, M.; Zitová, Martina; Holišová, Petra; Šprtová, Miroslava; Klem, Karel; Calfapietra, Carlo; De Angelis, Paolo; Marek, Michal V.

    2012-01-01

    Roč. 58, SEP 2012 (2012), s. 135-141 ISSN 0981-9428 R&D Projects: GA AV ČR IAA600870701; GA MŽP(CZ) SP/2D1/93/07; GA ČR(CZ) GAP501/10/0340; GA MŠk(CZ) LM2010007; GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : Activation state * Electron transport rate * Norway spruce * Photosynthetic acclimation * Rubisco carboxylation * Rubisco specific activity Subject RIV: EH - Ecology, Behaviour Impact factor: 2.775, year: 2012

  7. Isotopes in biological dinitrogen fixation

    1978-10-01

    Nineteen papers were presented at the conference. Some topics discussed are as follows: biochemistry and genetics of dinitrogen fixation; genetics of the Rhizobium-legume symbiosis and of the nitrogen-fixing bacteria; studies on nonsymbiotic dinitrogen fixation in grass-bacteria associations and blue--green algae; use of /sup 15/N and /sup 13/N for the assay of dinitrogen fixation; effects of management practices on dinitrogen fixation; economy of C and N in nitrogen-fixing legumes; and survey of international and national programs on dinitrogen fixation. (HLW)

  8. Enhanced Thermostability of Arabidopsis Rubisco activase improves photosynthesis and growth rates under moderate heat stress.

    Kurek, Itzhak; Chang, Thom Kai; Bertain, Sean M; Madrigal, Alfredo; Liu, Lu; Lassner, Michael W; Zhu, Genhai

    2007-10-01

    Plant photosynthesis declines when the temperature exceeds its optimum range. Recent evidence indicates that the reduction in photosynthesis is linked to ribulose-1,5-bis-phosphate carboxylase/oxygenase (Rubisco) deactivation due to the inhibition of Rubisco activase (RCA) under moderately elevated temperatures. To test the hypothesis that thermostable RCA can improve photosynthesis under elevated temperatures, we used gene shuffling technology to generate several Arabidopsis thaliana RCA1 (short isoform) variants exhibiting improved thermostability. Wild-type RCA1 and selected thermostable RCA1 variants were introduced into an Arabidopsis RCA deletion (Deltarca) line. In a long-term growth test at either constant 26 degrees C or daily 4-h 30 degrees C exposure, the transgenic lines with the thermostable RCA1 variants exhibited higher photosynthetic rates, improved development patterns, higher biomass, and increased seed yields compared with the lines expressing wild-type RCA1 and a slight improvement compared with untransformed Arabidopsis plants. These results provide clear evidence that RCA is a major limiting factor in plant photosynthesis under moderately elevated temperatures and a potential target for genetic manipulation to improve crop plants productivity under heat stress conditions.

  9. Photosynthetic limitations in two Antarctic vascular plants: importance of leaf anatomical traits and Rubisco kinetic parameters.

    Sáez, Patricia L; Bravo, León A; Cavieres, Lohengrin A; Vallejos, Valentina; Sanhueza, Carolina; Font-Carrascosa, Marcel; Gil-Pelegrín, Eustaquio; Javier Peguero-Pina, José; Galmés, Jeroni

    2017-05-17

    Particular physiological traits allow the vascular plants Deschampsia antarctica Desv. and Colobanthus quitensis (Kunth) Bartl. to inhabit Antarctica. The photosynthetic performance of these species was evaluated in situ, focusing on diffusive and biochemical constraints to CO2 assimilation. Leaf gas exchange, Chl a fluorescence, leaf ultrastructure, and Rubisco catalytic properties were examined in plants growing on King George and Lagotellerie islands. In spite of the species- and population-specific effects of the measurement temperature on the main photosynthetic parameters, CO2 assimilation was highly limited by CO2 diffusion. In particular, the mesophyll conductance (gm)-estimated from both gas exchange and leaf chlorophyll fluorescence and modeled from leaf anatomy-was remarkably low, restricting CO2 diffusion and imposing the strongest constraint to CO2 acquisition. Rubisco presented a high specificity for CO2 as determined in vitro, suggesting a tight co-ordination between CO2 diffusion and leaf biochemistry that may be critical ultimately to optimize carbon balance in these species. Interestingly, both anatomical and biochemical traits resembled those described in plants from arid environments, providing a new insight into plant functional acclimation to extreme conditions. Understanding what actually limits photosynthesis in these species is important to anticipate their responses to the ongoing and predicted rapid warming in the Antarctic Peninsula. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  10. Thermochemistry of a Biomimetic and Rubisco-Inspired CO2 Capture System from Air

    Andrew Muelleman

    2016-07-01

    Full Text Available In theoretical studies of chemical reactions the reaction thermochemistry is usually reported for the stoichiometric reaction at standard conditions (ΔG°, ΔH°, ΔS°. We describe the computation of the equilibrium concentrations of the CO2-adducts for the general capture reaction CO2 + Capture System ⇆ CO2-adduct (GCR and the rubisco-type capture reaction CO2 + Capture System ⇆ CO2-adduct + H2O (RCR with consideration of the reaction CO2(g ⇆ CO2(aq via Henry’s law. The resulting equations are evaluated and graphically illustrated as a function of atmospheric CO2 concentration and as a function of temperature. The equations were applied to the thermochemistry of small molecule rubisco-model reactions and series of additional model reactions to illustrate the range of the Gibbs free enthalpy for the effective reversible capture and of the reaction entropy for economic CO2 release at elevated temperature. A favorable capture of free enthalpy is of course a design necessity, but not all exergonic reactions are suitable CO2 capture systems. Successful CO2 capture systems must allow for effective release as well, and this feature is controlled by the reaction entropy. The principle of using a two-pronged capture system to ensure a large negative capture entropy is explained and highlighted in the graphical abstract. It is hoped that the presentation of the numerical examples provides useful guidelines for the design of more efficient capture systems.

  11. Biomechanics of lumbar cortical screw-rod fixation versus pedicle screw-rod fixation with and without interbody support.

    Perez-Orribo, Luis; Kalb, Samuel; Reyes, Phillip M; Chang, Steve W; Crawford, Neil R

    2013-04-15

    Seven different combinations of posterior screw fixation, with or without interbody support, were compared in vitro using nondestructive flexibility tests. To study the biomechanical behavior of a new cortical screw (CS) fixation construct relative to the traditional pedicle screw (PS) construct. The CS is an alternative to the PS for posterior fixation of the lumbar spine. The CS trajectory is more sagittally and cranially oriented than the PS, being anchored in the pars interarticularis. Like PS fixation, CS fixation uses interconnecting rods fastened with top-locking connectors. Stability after bilateral CS fixation was compared with stability after bilateral PS fixation in the setting of intact disc and with direct lateral interbody fixation (DLIF) or transforaminal lateral interbody fixation (TLIF) support. Standard nondestructive flexibility tests were performed in cadaveric lumbar specimens, allowing non-paired comparisons of specific conditions from 28 specimens (4 groups of 7) within a larger experiment of multiple hardware configurations. Condition tested and group from which results originated were as follows: (1) intact (all groups); (2) with L3-L4 bilateral PS-rods (group 1); (3) with bilateral CS-rods (group 2); (4) with DLIF (group 3); (5) with DLIF + CS-rods (group 4); (6) with DLIF + PS-rods (group 3); (7) with TLIF + CS-rods (group 2), and (8) with TLIF + PS-rods (group 2). To assess spinal stability, the mean range of motion, lax zone, and stiff zone at L3-L4 were compared during flexion-extension, lateral bending, and axial rotation. With intact disc, stability was equivalent after PS-rod and CS-rod fixation, except that PS-rod fixation was stiffer during axial rotation. With DLIF support, there was no significant difference in stability between PS-rod and CS-rod fixation. With TLIF support, PS-rod fixation was stiffer than CS-rod fixation during lateral bending. Bilateral CS-rod fixation provided about the same stability in cadaveric specimens

  12. CARBON DIOXIDE FIXATION.

    FUJITA,E.

    2000-01-12

    Solar carbon dioxide fixation offers the possibility of a renewable source of chemicals and fuels in the future. Its realization rests on future advances in the efficiency of solar energy collection and development of suitable catalysts for CO{sub 2} conversion. Recent achievements in the efficiency of solar energy conversion and in catalysis suggest that this approach holds a great deal of promise for contributing to future needs for fuels and chemicals.

  13. Fixation distance and fixation duration to vertical road signs.

    Costa, Marco; Simone, Andrea; Vignali, Valeria; Lantieri, Claudio; Palena, Nicola

    2018-05-01

    The distance of first-fixation to vertical road signs was assessed in 22 participants while driving a route of 8.34 km. Fixations to road signs were recorded by a mobile eye-movement-tracking device synchronized to GPS and kinematic data. The route included 75 road signs. First-fixation distance and fixation duration distributions were positively skewed. Median distance of first-fixation was 51 m. Median fixation duration was 137 ms with a modal value of 66 ms. First-fixation distance was linearly related to speed and fixation duration. Road signs were gazed at a much closer distance than their visibility distance. In a second study a staircase procedure was used to test the presentation-time threshold that lead to a 75% accuracy in road sign identification. The threshold was 35 ms, showing that short fixations to a road signs could lead to a correct identification. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Understanding Nitrogen Fixation

    Paul J. Chirik

    2012-05-25

    synthesis of ammonia, NH{sub 3}, from its elements, H{sub 2} and N{sub 2}, via the venerable Haber-Bosch process is one of the most significant technological achievements of the past century. Our research program seeks to discover new transition metal reagents and catalysts to disrupt the strong N {triple_bond} N bond in N{sub 2} and create new, fundamental chemical linkages for the construction of molecules with application as fuels, fertilizers and fine chemicals. With DOE support, our group has discovered a mild method for ammonia synthesis in solution as well as new methods for the construction of nitrogen-carbon bonds directly from N{sub 2}. Ideally these achievements will evolve into more efficient nitrogen fixation schemes that circumvent the high energy demands of industrial ammonia synthesis. Industrially, atmospheric nitrogen enters the synthetic cycle by the well-established Haber-Bosch process whereby N{sub 2} is hydrogenated to ammonia at high temperature and pressure. The commercialization of this reaction represents one of the greatest technological achievements of the 20th century as Haber-Bosch ammonia is responsible for supporting approximately 50% of the world's population and serves as the source of half of the nitrogen in the human body. The extreme reaction conditions required for an economical process have significant energy consequences, consuming 1% of the world's energy supply mostly in the form of pollution-intensive coal. Moreover, industrial H{sub 2} synthesis via the water gas shift reaction and the steam reforming of methane is fossil fuel intensive and produces CO{sub 2} as a byproduct. New synthetic methods that promote this thermodynamically favored transformation ({Delta}G{sup o} = -4.1 kcal/mol) under milder conditions or completely obviate it are therefore desirable. Most nitrogen-containing organic molecules are derived from ammonia (and hence rely on the Haber-Bosch and H{sub 2} synthesis processes) and direct synthesis from

  15. Miniplate fixation of Le Fort I osteotomies.

    Rosen, H M

    1986-12-01

    The use of rigid, internal, three-dimensional fixation using vitallium bone plates in 28 consecutive Le Fort I osteotomies is presented. A minimum follow-up period of 6 months was required for inclusion in this patient group. Maxillary movements included advancements (17), intrusions (9), lengthenings (5), and retrusions (2). The majority of maxillae were moved in more than one plane of space. Technical details, complications, and relapse potential are discussed. Advantages of rigid plate fixation include marked reductions in the length of intermaxillary fixation with light training elastics only. Immediate postoperative airway problems are thereby eliminated. Six months of follow-up would appear to indicate a low potential for osseous relapse when compared to wire osteosynthesis, regardless of the direction of maxillary movement. The major disadvantage is the decreased ability of postoperative orthodontics to move dento-osseous segments if skeletal occlusal disharmony persists postoperatively. For this reason, close attention to preoperative planning and operative technique is critical for the success of this fixation method.

  16. Rubisco activity is associated with photosynthetic thermotolerance in a wild rice (Oryza meridionalis).

    Scafaro, Andrew P; Yamori, Wataru; Carmo-Silva, A Elizabete; Salvucci, Michael E; von Caemmerer, Susanne; Atwell, Brian J

    2012-09-01

    Oryza meridionalis is a wild species of rice, endemic to tropical Australia. It shares a significant genome homology with the common domesticated rice Oryza sativa. Exploiting the fact that the two species are highly related but O. meridionalis has superior heat tolerance, experiments were undertaken to identify the impact of temperature on key events in photosynthesis. At an ambient CO(2) partial pressure of 38 Pa and irradiance of 1500 µmol quanta m(-2) s(-1), the temperature optimum of photosynthesis was 33.7 ± 0.8°C for O. meridionalis, significantly higher than the 30.6 ± 0.7°C temperature optimum of O. sativa. To understand the basis for this difference, we measured gas exchange and rubisco activation state between 20 and 42°C and modeled the response to determine the rate-limiting steps of photosynthesis. The temperature response of light respiration (R(light)) and the CO(2) compensation point in the absence of respiration (Γ(*)) were determined and found to be similar for the two species. C3 photosynthesis modeling showed that despite the difference in susceptibility to high temperature, both species had a similar temperature-dependent limitation to photosynthesis. Both rice species were limited by ribulose-1,5-bisphosphate (RuBP) regeneration at temperatures of 25 and 30°C but became RuBP carboxylation limited at 35 and 40°C. The activation state of rubisco in O. meridionalis was more stable at higher temperatures, explaining its greater heat tolerance compared with O. sativa. Copyright © Physiologia Plantarum 2012.

  17. Two rubisco activase genes from ipomoea batatas have different roles in photosynthesis of arabidopsis

    Jiang, Y.

    2014-01-01

    Rubisco activase (RCA) that functions as a molecular chaperone regulates the activity of the Calvin-Benson cycle via regulation of the Rubisco activity. In plants such as Arabidopsis thaliana, Spinacia oleracea, and Oryza sativa, there are two RCA isoforms from two mRNAs that are produced from alternative splicing of the transcribed pre-mRNA of a single RCA gene. However, this research reported that the transcripts of the two IbRCA isoforms in sweet potato (Ipomoea batatas) were transcribed from two different genes. To study the roles of these two IbRCA isoforms in photosynthesis, we inserted these two IbRCA genes into the genome of Arabidopsis with deletion of RCA gene (RCA), resulting in IbRCAs- and IbRCAl-expressing plants, respectively. Analysis of these transgenic Arabidopsis indicated that the IbRCAs-expressing plants were similar to wild-type plants under ambient CO/sub 2/ concentration and 22 degree C conditions, suggesting that expression of IbRCAs gene was sufficient for functional complementation of RCA plants under normal conditions. However, IbRCAs-expressing plants were more susceptible to moderate heat stress (26 degree C) compared to wild-type plants. In contrast, although the IbRCAl-expressing plants had to grow normally in high CO/sub 2/ concentration conditions, there were almost no differences in growth and photosynthesis between normally grown and heat-treated plants, implying that IbRCAl-expressing plants had a better heat-resistance than IbRCAs-expressing plants. (author)

  18. Functional analysis of the rice rubisco activase promoter in transgenic Arabidopsis

    Yang, Zhipan; Lu, Qingtao; Wen, Xiaogang [Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093 (China); Chen, Fan [Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100080 (China); Lu, Congming, E-mail: lucm@ibcas.ac.cn [Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093 (China)

    2012-02-17

    Highlights: Black-Right-Pointing-Pointer Rice rubisco activase promoter was analyzed in transgenic Arabidopsis system. Black-Right-Pointing-Pointer Region conferring tissue specific and light inducible expression of Rca was identified. Black-Right-Pointing-Pointer -58 to +43 bp region mediates tissue-specific expression of rice Rca. Black-Right-Pointing-Pointer Light inducible expression of rice Rca is mediated by -297 to -58 bp region. Black-Right-Pointing-Pointer Rice nuclear proteins bind specifically with the light inducible region. -- Abstract: To gain a better understanding of the regulatory mechanism of the rice rubisco activase (Rca) gene, variants of the Rca gene promoter (one full-length and four deletion mutants) fused to the coding region of the bacterial reporter gene {beta}-glucuronidase (GUS) were introduced into Arabidopsis via Agrobacterium-mediated transformation. Our results show that a 340 bp fragment spanning from -297 to +43 bp relative to the transcription initiation site is enough to promote tissue-specific and light-inducible expression of the rice Rca gene as done by the full-length promoter (-1428 to +43 bp). Further deletion analysis indicated that the region conferring tissue-specificity of Rca expression is localized within a 105 bp fragment from -58 to +43 bp, while light-inducible expression of Rca is mediated by the region from -297 to -58 bp. Gel shift assays and competition experiments demonstrated that rice nuclear proteins bind specifically with the fragment conferring light responsiveness at more than one binding site. This implies that multiple cis-elements may be involved in light-induced expression of the rice Rca gene. These works provide a useful reference for understanding transcriptional regulation mechanism of the rice Rca gene, and lay a strong foundation for further detection of related cis-elements and trans-factors.

  19. Functional analysis of the rice rubisco activase promoter in transgenic Arabidopsis

    Yang, Zhipan; Lu, Qingtao; Wen, Xiaogang; Chen, Fan; Lu, Congming

    2012-01-01

    Highlights: ► Rice rubisco activase promoter was analyzed in transgenic Arabidopsis system. ► Region conferring tissue specific and light inducible expression of Rca was identified. ► −58 to +43 bp region mediates tissue-specific expression of rice Rca. ► Light inducible expression of rice Rca is mediated by −297 to −58 bp region. ► Rice nuclear proteins bind specifically with the light inducible region. -- Abstract: To gain a better understanding of the regulatory mechanism of the rice rubisco activase (Rca) gene, variants of the Rca gene promoter (one full-length and four deletion mutants) fused to the coding region of the bacterial reporter gene β-glucuronidase (GUS) were introduced into Arabidopsis via Agrobacterium-mediated transformation. Our results show that a 340 bp fragment spanning from −297 to +43 bp relative to the transcription initiation site is enough to promote tissue-specific and light-inducible expression of the rice Rca gene as done by the full-length promoter (−1428 to +43 bp). Further deletion analysis indicated that the region conferring tissue-specificity of Rca expression is localized within a 105 bp fragment from −58 to +43 bp, while light-inducible expression of Rca is mediated by the region from −297 to −58 bp. Gel shift assays and competition experiments demonstrated that rice nuclear proteins bind specifically with the fragment conferring light responsiveness at more than one binding site. This implies that multiple cis-elements may be involved in light-induced expression of the rice Rca gene. These works provide a useful reference for understanding transcriptional regulation mechanism of the rice Rca gene, and lay a strong foundation for further detection of related cis-elements and trans-factors.

  20. Functions, Compositions, and Evolution of the Two Types of Carboxysomes: Polyhedral Microcompartments That Facilitate CO2 Fixation in Cyanobacteria and Some Proteobacteria

    Rae, Benjamin D.; Long, Benedict M.; Badger, Murray R.

    2013-01-01

    SUMMARY Cyanobacteria are the globally dominant photoautotrophic lineage. Their success is dependent on a set of adaptations collectively termed the CO2-concentrating mechanism (CCM). The purpose of the CCM is to support effective CO2 fixation by enhancing the chemical conditions in the vicinity of the primary CO2-fixing enzyme, d-ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO), to promote the carboxylase reaction and suppress the oxygenase reaction. In cyanobacteria and some proteobacteria, this is achieved by encapsulation of RubisCO within carboxysomes, which are examples of a group of proteinaceous bodies called bacterial microcompartments. Carboxysomes encapsulate the CO2-fixing enzyme within the selectively permeable protein shell and simultaneously encapsulate a carbonic anhydrase enzyme for CO2 supply from a cytoplasmic bicarbonate pool. These bodies appear to have arisen twice and undergone a process of convergent evolution. While the gross structures of all known carboxysomes are ostensibly very similar, with shared gross features such as a selectively permeable shell layer, each type of carboxysome encapsulates a phyletically distinct form of RubisCO enzyme. Furthermore, the specific proteins forming structures such as the protein shell or the inner RubisCO matrix are not identical between carboxysome types. Each type has evolutionarily distinct forms of the same proteins, as well as proteins that are entirely unrelated to one another. In light of recent developments in the study of carboxysome structure and function, we present this review to summarize the knowledge of the structure and function of both types of carboxysome. We also endeavor to cast light on differing evolutionary trajectories which may have led to the differences observed in extant carboxysomes. PMID:24006469

  1. Fixation Time for Evolutionary Graphs

    Nie, Pu-Yan; Zhang, Pei-Ai

    Evolutionary graph theory (EGT) is recently proposed by Lieberman et al. in 2005. EGT is successful for explaining biological evolution and some social phenomena. It is extremely important to consider the time of fixation for EGT in many practical problems, including evolutionary theory and the evolution of cooperation. This study characterizes the time to asymptotically reach fixation.

  2. Complement fixation test to C burnetii

    ... complement fixation test; Coxiella burnetii - complement fixation test; C burnetii - complement fixation test ... a specific foreign substance ( antigen ), in this case, C burnetii . Antibodies defend the body against bacteria, viruses, ...

  3. Eighth international congress on nitrogen fixation

    1990-01-01

    This volume contains the proceedings of the Eighth International Congress on Nitrogen Fixation held May 20--26, 1990 in Knoxville, Tennessee. The volume contains abstracts of individual presentations. Sessions were entitled Recent Advances in the Chemistry of Nitrogen Fixation, Plant-microbe Interactions, Limiting Factors of Nitrogen Fixation, Nitrogen Fixation and the Environment, Bacterial Systems, Nitrogen Fixation in Agriculture and Industry, Plant Function, and Nitrogen Fixation and Evolution.

  4. Enhancing biological nitrogen fixation

    Danso, S.K.A.; Eskew, D.L. (Joint FAO/IAEA Div. of Isotope and Radiation Applications of Atomic Energy for Food and Agricultural Development, Vienna (Austria))

    1984-06-01

    Several co-ordinated research programmes (CRPs) conducted by the Soil Fertility, Irrigation and Crop Production Section of the Joint FAO/IAEA Division have concentrated on finding the most efficient way of applying nitrogen fertilizers to various crops, using nitrogen-15 (/sup 15/N) as a tracer. The findings of these studies have been adopted in many countries around the world, resulting in savings of nitrogen fertilizers worth many millions of dollars every year. More recently, the Section's CRPs have focused on enhancing the natural process of biological di-nitrogen fixation. The /sup 15/N isotope technique has proven to be very valuable in studies of the legume-Rhizobium symbiosis, allowing many more experiments than before to be done and yielding much new practical information. The Soils Section is now working to extend the use of the technique to other nitrogen-fixing symbioses.

  5. Cysteine proteinases regulate chloroplast protein content and composition in tobacco leaves: a model for dynamic interactions with ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) vesicular bodies.

    Prins, Anneke; van Heerden, Philippus D R; Olmos, Enrique; Kunert, Karl J; Foyer, Christine H

    2008-01-01

    The roles of cysteine proteinases (CP) in leaf protein accumulation and composition were investigated in transgenic tobacco (Nicotiana tabacum L.) plants expressing the rice cystatin, OC-1. The OC-1 protein was present in the cytosol, chloroplasts, and vacuole of the leaves of OC-1 expressing (OCE) plants. Changes in leaf protein composition and turnover caused by OC-1-dependent inhibition of CP activity were assessed in 8-week-old plants using proteomic analysis. Seven hundred and sixty-five soluble proteins were detected in the controls compared to 860 proteins in the OCE leaves. A cyclophilin, a histone, a peptidyl-prolyl cis-trans isomerase, and two ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase isoforms were markedly altered in abundance in the OCE leaves. The senescence-related decline in photosynthesis and Rubisco activity was delayed in the OCE leaves. Similarly, OCE leaves maintained higher leaf Rubisco activities and protein than controls following dark chilling. Immunogold labelling studies with specific antibodies showed that Rubisco was present in Rubisco vesicular bodies (RVB) as well as in the chloroplasts of leaves from 8-week-old control and OCE plants. Western blot analysis of plants at 14 weeks after both genotypes had flowered revealed large increases in the amount of Rubisco protein in the OCE leaves compared to controls. These results demonstrate that CPs are involved in Rubisco turnover in leaves under optimal and stress conditions and that extra-plastidic RVB bodies are present even in young source leaves. Furthermore, these data form the basis for a new model of Rubisco protein turnover involving CPs and RVBs.

  6. Whole-plant growth and N utilization in transgenic rice plants with increased or decreased Rubisco content under different CO2 partial pressures.

    Sudo, Emi; Suzuki, Yuji; Makino, Amane

    2014-11-01

    Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) strongly limits photosynthesis at lower CO2 concentration [CO2] whereas [corrected] Rubisco limitation is cancelled by elevated [CO2]. Therefore, increase or reduction in Rubisco content by transformation with a sense or an antisense RBCS construct are expected to alter the biomass production under different CO2 levels. RBCS-sense (125% Rubisco of wild-type) and -antisense (35% Rubisco of wild-type) rice (Oryza sativa L.) plants were grown for 63 days at three different CO2 levels: low [CO2] (28 Pa), normal [CO2] (40 Pa) and elevated [CO2] (120 Pa). The biomass of RBCS-sense plants was 32% and 15% greater at low [CO2] and normal [CO2] than that of the wild-type plants, respectively, but did not differ at elevated [CO2]. Conversely, the biomass of RBCS-antisense plants was the smallest at low [CO2]. Thus, overproduction of Rubisco was effective for biomass production at low [CO2]. Greater biomass production at low [CO2] in RBCS-sense plants was caused by an increase in the net assimilation rate, and associated with an increase in the amount of N uptake. Furthermore, Rubisco overproduction in RBCS-sense plants was also promoted at low [CO2]. Although it seems that low [CO2]-growth additionally stimulates the effect of RBCS overexpression, such a phenomenon observed at low [CO2] was mediated through an increase in total leaf N content. Thus, the dependence of the growth improvement in RBCS-sense rice on growth [CO2] was closely related to the degree of Rubisco overproduction which was accompanied not only by leaf N content but also by whole plant N content. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  7. Intrasacral rod fixation for pediatric lumbopelvic fusion.

    Ilharreborde, Brice; Mazda, Keyvan

    2014-07-01

    This paper reports the authors' 19 years experience with pediatric intrasacral rod fixation. After insertion of two cannulated screws in S1 with and an original template guiding them into the anterior third of the endplate, two short fusion rods were inserted into the sacrum according to Jackson's technique distally to S3. In neuromuscular scoliosis, pelvic obliquity was reduced by connecting the proximal and distal constructs, distraction or compression, and in situ rod bending. In children with high-grade spondylolisthesis, lumbosacral kyphosis was reduced by rotation of the sacrum and in situ bending. There were no direct neurological or vascular injuries. The main complication was infection (7%). No pseudarthrosis or significant loss of correction at the lumbosacral junction was observed during follow-up. Intrasacral rod fixation appears to be safe and reliable for lumbopelvic fusion in pediatric patients.

  8. [Long-term efficacy of open reduction and internal fixation versus external fixation for unstable distal radius fractures: a meta-analysis].

    Yang, Z; Yuan, Z Z; Ma, J X; Ma, X L

    2017-11-07

    Objective: To make a systematic assessment of the Long-term efficacy of open reduction and internal fixation versus external fixation for unstable distal radius fractures. Methods: A computer-based online search of PubMed, ScienceDirect, EMBASE, BIOSIS, Springer and Cochrane Library were performed. The randomized and controlled trials of open reduction and internal fixation versus external fixation for unstable distal radius fractures were collected. The included trials were screened out strictly based on the criterion of inclusion and exclusion. The quality of included trials was evaluated. RevMan 5.0 was used for data analysis. Results: Sixteen studies involving 1 268 patients were included. There were 618 patients with open reduction and internal fixation and 650 with external fixation. The results of meta-analysis indicated that there were statistically significant differences with regard to the complications postoperatively (infection( I (2)=0%, RR =0.27, 95% CI 0.16-0.45, Z =4.92, P internal fixation and external fixation are effective treatment for unstable distal radius fractures. Compared with external fixation, open reduction and internal fixation provides reduced complications postoperatively, lower DASH scores and better restoration of volar tilt for treatment of distal radius fractures.

  9. Crystallization and Characterization of Galdieria sulphuraria RUBISCO in Two Crystal Forms: Structural Phase Transition Observed in P21 Crystal Form

    Boguslaw Stec

    2007-10-01

    Full Text Available We have isolated ribulose-1,5-bisphosphate-carboxylase/oxygenase (RUBISCOfrom the red algae Galdieria Sulphuraria. The protein crystallized in two different crystalforms, the I422 crystal form being obtained from high salt and the P21 crystal form beingobtained from lower concentration of salt and PEG. We report here the crystallization,preliminary stages of structure determination and the detection of the structural phasetransition in the P21 crystal form of G. sulphuraria RUBISCO. This red algae enzymebelongs to the hexadecameric class (L8S8 with an approximate molecular weight 0.6MDa.The phase transition in G. sulphuraria RUBISCO leads from two hexadecamers to a singlehexadecamer per asymmetric unit. The preservation of diffraction power in a phasetransition for such a large macromolecule is rare.

  10. Role of the Rubisco small subunit. Final report for period May 1, 1997--April 30,2000

    Spreitzer, Robert J.

    2000-10-04

    CO{sub 2} and O{sub 2} are mutually competitive at the active site of ribulose-1,5-biphosphate (RuBP) carboxylase/oxygenase (Rubisco). Rubisco contains two subunits, each present in eight copies. The 15-kD small subunit is coded by a family of nuclear RbcS genes. Until now, the role of the small subunit in Rubisco structure or catalytic efficiency is not known. Because of other work in eliminating the two RbcS genes in the green algo Chlamydomonas reinhardtii, it is now possible to address questions about the structure-function relationships of the eukaryotic small subunit. There are three specific aims in this project: (1) Alanine scanning mutagenesis is being used to dissect the importance of the {beta}A/{beta}B loop, a feature unique to the eukaryotic small subunit. (2) Random mutagenesis is being used to identify additional residues or regions of the small subunit that are important for holoenzyme assembly and function. (3) Attempts are being made to express foreign small subunits in Chlamydomonas to examine the contribution of small subunits to holoenzyme assembly, catalytic efficiency, and CO{sub 2}/O{sub 2} specificity.

  11. REVISION ANKLE SYNDESMOSIS FIXATION - FUNCTIONAL OUTCOME AFTER TIGHTROPE ® FIXATION

    Sendhilvelan Rajagopalan

    2016-07-01

    Full Text Available BACKGROUND Syndesmotic disruptions are often seen in ankle fractures. Malreduction of these fractures can result in arthritis and instability. A proportion of these patients with malreduction require revision fixation. This study presents the results of revision fixation in such patients, using the Ankle TightRope ® (Arthrex system. METHODS Between January 2000 to December 2009, 124 patients who underwent ankle fracture fixations with syndesmotic stabilisation were analysed. Out of 124 patients, 8 patients were diagnosed with failure of primary stabilisation (based on radiological and clinical criteria and subjected to revision fixation using the Ankle TightRope ® (Arthrex system. Followup was done at periodic time intervals of 3, 6 and 12 months. Both clinical and radiological assessment was performed. Complications and duration of hospital stay was recorded. Functional evaluation was performed using the American Orthopaedic Foot and Ankle Society (AOFAS scoring system. RESULTS Five patients had good results, one satisfactory and two had poor outcomes. CONCLUSIONS Ankle TightRope ® fixation is an alternative method of stabilisation in patients who require revision syndesmosis fixation. Further studies are required to evaluate this method of revision stabilisation as compared to screws.

  12. Strong thermal acclimation of photosynthesis in tropical and temperate wet-forest tree species: the importance of altered Rubisco content.

    Scafaro, Andrew P; Xiang, Shuang; Long, Benedict M; Bahar, Nur H A; Weerasinghe, Lasantha K; Creek, Danielle; Evans, John R; Reich, Peter B; Atkin, Owen K

    2017-07-01

    Understanding of the extent of acclimation of light-saturated net photosynthesis (A n ) to temperature (T), and associated underlying mechanisms, remains limited. This is a key knowledge gap given the importance of thermal acclimation for plant functioning, both under current and future higher temperatures, limiting the accuracy and realism of Earth system model (ESM) predictions. Given this, we analysed and modelled T-dependent changes in photosynthetic capacity in 10 wet-forest tree species: six from temperate forests and four from tropical forests. Temperate and tropical species were each acclimated to three daytime growth temperatures (T growth ): temperate - 15, 20 and 25 °C; tropical - 25, 30 and 35 °C. CO 2 response curves of A n were used to model maximal rates of RuBP (ribulose-1,5-bisphosphate) carboxylation (V cmax ) and electron transport (J max ) at each treatment's respective T growth and at a common measurement T (25 °C). SDS-PAGE gels were used to determine abundance of the CO 2 -fixing enzyme, Rubisco. Leaf chlorophyll, nitrogen (N) and mass per unit leaf area (LMA) were also determined. For all species and T growth , A n at current atmospheric CO 2 partial pressure was Rubisco-limited. Across all species, LMA decreased with increasing T growth . Similarly, area-based rates of V cmax at a measurement T of 25 °C (V cmax 25 ) linearly declined with increasing T growth , linked to a concomitant decline in total leaf protein per unit leaf area and Rubisco as a percentage of leaf N. The decline in Rubisco constrained V cmax and A n for leaves developed at higher T growth and resulted in poor predictions of photosynthesis by currently widely used models that do not account for T growth -mediated changes in Rubisco abundance that underpin the thermal acclimation response of photosynthesis in wet-forest tree species. A new model is proposed that accounts for the effect of T growth -mediated declines in V cmax 25 on A n , complementing current

  13. An in-vitro biomechanical study of different fixation techniques for the extended trochanteric osteotomy in revision THA.

    Zhu, Zhonglin; Ding, Hui; Shao, Hongyi; Zhou, Yixin; Wang, Guangzhi

    2013-04-09

    The wire fixation and the cable grip fixation have been developed for the extended trochanteric osteotomy (ETO) in the revision of total hip arthroplasty (THA). Many studies reported the postoperative performance of the patients, but with little quantitative biomechanical comparison of the two fixation systems. An in-vitro testing approach was designed to record the loosening between the femoral bed and the greater trochanter after fixations. Ten cadaveric femurs were chosen in this study. Each femur underwent the THA, revision by ETO and fixations. The tension to the greater trochanter was from 0 to 500N in vertical and lateral direction, respectively. The translation and rotation of the greater trochanter with respect to the bony bed were captured by an optical tracking system. In the vertical tension tests, the overall translation of the greater trochanter was observed 0.4 mm in the cable fixations and 7.0 mm in the wire fixations. In the lateral tension tests, the overall motion of the greater trochanter was 2.0 mm and 1.2° in the cable fixations, while it was 6.2 mm and 5.3° in the wire fixations. The result was significantly different between the two fixation systems. The stability of the proximal femur after ETO using different fixations in the revision THA was investigated. The cable grip fixation was significantly more stable than the wire fixation.

  14. A "footprint" of plant carbon fixation cycle functions during the development of a heterotrophic fungus.

    Lyu, Xueliang; Shen, Cuicui; Xie, Jiatao; Fu, Yanping; Jiang, Daohong; Hu, Zijin; Tang, Lihua; Tang, Liguang; Ding, Feng; Li, Kunfei; Wu, Song; Hu, Yanping; Luo, Lilian; Li, Yuanhao; Wang, Qihua; Li, Guoqing; Cheng, Jiasen

    2015-08-11

    Carbon fixation pathway of plants (CFPP) in photosynthesis converts solar energy to biomass, bio-products and biofuel. Intriguingly, a large number of heterotrophic fungi also possess enzymes functionally associated with CFPP, raising the questions about their roles in fungal development and in evolution. Here, we report on the presence of 17 CFPP associated enzymes (ten in Calvin-Benson-Basham reductive pentose phosphate pathway and seven in C4-dicarboxylic acid cycle) in the genome of Sclerotinia sclerotiorum, a heterotrophic phytopathogenic fungus, and only two unique enzymes: ribulose-1, 5-bisphosphate carboxylase-oxygenase (Rubisco) and phosphoribulokinase (PRK) were absent. This data suggested an incomplete CFPP-like pathway (CLP) in fungi. Functional profile analysis demonstrated that the activity of the incomplete CLP was dramatically regulated during different developmental stages of S. sclerotiorum. Subsequent experiments confirmed that many of them were essential to the virulence and/or sclerotial formation. Most of the CLP associated genes are conserved in fungi. Phylogenetic analysis showed that many of them have undergone gene duplication, gene acquisition or loss and functional diversification in evolutionary history. These findings showed an evolutionary links in the carbon fixation processes of autotrophs and heterotrophs and implicated the functions of related genes were in course of continuous change in different organisms in evolution.

  15. Permanganate Fixation of Plant Cells

    Mollenhauer, Hilton H.

    1959-01-01

    In an evaluation of procedures explored to circumvent some of the problems of osmium tetroxide-fixation and methacrylate embedding of plant materials, excised segments of root tips of Zea mays were fixed for electron microscopy in potassium permanganate in the following treatment variations: unbuffered and veronal-acetate buffered solutions of 0.6, 2.0, and 5.0 per cent KMnO4 at pH 5.0, 6.0, 6.7, and 7.5, and temperatures of 2–4°C. and 22°C. After fixation the segments were dehydrated, embedded in epoxy resin, sectioned, and observed or photographed. The cells of the central region of the rootcap are described. The fixation procedures employing unbuffered solutions containing 2.0 to 5.0 per cent KMnO4 at a temperature of 22°C. gave particularly good preservation of cell structure and all membrane systems. Similar results were obtained using a solution containing 2.0 per cent KMnO4, buffered with veronal-acetate to pH 6.0, and a fixation time of 2 hours at 22°C. The fixation procedure utilizing veronal-acetate buffered, 0.6 per cent KMnO4 at 2–4°C. and pH 6.7 also gave relatively good preservation of most cellular constituents. However, preservation of the plasma membrane was not so good, nor was the intensity of staining so great, as that with the group of fixatives containing greater concentrations of KMnO4. The other fixation procedures did not give satisfactory preservation of fine structure. A comparison is made of cell structures as fixed in KMnO4 or OsO4. PMID:14423414

  16. External fixation of "intertrochanteric" fractures.

    Gani, Naseem Ul; Kangoo, Khursheed Ahmed; Bashir, Arshad; Muzaffer, Rahil; Bhat, Mohammad Farooq; Farooq, Munir; Badoo, Abdul Rashid; Dar, Imtiyaz Hussian; Wani, Mudassir Maqbool

    2009-10-10

    In developing countries, due to limited availability of modern anesthesia and overcrowding of the hospitals with patients who need surgery, high-risk patients with "intertrochanteric" fractures remain unsuita ble for open reduction and internal fixation.The aim of this study was to analyze the results of external fixation of "intertrochanteric" fractures in high-risk geriatric patients in a developing country.The results of 62 ambulatory high-risk geriatric patients with a mean age of 70 years (range 58-90 years) with "intertrochanteric" fractures, in whom external fixation was performed, are reported.Eight patients died during follow-up due to medical causes unrelated to the surgical procedure. So only 54 patients were available for final assessment. Procedure is simple, performed under local anesthesia, requires less time for surgery and is associated with less blood loss. Good fixation and early ambulation was achieved in most of the patients. Average time to union was 14 weeks. Thirty-one patients developed superficial pin tract infection and 28 patients had average shortening of 15 mm due to impaction and varus angulation. Functional outcome was assessed using Judet's point system. Good to excellent results were achieved in 44 patients.This study demonstrated that external fixation of "intertrochantric" fractures performed under local anesthesia offers significant advantage in ambulatory high-risk geriatric patients especially in a developing country.

  17. Comparison of Outcomes of Operatively Treated Bicondylar Tibial Plateau Fractures by External Fixation and Internal Fixation

    CC Chan

    2012-03-01

    Full Text Available The outcome of bicondylar tibial plateau fractures treated with either external fixation (35 patients or internal fixation (24 patients was reviewed. Outcome measures included the Rasmussen score, clinical complications, development of osteoarthritis and the requirement for total knee replacement (TKR. Twenty-two (92% anatomical reductions were achieved in the internal fixation group compared to 27 (77% in the external fixation group. Infective complications were more common in the external fixation group (9 patients, 26% due to pin tract infection. There were no deep infections in the internal fixation group. The mean Rasmussen score was not significantly different (mean score 32 in external fixation and 29 in internal fixation between the two groups and the incidence of osteoarthritis was the same in both groups. Four patients in the external fixation group underwent a TKR compared to 5 patients in the internal fixation group. Bicondylar tibial plateau fractures have similar outcomes following external or internal fixation.

  18. Fixating the pelvis in the horizontal plane affects gait characteristics

    Veneman, J.F.; Menger, Jasper; van Asseldonk, Edwin H.F.; van der Helm, F.C.T.; van der Kooij, Herman

    2008-01-01

    In assistive devices for neuro-rehabilitation, natural human motions are partly restricted by the device. This may affect the normality of walking during training. This research determines effects on gait of fixating the pelvis translations in the horizontal plane during treadmill walking. Direct

  19. Acromioclavicular joint dislocation: a Dog Bone button fixation alone versus Dog Bone button fixation augmented with acromioclavicular repair-a finite element analysis study.

    Sumanont, Sermsak; Nopamassiri, Supachoke; Boonrod, Artit; Apiwatanakul, Punyawat; Boonrod, Arunnit; Phornphutkul, Chanakarn

    2018-03-20

    Suspension suture button fixation was frequently used to treat acromioclavicular joint (ACJ) dislocation. However, there were many studies reporting about complications and residual horizontal instability after fixation. Our study compared the stability of ACJ after fixation between coracoclavicular (CC) fixation alone and CC fixation combined with ACJ repair by using finite element analysis (FEA). A finite element model was created by using CT images from the normal shoulder. The model 1 was CC fixation with suture button alone, and the model 2 was CC fixation with suture button combined with ACJ repair. Three different forces (50, 100, 200 N) applied to the model in three planes; inferior, anterior and posterior direction load to the acromion. The von Mises stress of the implants and deformation at ACJs was recorded. The ACJ repair in the model 2 could reduce the peak stress on the implant after applying the loading forces to the acromion which the ACJ repair could reduce the peak stress of the FiberWire at suture button about 90% when compared to model 1. And, the ACJ repair could reduce the deformation of the ACJ after applying the loading forces to the acromion in both vertical and horizontal planes. This FEA supports that the high-grade injuries of the ACJ should be treated with CC fixation combined with ACJ repair because this technique provides excellent stability in both vertical and horizontal planes and reduces stress to the suture button.

  20. Buckminsterfullerenes: a non-metal system for nitrogen fixation.

    Nishibayashi, Yoshiaki; Saito, Makoto; Uemura, Sakae; Takekuma, Shin-Ichi; Takekuma, Hideko; Yoshida, Zen-Ichi

    2004-03-18

    In all nitrogen-fixation processes known so far--including the industrial Haber-Bosch process, biological fixation by nitrogenase enzymes and previously described homogeneous synthetic systems--the direct transformation of the stable, inert dinitrogen molecule (N2) into ammonia (NH3) relies on the powerful redox properties of metals. Here we show that nitrogen fixation can also be achieved by using a non-metallic buckminsterfullerene (C60) molecule, in the form of a water-soluble C60:gamma-cyclodextrin (1:2) complex, and light under nitrogen at atmospheric pressure. This metal-free system efficiently fixes nitrogen under mild conditions by making use of the redox properties of the fullerene derivative.

  1. Enhanced Thermostability of Arabidopsis Rubisco Activase Improves Photosynthesis and Growth Rates under Moderate Heat Stress[OA

    Kurek, Itzhak; Chang, Thom Kai; Bertain, Sean M.; Madrigal, Alfredo; Liu, Lu; Lassner, Michael W.; Zhu, Genhai

    2007-01-01

    Plant photosynthesis declines when the temperature exceeds its optimum range. Recent evidence indicates that the reduction in photosynthesis is linked to ribulose-1,5-bis-phosphate carboxylase/oxygenase (Rubisco) deactivation due to the inhibition of Rubisco activase (RCA) under moderately elevated temperatures. To test the hypothesis that thermostable RCA can improve photosynthesis under elevated temperatures, we used gene shuffling technology to generate several Arabidopsis thaliana RCA1 (short isoform) variants exhibiting improved thermostability. Wild-type RCA1 and selected thermostable RCA1 variants were introduced into an Arabidopsis RCA deletion (Δrca) line. In a long-term growth test at either constant 26°C or daily 4-h 30°C exposure, the transgenic lines with the thermostable RCA1 variants exhibited higher photosynthetic rates, improved development patterns, higher biomass, and increased seed yields compared with the lines expressing wild-type RCA1 and a slight improvement compared with untransformed Arabidopsis plants. These results provide clear evidence that RCA is a major limiting factor in plant photosynthesis under moderately elevated temperatures and a potential target for genetic manipulation to improve crop plants productivity under heat stress conditions. PMID:17933901

  2. Numerical analysis of an osseointegrated prosthesis fixation with reduced bone failure risk and periprosthetic bone loss

    Tomaszewski, P. M.; van Diest, M.; Bulstra, S. K.; Verdonschot, N.; Verkerke, G. J.

    2012-01-01

    Currently available implants for direct attachment of prosthesis to the skeletal system after transfemoral amputation (OPRA system. Integrum AB, Sweden and ISP Endo/Exo prosthesis, ESKA Implants AG, Germany) show many advantages over the conventional socket fixation. However, restraining

  3. Anterior fixation of the axis.

    Traynelis, Vincent C; Fontes, Ricardo B V

    2010-09-01

    Although anterior fixation of the axis is not commonly performed, plate fixation of C2 is an important technique for treating select upper cervical traumatic injuries and is also useful in the surgical management of spondylosis. To report the technique and outcomes of C2 anterior plate fixation for a series of patients in which the majority presented with symptomatic degenerative spondylosis. Forty-six consecutive patients underwent single or multilevel fusions over a 7-year period; 30 of these had advanced degenerative disease manifested by myelopathy or deformity. Exposure was achieved with rostral extension of the standard anterior cervical exposure via careful soft tissue dissection, mobilization of the superior thyroid artery, and the use of a table-mounted retractor. It was not necessary to remove the submandibular gland, section the digastric muscle, or make additional skin incisions. Screws were placed an average of 4.6 mm (+/- 2.3 mm) from the inferior C2 endplate with a mean sagittal trajectory of 15.7 degrees (+/- 7.6 degrees). Short- and long-term procedure-related mortality was 4.4%, and perioperative morbidity was 8.9%. Patients remained intubated an average of 2.5 days following surgery. Dysphagia was initially reported by 15.2% of patients but resolved by the 8th postoperative week in all patients. Arthrodesis was achieved in all patients available for long-term follow-up. Multilevel fusions were not associated with longer hospitalization or morbidity. Anterior plate fixation of the axis for degenerative disease can be accomplished with acceptable morbidity employing an extension of the standard anterolateral route.

  4. Smaller Fixation Target Size Is Associated with More Stable Fixation and Less Variance in Threshold Sensitivity.

    Kazunori Hirasawa

    Full Text Available The aims of this randomized observational case control study were to quantify fixation behavior during standard automated perimetry (SAP with different fixation targets and to evaluate the relationship between fixation behavior and threshold variability at each test point in healthy young participants experienced with perimetry. SAP was performed on the right eyes of 29 participants using the Octopus 900 perimeter, program 32, dynamic strategy. The fixation targets of Point, Cross, and Ring were used for SAP. Fixation behavior was recorded using a wearable eye-tracking glass. All participants underwent SAP twice with each fixation target in a random fashion. Fixation behavior was quantified by calculating the bivariate contour ellipse area (BCEA and the frequency of deviation from the fixation target. The BCEAs (deg2 of Point, Cross, and Ring targets were 1.11, 1.46, and 2.02, respectively. In all cases, BCEA increased significantly with increasing fixation target size (p < 0.05. The logarithmic value of BCEA demonstrated the same tendency (p < 0.05. A positive correlation was identified between fixation behavior and threshold variability for the Point and Cross targets (ρ = 0.413-0.534, p < 0.05. Fixation behavior increased with increasing fixation target size. Moreover, a larger fixation behavior tended to be associated with a higher threshold variability. A small fixation target is recommended during the visual field test.

  5. Alterations in Rubisco activity and in stomatal behavior induce a daily rhythm in photosynthesis of aerial leaves in the amphibious-plant Nuphar lutea.

    Snir, Ainit; Gurevitz, Michael; Marcus, Yehouda

    2006-12-01

    Nuphar lutea is an amphibious plant with submerged and aerial foliage, which raises the question how do both leaf types perform photosynthetically in two different environments. We found that the aerial leaves function like terrestrial sun-leaves in that their photosynthetic capability was high and saturated under high irradiance (ca. 1,500 mumol photons m(-2) s(-1)). We show that stomatal opening and Rubisco activity in these leaves co-limited photosynthesis at saturating irradiance fluctuating in a daily rhythm. In the morning, sunlight stimulated stomatal opening, Rubisco synthesis, and the neutralization of a night-accumulated Rubisco inhibitor. Consequently, the light-saturated quantum efficiency and rate of photosynthesis increased 10-fold by midday. During the afternoon, gradual closure of the stomata and a decrease in Rubisco content reduced the light-saturated photosynthetic rate. However, at limited irradiance, stomatal behavior and Rubisco content had only a marginal effect on the photosynthetic rate, which did not change during the day. In contrast to the aerial leaves, the photosynthesis rate of the submerged leaves, adapted to a shaded environment, was saturated under lower irradiance. The light-saturated quantum efficiency of these leaves was much lower and did not change during the day. Due to their low photosynthetic affinity for CO(2) (35 muM) and inability to utilize other inorganic carbon species, their photosynthetic rate at air-equilibrated water was CO(2)-limited. These results reveal differences in the photosynthetic performance of the two types of Nuphar leaves and unravel how photosynthetic daily rhythm in the aerial leaves is controlled.

  6. Metals and Nicotine Level in Preparations of Rubisco Purified from Cuban Tobacco Varieties, for Chronic Renal Insufficiency Patients

    Geada, D.; Ares, D.; Del Castillo, N.; Valdes, R.; Gonzalez, M.; Rodriguez, D.; Ferro, W.; Gomez, L.; Padilla, S.; Roman, M. R.; Hidalgo, A.; Zamora, A.

    2003-01-01

    Full Text: Foods are the major source of metals accumulation in the humans. Plants contain large quantities of Rubisco to attain reasonable rates of photosynthesis, and thus, is the most abundant protein on Earth. Rubisco could be used as additive in nutrition for people with renal insufficiency, comatose state and severely restrict Na and K because the absence of these metals can greatly reduce the frequency of haemodialysis. Our purpose was to measure the metal levels and estimate the potential intake of copper, iron, zinc and manganese in patients under haemodialysis treatment and coma. Additionally we also studied sodium, potassium, calcium and magnesium quantities. Intakes of these metals were estimated, attending to the quantity of protein by person, from their daily diets and compared with the Provisional Tolerable Weekly Intakes (PTWI) as established by the FAO/WHO and the US Recommended Daily Allowances (RDA) or the US Safe and Adequate Daily Dietary Intakes (ESADDI). All the determinations of these metals were done using atomic absorption spectrometry and none of them exceeds PTWI, RDA and ESADDI values; nevertheless they were higher than the values previously obtained. The highest metal value, respect the daily allowances, was obtained for iron. Lowest values were reported for sodium, potassium and copper which support the protein use as a nutritional supplement. On the other hand, nicotine is a very harmful alkaloid in tobacco plants and the LD 50 oral is 40mg in humans. The nicotine contents were analyzed by gas chromatography and it does not exceed the 7ug/ml

  7. Overcoming fixation with repeated memory suppression.

    Angello, Genna; Storm, Benjamin C; Smith, Steven M

    2015-01-01

    Fixation (blocks to memories or ideas) can be alleviated not only by encouraging productive work towards a solution, but, as the present experiments show, by reducing counterproductive work. Two experiments examined relief from fixation in a word-fragment completion task. Blockers, orthographically similar negative primes (e.g., ANALOGY), blocked solutions to word fragments (e.g., A_L_ _GY) in both experiments. After priming, but before the fragment completion test, participants repeatedly suppressed half of the blockers using the Think/No-Think paradigm, which results in memory inhibition. Inhibiting blockers did not alleviate fixation in Experiment 1 when conscious recollection of negative primes was not encouraged on the fragment completion test. In Experiment 2, however, when participants were encouraged to remember negative primes at fragment completion, relief from fixation was observed. Repeated suppression may nullify fixation effects, and promote creative thinking, particularly when fixation is caused by conscious recollection of counterproductive information.

  8. Accuracy of a hexapod parallel robot kinematics based external fixator.

    Faschingbauer, Maximilian; Heuer, Hinrich J D; Seide, Klaus; Wendlandt, Robert; Münch, Matthias; Jürgens, Christian; Kirchner, Rainer

    2015-12-01

    Different hexapod-based external fixators are increasingly used to treat bone deformities and fractures. Accuracy has not been measured sufficiently for all models. An infrared tracking system was applied to measure positioning maneuvers with a motorized Precision Hexapod® fixator, detecting three-dimensional positions of reflective balls mounted in an L-arrangement on the fixator, simulating bone directions. By omitting one dimension of the coordinates, projections were simulated as if measured on standard radiographs. Accuracy was calculated as the absolute difference between targeted and measured positioning values. In 149 positioning maneuvers, the median values for positioning accuracy of translations and rotations (torsions/angulations) were below 0.3 mm and 0.2° with quartiles ranging from -0.5 mm to 0.5 mm and -1.0° to 0.9°, respectively. The experimental setup was found to be precise and reliable. It can be applied to compare different hexapod-based fixators. Accuracy of the investigated hexapod system was high. Copyright © 2014 John Wiley & Sons, Ltd.

  9. Relocatable fixation systems in intracranial stereotactic radiotherapy. Accuracy of serial CT scans and patient acceptance in a randomized design.

    Theelen, A; Martens, J; Bosmans, G; Houben, R; Jager, J J; Rutten, I; Lambin, P; Minken, A W; Baumert, B G

    2012-01-01

    The goal was to provide a quantitative evaluation of the accuracy of three different fixation systems for stereotactic radiotherapy and to evaluate patients' acceptance for all fixations. A total of 16 consecutive patients with brain tumours undergoing fractionated stereotactic radiotherapy (SCRT) were enrolled after informed consent (Clinical trials.gov: NCT00181350). Fixation systems evaluated were the BrainLAB® mask, with and without custom made bite-block (fixations S and A) and a homemade neck support with bite-block (fixation B) based on the BrainLAB® frame. The sequence of measurements was evaluated in a randomized manner with a cross-over design and patients' acceptance by a questionnaire. The mean three-dimensional (3D) displacement and standard deviations were 1.16 ± 0.68 mm for fixation S, 1.92 ± 1.28 and 1.70 ± 0.83 mm for fixations A and B, respectively. There was a significant improvement of the overall alignment (3D vector) when using the standard fixation instead of fixation A or B in the craniocaudal direction (p = 0.037). Rotational deviations were significantly less for the standard fixation S in relation to fixations A (p = 0.005) and B (p = 0.03). EPI imaging with off-line correction further improved reproducibility. Five out of 8 patients preferred the neck support with the bite-block. The mask fixation system in conjunction with a bite-block is the most accurate fixation for SCRT reducing craniocaudal and rotational movements. Patients favoured the more comfortable but less accurate neck support. To optimize the accuracy of SCRT, additional regular portal imaging is warranted.

  10. Relocatable fixation systems in intracranial stereotactic radiotherapy. Accuracy of serial CT scans and patient acceptance in a randomized design

    Theelen, A.; Martens, J.; Bosmans, G.; Houben, R.; Jager, J.J.; Rutten, I.; Lambin, P.; Baumert, B.G.; Minken, A.W.; Radiotherapeutic Inst. RISO, Deventer

    2012-01-01

    The goal was to provide a quantitative evaluation of the accuracy of three different fixation systems for stereotactic radiotherapy and to evaluate patients' acceptance for all fixations. Methods A total of 16 consecutive patients with brain tumours undergoing fractionated stereotactic radiotherapy (SCRT) were enrolled after informed consent (Clinical trials.gov: NCT00181350). Fixation systems evaluated were the BrainLAB registered mask, with and without custom made bite-block (fixations S and A) and a homemade neck support with bite-block (fixation B) based on the BrainLAB registered frame. The sequence of measurements was evaluated in a randomized manner with a cross-over design and patients' acceptance by a questionnaire. Results The mean three-dimensional (3D) displacement and standard deviations were 1.16 ± 0.68 mm for fixation S, 1.92 ± 1.28 and 1.70 ± 0.83 mm for fixations A and B, respectively. There was a significant improvement of the overall alignment (3D vector) when using the standard fixation instead of fixation A or B in the craniocaudal direction (p = 0.037). Rotational deviations were significantly less for the standard fixation S in relation to fixations A (p = 0.005) and B (p = 0.03). EPI imaging with off-line correction further improved reproducibility. Five out of 8 patients preferred the neck support with the bite-block. Conclusion The mask fixation system in conjunction with a bite-block is the most accurate fixation for SCRT reducing craniocaudal and rotational movements. Patients favoured the more comfortable but less accurate neck support. To optimize the accuracy of SCRT, additional regular portal imaging is warranted. (orig.)

  11. Polymeric media for tritium fixation. Supplement I

    Franz, J.A.; Burger, L.L.

    1976-01-01

    Procedures for the fixation of tritium as TH or THO in two different polymeric media are described. The complete procedure for THO fixation in a polyureylene-polyurethane polumer, including polymer molding procedures and leach tests is presented. The catalytic tritiation of polystyrene under very mild conditions using a rhodium catalyst is also described. Thermal stabilities and cost estimates for the polymers examined under this program are discussed. Organic polymers were found to have attractive features for the fixation and storage of concentrated tritium wastes due to the convenience of fixation procedures and favorable properties of the resulting media

  12. Modeling fixation locations using spatial point processes.

    Barthelmé, Simon; Trukenbrod, Hans; Engbert, Ralf; Wichmann, Felix

    2013-10-01

    Whenever eye movements are measured, a central part of the analysis has to do with where subjects fixate and why they fixated where they fixated. To a first approximation, a set of fixations can be viewed as a set of points in space; this implies that fixations are spatial data and that the analysis of fixation locations can be beneficially thought of as a spatial statistics problem. We argue that thinking of fixation locations as arising from point processes is a very fruitful framework for eye-movement data, helping turn qualitative questions into quantitative ones. We provide a tutorial introduction to some of the main ideas of the field of spatial statistics, focusing especially on spatial Poisson processes. We show how point processes help relate image properties to fixation locations. In particular we show how point processes naturally express the idea that image features' predictability for fixations may vary from one image to another. We review other methods of analysis used in the literature, show how they relate to point process theory, and argue that thinking in terms of point processes substantially extends the range of analyses that can be performed and clarify their interpretation.

  13. Methanotrophy induces nitrogen fixation during peatland development

    Larmola, Tuula; Leppänen, Sanna M.; Tuittila, Eeva-Stiina; Aarva, Maija; Merilä, Päivi; Fritze, Hannu; Tiirola, Marja

    2014-01-01

    Nitrogen (N) accumulation rates in peatland ecosystems indicate significant biological atmospheric N2 fixation associated with Sphagnum mosses. Here, we show that the linkage between methanotrophic carbon cycling and N2 fixation may constitute an important mechanism in the rapid accumulation of N during the primary succession of peatlands. In our experimental stable isotope enrichment study, previously overlooked methane-induced N2 fixation explained more than one-third of the new N input in the younger peatland stages, where the highest N2 fixation rates and highest methane oxidation activities co-occurred in the water-submerged moss vegetation. PMID:24379382

  14. Bacteria on External Fixators: Which Prep is Best?

    2012-01-01

    aureus (lux). After 12 hours in the broth, a sufficient time to allow biofilm formation ,11 the constructs were individually removed and baseline imaging...difference when cleansing components consisting of stainless steel and alumi- num.15–17 We also found that a simulated external fixator adjustment exposed...Albert E, et al. Direct continuous method for monitoring biofilm infection in a mouse model. Infect Immun. 2003;71: 882–890. 11. Charles CA, Ricotti CA

  15. [Comparison of external fixation with or without limited internal fixation for open knee fractures].

    Li, K N; Lan, H; He, Z Y; Wang, X J; Yuan, J; Zhao, P; Mu, J S

    2018-03-01

    Objective: To explore the characteristics and methods of different fixation methods and prevention of open knee joint fracture. Methods: The data of 86 cases of open knee joint fracture admitted from January 2002 to December 2015 in Department of Orthopaedics, Affiliated Hospital of Chengdu University were analyzed retrospectively.There were 65 males and 21 females aged of 38.6 years. There were 38 cases treated with trans articular external fixation alone, 48 cases were in the trans articular external fixation plus auxiliary limited internal fixation group. All the patients were treated according to the same three stages except for different fixation methods. Observation of external fixation and fracture fixation, fracture healing, wound healing and treatment, treatment and related factors of infection control and knee function recovery. χ(2) test was used to analyze data. Results: Eleven patients had primary wound healing, accounting for 12.8%. Seventy-five patients had two wounds healed, accounting for 87.2%. Only 38 cases of trans articular external fixator group had 31 cases of articular surface reduction, accounting for 81.6%; Five cases of trans articular external fixator assisted limited internal fixation group had 5 cases of poor reduction, accounting for 10.4%; There was significant difference between the two groups (χ(2)=44.132, P external fixation group, a total of 23 cases of patients with infection, accounted for 60.5% of external fixation group; trans articular external fixation assisted limited internal fixation group there were 30 cases of patients with infection, accounting for the assistance of external fixator and limited internal fixation group 62.5%; There was significant difference between the two groups(χ(2)=0.035, P >0.05). Five cases of fracture nonunion cases of serious infection, patients voluntarily underwent amputation. The Lysholm Knee Scale: In the external fixation group, 23 cases were less than 50 points, accounting for 60

  16. Improper tube fixation causing a leaky cuff

    Gupta Babita

    2010-01-01

    Full Text Available Leaking endotracheal tube cuffs are common problems in intensive care units. We report a case wherein the inflation tube was damaged by the adhesive plaster used for tube fixation and resulted in leaking endotracheal tube cuff. We also give some suggestions regarding the tube fixation and some remedial measures for damaged inflation system.

  17. Nitrogen fixation by legumes in retorted shale

    Hersman, L E; Molitoris, E; Klein, D A

    1981-01-01

    A study was made to determine whether retorted shale additions would significantly affect symbiotic N/sub 2/ fixation. Results indicate that small additions of the shale may stimulate plant growth but with higher concentrations plants are stressed, resulting in a decreased biomass and a compensatory effect of an increased number of nodules and N/sub 2/ fixation potential. (JMT)

  18. Outcome of rail fixator system in reconstructing bone gap

    Amit Lakhani

    2014-01-01

    Conclusion: All patients well tolerated rail fixator with good functional results and gap reconstruction. Easy application of rail fixator and comfortable distraction procedure suggest rail fixator a good alternative for gap reconstruction of limbs.

  19. EFFECT OF EMBEDDING METHODS VERSUS FIXATIVE TYPE ON KARYOMETRIC MEASURES

    BOON, ME; VANDERPOEL, HG; TAN, CJA; KOK, LP

    The influence of fixation and embedding methods in seven urologic tumor samples was studied karyometrically for 12 preparatory techniques. Routine histologic formalin fixation was compared with Carbowax and Kryofix fixatives. Also, histologic material was studied embedded in paraffin and plastic

  20. Eighth international congress on nitrogen fixation. Final program

    1990-12-31

    This volume contains the proceedings of the Eighth International Congress on Nitrogen Fixation held May 20--26, 1990 in Knoxville, Tennessee. The volume contains abstracts of individual presentations. Sessions were entitled Recent Advances in the Chemistry of Nitrogen Fixation, Plant-microbe Interactions, Limiting Factors of Nitrogen Fixation, Nitrogen Fixation and the Environment, Bacterial Systems, Nitrogen Fixation in Agriculture and Industry, Plant Function, and Nitrogen Fixation and Evolution.

  1. Polymeric media for tritium fixation

    Franz, J.A.; Burger, L.L.

    1975-01-01

    The synthesis and leach testing of several polymeric media for tritium fixation are presented. Tritiated bakelite, poly(acrylonitrile) and polystyrene successfully fixed tritium. Tritium leach rates at the tracer level appear to be negligible. Advantages and disadvantages of the processes are discussed, and further bench-scale investigations underway are reported. Rough cost estimates are presented for the different media and are compared with alternate approaches such as deep-well injection and long-term tank storage. Polymeric media costs are high compared to deep-well storage and are of the same order of magnitude per liter of water as for isotopic enrichment. With this limitation, polymeric media can be economically feasible only for highly concentrated tritiated wastes. It is recommended that the bakelite and polystyrene processes be examined on a larger scale to permit more accurate cost analysis and process design. (auth)

  2. Radionuclide fixation mechanisms in rocks

    Nakashima, S.

    1991-01-01

    In the safety evaluation of the radioactive waste disposal in geological environment, the mass balance equation for radionuclide migration is given. The sorption of radionuclides by geological formations is conventionally represented by the retardation of the radionuclides as compared with water movement. In order to quantify the sorption of radionuclides by rocks and sediments, the distribution ratio is used. In order to study quantitatively the long term behavior of waste radionuclides in geological environment, besides the distribution ratio concept in short term, slower radionuclide retention reaction involving mineral transformation should be considered. The development of microspectroscopic method for long term reaction path modeling, the behavior of iron during granite and water interaction, the reduction precipitation of radionuclides, radionuclide migration pathways, and the representative scheme of radionuclide migration and fixation in rocks are discussed. (K.I.)

  3. Arabidopsis thaliana ggt1 photorespiratory mutants maintain leaf carbon/nitrogen balance by reducing RuBisCO content and plant growth.

    Dellero, Younès; Lamothe-Sibold, Marlène; Jossier, Mathieu; Hodges, Michael

    2015-09-01

    Metabolic and physiological analyses of glutamate:glyoxylate aminotransferase 1 (GGT1) mutants were performed at the global leaf scale to elucidate the mechanisms involved in their photorespiratory growth phenotype. Air-grown ggt1 mutants showed retarded growth and development, that was not observed at high CO2 (3000 μL L(-1) ). When compared to wild-type (WT) plants, air-grown ggt1 plants exhibited glyoxylate accumulation, global changes in amino acid amounts including a decrease in serine content, lower organic acid levels, and modified ATP/ADP and NADP(+) /NADPH ratios. When compared to WT plants, their net CO2 assimilation rates (An ) were 50% lower and this mirrored decreases in ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) contents. High CO2 -grown ggt1 plants transferred to air revealed a rapid decrease of An and photosynthetic electron transfer rate while maintaining a high energetic state. Short-term (a night period and 4 h of light) transferred ggt1 leaves accumulated glyoxylate and exhibited low serine contents, while other amino acid levels were not modified. RuBisCO content, activity and activation state were not altered after a short-term transfer while the ATP/ADP ratio was lowered in ggt1 rosettes. However, plant growth and RuBisCO levels were both reduced in ggt1 leaves after a long-term (12 days) acclimation to air from high CO2 when compared to WT plants. The data are discussed with respect to a reduced photorespiratory carbon recycling in the mutants. It is proposed that the low An limits nitrogen-assimilation, this decreases leaf RuBisCO content until plants attain a new homeostatic state that maintains a constant C/N balance and leads to smaller, slower growing plants. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

  4. Effect of CO2 enrichment and high photosynthetic photon flux densities (PPFD) on rubisco and PEP-case activities of in vitro cultured strawberry plants

    Desjardins, Y.; Beeson, R.; Gosselin, A.

    1989-01-01

    Standard growing conditions in vitro (low light and CO 2 ) are not conducive to autotrophy. An experiment was conducted to improve photosynthesis in vitro in the hope of increasing survival in acclimatization. A factorial experiment was elaborated where CO 2 and PPFD were supplied to in vitro cultured strawberry plants in the rooting stage. Activities of carboxylating enzymes were determined after 4 weeks of culture. The activities of non-activated and activated rubisco and PEP-Case were measured after extraction of the enzymes and a reaction with NaH 14 CO 3 followed by scintillation counting spectroscopy. High CO 2 concentration significantly increased net assimilation rates (NAR) by 165% over the control for both 1650 and 3000 ppm CO 2 . High PPFD only increased NAR by 12 and 35% for 150 and 250 μmol·m -2 ·s -1 respectively over the control. Plants grown at 3000 ppm CO 2 had the highest level of chlorophyll/g FW with 97% more than the control. The activity of PEP-Case was the highest at high light levels and high CO 2 with rates of 1.65 for 1650 ppm versus 1.22 mmol CO 2 mg -1 chl. h -1 at 250 μmol·m -2 ·s -1 . There was no difference in PEP activity at low light levels. The rubisco activity was lower at 1650 and 3000 ppm CO 2 . Increases in NAR correlate more closely to the PEP-Case than to Rubisco activity. Physiological significance of high activity of PEP-Case over rubisco will be discussed

  5. Dinitrogen fixation in aphotic oxygenated marine environments

    Eyal eRahav

    2013-08-01

    Full Text Available We measured N2 fixation rates from oceanic zones that have traditionally been ignored as sources of biological N2 fixation; the aphotic, fully oxygenated, nitrate (NO3--rich, waters of the oligotrophic Levantine Basin (LB and the Gulf of Aqaba (GA. N2 fixation rates measured from pelagic aphotic waters to depths up to 720 m, during the mixed and stratified periods, ranged from 0.01 nmol N L-1 d-1 to 0.38 nmol N L-1 d-1. N2 fixation rates correlated significantly with bacterial productivity and heterotrophic diazotrophs were identified from aphotic as well as photic depths. Dissolved free amino acid amendments to whole water from the GA enhanced bacterial productivity by 2to 3.5 and N2 fixation rates by ~ 2 fold in samples collected from aphotic depths while in amendments to water from photic depths bacterial productivity increased 2 to 6 fold while N2 fixation rates increased by a factor of 2 to 4 illustrating that both BP an heterotrophic N2 fixation are carbon limited. Experimental manipulations of aphotic waters from the LB demonstrated a significant positive correlation between transparent exopolymeric particles (TEP concentration and N2 fixation rates. This suggests that sinking organic material and high carbon (C: nitrogen (N micro-environments (such as TEP-based aggregates or marine snow could support high heterotrophic N2 fixation rates in oxygenated surface waters and in the aphotic zones. Indeed, our calculations show that aphotic N2 fixation accounted for 37 to 75 % of the total daily integrated N2 fixation rates at both locations in the Mediterranean and Red Seas with rates equal or greater to those measured from the photic layers. Moreover, our results indicate that that while N2 fixation may be limited in the surface waters, aphotic, pelagic N2 fixation may contribute significantly to new N inputs in other oligotrophic basins, yet it is currently not included in regional or global N budgets.

  6. Field evaluation of N2 fixation by seventeen mung bean genotypes in the Philippines

    Rosales, C.M.; Rivera, F.; Hautia, R.A.; Del Rosario, E.

    1994-12-01

    Seventeen mung bean genotypes were screened for biological nitrogen fixation (BNF) during the late dry (March-May) and early dry (October-December) seasons of 1992 in the Philippines. The 15 N isotope dilution method was used to measure N 2 fixation. Performances were quantified based on both indirect and direct measurements of N 2 fixation. Genetic variation was observed among varieties tested for some BNF characteristic. However, genetic variability for percent N derived from fixation (%Ndfa) was not evident. PAEC 3 mutant, Taiwan Green, Acc 687 and Pagasa 7 were the best performers. Whereas Acc 2041 consistently performed poorly for most of the BNF characters tested. (author). 14 refs., 1 fig., 2 tabs

  7. Immaturity of Visual Fixations in Dyslexic Children.

    TIADI eBi Kuyami Guy Aimé

    2016-02-01

    Full Text Available To our knowledge, behavioral studies recording visual fixations abilities in dyslexic children are scarce. The object of this paper is to explore further the visual fixation ability in dyslexics compared to chronological age-matched and reading age-matched non-dyslexic children. Fifty-five dyslexic children from 7 to 14 years old, fifty-five chronological age-matched non-dyslexic children and fifty-five reading age-matched non-dyslexic children participated to this study. Eye movements from both eyes were recorded horizontally and vertically by a video-oculography system (EyeBrain® T2. The fixation task consisted in fixating a white-filled circle appearing in the centre of the screen for 30 seconds. Results showed that dyslexic children produced a significantly higher number of unwanted saccades than both groups of non-dyslexic children. Moreover, the number of unwanted saccades significantly decreased with age in both groups of non-dyslexic children, but not in dyslexics. Furthermore, dyslexics made more saccades during the last 15 sec of fixation period with respect to both groups of non-dyslexic children. Such poor visual fixation capability in dyslexic children could be due to impaired attention abilities, as well as to an immaturity of the cortical areas controlling the fixation system.

  8. Sutureless Intrascleral Fixated Intraocular Lens Implantation.

    Karadag, Remzi; Celik, Haci Ugur; Bayramlar, Huseyin; Rapuano, Christopher J

    2016-08-01

    To review sutureless intrascleral intraocular lens (IOL) fixation methods. Review of published literature. Sutureless intrascleral IOL fixation methods are newer and have been developed to eliminate the suture-related complications of sutured scleral fixation methods such as suture-induced inflammation or infection and IOL dislocation or subluxation due to suture degradation or suture breakage. Sutureless intrascleral fixation methods aim for intrascleral haptic fixation to achieve stability of the IOL. Various methods of sutureless scleral fixation have been described. Using a needle, a blade, or a trochar, sclerostomies are created in all techniques for intraocular access. Some surgeons prefer to create scleral tunnels, whereas others use scleral flaps for scleral fixation of haptics. The stability of IOLs is attained by the scar tissue formed around the haptics. Short-term results of these new methods are acceptable; studies including more cases with longer follow-up are needed to determine their long-term success. [J Cataract Refract Surg. 2016;32(9):586-597.]. Copyright 2016, SLACK Incorporated.

  9. 14CO2 fixation pattern of cyanobacteria

    Erdmann, N.; Schiewer, U.

    1985-01-01

    The 14 CO 2 fixation pattern of three cyanobacteria in the light and dark were studied. Two different chromatographic methods widely used for separating labelled photosynthetic intermediates were compared. After ethanolic extraction, a rather uniform fixation pattern reflecting mainly the β-carboxylation pathway is obtained for all 3 species. Of the intermediates, glucosylglycerol is specific and high citrulline and low malate contents are fairly specific to cyanobacteria. The composition of the 14 CO 2 fixation pattern is hardly affected by changes in temperature or light intensity, but it is severely affected by changes in the water potential of the medium. (author)

  10. Carbon dioxide fixation in isolated Kalanchoe chloroplasts

    Levi, C.; Gibbs, M.

    1975-07-01

    Chloroplasts isolated from Kalanchoe diagremontiana leaves were capable of photosynthesizing at a rate of 5.4 ..mu..moles of CO/sub 2/ per milligram of chlorophyll per hour. The dark rate of fixation was about 1 percent of the light rate. A high photosynthetic rate was associated with low starch content of the leaves. Ribose 5-phosphate, fructose 1, 6-diphosphate, and dithiothreitol stimulated fixation, whereas phosphoenolpyruvate and azide were inhibitors. The products of CO/sub 2/ fixation were primarily those of the photosynthetic carbon reduction cycle. (auth)

  11. Noninvasive patient fixation for extracranial stereotactic radiotherapy

    Lohr, Frank; Debus, Juergen; Frank, Claudia; Herfarth, Klaus; Pastyr, Otto; Rhein, Bernhard; Bahner, Malte L.; Schlegel, Wolfgang; Wannenmacher, Michael

    1999-01-01

    Purpose: To evaluate the setup accuracy that can be achieved with a novel noninvasive patient fixation technique based on a body cast attached to a recently developed stereotactic body frame during fractionated extracranial stereotactic radiotherapy. Methods and Materials: Thirty-one CT studies (≥ 20 slices, thickness: 3 mm) from 5 patients who were immobilized in a body cast attached to a stereotactic body frame for treatment of para medullary tumors in the thoracic or lumbar spine were evaluated with respect to setup accuracy. The immobilization device consisted of a custom-made wrap-around body cast that extended from the neck to the thighs and a separate head mask, both made from Scotchcast. Each CT study was performed immediately before or after every second or third actual treatment fraction without repositioning the patient between CT and treatment. The stereotactic localization system was mounted and the isocenter as initially located stereo tactically was marked with fiducials for each CT study. Deviation of the treated isocenter as compared to the planned position was measured in all three dimensions. Results: The immobilization device can be easily handled, attached to and removed from the stereotactic frame and thus enables treatment of multiple patients with the same stereotactic frame each day. Mean patient movements of 1.6 mm ± 1.2 mm (laterolateral [LL]), 1.4 mm ± 1.0 mm (anterior-posterior [AP]), 2.3 mm ± 1.3 mm (transversal vectorial error [VE]) and < slice thickness = 3 mm (cranio caudal [CC]) were recorded for the targets in the thoracic spine and 1.4 mm ± 1.0 mm (LL), 1.2 mm ± 0.7 mm (AP), 1.8 mm ± 1.2 mm (VE), and < 3 mm (CC) for the lumbar spine. The worst case deviation was 3.9 mm for the first patient with the target in the thoracic spine (in the LL direction). Combining those numbers (mean transversal VE for both locations and maximum CC error of 3 mm), the mean three-dimensional vectorial patient movement and thus the mean overall

  12. [Effectiveness comparison of suspension fixation plus hinged external fixator and double plate internal fixation in treatment of type C humeral intercondylar fractures].

    Zhang, Jian; Lin, Xu; Zhong, Zeli; Wu, Chao; Tan, Lun

    2017-07-01

    To compare the effectiveness of suspension fixation plus hinged external fixator with double plate internal fixation in the treatment of type C humeral intercondylar fractures. Between January 2014 and April 2016, 30 patients with type C (Association for the Study of Internal Fixation, AO/ASIF) humeral intercondylar fractures were treated. Kirschner wire suspension fixation plus hinged external fixator was used in 14 cases (group A), and double plate internal fixation in 16 cases (group B). There was no significant difference in gender, age, injury cause, disease duration, injury side, and type of fracture between 2 groups ( P >0.05). There was no significant difference in operation time and hospitalization stay between 2 groups ( P >0.05). But the intraoperative blood loss in group A was significantly less than that in group B ( P internal fixation removal, the intraoperative blood loss, and VAS score at 1 day and 3 days after operation in group A were significant better than those in group B ( P external fixator and double plate internal fixation for the treatment of type C humeral intercondylar fractures have ideal outcome in elbow function. But the suspension fixation plus hinged external fixator is better than double plate internal fixation in intraoperative blood loss, postoperative VAS score, and time of internal fixation removal.

  13. Transcriptional Profiling of Nitrogen Fixation in Azotobacter vinelandii▿†

    Hamilton, Trinity L.; Ludwig, Marcus; Dixon, Ray; Boyd, Eric S.; Dos Santos, Patricia C.; Setubal, João C.; Bryant, Donald A.; Dean, Dennis R.; Peters, John W.

    2011-01-01

    Most biological nitrogen (N2) fixation results from the activity of a molybdenum-dependent nitrogenase, a complex iron-sulfur enzyme found associated with a diversity of bacteria and some methanogenic archaea. Azotobacter vinelandii, an obligate aerobe, fixes nitrogen via the oxygen-sensitive Mo nitrogenase but is also able to fix nitrogen through the activities of genetically distinct alternative forms of nitrogenase designated the Vnf and Anf systems when Mo is limiting. The Vnf system appears to replace Mo with V, and the Anf system is thought to contain Fe as the only transition metal within the respective active site metallocofactors. Prior genetic analyses suggest that a number of nif-encoded components are involved in the Vnf and Anf systems. Genome-wide transcription profiling of A. vinelandiicultured under nitrogen-fixing conditions under various metal amendments (e.g., Mo or V) revealed the discrete complement of genes associated with each nitrogenase system and the extent of cross talk between the systems. In addition, changes in transcript levels of genes not directly involved in N2fixation provided insight into the integration of central metabolic processes and the oxygen-sensitive process of N2fixation in this obligate aerobe. The results underscored significant differences between Mo-dependent and Mo-independent diazotrophic growth that highlight the significant advantages of diazotrophic growth in the presence of Mo. PMID:21724999

  14. Fixation probability on clique-based graphs

    Choi, Jeong-Ok; Yu, Unjong

    2018-02-01

    The fixation probability of a mutant in the evolutionary dynamics of Moran process is calculated by the Monte-Carlo method on a few families of clique-based graphs. It is shown that the complete suppression of fixation can be realized with the generalized clique-wheel graph in the limit of small wheel-clique ratio and infinite size. The family of clique-star is an amplifier, and clique-arms graph changes from amplifier to suppressor as the fitness of the mutant increases. We demonstrate that the overall structure of a graph can be more important to determine the fixation probability than the degree or the heat heterogeneity. The dependence of the fixation probability on the position of the first mutant is discussed.

  15. Fixation of Selenium by Clay Minerals and Iron Oxides

    Hamdy, A. A.; Nielsen, Gunnar Gissel

    1977-01-01

    In studying Se fixation, soil components capable of retaining Se were investigated. The importance of Fe hydrous oxides in the fixation of Se was established. The clay minerals common to soils, such as kaolinite, montmorillonite and vermiculite, all exhibited Se fixation, but greater fixation occ...

  16. Biomechanical Evaluation of Standard Versus Extended Proximal Fixation Olecranon Plates for Fixation of Olecranon Fractures.

    Boden, Allison L; Daly, Charles A; Dalwadi, Poonam P; Boden, Stephanie A; Hutton, William C; Muppavarapu, Raghuveer C; Gottschalk, Michael B

    2018-01-01

    Small olecranon fractures present a significant challenge for fixation, which has resulted in development of plates with proximal extension. Olecranon-specific plates with proximal extensions are widely thought to offer superior fixation of small proximal fragments but have distinct disadvantages: larger dissection, increased hardware prominence, and the increased possibility of impingement. Previous biomechanical studies of olecranon fracture fixation have compared methods of fracture fixation, but to date there have been no studies defining olecranon plate fixation strength for standard versus extended olecranon plates. The purpose of this study is to evaluate the biomechanical utility of the extended plate for treatment of olecranon fractures. Sixteen matched pairs of fresh-frozen human cadaveric elbows were used. Of the 16, 8 matched pairs received a transverse osteotomy including 25% and 8 including 50% of the articular surface on the proximal fragment. One elbow from each pair was randomly assigned to a standard-length plate, and the other elbow in the pair received the extended-length plate, for fixation of the fracture. The ulnae were cyclically loaded and subsequently loaded to failure, with ultimate load, number of cycles, and gap formation recorded. There was no statistically significant difference between the standard and extended fixation plates in simple transverse fractures at either 25% or 50% from the proximal most portion of the articular surface of the olecranon. Standard fixation plates are sufficient for the fixation of small transverse fractures, but caution should be utilized particularly with comminution and nontransverse fracture patterns.

  17. Maxwellian Eye Fixation during Natural Scene Perception

    Jean Duchesne

    2012-01-01

    Full Text Available When we explore a visual scene, our eyes make saccades to jump rapidly from one area to another and fixate regions of interest to extract useful information. While the role of fixation eye movements in vision has been widely studied, their random nature has been a hitherto neglected issue. Here we conducted two experiments to examine the Maxwellian nature of eye movements during fixation. In Experiment 1, eight participants were asked to perform free viewing of natural scenes displayed on a computer screen while their eye movements were recorded. For each participant, the probability density function (PDF of eye movement amplitude during fixation obeyed the law established by Maxwell for describing molecule velocity in gas. Only the mean amplitude of eye movements varied with expertise, which was lower in experts than novice participants. In Experiment 2, two participants underwent fixed time, free viewing of natural scenes and of their scrambled version while their eye movements were recorded. Again, the PDF of eye movement amplitude during fixation obeyed Maxwell’s law for each participant and for each scene condition (normal or scrambled. The results suggest that eye fixation during natural scene perception describes a random motion regardless of top-down or of bottom-up processes.

  18. Maxwellian Eye Fixation during Natural Scene Perception

    Duchesne, Jean; Bouvier, Vincent; Guillemé, Julien; Coubard, Olivier A.

    2012-01-01

    When we explore a visual scene, our eyes make saccades to jump rapidly from one area to another and fixate regions of interest to extract useful information. While the role of fixation eye movements in vision has been widely studied, their random nature has been a hitherto neglected issue. Here we conducted two experiments to examine the Maxwellian nature of eye movements during fixation. In Experiment 1, eight participants were asked to perform free viewing of natural scenes displayed on a computer screen while their eye movements were recorded. For each participant, the probability density function (PDF) of eye movement amplitude during fixation obeyed the law established by Maxwell for describing molecule velocity in gas. Only the mean amplitude of eye movements varied with expertise, which was lower in experts than novice participants. In Experiment 2, two participants underwent fixed time, free viewing of natural scenes and of their scrambled version while their eye movements were recorded. Again, the PDF of eye movement amplitude during fixation obeyed Maxwell's law for each participant and for each scene condition (normal or scrambled). The results suggest that eye fixation during natural scene perception describes a random motion regardless of top-down or of bottom-up processes. PMID:23226987

  19. Community structure and soil pH determine chemoautotrophic carbon dioxide fixation in drained paddy soils.

    Long, Xi-En; Yao, Huaiying; Wang, Juan; Huang, Ying; Singh, Brajesh K; Zhu, Yong-Guan

    2015-06-16

    Previous studies suggested that microbial photosynthesis plays a potential role in paddy fields, but little is known about chemoautotrophic carbon fixers in drained paddy soils. We conducted a microcosm study using soil samples from five paddy fields to determine the environmental factors and quantify key functional microbial taxa involved in chemoautotrophic carbon fixation. We used stable isotope probing in combination with phospholipid fatty acid (PLFA) and molecular approaches. The amount of microbial (13)CO2 fixation was determined by quantification of (13)C-enriched fatty acid methyl esters and ranged from 21.28 to 72.48 ng of (13)C (g of dry soil)(-1), and the corresponding ratio (labeled PLFA-C:total PLFA-C) ranged from 0.06 to 0.49%. The amount of incorporationof (13)CO2 into PLFAs significantly increased with soil pH except at pH 7.8. PLFA and high-throughput sequencing results indicated a dominant role of Gram-negative bacteria or proteobacteria in (13)CO2 fixation. Correlation analysis indicated a significant association between microbial community structure and carbon fixation. We provide direct evidence of chemoautotrophic C fixation in soils with statistical evidence of microbial community structure regulation of inorganic carbon fixation in the paddy soil ecosystem.

  20. Nitrogen fixation in trees - 1

    Dobereiner, J.; Gauthier, D.L.; Diem, H.G.; Dommergues, Y.R.; Bonetti, R.; Oliveira, L.A.; Magalhaes, F.M.M.; Faria, S.M. de; Franco, A.A.; Menandro, M.S.

    1984-01-01

    Six papers are presented from the symposium. Dobereiner, J.; Nodulation and nitrogen fixation in leguminous trees, 83-90, (15 ref.), reviews studies on Brazilian species. Gauthier, D.L., Diem, H.G., Dommergues, Y.R., Tropical and subtropical actinorhizal plants, 119-136, (Refs. 50), reports on studies on Casuarinaceae. Bonetti, R., Oliveira, L.A., Magalhaes, F.M.M.; Rhizobium populations and occurrence of VA mycorrhizae in plantations of forest trees, 137-142, (Refs. 15), studies Amazonia stands of Cedrelinga catenaeformis, Calophyllum brasiliense, Dipteryx odorata, D. potiphylla, Carapa guianensis, Goupia glabra, Tabebuia serratifolia, Clarisia racemosa, Pithecellobium racemosum, Vouacapoua pallidior, Eperua bijuga, and Diplotropis species. Nodulation was observed in Cedrelinga catenaeformis and V. pallidior. Faria, S.M. de, Franco, A.A., Menandro, M.S., Jesus, R.M. de, Baitello, J.B.; Aguiar, O.T. de, Doebereiner, J; survey of nodulation in leguminous tree species native to southeastern Brazil, 143-153, (Refs. 7), reports on 119 species, with first reports of nodulation in the genera Bowdichia, Poecilanthe, Melanoxylon, Moldenhaurea (Moldenhawera), and Pseudosamanea. Gaiad, S., Carpanezzi, A.A.; Occurrence of Rhizobium in Leguminosae of silvicultural interest for south Brazil, 155-158, (Refs. 2). Nodulation is reported in Mimosa scabrella, Acacia mearnsii, A. longifolia various trinervis, Enterolobium contortisiliquum, and Erythrina falcata. Magalhaes, L.M.S., Blum, W.E.H., Nodulation and growth of Cedrelinga catanaeformis in experimental stands in the Manaus region - Amazonas, 159-164, (Refs. 5). Results indicate that C. catenaeformis can be used in degraded areas of very low soil fertility.

  1. Rubisco activase is required for optimal photosynthesis in the green alga Chlamydomonas reinhardtii in a low-CO(2) atmosphere.

    Pollock, Steve V; Colombo, Sergio L; Prout, Davey L; Godfrey, Ashley C; Moroney, James V

    2003-12-01

    This report describes a Chlamydomonas reinhardtii mutant that lacks Rubisco activase (Rca). Using the BleR (bleomycin resistance) gene as a positive selectable marker for nuclear transformation, an insertional mutagenesis screen was performed to select for cells that required a high-CO2 atmosphere for optimal growth. The DNA flanking the BleR insert of one of the high-CO2-requiring strains was cloned using thermal asymmetric interlaced-polymerase chain reaction and inverse polymerase chain reaction and sequenced. The flanking sequence matched the C. reinhardtii Rca cDNA sequence previously deposited in the National Center for Biotechnology Information database. The loss of a functional Rca in the strain was confirmed by the absence of Rca mRNA and protein. The open reading frame for Rca was cloned and expressed in pSL18, a C. reinhardtii expression vector conferring paromomycin resistance. This construct partially complemented the mutant phenotype, supporting the hypothesis that the loss of Rca was the reason the mutant grew poorly in a low-CO2 atmosphere. Sequencing of the C. reinhardtii Rca gene revealed that it contains 10 exons ranging in size from 18 to 470 bp. Low-CO2-grown rca1 cultures had a growth rate and maximum rate of photosynthesis 60% of wild-type cells. Results obtained from experiments on a cia5 rca1 double mutant also suggest that the CO2-concentrating mechanism partially compensates for the absence of an active Rca in the green alga C. reinhardtii.

  2. Nitrogen fixation in denitrified marine waters.

    Camila Fernandez

    Full Text Available Nitrogen fixation is an essential process that biologically transforms atmospheric dinitrogen gas to ammonia, therefore compensating for nitrogen losses occurring via denitrification and anammox. Currently, inputs and losses of nitrogen to the ocean resulting from these processes are thought to be spatially separated: nitrogen fixation takes place primarily in open ocean environments (mainly through diazotrophic cyanobacteria, whereas nitrogen losses occur in oxygen-depleted intermediate waters and sediments (mostly via denitrifying and anammox bacteria. Here we report on rates of nitrogen fixation obtained during two oceanographic cruises in 2005 and 2007 in the eastern tropical South Pacific (ETSP, a region characterized by the presence of coastal upwelling and a major permanent oxygen minimum zone (OMZ. Our results show significant rates of nitrogen fixation in the water column; however, integrated rates from the surface down to 120 m varied by ∼30 fold between cruises (7.5±4.6 versus 190±82.3 µmol m(-2 d(-1. Moreover, rates were measured down to 400 m depth in 2007, indicating that the contribution to the integrated rates of the subsurface oxygen-deficient layer was ∼5 times higher (574±294 µmol m(-2 d(-1 than the oxic euphotic layer (48±68 µmol m(-2 d(-1. Concurrent molecular measurements detected the dinitrogenase reductase gene nifH in surface and subsurface waters. Phylogenetic analysis of the nifH sequences showed the presence of a diverse diazotrophic community at the time of the highest measured nitrogen fixation rates. Our results thus demonstrate the occurrence of nitrogen fixation in nutrient-rich coastal upwelling systems and, importantly, within the underlying OMZ. They also suggest that nitrogen fixation is a widespread process that can sporadically provide a supplementary source of fixed nitrogen in these regions.

  3. Nitrogen Fixation in Denitrified Marine Waters

    Fernandez, Camila; Farías, Laura; Ulloa, Osvaldo

    2011-01-01

    Nitrogen fixation is an essential process that biologically transforms atmospheric dinitrogen gas to ammonia, therefore compensating for nitrogen losses occurring via denitrification and anammox. Currently, inputs and losses of nitrogen to the ocean resulting from these processes are thought to be spatially separated: nitrogen fixation takes place primarily in open ocean environments (mainly through diazotrophic cyanobacteria), whereas nitrogen losses occur in oxygen-depleted intermediate waters and sediments (mostly via denitrifying and anammox bacteria). Here we report on rates of nitrogen fixation obtained during two oceanographic cruises in 2005 and 2007 in the eastern tropical South Pacific (ETSP), a region characterized by the presence of coastal upwelling and a major permanent oxygen minimum zone (OMZ). Our results show significant rates of nitrogen fixation in the water column; however, integrated rates from the surface down to 120 m varied by ∼30 fold between cruises (7.5±4.6 versus 190±82.3 µmol m−2 d−1). Moreover, rates were measured down to 400 m depth in 2007, indicating that the contribution to the integrated rates of the subsurface oxygen-deficient layer was ∼5 times higher (574±294 µmol m−2 d−1) than the oxic euphotic layer (48±68 µmol m−2 d−1). Concurrent molecular measurements detected the dinitrogenase reductase gene nifH in surface and subsurface waters. Phylogenetic analysis of the nifH sequences showed the presence of a diverse diazotrophic community at the time of the highest measured nitrogen fixation rates. Our results thus demonstrate the occurrence of nitrogen fixation in nutrient-rich coastal upwelling systems and, importantly, within the underlying OMZ. They also suggest that nitrogen fixation is a widespread process that can sporadically provide a supplementary source of fixed nitrogen in these regions. PMID:21687726

  4. Infra-red process for colour fixation on fabrics

    Raymond, D.J.; Biau, D.

    1983-01-01

    Infra-red radiations find wide application in industrial processes as heating, drying, stoving and forming. The results are often far better than those from the other techniques: convection oven, gas IR etc ... They come from the electric IR specific advantages: energy direct transmission, emitter and product spectral coupling, possible selectivity. That is the case in the Textile Industry, where experiments showed that infra-red process heating could be efficient for colour fixation on fabrics. Shorter production cycles and energy saving are the main results

  5. Levels of daily light doses under changed day-night cycles regulate temporal segregation of photosynthesis and N2 Fixation in the cyanobacterium Trichodesmium erythraeum IMS101.

    Cai, Xiaoni; Gao, Kunshan

    2015-01-01

    While the diazotrophic cyanobacterium Trichodesmium is known to display inverse diurnal performances of photosynthesis and N2 fixation, such a phenomenon has not been well documented under different day-night (L-D) cycles and different levels of light dose exposed to the cells. Here, we show differences in growth, N2 fixation and photosynthetic carbon fixation as well as photochemical performances of Trichodesmium IMS101 grown under 12L:12D, 8L:16D and 16L:8D L-D cycles at 70 μmol photons m-2 s-1 PAR (LL) and 350 μmol photons m-2 s-1 PAR (HL). The specific growth rate was the highest under LL and the lowest under HL under 16L:8D, and it increased under LL and decreased under HL with increased levels of daytime light doses exposed under the different light regimes, respectively. N2 fixation and photosynthetic carbon fixation were affected differentially by changes in the day-night regimes, with the former increasing directly under LL with increased daytime light doses and decreased under HL over growth-saturating light levels. Temporal segregation of N2 fixation from photosynthetic carbon fixation was evidenced under all day-night regimes, showing a time lag between the peak in N2 fixation and dip in carbon fixation. Elongation of light period led to higher N2 fixation rate under LL than under HL, while shortening the light exposure to 8 h delayed the N2 fixation peaking time (at the end of light period) and extended it to night period. Photosynthetic carbon fixation rates and transfer of light photons were always higher under HL than LL, regardless of the day-night cycles. Conclusively, diel performance of N2 fixation possesses functional plasticity, which was regulated by levels of light energy supplies either via changing light levels or length of light exposure.

  6. Isolation of intact and pure chloroplasts from leaves of Arabidopsis thaliana plants acclimated to low irradiance for studies on Rubisco regulation

    Magda Grabsztunowicz

    2012-11-01

    Full Text Available A protocol is presented for low-cost and fast isolation of intact and pure chloroplasts from leaves of plants acclimated to low irradiance. The protocol is based on a differential centrifugation of cleared leaf homogenate and omits a centrifugation on Percoll gradient step. The intactness and purity of the chloroplasts isolated from leaves of low irradiance-acclimated plants by using this protocol (confirmed by phase contrast microscopy as well as enzymatic and immunological approaches allows plausible studies on low irradiance-dependent Rubisco regulation.

  7. Graft fixation in cruciate ligament reconstruction.

    Brand, J; Weiler, A; Caborn, D N; Brown, C H; Johnson, D L

    2000-01-01

    Cruciate ligament reconstruction has progressed dramatically in the last 20 years. Anatomic placement of ligament substitutes has fostered rehabilitation efforts that stress immediate and full range of motion, immediate weightbearing, neuromuscular strength and coordination, and early return to athletic competition (3 months). This has placed extreme importance on secure graft fixation at the time of ligament reconstruction. Current ligament substitutes require a bony or soft tissue component to be fixed within a bone tunnel or on the periosteum at a distance from the normal ligament attachment site. Fixation devices have progressed from metal to biodegradable and from far to near-normal native ligament attachment sites. Ideally, the biomechanical properties of the entire graft construct would approach those of the native ligament and facilitate biologic incorporation of the graft. Fixation should be done at the normal anatomic attachment site of the native ligament (aperture fixation) and, over time, allow the biologic return of the histologic transition zone from ligament to fibrocartilage, to calcified fibrocartilage, to bone. The purpose of this article is to review current fixation devices and techniques in cruciate ligament surgery.

  8. External fixation of “intertrochanteric” fractures

    Gani, Naseem ul; Kangoo, Khursheed Ahmed; Bashir, Arshad; Muzaffer, Rahil; Bhat, Mohammad Farooq; Farooq, Munir; Badoo, Abdul Rashid; Dar, Imtiyaz Hussian; Wani, Mudassir Maqbool

    2009-01-01

    In developing countries, due to limited availability of modern anesthesia and overcrowding of the hospitals with patients who need surgery, high-risk patients with “intertrochanteric” fractures remain unsuita ble for open reduction and internal fixation. The aim of this study was to analyze the results of external fixation of “intertrochanteric” fractures in high-risk geriatric patients in a developing country. The results of 62 ambulatory high-risk geriatric patients with a mean age of 70 years (range 58–90 years) with “intertrochanteric” fractures, in whom external fixation was performed, are reported. Eight patients died during follow-up due to medical causes unrelated to the surgical procedure. So only 54 patients were available for final assessment. Procedure is simple, performed under local anesthesia, requires less time for surgery and is associated with less blood loss. Good fixation and early ambulation was achieved in most of the patients. Average time to union was 14 weeks. Thirty-one patients developed superficial pin tract infection and 28 patients had average shortening of 15 mm due to impaction and varus angulation. Functional outcome was assessed using Judet's point system. Good to excellent results were achieved in 44 patients. This study demonstrated that external fixation of “intertrochantric” fractures performed under local anesthesia offers significant advantage in ambulatory high-risk geriatric patients especially in a developing country. PMID:21808680

  9. External fixation of “intertrochanteric” fractures

    Naseem ul Gani

    2009-08-01

    Full Text Available In developing countries, due to limited availability of modern anesthesia and overcrowding of the hospitals with patients who need surgery, high-risk patients with “intertro-chanteric” fractures remain unsuitable for open reduction and internal fixation. The aim of this study was to analyze the results of external fixation of “intertro-chanteric” fractures in high-risk geriatric patients in a developing country. The results of 62 ambulatory high-risk geriatric patients with a mean age of 70 years (range 58-90 years with “intertrochanteric” fractures, in whom external fixation was performed, are reported. Eight patients died during follow-up due to medical causes unrelated to the surgical procedure. So only 54 patients were available for final assessment. Procedure is simple, performed under local anesthesia, requires less time for surgery and is associated with less blood loss. Good fixation and early ambulation was achieved in most of the patients. Average time to union was 14 weeks. Thirty-one patients developed superficial pin tract infection and 28 patients had average shortening of 15 mm due to impaction and varus angulation. Functional outcome was assessed using Judet’s point system. Good to excellent results were achieved in 44 patients. This study demonstrated that external fixation of “intertrochantric” fractures performed under local anesthesia offers significant advantage in ambulatory high-risk geriatric patients especially in a developing country.

  10. A Small Decrease in Rubisco Content by Individual Suppression of RBCS Genes Leads to Improvement of Photosynthesis and Greater Biomass Production in Rice Under Conditions of Elevated CO2.

    Kanno, Keiichi; Suzuki, Yuji; Makino, Amane

    2017-03-01

    Rubisco limits photosynthesis at low CO2 concentrations ([CO2]), but does not limit it at elevated [CO2]. This means that the amount of Rubisco is excessive for photosynthesis at elevated [CO2]. Therefore, we examined whether a small decrease in Rubisco content by individual suppression of the RBCS multigene family leads to increases in photosynthesis and biomass production at elevated [CO2] in rice (Oryza sativa L.). Our previous studies indicated that the individual suppression of RBCS decreased Rubisco content in rice by 10-25%. Three lines of BC2F2 progeny were selected from transgenic plants with individual suppression of OsRBCS2, 3 and 5. Rubisco content in the selected lines was 71-90% that of wild-type plants. These three transgenic lines showed lower rates of CO2 assimilation at low [CO2] (28 Pa) but higher rates of CO2 assimilation at elevated [CO2] (120 Pa). Similarly, the biomass production and relative growth rate (RGR) of the two lines were also smaller at low [CO2] but greater than that of wild-type plants at elevated [CO2]. This greater RGR was caused by the higher net assimilation rate (NAR). When the nitrogen use efficiency (NUE) for the NAR was estimated by dividing the NAR by whole-plant leaf N content, the NUE for NAR at elevated [CO2] was higher in these two lines. Thus, a small decrease in Rubisco content leads to improvements of photosynthesis and greater biomass production in rice under conditions of elevated CO2. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  11. Loads applied to fixations for chain stretching

    Ahrens, K; Brychta, P

    1985-06-01

    The chains of scraper chain conveyors must be pre-stretched during standstill in order to compensate the elongations occurring during operation. They require frequent retensiening in order to meet the varying operational requirements. During tensioning, the chains are fixed in a point in the top run by means of fixation elements. The authors present a method for calculating the retaining force needed in the fixations. There are three different initial conditions of the chain before trensioning: Tensionsfree chain, pretensioned chain (stressed chain), slack chain. In all three cases, it is important to find out whether or nor the tensioning drive reaches full speed. The method of calculation is illustrated by the example of a scraper chain conveyor; it enables the establishment of rules for tensioning without damaging the chain and is a good basis for the dimensioning of new types of fixation elements.

  12. Biometric recognition via fixation density maps

    Rigas, Ioannis; Komogortsev, Oleg V.

    2014-05-01

    This work introduces and evaluates a novel eye movement-driven biometric approach that employs eye fixation density maps for person identification. The proposed feature offers a dynamic representation of the biometric identity, storing rich information regarding the behavioral and physical eye movement characteristics of the individuals. The innate ability of fixation density maps to capture the spatial layout of the eye movements in conjunction with their probabilistic nature makes them a particularly suitable option as an eye movement biometrical trait in cases when free-viewing stimuli is presented. In order to demonstrate the effectiveness of the proposed approach, the method is evaluated on three different datasets containing a wide gamut of stimuli types, such as static images, video and text segments. The obtained results indicate a minimum EER (Equal Error Rate) of 18.3 %, revealing the perspectives on the utilization of fixation density maps as an enhancing biometrical cue during identification scenarios in dynamic visual environments.

  13. N2-fixation by freshly isolated Nostoc from coralloid roots of the cycad Macrozamia riedlei (Fisch. ex Gaud.) Gardn

    Lindblad, P.; Atkins, C.A.; Pate, J.S.

    1991-01-01

    Nitrogenase (EC 1.7.99.2) activity (acetylene reduction) and nitrogen fixation ( 15 N 2 fixation) were measured in cyanobacteria freshly isolated from the coralloid roots of Macrozamia riedlei (Fisch. ex Gaud.) Gardn. The data indicate that cyanobacteria within cycad coralloid roots are differentiated specifically for symbiotic functioning in a microaerobic environment. Specializations include a high heterocyst frequency, enhanced permeability to O 2 , and a direct dependence on the cycad for substrates to support nitrogenase activity

  14. Tricortical cervical inter-body screw fixation.

    Goel A

    1997-01-01

    Full Text Available A new tricortical method of screw implantation for anterior cervical interbody plate fixation is described. The screws are placed obliquely such that they engage the anterior cortex of the body and traverse through the cortices adjoining the disc space. By this method the screws not only hold the plate firmly with a tricortical purchase, but by virtue of their course stabilize the two adjoining vertebral bodies by themselves. Sixteen patients were treated by this method. In three of these cases only tricortical screws without the metal plate were used for fixation. The advantages of the technique are discussed.

  15. Cosmetic arm lengthening with monorail fixator.

    Agrawal, Hemendra Kumar; Singh, Balvinder; Garg, Mohit; Khatkar, Vipin; Batra, Sumit; Sharma, Vinod Kumar

    2015-01-01

    Upper limb length discrepancy is a rare occurrence. Humerus shortening may need specialized treatment to restore the functional and cosmetic status of upper limb. We report a case of humerus lengthening of 9 cm with a monorail external fixator and the result was observed during a 2-year follow-up. Humerus lengthening needs specialized focus as it is not only a cosmetic issue but also a functional demand. The monorail unilateral fixator is more functional and cosmetically acceptable, and thus becomes an effective treatment option.

  16. Transient improvements in fixational stability in strabismic amblyopes following bifoveal fixation and reduced interocular suppression.

    Raveendran, Rajkumar Nallour; Babu, Raiju J; Hess, Robert F; Bobier, William R

    2014-03-01

    To test the hypothesis that fixational stability of the amblyopic eye in strabismics will improve when viewing provides both bifoveal fixation and reduced inter-ocular suppression by reducing the contrast to the fellow eye. Seven strabismic amblyopes (Age: 29.2 ± 9 years; five esotropes and two exotropes) showing clinical characteristics of central suppression were recruited. Interocular suppression was measured by a global motion task. For each participant, a balance point was determined which defined contrast levels for each eye where binocular combination was optimal (interocular suppression minimal). When the balance point could not be determined, this participant was excluded. Bifoveal fixation was established by ocular alignment using a haploscope. Participants dichoptically viewed similar targets (a cross of 2.3° surrounded by a square of 11.3°) at 40 cm. Target contrasts presented to each eye were either high contrast (100% to both eyes) or balanced contrast (attenuated contrast in the fellow fixing eye). Fixation stability was measured over a 5 min period and quantified using bivariate contour ellipse areas in four different binocular conditions; unaligned/high contrast, unaligned/balance point, aligned/high contrast and aligned/balance point. Fixation stability was also measured in six control subjects (Age: 25.3 ± 4 years). Bifoveal fixation in the strabismics was transient (58.15 ± 15.7 s). Accordingly, fixational stability was analysed over the first 30 s using repeated measures anova. Post hoc analysis revealed that for the amblyopic subjects, the fixational stability of the amblyopic eye was significantly improved in aligned/high contrast (p = 0.01) and aligned/balance point (p suppression. However, once initiated, bifoveal fixation is transient with the strabismic eye drifting away from foveal alignment, thereby increasing the angle of strabismus. © 2014 The Authors Ophthalmic & Physiological Optics © 2014 The College of Optometrists.

  17. Fixation process for radioactive waste

    Theysohn, F.

    1977-01-01

    An improvement on the method of solidification of radioactive liquid waste in bitumen with the aid of extruders is described. So far, it has been difficult to remove large amounts of water. The waste sludge, as proposed here, is pre-dried in the extruder and then mixed with the bitumen. The extruder is inclined upward in the transport direction, and its barrel extruders have through holes parallel to the direction of transport in the raised sides of the passages, so that water runs back. Also the waste steam nozzles are arranged before the bitumen inlet. (UWI) [de

  18. A comparative finite-element analysis of bone failure and load transfer of osseointegrated prostheses fixations.

    Tomaszewski, P.K.; Verdonschot, N.J.J.; Bulstra, S.K.; Verkerke, G.J.

    2010-01-01

    An alternative solution to conventional stump-socket prosthetic limb attachment is offered by direct skeletal fixation. This study aimed to assess two percutaneous trans-femoral implants, the OPRA system (Integrum AB, Goteborg, Sweden), and the ISP Endo/Exo prosthesis (ESKA Implants AG, Lubeck,

  19. A Comparative Finite-Element Analysis of Bone Failure and Load Transfer of Osseointegrated Prostheses Fixations

    Tomaszewski, P. K.; Verdonschot, N.; Bulstra, S. K.; Verkerke, G. J.

    An alternative solution to conventional stump-socket prosthetic limb attachment is offered by direct skeletal fixation. This study aimed to assess two percutaneous trans-femoral implants, the OPRA system (Integrum AB, Goteborg, Sweden), and the ISP Endo/Exo prosthesis (ESKA Implants AG, Lubeck,

  20. A Comparative Finite-Element Analysis of Bone Failure and Load Transfer of Osseointegrated Prostheses Fixations.

    Tomaszewski, P.K.; Verdonschot, Nicolaas Jacobus Joseph; Bulstra, S.K.; Verkerke, Gijsbertus Jacob

    2010-01-01

    An alternative solution to conventional stump–socket prosthetic limb attachment is offered by direct skeletal fixation. This study aimed to assess two percutaneous trans-femoral implants, the OPRA system (Integrum AB, Göteborg, Sweden), and the ISP Endo/Exo prosthesis (ESKA Implants AG, Lübeck,

  1. Studies in Sri Lanka on cowpea: N2 fixation, growth, yield, and effects on cereals

    Senaratne, R.; Dayatilake, G.A.; Subasinghe, S.

    1998-01-01

    The impact of seed inoculation and N-fertilization on nodulation, plant dry-matter production, and seed yield was studied through a series of field experiments with cultivars of cowpea. In some instances there were positive growth responses to applied N, indicating the potential to improve N 2 fixation and yields by combining compatible genotypes and bradyrhizobial strains. Beneficial residual effects on growth of subsequent maize could not be related to N 2 fixation by the preceding cowpea. Although there was no evidence of direct transfer of N from cowpea to intercropped maize, there was greater efficiency of use of N for total crop production during intercropping

  2. Successful operative rib fixation of traumatic flail chest in a patient with osteogenesis imperfecta.

    Kulaylat, Afif N; Chesnut, Charles H; Santos, Ariel P; Armen, Scott B

    2014-09-01

    Increasing attention has been directed towards operative rib fixation of traumatic flail chest; reported benefits include more rapid weaning from the ventilator, decreased intensive care unit stays, decreased complications and improved functional results. The outcomes of this surgical intervention in patients with osteogenesis imperfecta, a rare condition characterized by low bone density and bone fragility, are unknown. This case demonstrates that, in the management of traumatic flail chest in a patient with osteogenesis imperfecta, surgical fixation can be successful and should be considered early. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  3. Effect of vanadium and tungsten on nitrogen fixation and the growth of Medicago sativa

    Jha, K K

    1969-01-01

    In sand culture, it was found that vanadium had no stimulatory effect on nitrogen content or the growth of Medicago sativa inoculated with an effective strain of Rhizobium meliloti or supplied with ammonium nitrate. At the level of 500 ppm it reduced the plant growth, the inhibitory effect being particularly severe on the root. On the other hand tungsten increased nitrogen fixation and the dry matter yield of the inoculated plants. The results are suggestive of a direct role of tungsten in symbiotic nitrogen fixation. 4 references, 2 tables.

  4. Fixation Characteristics of Severe Amblyopia Subtypes: Which One is Worse?

    Koylu, Mehmet Talay; Ozge, Gokhan; Kucukevcilioglu, Murat; Mutlu, Fatih Mehmet; Ceylan, Osman Melih; Akıncıoglu, Dorukcan; Ayyıldız, Onder

    2017-01-01

    To determine differences in macular sensitivity and fixation patterns in different subtypes of severe amblyopia. This case-control study enrolled a total of 73 male adults, including 18 with pure strabismic severe amblyopia, 19 with pure anisometropic severe amblyopia, 18 with mixed (strabismic plus anizometropic) severe amblyopia, and 18 healthy controls. MP-1 microperimetry was used to evaluate macular sensitivity, location of fixation, and stability of fixation. Mean macular sensitivity, stability of fixation, and location of fixation were significantly worse in all amblyopia subtypes when compared with healthy controls. Intergroup comparisons between amblyopia subtypes revealed that mean macular sensitivity, stability of fixation, and location of fixation were significantly worse in pure strabismic and mixed amblyopic eyes when compared with pure anisometropic amblyopic eyes. Strabismus seems to be a worse prognostic factor in severe amblyopia than anisometropia in terms of fixation characteristics and retinal sensitivity.

  5. Sacroiliac screw fixation for tile B fractures.

    Bosch, E.W. van den; Zwienen, C.M. van; Hoek van Dijke, G.A.; Snijders, C.J.; Vugt, A.B. van

    2003-01-01

    BACKGROUND: The purpose of this comparative cadaveric study was to investigate whether the stability of partially unstable pelvic fractures can be improved by combining plate fixation of the symphysis with a posterior sacroiliac screw. METHODS: In six specimens, a Tile B1 (open-book) pelvic fracture

  6. Heterotrophic fixation of CO2 in soil

    Šantrůčková, Hana; Bird, M. I.; Elhottová, Dana; Novák, Jaroslav; Picek, T.; Šimek, Miloslav; Tykva, Richard

    2005-01-01

    Roč. 49, č. 2 (2005), s. 218-225 ISSN 0095-3628 R&D Projects: GA ČR(CZ) GA206/02/1036; GA AV ČR(CZ) IAA6066901 Institutional research plan: CEZ:AV0Z60660521 Keywords : heterotrophic fixation * CO2 * soil Subject RIV: EH - Ecology, Behaviour Impact factor: 2.674, year: 2005

  7. Biodegradable interlocking nails for fracture fixation

    van der Elst, M.; Bramer, J. A.; Klein, C. P.; de Lange, E. S.; Patka, P.; Haarman, H. J.

    1998-01-01

    Serious problems such as stress shielding, allergic reactions, and corrosion are associated with the use of metallic fracture fixation devices in fractured long bones. Metal implants often are removed during a second retrieval operation after fracture healing has completed. A biocompatible implant

  8. Headspace analysis of foams and fixatives

    Harper, Kyle [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Truong, Thanh-Tam [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Magwood, Leroy [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Peters, Brent [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Nicholson, James [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Washington, II, Aaron L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-07-27

    In the process of decontaminating and decommissioning (D&D) older nuclear facilities, special precautions must be taken with removable or airborne contamination. One possible strategy utilizes foams and fixatives to affix these loose contaminants. Many foams and fixatives are already commercially available, either generically or sold specifically for D&D. However, due to a lack of revelant testing in a radioactive environment, additional verification is needed to confirm that these products not only affix contamination to their surfaces, but also will function in a D&D environment. Several significant safety factors, including flammability and worker safety, can be analyzed through the process of headspace analysis, a technique that analyzes the off gas formed before or during the curing process of the foam/fixative, usually using gas chromatography-mass spectrometry (GC-MS). This process focuses on the volatile components of a chemical, which move freely between the solid/liquid form within the sample and the gaseous form in the area above the sample (the headspace). Between possibly hot conditions in a D&D situation and heat created in a foaming reaction, the volatility of many chemicals can change, and thus different gasses can be released at different times throughout the reaction. This project focused on analysis of volatile chemicals involved in the process of using foams and fixatives to identify any potential hazardous or flammable compounds.

  9. Large fluctuations and fixation in evolutionary games

    Assaf, Michael; Mobilia, Mauro

    2010-01-01

    We study large fluctuations in evolutionary games belonging to the coordination and anti-coordination classes. The dynamics of these games, modeling cooperation dilemmas, is characterized by a coexistence fixed point separating two absorbing states. We are particularly interested in the problem of fixation that refers to the possibility that a few mutants take over the entire population. Here, the fixation phenomenon is induced by large fluctuations and is investigated by a semiclassical WKB (Wentzel–Kramers–Brillouin) theory generalized to treat stochastic systems possessing multiple absorbing states. Importantly, this method allows us to analyze the combined influence of selection and random fluctuations on the evolutionary dynamics beyond the weak selection limit often considered in previous works. We accurately compute, including pre-exponential factors, the probability distribution function in the long-lived coexistence state and the mean fixation time necessary for a few mutants to take over the entire population in anti-coordination games, and also the fixation probability in the coordination class. Our analytical results compare excellently with extensive numerical simulations. Furthermore, we demonstrate that our treatment is superior to the Fokker–Planck approximation when the selection intensity is finite

  10. 15N in biological nitrogen fixation studies

    Faust, H.

    1986-05-01

    A bibliography with 298 references on the use of the stable nitrogen isotope 15 N in the research on the biological fixation of dinitrogen is presented. The literature pertaining to this bibliography covers the period from 1975 to the middle of 1985. (author)

  11. The effect of fixation on esterases

    Kirkeby, S; Moe, D

    1984-01-01

    The localization of reaction product for non-specific esterase from fresh and aldehyde treated glandular tissue was examined. The electrophoretical studies showed a selective inhibition of certain isoenzymes and a change in mobility of some bands caused by aldehyde fixation. In sections a granular...

  12. Osteomyelitis in burn patients requiring skeletal fixation

    Barret, JP; Desai, MH; Herndon, DN

    Deep and severe burns often present with the exposure of musculoskeletal structures and severe deformities. Skeletal fixation, suspension and/or traction are part of their comprehensive treatment. Several factors put burn patients at risk for osteomyelitis, osteosynthesis material being one of them.

  13. Locking plate fixation for proximal humerus fractures.

    Burke, Neil G

    2012-02-01

    Locking plates are increasingly used to surgically treat proximal humerus fractures. Knowledge of the bone quality of the proximal humerus is important. Studies have shown the medial and dorsal aspects of the proximal humeral head to have the highest bone strength, and this should be exploited by fixation techniques, particularly in elderly patients with osteoporosis. The goals of surgery for proximal humeral fractures should involve minimal soft tissue dissection and achieve anatomic reduction of the head complex with sufficient stability to allow for early shoulder mobilization. This article reviews various treatment options, in particular locking plate fixation. Locking plate fixation is associated with a high complication rate, such as avascular necrosis (7.9%), screw cutout (11.6%), and revision surgery (13.7%). These complications are frequently due to the varus deformation of the humeral head. Strategic screw placement in the humeral head would minimize the possibility of loss of fracture reduction and potential hardware complications. Locking plate fixation is a good surgical option for the management of proximal humerus fractures. Complications can be avoided by using better bone stock and by careful screw placement in the humeral head.

  14. Plasma catalysis for nitrogen fixation reactions

    Patil, B.S.; Wang, Q.; Hessel, V.; Lang, J.; Stankiewicz, A.; Stefanidis, G.

    2016-01-01

    The preferences for localized chemicals production and changing scenarios of renewable electricity cost gives a renewed boost to plasma-assisted valuable chemicals production. Especially, plasma-assisted nitrogen fixation for fertilizer production has the potential to largely change the energy

  15. Comparative study of fixation density maps

    Engelke, U.; Liu, H.; Wang, Junle; Callet, Le P.; Heynderickx, I.E.J.; Zepernick, H.-J.; Maeder, A.

    2013-01-01

    Fixation density maps (FDM) created from eye tracking experiments are widely used in image processing applications. The FDM are assumed to be reliable ground truths of human visual attention and as such, one expects a high similarity between FDM created in different laboratories. So far, no studies

  16. Fixation-free assessment of the Hirschberg ratio.

    Model, Dmitri; Eizenman, Moshe; Sturm, Veit

    2010-08-01

    To describe a novel methodology by which to measure the Hirschberg ratio (HR) in infants. The methodology does not require fixation on specific points, and measurements are made while infants look naturally at a display. The HR is calculated automatically from measurements of the direction of the optical axis, the position of the pupil center, and corneal reflexes in video images from an advanced two-camera eye-tracking system. The performance of the novel fixation-free procedure (FFP) was evaluated in 43 adults by measuring the average difference and the 95% limits of agreement with the standard fixation-based procedure (FBP). Repeatability of the HR measurements was evaluated by assessing the 95% limits of agreement between two independent measurements. Performance of the FFP was also evaluated in five infants. In adults, the average HR was 12.89 +/- 1.22 degrees/mm for FFP and 12.81 +/- 1.22 degrees/mm for FBP. FFP and FBP measurements were highly correlated (r = 0.95; P limits of agreement between FFP and FBP were +/-0.86 degrees/mm. The 95% limits of agreement of repeated measurements were +/-0.66 degrees/mm for FFP and +/-0.77 degrees/mm for FBP. In infants, the 95% limits of agreement of repeated measurements by FFP were +/-0.63 degrees/mm. In adults, the FFP provides accurate measurements of the HR that are in excellent agreement with measurements by FBP. In infants, measurements of HR by FFP show the same repeatability and consistency.

  17. Radial nerve injury following elbow external fixator: report of three cases and literature review.

    Trigo, Luis; Sarasquete, Juan; Noguera, Laura; Proubasta, Ignacio; Lamas, Claudia

    2017-07-01

    Radial nerve palsy is a rare but serious complication following elbow external fixation. Only 11 cases have been reported in the literature to date, but the incidence may be underreported. We present three new cases of this complication. We analyzed the three cases of radial palsy seen in our center following the application of an external fixator as treatment for complex elbow injuries. Mean patient age at surgery was 50 years. Two patients were female and one was male. In the three cases, the initial lesion was a posterior elbow dislocation, associated with a fracture of the radial shaft in one and a radial head fracture and coronoid fracture, respectively, in the other two. Due to persistent elbow instability, an external fixator was applied in all three cases. The fixator pins were introduced percutaneously in two cases and under direct vision in an open manner in the third case. Radial palsy was noted immediately postoperatively in all cases. It was permanent in two cases and temporary in the third. Radial nerve palsy after placement of an external elbow fixator was resolved in only 1 of our 3 cases and in 6 of the 11 cases in the literature to date. Although the event is rare, these alarming results highlight the need for recommendations to avoid this complication.

  18. Kinetics of transfemoral amputees with osseointegrated fixation performing common activities of daily living.

    Lee, Winson C C; Frossard, Laurent A; Hagberg, Kerstin; Haggstrom, Eva; Brånemark, Rickard; Evans, John H; Pearcy, Mark J

    2007-07-01

    Direct anchorage of a lower-limb prosthesis to the bone through an implanted fixation (osseointegration) has been suggested as an excellent alternative for amputees experiencing complications from use of a conventional socket-type prosthesis. However, an attempt needs to be made to optimize the mechanical design of the fixation and refine the rehabilitation program. Understanding the load applied on the fixation is a crucial step towards this goal. The load applied on the osseointegrated fixation of nine transfemoral amputees was measured using a load transducer, when the amputees performed activities which included straight-line level walking, ascending and descending stairs and a ramp as well as walking around a circle. Force and moment patterns along each gait cycle, magnitudes and time of occurrence of the local extrema of the load, as well as impulses were analysed. Managing a ramp and stairs, and walking around a circle did not produce a significant increase (P>0.05) in load compared to straight-line level walking. The patterns of the moment about the medio-lateral axis were different among the six activities which may reflect the different strategies used in controlling the prosthetic knee joint. This study increases the understanding of biomechanics of bone-anchored osseointegrated prostheses. The loading data provided will be useful in designing the osseointegrated fixation to increase the fatigue life and to refine the rehabilitation protocol.

  19. Is mask-based stereotactic head-and-neck fixation as precise as stereotactic head fixation for precision radiotherapy?

    Georg, Dietmar; Bogner, Joachim; Dieckmann, Karin; Poetter, Richard

    2006-01-01

    Background: The aim of this study was to compare setup accuracy and reproducibility of a stereotactic head and a head-and-neck fixation system, both based on thermoplastic material. Methods and Material: Ten patients were immobilized with a head and a head-and-neck fixation system (both BrainLAB, Germany). Both mask systems were modified with a custom-made mouthpiece and a strip of thermoplastic material attached to the lower part of the mask. During the first treatment session, after positioning patients using room lasers, two orthogonal portal images were taken as reference. Later on, at least five sets of orthogonal portal images were acquired for each patient. The isocentric setup accuracy was determined by comparing field edges and anatomic landmarks and the repositioning accuracy in the mask was obtained by comparing individual anatomic landmarks with respect to the metal balls, fixed on the masks. Systematic and random deviations and resulting three-dimensional (3D) vectors were calculated. Additionally, margins were derived from the systematic and random component of the isocentric setup accuracy. Finally, inter- and intraobserver variations were analyzed. Results: The systematic variation of the isocentric setup accuracy was very similar for the two mask systems, but the random variations were slightly larger for the head-and-neck system, resulting in a 0.4-mm larger 3D vector. The repositioning variations for the head mask were smaller compared with the head-and-neck mask, resulting in smaller 3D vectors for the random (∼0.4 mm) and systematic variations (∼0.6 mm). For both mask systems, a 2-mm margin can be used in lateral and anteroposterior direction, whereas in craniocaudal direction, this margin should be extended to 2.5 mm for the head mask and to 3 mm for the head-and-neck mask. The average absolute differences between two observers were within 0.5 mm, maximum deviations around 1 mm. Conclusion: Thermoplastic mask-based stereotactic head

  20. Translaminar screw fixation in the lumbar spine: technique, indications, results

    Grob, D.; Humke, T.

    1998-01-01

    Translaminar screw fixation of the lumbar spine represents a simple and effective technique for short segment fusion in the degenerative spine. Clinical experience with 173 patients who underwent translaminar screw fixation revealed a fusion rate of 94%. The indications for translaminar screw fixation as a primary fixation procedure are: segmental dysfunction, lumbar spinal stenosis with painful degenerative changes, segmental revision surgery after discectomies, and painful disc-related synd...

  1. Characterization for Soil Fixation by Polyelectrolyte Complex

    Choi, Yong Suk; Kwon, Sang Woon; Yang, Heeman; Lee, Kune Woo; Seo, Bumkyoung; Moon, Jei Kwon

    2014-01-01

    According to report, the radioactivity bulk (approx. 95%) is localized within topsoil. Therefore soil surface on topsoil should be fixed to prevent the spreading of the contaminated soils with Cs-137 by wind and water erosion. Many methods have been developing for soil fixation to remove radioactive contaminants in soil and prevent to diffuse radioactive materials. Various materials have been also used as fixatives such as clays, molecular sieves, polymer, and petroleum based products. One of the methods is a soil fixation or solidification using polyelectrolyte. Polyelectrolytes have many ionic groups and make into the polyelectrolyte complex (PEC) due to electrostatic interaction of polyanion and polycation in an aqueous solution. It can be avoids using the chemical cross-linking agents, and reducing the possible toxicity and other undesirable effects of the reagents. PEC can fix soil particles by flocculation and formation of crust between soil. The method can also prevent a spread of radioactive material by floating on a soil surface. Recently, PEC used for the solidification of soil near the Fukushima nuclear power plant in Japan. The decontamination efficiency of the surface soils reached 90%, and dust release was effectively suppressed during the removal of surface soils. In this study, it was investigated the fixation of the soil by PEC to avoid the spread of the contamination in addition to the separation of soil and PEC. The physicochemical properties of polyelectrolyte complex solution and the stability of fixed soil by PEC were investigated. The mode of the addition is important to prepare the polyelectrolytes complex without PAA agglomerate. The concentration of salt in the polyelectrolyte complex solution is a very important parameter for the soil fixation

  2. Characterization for Soil Fixation by Polyelectrolyte Complex

    Choi, Yong Suk; Kwon, Sang Woon; Yang, Heeman; Lee, Kune Woo; Seo, Bumkyoung; Moon, Jei Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    According to report, the radioactivity bulk (approx. 95%) is localized within topsoil. Therefore soil surface on topsoil should be fixed to prevent the spreading of the contaminated soils with Cs-137 by wind and water erosion. Many methods have been developing for soil fixation to remove radioactive contaminants in soil and prevent to diffuse radioactive materials. Various materials have been also used as fixatives such as clays, molecular sieves, polymer, and petroleum based products. One of the methods is a soil fixation or solidification using polyelectrolyte. Polyelectrolytes have many ionic groups and make into the polyelectrolyte complex (PEC) due to electrostatic interaction of polyanion and polycation in an aqueous solution. It can be avoids using the chemical cross-linking agents, and reducing the possible toxicity and other undesirable effects of the reagents. PEC can fix soil particles by flocculation and formation of crust between soil. The method can also prevent a spread of radioactive material by floating on a soil surface. Recently, PEC used for the solidification of soil near the Fukushima nuclear power plant in Japan. The decontamination efficiency of the surface soils reached 90%, and dust release was effectively suppressed during the removal of surface soils. In this study, it was investigated the fixation of the soil by PEC to avoid the spread of the contamination in addition to the separation of soil and PEC. The physicochemical properties of polyelectrolyte complex solution and the stability of fixed soil by PEC were investigated. The mode of the addition is important to prepare the polyelectrolytes complex without PAA agglomerate. The concentration of salt in the polyelectrolyte complex solution is a very important parameter for the soil fixation.

  3. External fixation combined with delayed internal fixation in treatment of tibial plateau fractures with dislocation.

    Tao, Xingguang; Chen, Nong; Pan, Fugen; Cheng, Biao

    2017-10-01

    The aim of this study was to evaluate the clinical efficacy of external fixation, delayed open reduction, and internal fixation in treating tibial plateau fracture with dislocation.Clinical data of 34 patients diagnosed with tibial plateau fracture complicated with dislocation between January 2009 and May 2015 were retrospectively analyzed. Fifteen patients in group A underwent early calcaneus traction combined with open reduction and internal fixation and 19 in group B received early external fixation combined with delayed open reduction and internal fixation. Operation time, postoperative complication, bone healing time, knee joint range of motion, initial weight-bearing time, Rasmussen tibial plateau score, and knee function score (HSS) were statistically compared between 2 groups.The mean follow-up time was 18.6 months (range: 5-24 months). The mean operation time in group A was 96 minutes, significantly longer than 71 minutes in group B (P  .05). In group A, initial weight-bearing time in group A was (14.0 ± 3.6) weeks, significantly differing from (12.9 ± 2.8) weeks in group B (P  0.05). Rasmussen tibial plateau score in group A was slightly lower than that in group B (P > .05). The excellent rate of knee joint function in group A was 80% and 84.21% in group B (P > .05).External fixation combined with delayed open reduction and internal fixation is a safer and more efficacious therapy of tibial plateau fracture complicated with dislocation compared with early calcaneus traction and open reduction and internal fixation.

  4. [Treatment of pediatric distal femur fractures by external fixator combined with limited internal fixation].

    Wei, Sheng-wang; Shi, Zhan-ying; Hu, Ju-zheng; Wu, Hao

    2016-03-01

    To discuss the clinical effects of external fixator combined with limited internal fixation in the treatment of pediatric distal femur fractures. From January 2008 to June 2014, 17 children of distal femur fractures were treated by external fixator combined with limited internal fixation. There were 12 males and 5 females, aged from 6 to 13 years old with an average of 10.2 years, ranged in the course of disease from 1 h to 2 d. Preoperative diagnoses were confirmed by X-ray films in all children. There were 11 patients with supracondylar fracture , and 6 patients with intercondylar comminuted fracture. According to AO/ASIF classification, 9 fractures were type A1, 5 cases were type A2,and 3 cases were type C1. The intraoperative and postoperative complications, postoperative radiological examination, lower limbs length and motion of knee joints were observed. Knee joint function was assessed by KSS score. All the patients were followed up from 6 to 38 months with an average of 24.4 months. No nerve or blood vessel injury was found. One case complicated with the external fixation loosening, 2 cases with the infection of pin hole and 3 cases with the leg length discrepancy. Knee joint mobility and length measurement (compared with the contralateral), the average limited inflexion was 10 degrees (0 degrees to 20 degrees), the average limited straight was 4 degrees (0 degrees to 10), the average varus or valgus angle was 3 degrees (0 degrees to 5 degrees). KSS of the injured side was (96.4 +/- 5.0) points at final follow-up, 16 cases got excellent results and 1 good. All fractures obtained healing and no epiphyseal closed early was found. External fixator combined with limited internal fixation has advantages of simple operation, reliable fixation, early functional exercise in treating pediatric distal femurs fractures.

  5. Toward FRP-Based Brain-Machine Interfaces-Single-Trial Classification of Fixation-Related Potentials.

    Andrea Finke

    Full Text Available The co-registration of eye tracking and electroencephalography provides a holistic measure of ongoing cognitive processes. Recently, fixation-related potentials have been introduced to quantify the neural activity in such bi-modal recordings. Fixation-related potentials are time-locked to fixation onsets, just like event-related potentials are locked to stimulus onsets. Compared to existing electroencephalography-based brain-machine interfaces that depend on visual stimuli, fixation-related potentials have the advantages that they can be used in free, unconstrained viewing conditions and can also be classified on a single-trial level. Thus, fixation-related potentials have the potential to allow for conceptually different brain-machine interfaces that directly interpret cortical activity related to the visual processing of specific objects. However, existing research has investigated fixation-related potentials only with very restricted and highly unnatural stimuli in simple search tasks while participant's body movements were restricted. We present a study where we relieved many of these restrictions while retaining some control by using a gaze-contingent visual search task. In our study, participants had to find a target object out of 12 complex and everyday objects presented on a screen while the electrical activity of the brain and eye movements were recorded simultaneously. Our results show that our proposed method for the classification of fixation-related potentials can clearly discriminate between fixations on relevant, non-relevant and background areas. Furthermore, we show that our classification approach generalizes not only to different test sets from the same participant, but also across participants. These results promise to open novel avenues for exploiting fixation-related potentials in electroencephalography-based brain-machine interfaces and thus providing a novel means for intuitive human-machine interaction.

  6. Comparison of skeletal stability after sagittal split ramus osteotomy among mono-cortical plate fixation, bi-cortical plate fixation, and hybrid fixation using absorbable plates and screws.

    Ueki, Koichiro; Moroi, Akinori; Yoshizawa, Kunio; Hotta, Asami; Tsutsui, Takamitsu; Fukaya, Kenichi; Hiraide, Ryota; Takayama, Akihiro; Tsunoda, Tatsuta; Saito, Yuki

    2017-02-01

    The purpose of this study was to examine skeletal stability and plate breakage after sagittal split ramus osteotomy (SSRO) with the mono-cortical plate fixation, bi-cortical plate fixation, and hybrid fixation techniques using absorbable plates and screws. A total of 76 Japanese patients diagnosed with mandibular prognathism with and without maxillary deformity were divided into 3 groups randomly. A total of 28 patients underwent SSRO with mono-cortical plate fixation, 23 underwent SSRO with bi-cortical plate fixation, and 25 underwent SSRO with hybrid fixation. Skeletal stability and horizontal condylar angle were analyzed by axial, frontal, and lateral cephalograms from before the operation to 1 year postoperatively. Breakage of the plate and screws was observed by 3-dimensional computed tomography (3DCT) immediately after surgery and after 1 year. Although there was a significant difference between the mono-cortical plate fixation group and hybrid fixation group regarding right MeAg in T1 (P = 0.0488) and occlusal plane in T1 (P = 0.0346), there were no significant differences between the groups for the other measurements in each time interval. In 2 cases, namely, 6 sides in the mono-cortical plate fixation group, breakage of the absorbable plate was found by 3DCT. However, there was no breakage in the bi-cortical plate fixation group and hybrid fixation group. This study results suggested that there were no significant differences in the postoperative skeletal stability among the 3 groups, and bi-cortical fixation as well as hybrid fixation was a reliable and useful method to prevent plate breakage even if an absorbable material was used. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  7. Hydrologic Control on Bacterial Nitrogen Fixation in the Holocene Black Sea

    Fulton, J. M.; Arthur, M. A.; Freeman, K. H.

    2008-12-01

    Stratified oceans of the Phanerozoic Oceanic Anoxic Events apparently were dominated by bacterial nitrogen fixation. Decreased marine N:P nutrient ratios resulting from increased denitrification and decreased phosphate burial efficiency under anoxic waters drove this nutrient regime. This model is upheld by the presence of cyanobacterial hopanoid biomarkers in sedimentary records and δ15N values indicative of nitrogen fixation. However, in the largest modern redox-stratified marine basin, the Black Sea, bacterial nitrogen fixation seems to be only a minor contributor to the nitrogen cycle. In this study, we use geochemical proxies to evaluate the role of bacterial nitrogen fixation during the deposition of the Holocene Black Sea sapropel, starting 7.8 ka. We report compound-specific nitrogen and carbon stable isotope values of pyropheophytin a, a chlorophyll degradation product, and bacteriochlorophyll e produced by green sulfur bacteria. We also present the surprising finding of scytonemin, a pigment produced only by filamentous cyanobacteria exposed to ultraviolet radiation, in certain intervals in these sediments. In the Holocene, nitrogen fixation in the Black Sea is most prominent during times of reduced river water influx. This directly decreases the external flux of nitrate into the surface waters. Reduced freshwater influx also decreases the volume of low salinity water dispersed around the sea by the Rim Current, allowing the chemocline to shoal along the margins. Previous geochemical studies have described this changing chemocline geometry. The exposure of shallow water sediments to anoxic waters further stimulates nitrogen fixation by releasing more phosphorus to the system. Nitrogen fixation is recorded in the sediments as bulk and compound-specific pyropheophytin a δ15N values near 0 ‰ and -5 ‰, respectively. We have also detected scytonemin in two intervals characterized by especially low δ15N values. This compound suggests abundant filamentous

  8. Nitrogen fixation improvement in Faidherbia albida

    Toure, O.; Dasilva, M.C.; Badji, S.; Dianda, M.; Ndoye, I.; Gueye, M.

    1998-01-01

    A greenhouse experiment investigated growth, N accumulation and N 2 fixation (using the 15 N-dilution method) by Faidherbia albida in comparison with three species of Acacia, with Parkia biglobosa and Tamarindus indica as non-fixing reference plants. Faidherbia albida was mediocre in comparison with A. seyel, therefore seven provenances of the former were examined in a second pot experiment to investigate within-species variability for the same performance components; a provenance from Kabrousse, Senegal, showed particular promise in terms of dry weight and N accumulation, and fixation of N. This promise was confirmed with a 15-month field experiment, but revealed that there is opportunity for further improvement in N 2 -fixing ability. Faidherbia albida is a slow-growing tree, therefore further field experiments with provenance Kabrousse should be longer term in scope. The data indicate that trenching of the 15 N-labelled area may not be necessary. (author)

  9. Taking a(c)count of eye movements: Multiple mechanisms underlie fixations during enumeration.

    Paul, Jacob M; Reeve, Robert A; Forte, Jason D

    2017-03-01

    We habitually move our eyes when we enumerate sets of objects. It remains unclear whether saccades are directed for numerosity processing as distinct from object-oriented visual processing (e.g., object saliency, scanning heuristics). Here we investigated the extent to which enumeration eye movements are contingent upon the location of objects in an array, and whether fixation patterns vary with enumeration demands. Twenty adults enumerated random dot arrays twice: first to report the set cardinality and second to judge the perceived number of subsets. We manipulated the spatial location of dots by presenting arrays at 0°, 90°, 180°, and 270° orientations. Participants required a similar time to enumerate the set or the perceived number of subsets in the same array. Fixation patterns were systematically shifted in the direction of array rotation, and distributed across similar locations when the same array was shown on multiple occasions. We modeled fixation patterns and dot saliency using a simple filtering model and show participants judged groups of dots in close proximity (2°-2.5° visual angle) as distinct subsets. Modeling results are consistent with the suggestion that enumeration involves visual grouping mechanisms based on object saliency, and specific enumeration demands affect spatial distribution of fixations. Our findings highlight the importance of set computation, rather than object processing per se, for models of numerosity processing.

  10. Scaphoid Fracture Fixation with an Acutrak? Screw

    Loving, Vilert A.; Richardson, Michael L.

    2015-01-01

    We report a case of fixation of a scaphoid fracture using an Acutrak? screw. This screw is cannulated and headless, which allows it to be implanted below the surface of the bone. It uses the same concept of variable thread pitch as the Herbert screw, but unlike the Herbert screw, is fully threaded, with continuously varying pitch along its length. This variable pitch creates constant compression across a fracture as the screw is advanced, and gives the screw its unique appearance. This featur...

  11. Multivariate analysis and determination of the best indirect selection criteria to genetic improvement the biological nitrogen fixation ability in common bean genotypes (Phaseolus vulgaris L.

    Golparvar Reza Ahmad

    2012-01-01

    Full Text Available In order to determine the best indirect selection criteria for genetic improvement of biological nitrogen fixation, sixty four common bean genotypes were cultivated in two randomized complete block design. Genotypes were inoculated with bacteria Rhizobium legominosarum biovar Phaseoli isolate L-109 only in one of the experiments. The second experiment was considered as check for the first. Correlation analysis showed positive and highly significant correlation of majority of the traits with percent of nitrogen fixation. Step-wise regression designated that traits percent of total nitrogen of shoot, number of nodule per plant and biological yield accounted for 92.3 percent of variation exist in percent of nitrogen fixation. Path analysis indicated that these traits have direct and positive effect on percent of nitrogen fixation. Hence, these traits are promising indirect selection criteria for genetic improvement of nitrogen fixation capability in common bean genotypes especially in early generations.

  12. High level waste fixation in cermet form

    Kobisk, E.H.; Aaron, W.S.; Quinby, T.C.; Ramey, D.W.

    1981-01-01

    Commercial and defense high level waste fixation in cermet form is being studied by personnel of the Isotopes Research Materials Laboratory, Solid State Division (ORNL). As a corollary to earlier research and development in forming high density ceramic and cermet rods, disks, and other shapes using separated isotopes, similar chemical and physical processing methods have been applied to synthetic and real waste fixation. Generally, experimental products resulting from this approach have shown physical and chemical characteristics which are deemed suitable for long-term storage, shipping, corrosive environments, high temperature environments, high waste loading, decay heat dissipation, and radiation damage. Although leach tests are not conclusive, what little comparative data are available show cermet to withstand hydrothermal conditions in water and brine solutions. The Soxhlet leach test, using radioactive cesium as a tracer, showed that leaching of cermet was about X100 less than that of 78 to 68 glass. Using essentially uncooled, untreated waste, cermet fixation was found to accommodate up to 75% waste loading and yet, because of its high thermal conductivity, a monolith of 0.6 m diameter and 3.3 m-length would have only a maximum centerline temperature of 29 K above the ambient value

  13. Nitrogen fixation in Red Sea seagrass meadows

    Abdallah, Malak

    2017-05-01

    Seagrasses are key coastal ecosystems, providing many ecosystem services. Seagrasses increase biodiversity as they provide habitat for a large set of organisms. In addition, their structure provides hiding places to avoid predation. Seagrasses can grow in shallow marine coastal areas, but several factors regulate their growth and distribution. Seagrasses can uptake different kinds of organic and inorganic nutrients through their leaves and roots. Nitrogen and phosphorous are the most important nutrients for seagrass growth. Biological nitrogen fixation is the conversion of atmospheric nitrogen into ammonia by diazotrophic bacteria. This process provides a significant source of nitrogen for seagrass growth. The nitrogen fixation is controlled by the nif genes which are found in diazotrophs. The main goal of the project is to measure nitrogen fixation rates on seagrass sediments, in order to compare among various seagrass species from the Red Sea. Moreover, we will compare the fixing rates of the Vegetated areas with the bare sediments. This project will help to ascertain the role of nitrogen fixing bacteria in the development of seagrass meadows.

  14. Effectiveness of external fixator combined with T-plate internal fixation for the treatment of comminuted distal radius fractures.

    Han, L R; Jin, C X; Yan, J; Han, S Z; He, X B; Yang, X F

    2015-03-31

    This study compared the efficacy between external fixator combined with palmar T-plate internal fixation and simple plate internal fixation for the treatment of comminuted distal radius fractures. A total of 61 patients classified as type C according to the AO/ASIF classification underwent surgery for comminuted distal radius fractures. There were 54 and 7 cases of closed and open fractures, respectively. Moreover, 19 patients received an external fixator combined with T-plate internal fixation, and 42 received simple plate internal fixation. All patients were treated successfully during 12-month postoperative follow-up. The follow-up results show that the palmar flexion and dorsiflexion of the wrist, radial height, and palmar angle were significantly better in those treated with the external fixator combined with T-plate compared to those treated with the simple plate only (P 0.05). Hence, the effectiveness of external fixator combined with T-plate internal fixation for the treatment of comminuted distal radius fractures was satisfactory. Patients sufficiently recovered wrist, forearm, and hand function. In conclusion, compared to the simple T-plate, the external fixator combined with T-plate internal fixation can reduce the possibility of the postoperative re-shifting of broken bones and keep the distraction of fractures to maintain radial height and prevent radial shortening.

  15. Comparison of screw fixation with elastic fixation methods in the treatment of syndesmosis injuries in ankle fractures.

    Seyhan, Mustafa; Donmez, Ferdi; Mahirogullari, Mahir; Cakmak, Selami; Mutlu, Serhat; Guler, Olcay

    2015-07-01

    17 patients with ankle syndesmosic injury were treated with a 4.5mm single cortical screw fixation (passage of screw 4 cortices) and 15 patients were treated with single-level elastic fixation material. All patients were evaluated according to the AOFAS ankle and posterior foot scale at the third, sixth and twelfth months after the fixation. The ankle range of movement was recorded together with the healthy side. The Student's t test was used for statistical comparisons. No statistical significant difference was observed between the AOFAS scores (p>0.05). The range of dorsiflexion and plantar flexion motion of the elastic fixation group at the 6th and 12th months were significantly better compared to the screw fixation group (pankle syndesmosis injuries. The unnecessary need of a second surgical intervention for removal of the fixation material is another advantageous aspect of this method of fixation. Copyright © 2015. Published by Elsevier Ltd.

  16. [Extramedullary fixation combined with intramedullary fixation in the surgical reduction of sagittal mandibular condylar fractures].

    Chuanjun, Chen; Xiaoyang, Chen; Jing, Chen

    2016-10-01

    This study aimed to evaluate the clinical effect of extramedullary fixation combined with intramedullary fixation during the surgical reduction of sagittal mandibular condylar fractures. Twenty-four sagittal fractures of the mandibular condyle in18 patients were fixed by two appliances: intramedullary with one long-screw osteosynthesis or Kirschner wire and extramedullary with one micro-plate. The radiologically-recorded post-operative stability-associated com-plications included the screw/micro-plate loosening, micro-plate twisting, micro-plate fractures, and fragment rotation. The occluding relations, the maximalinter-incisal distances upon mouth opening, and the mandibular deflection upon mouth opening were evaluated based on follow-up clinical examination. Postoperative panoramic X-ray and CT scans showed good repositioning of the fragment, with no redislocation or rotation, no screw/plate loosening, and no plate-twisting or fracture. Clinical examination showed that all patients regained normal mandibular movements, ideal occlusion, and normal maximal inter-incisal distances upon mouth opening. Extramedullary fixation combined with intramedullary fixation is highly recommended for sagittal condylar fractures because of the anti-rotation effect of the fragment and the reasonable place-ment of the fixation appliances.

  17. Photosynthesis and Rubisco kinetics in spring wheat and meadow fescue under conditions of simulated climate change with elevated CO2 and increased temperatures

    K. HAKALA

    2008-12-01

    Full Text Available Spring wheat (Triticum aestivum L.cv.Polkkaand meadow fescue (Festuca pratensis Hudson cv. Kalevicwere grown in ambient and elevated (700 µl l -1 carbon dioxide concentration both at present ambient temperatures and at temperatures 3°C higher than at present simulating a future climate.The CO2 concentrations were elevated in large (3 m in diameteropen top chambers and the temperatures in a greenhouse built over the experimental field.The photosynthetic rate of both wheat and meadow fescue was 31 –37%higher in elevated carbon dioxide (eCO2 than in ambient CO 2 (aCO2 throughout the growing season.The enhancement in wheat photosynthesis in eCO2 declined 10 –13 days before yellow ripeness,at which point the rate of photosynthesis in both CO 2 treatments declined.The stomatal conductance of wheat and meadow fescue was 23–36% lower in eCO2 than in aCO2 .The amount and activity of ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco in wheat were lower under conditions of eCO2 ,except at elevated temperatures in 1993 when there was a clear yield increase.There was no clear change in the amount and activity of Rubisco in meadow fescue under eCO2 at either elevated or ambient temperature.This suggests that adaptation to elevated CO2 at biochemical level occurs only when there is insufficient sink for photosynthetic products.While the sink size of wheat can be increased only by introducing new,more productive genotypes,the sink size of meadow fescue can be regulated by fitting the cutting schedule to growth.;

  18. Present Status of Nitrogen Fixation by Reactor Radiation; Etat Actuel des Recherches sur l'oxydation directe de l'azote sous irradiation dans des reacteurs; Sovremennoe sostoyani opytov po okisleniyu azota izlucheniem iz reaktorov; Estado actual de las investigaciones sobre fijacion del nitrogeno por irradiacion en reactores

    Harteck, P; Dondes, S [Rensselaer Polytechnic Institute, Troy, NY (United States)

    1960-07-15

    Investigations in nitrogen fixation by reactor radiation which have been carried out at Rensselear and Brookhaven National Laboratory for a number of years, have used the fission recoil energy directly as ionizing radiation by means of the dispersion of U{sup 235} in glass fibers about five microns in diameter. The effects of temperature, pressure and nitrogen-oxygen ratio on the G-value for nitrogen fixation have been determined and reported in the literature. A brief summary of this work is given. The above work has been done in static systems; more recent work has involved both static and flow systems. In static systems, major emphasis has been placed on the effect of radiation intensity especially at the kinetic radiation equilibrium. It has been found that the production of N0{sub 2} and N{sub 2}0 in 4:1 and 2:1 nitrogen-oxygen mixtures proceeds to the point of total oxygen consumption. A flow (cycling) system is now operating in a loop in the Brookhaven reactor. Data are presented on the effects of temperature, pressure, mixture ratio and radiation intensity which may be applied to the design of a future chemonuclear reactor. The present system is operating at 10 atmospheres and 150{sup o}C. The temperature is a function of the fission energy released in the glass fibers and the heat resistance of the loop. Another loop to operate at 50 - 75 atmospheres and 600{sup o}C is under construction. These loops make possible the evaluation of the characteristics of a continuous system, including the behaviour of the fission products released in the gas stream. The complicated kinetics of nitrogen oxidation are outlined in three stages: initial reactions in the systems, reactions after some fixed nitrogen has been produced, and finally the kinetics at radiation equilibrium. The conditions for the formation of N{sub 2}0{sub 3}, N{sub 2}0{sub 4} and O{sub 3} are considered, together with their effects and the overall process. (author) [French] Des recherches sur l

  19. Gaze shifts and fixations dominate gaze behavior of walking cats

    Rivers, Trevor J.; Sirota, Mikhail G.; Guttentag, Andrew I.; Ogorodnikov, Dmitri A.; Shah, Neet A.; Beloozerova, Irina N.

    2014-01-01

    Vision is important for locomotion in complex environments. How it is used to guide stepping is not well understood. We used an eye search coil technique combined with an active marker-based head recording system to characterize the gaze patterns of cats walking over terrains of different complexity: (1) on a flat surface in the dark when no visual information was available, (2) on the flat surface in light when visual information was available but not required, (3) along the highly structured but regular and familiar surface of a horizontal ladder, a task for which visual guidance of stepping was required, and (4) along a pathway cluttered with many small stones, an irregularly structured surface that was new each day. Three cats walked in a 2.5 m corridor, and 958 passages were analyzed. Gaze activity during the time when the gaze was directed at the walking surface was subdivided into four behaviors based on speed of gaze movement along the surface: gaze shift (fast movement), gaze fixation (no movement), constant gaze (movement at the body’s speed), and slow gaze (the remainder). We found that gaze shifts and fixations dominated the cats’ gaze behavior during all locomotor tasks, jointly occupying 62–84% of the time when the gaze was directed at the surface. As visual complexity of the surface and demand on visual guidance of stepping increased, cats spent more time looking at the surface, looked closer to them, and switched between gaze behaviors more often. During both visually guided locomotor tasks, gaze behaviors predominantly followed a repeated cycle of forward gaze shift followed by fixation. We call this behavior “gaze stepping”. Each gaze shift took gaze to a site approximately 75–80 cm in front of the cat, which the cat reached in 0.7–1.2 s and 1.1–1.6 strides. Constant gaze occupied only 5–21% of the time cats spent looking at the walking surface. PMID:24973656

  20. A Novel Biodegradable Polycaprolactone Fixator for Osteosynthesis Surgery of Rib Fracture: In Vitro and in Vivo Study

    Yi-Hsun Yu

    2015-11-01

    Full Text Available Osteosynthesis surgery for rib fractures is controversial and challenging. This study developed a noval poly(ε-caprolactone (PCL-based biodegradable “cable-tie” fixator for osteosynthesis surgery for rib fractures. A biodegradable fixator specifically for fractured ribs was designed and fabricated by a micro-injection molding machine in our laboratory. The fixator has three belts that could be passed through matching holes individually. The locking mechanism allows the belt movement to move in only one direction. To examine the in vitro biomechanical performance, ribs 3–7 from four fresh New Zealand rabbits were employed. The load to failure and stress-strain curve was compared in the three-point bending test among native ribs, titanium plate-fixed ribs, and PCL fixator-fixed ribs. In the in vivo animal study, the sixth ribs of New Zealand rabbits were osteotomized and osteosynthesis surgery was performed using the PCL fixator. Outcomes were assessed by monthly X-ray examinations, a final micro-computed tomography (CT scan, and histological analysis. The experimental results suggested that the ribs fixed with the PCL fixator were significantly less stiff than those fixed with titanium plates (p < 0.05. All ribs fixed with the PCL fixators exhibited union. The bridging callus was confirmed by gross, radiographic micro-three-dimensional (3D CT, and histological examinations. In addition, there was no significant inflammatory response of the osteotomized ribs or the PCL-rib interface during application. The novel PCL fixator developed in this work achieves satisfactory results in osteosynthesis surgery for rib fractures, and may provide potential applications in other orthopedic surgeries.

  1. Fixation of displaced subcapital femoral fractures. Compression screw fixation versus double divergent pins.

    Christie, J; Howie, C R; Armour, P C

    1988-03-01

    One hundred and twenty-seven consecutive patients with displaced subcapital fractures of the femoral neck (Garden Grade III or IV) all under 80 years of age and independently mobile, were randomly allocated to fixation with either double divergent pins or a single sliding screw-plate device. The incidence of non-union and infection in the sliding screw-plate group was significantly higher, and we believe that when internal fixation is considered appropriate multiple pinning should be used. Mobility after treatment was disappointing in about half of the patients, and we feel that internal fixation can only be justified in patients who are physiologically well preserved and who maintain a high level of activity.

  2. Fusion Surgery Required for Recurrent Pediatric Atlantoaxial Rotatory Fixation after Failure of Temporary Fixation with Instrumentation

    Yoshiyuki Matsuyama

    2017-01-01

    Full Text Available In cases of chronic irreducible and recurrent unstable atlantoaxial rotatory fixation (AARF, closed reduction and its maintenance are often unsuccessful, requiring surgical treatment. The purpose of the present report is to describe a rare case of pediatric AARF that required multiple treatments. A 6-year-old boy was diagnosed as having type 2 AARF. After conservative treatment, the patient was treated with temporary fixation surgery (C1-C2 Magerl without a bone graft in consideration of motion preservation after screw removal. AARF recurred after the screw removal and required fusion surgery (Magerl–Brooks with an iliac bone graft. Ultimately, bone union was achieved and the screws were removed 11 months after the surgery. We recommend surgeons be cautious when choosing temporary fixation surgery for AARF in small children. Further investigation is needed to determine the optimal time before screw removal.

  3. [Pedicle flap transfer combined with external fixator to treat leg open fracture with soft tissue defect].

    Luo, Zhongchun; Lou, Hua; Jiang, Junwei; Song, Chunlin; Gong, Min; Wang, Yongcai

    2008-08-01

    To investigate the clinical results of treating leg open fracture with soft tissue defect by pedicle flap transfer in combination with external fixator. From May 2004 to June 2007, 12 cases of leg open fracture with soft tissue defect, 9 males and 3 females aged 18-75 years, were treated. Among them, 8 cases were caused by traffic accidents, 2 crush, 1 falling and 1 mechanical accident. According to the Gustilo Classification, there were 2 cases of type II, 5 of type IIIA and 5 of type IIIB. There were 2 cases of upper-tibia fracture, 3 of middle-tibia and 7 of middle-lower. The sizes of soft tissue defect ranged from 5 cm x 3 cm to 22 cm x 10 cm.The sizes of exposed bone ranged from 3 cm x 2 cm to 6 cm x 3 cm. The course of the disease was 1-12 hours. Fracture fixation was reached by external fixators or external fixators and limited internal fixation with Kirschner wire. The wounds with exposed tendons and bones were repaired by ipsilateral local rotation flap, sural neurocutaneous flap and saphenous nerve flap. The size of selected flap ranged from 5 cm x 4 cm to 18 cm x 12 cm. Granulation wounds were repaired by skin grafting or direct suture. All patients were followed up for 6 months to 2 years. All patients survived, among whom 2 with the wound edge infection and 1 with the distal necrosis were cured by changing the dressing, 8 with pin hole infection were treated by taking out the external fixator, 1 with nonunion received fracture healing after bone graft in comminuted fracture of lower tibia, 2 suffered delayed union in middle-lower tibia fracture. The ROM of ankle in 3 cases was mildly poor with surpass-joint fixation, with plantar extension of 0-10 degrees and plantar flexion of 10-30 degrees, while the others had plantar extension of 10-20 degrees and plantar flexion of 30-50 degrees. The method of pedicle flap transfer combined with external fixator is safe and effective for the leg open fracture with soft tissue defect.

  4. Results of application of external fixation with different types of fixators

    Grubor Predrag

    2012-01-01

    Full Text Available Introduction. Extra-focal or external fixation is the method of fracture fixation through the healthy part of the bone using pins or wires. Objective. The aim was to determine which external splints (Ortofix, Mitković, Charnley and Ilizarov had the best biomechanical properties in primary stabilization of spiral, transverse and commutative bone fractures. Methods. To determine the investigation methodology of biomechanical characteristics of the external fixator we used mathematical and computer simulator (software, juvidur physical model and clinical examination. Results. Values of advancing fragments in millimetres obtained by the study of mathematical and computer simulator (software: Charnley - 0.080 mm, Mitković M 20 - 0.785 mm, Ilizarov - 2.245 mm and Ortofix - 1.400 mm. In testing the juvidur model the following values were obtained: the external fixator Mitković M20 - 1.380 mm, Ortofix - 1.470 mm, Ilizarov - 2.410 mm, and Charnley - 2.510 mm. Clinical research of biomechanical characteristics of the effect of vertical force yielded the following results: Mitković M20 - 0.89 mm, Ortofix - 0.14 mm, Charnley - 0.80 mm and Ilizarov - 1.23 mm. Conclusion. When determining the total number of the stability test splints under the effect of vertical force (compression and force effect in antero-posterior, later-lateral plane of cross, spiral and comminuted long bone fractures, the best unified biomechanical stability was shown by the following external fixators: firstly, Mitković M20 (0.93mm, secondly, Charnley fixator (1.14 mm, thirdly, Ortofix (1.22 mm, and fourthly, Ilizarov (1.60 mm.

  5. Management and follow up of tibial plateau fractures by ′T′ clamp external fixator and limited internal fixation

    Thimmegowda M

    2005-01-01

    Full Text Available Background: Tibial plateau fractures are difficult to treat especially when soft tissue is compromised by open reduction and internal fixation. Many methods have be1en tried in the past to manage these cases of which external fixation were shown to be effective as they limit the soft tissue and wound complications. Methods: Complex tibial plateau fractures of sixteen patients were treated by closed reduction, fixation of articular fragments by screws and application of unilateral external fixator. The external fixator was kept in place till fracture united clinically and radiologically. The patients were followed up for at least one year to assess the function of the knee joint Results: The average duration of external fixation was 13 weeks. All the fractures healed. Pin track infection (five patients and instability (six patients of the knee were encountered with this procedure. The average duration of follow up was 62 weeks. The mean range of motion was 1250 arc. The IOWA knee score averaged 90.3 points. Conclusions: External fixation with limited internal fixation may be effective in the management of complex tibial plateau fractures which requires further support from studies with large sample size. ′T′ clamp external fixation with limited Internal fixation is the procedure of choice when alignment, stability, early mobilisation is required in a soft tissue compromised tibial plateau fractures.

  6. Improving Saliency Models by Predicting Human Fixation Patches

    Dubey, Rachit

    2015-04-16

    There is growing interest in studying the Human Visual System (HVS) to supplement and improve the performance of computer vision tasks. A major challenge for current visual saliency models is predicting saliency in cluttered scenes (i.e. high false positive rate). In this paper, we propose a fixation patch detector that predicts image patches that contain human fixations with high probability. Our proposed model detects sparse fixation patches with an accuracy of 84 % and eliminates non-fixation patches with an accuracy of 84 % demonstrating that low-level image features can indeed be used to short-list and identify human fixation patches. We then show how these detected fixation patches can be used as saliency priors for popular saliency models, thus, reducing false positives while maintaining true positives. Extensive experimental results show that our proposed approach allows state-of-the-art saliency methods to achieve better prediction performance on benchmark datasets.

  7. Improving Saliency Models by Predicting Human Fixation Patches

    Dubey, Rachit; Dave, Akshat; Ghanem, Bernard

    2015-01-01

    There is growing interest in studying the Human Visual System (HVS) to supplement and improve the performance of computer vision tasks. A major challenge for current visual saliency models is predicting saliency in cluttered scenes (i.e. high false positive rate). In this paper, we propose a fixation patch detector that predicts image patches that contain human fixations with high probability. Our proposed model detects sparse fixation patches with an accuracy of 84 % and eliminates non-fixation patches with an accuracy of 84 % demonstrating that low-level image features can indeed be used to short-list and identify human fixation patches. We then show how these detected fixation patches can be used as saliency priors for popular saliency models, thus, reducing false positives while maintaining true positives. Extensive experimental results show that our proposed approach allows state-of-the-art saliency methods to achieve better prediction performance on benchmark datasets.

  8. Atlantoaxial rotatory fixation as a rare complication from head positioning in otologic surgery: Report of two cases in young children.

    Sakaida, Hiroshi; Akeda, Koji; Sudo, Akihiro; Takeuchi, Kazuhiko

    2017-01-01

    Atlantoaxial rotatory fixation is a condition in which the first and second vertebrae of the cervical spine become interlocked in a rotated position. This condition can result in serious consequences and thus have a significant impact on patients, especially when diagnosis and treatment are delayed. Some cases of atlantoaxial rotatory fixation have been described in association with otologic surgery or plastic surgery involving the ear. We present the cases of two pediatric patients who developed atlantoaxial rotatory fixation following otologic surgery and we review the relevant literature. One patient was a 7-year-old boy who underwent tympanoplasty for cholesteatoma. The other patient was a 5-year-old girl with profound sensorineural hearing loss who underwent cochlear implantation. Both patients developed atlantoaxial rotatory fixation on the day after surgery, and they were treated conservatively. Our literature search using relevant terms identified 12 similar published cases. Thus, a total of 14 patients, including our 2 patients, were evaluated. Most of the patients were children and typically they complained of painful torticollis and exhibited a characteristic posture called the "cock-robin" position on the day after surgery. Mostly, the direction of torticollis was opposite to the side of surgery. Most of the patients received conservative treatment alone, but three underwent surgical treatment. The correlation between the direction of torticollis and the side of surgery suggests that rotation of the head during surgery has an impact on development of postoperative atlantoaxial rotatory fixation. Thus, children undergoing otologic surgery are thought to be at a risk of postoperative atlantoaxial rotatory fixation. Although rare, the surgical team needs to be aware of this adverse event and pay close attention to this possibility throughout the perioperative period. Perioperative management should include informed consent, preoperative assessment of the

  9. Effect of driving experience on anticipatory look-ahead fixations in real curve driving.

    Lehtonen, Esko; Lappi, Otto; Koirikivi, Iivo; Summala, Heikki

    2014-09-01

    Anticipatory skills are a potential factor for novice drivers' curve accidents. Behavioural data show that steering and speed regulation are affected by forward planning of the trajectory. When approaching a curve, the relevant visual information for online steering control and for planning is located at different eccentricities, creating a need to disengage the gaze from the guidance of steering to anticipatory look-ahead fixations over curves. With experience, peripheral vision can be increasingly used in the visual guidance of steering. This could leave experienced drivers more gaze time to invest on look-ahead fixations over curves, facilitating the trajectory planning. Eighteen drivers (nine novices, nine experienced) drove an instrumented vehicle on a rural road four times in both directions. Their eye movements were analyzed in six curves. The trajectory of the car was modelled and divided to approach, entry and exit phases. Experienced drivers spent less time on the road-ahead and more time on the look-ahead fixations over the curves. Look-ahead fixations were also more common in the approach than in the entry phase of the curve. The results suggest that with experience drivers allocate greater part of their visual attention to trajectory planning. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Features of Recent Codon Evolution: A Comparative Polymorphism-Fixation Study

    Zhongming Zhao

    2010-01-01

    Full Text Available Features of amino-acid and codon changes can provide us important insights on protein evolution. So far, investigators have often examined mutation patterns at either interspecies fixed substitution or intraspecies nucleotide polymorphism level, but not both. Here, we performed a unique analysis of a combined set of intra-species polymorphisms and inter-species substitutions in human codons. Strong difference in mutational pattern was found at codon positions 1, 2, and 3 between the polymorphism and fixation data. Fixation had strong bias towards increasing the rarest codons but decreasing the most frequently used codons, suggesting that codon equilibrium has not been reached yet. We detected strong CpG effect on CG-containing codons and subsequent suppression by fixation. Finally, we detected the signature of purifying selection against A∣U dinucleotides at synonymous dicodon boundaries. Overall, fixation process could effectively and quickly correct the volatile changes introduced by polymorphisms so that codon changes could be gradual and directional and that codon composition could be kept relatively stable during evolution.

  11. Bilateral Laparoscopic Totally Extraperitoneal Repair Without Mesh Fixation

    Dehal, Ahmed; Woodward, Brandon; Johna, Samir; Yamanishi, Frank

    2014-01-01

    Background and Objectives: Mesh fixation during laparoscopic totally extraperitoneal repair is thought to be necessary to prevent recurrence. However, mesh fixation may increase postoperative chronic pain. This study aimed to describe the experience of a single surgeon at our institution performing this operation. Methods: We performed a retrospective review of the medical records of all patients who underwent bilateral laparoscopic totally extraperitoneal repair without mesh fixation for ing...

  12. Application of monorail fixator for femoral gap nonunion

    Agrawal Hemendra Kumar

    2014-07-01

    Full Text Available 【Abstract】Difficult femoral nonunion takes account of infective nonunion and aseptic gap nonunion. Limb length discrepancy and nonunion need to be tackled simultaneously. Conventionally Ilizarov ring fixator is in vogue but it has some limitations. To overcome these, monorail fixator is an effective alternative. Persistent good results can be obtained if we can get a perfect anatomical alignment and good regeneration. Key words: Femur; Ilizarov technique; External fixators

  13. Survey report for fiscal 1998. Survey of the current state and tasks of research and development of technologies for effectively utilizing CO{sub 2} fixation by higher vegetation; 1998 nendo chosa hokokusho. Koto shokubutsu ni okeru nisanka tanso koteika yuko riyo gijutsu no kenkyu kaihatsu no genjo to kadai ni kansuru chosa

    NONE

    1999-03-01

    Investigations and studies are conducted seeking for a CO2 fixation method improved by utilizing the photosynthesizing function of higher vegetation. Details of higher vegetation genes are being disclosed thanks to the rapid progress of studies making use of molecular biological techniques, and the application of the genetic mechanism to scientific and technological fields is becoming increasingly feasible. In particular, the role of the CO2 fixation enzyme RuBisCO has been elucidated almost completely. It has been learned that, in terms of photosynthesizing capability, the C{sub 4} plants (corn etc.) are 2-3 times higher than the C{sub 3} plants (rice, wheat, etc.), and 5-10 times higher than the CAM plants (cactuses etc.). Studies are also under way about the rice genome so that a photosynthesizing capability so high as that of the C{sub 4} plants may be endowed the rice plant. The metabolism and control of useful substances produced in the CO2 fixation process etc. in the higher vegetation are being investigated, and it is now expected that some day such useful substances will be produced and utilized efficiently. Researches are under way into the relationship between the green leaf that is the organ that performs photosynthesis and the organ (sink) that stores and utilizes starch and sugar is in progress, and now a new field is going to open where vegetables will be fully utilized. (NEDO)

  14. Rib Fracture Fixation: Indications and Outcomes.

    Senekjian, Lara; Nirula, Raminder

    2017-01-01

    Rib fractures are a frequently identified injury in the trauma population. Not only are multiple rib fractures painful, but they are associated with an increased risk of adverse outcomes. Pneumonia in particular can be devastating, especially to an elderly patient, but other complications such as prolonged ventilation and increased intensive care and hospital durations of stay have a negative impact on the patient. Computed tomography scan is the best modality to diagnosis rib fractures but the treatment of fractures is still evolving. Currently patient care involves a multidisciplinary approach that includes pain control, aggressive pulmonary therapy, and possibly surgical fixation. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Nitrogen fixation on a coral reef

    Mague, T.H.; Holm-Hansen, O.

    1975-06-01

    Benthic, heterocystous blue-green algae (genera Calothrix, Hormothamnion and Nostoc) from Eniwetok Atoll were found to reduce acetylene at rapid rates. Slight acetylene reduction was associated with samples of Rhizoclonium (Chlorophyceae) and Oscillatoria (a cyanophyte lacking heterocysts), but this may have been due to contamination by epiphytes. There was virtually no acetylene reduction by phytoplankton, and nutrient enrichment experiments failed to selectively increase the numbers or activity of N/sub 2/-fixing algae in surface water samples. The Nostoc required light for acetylene reduction. Nitrogen fixation by this species could have supplied up to 11 ..mu..g N/cm/sup 2//day to the ecosystem. (auth)

  16. Distal fingertip replantation without skeletal fixation.

    Sabapathy, S Raja; Venkatramani, Hari; Bharathi, R Ravindra; Sebastin, Sandeep J

    2005-01-01

    The replantation of fingertip amputation (through the nail bed) requires repair of the artery and vein on the palmar side. These structures are present in different planes, with the artery being deeper and the veins superficial. The authors believe that vascular repair in such cases is facilitated by stabilization of the amputated part by nail-bed repair alone. This provides a certain degree of flexibility, which allows for easier placement of clamps in the limited space available. Although Kirschner wires were not used for bony fixation, bony union was achieved in all five cases in which this technique was used.

  17. Overcoming design fixation through education and creativity methods

    Howard, Thomas J.; Maier, Anja; Onarheim, Balder

    2013-01-01

    . The first intervention consisted of educating each team on the phenomena and effects of design fixation. The results showed that this intervention reduced the number of fixation elements in comparison to the control group (p=0.025). The second intervention involved using Dix et als' (2006) 'Bad Ideas...... of ideas produced per group and the groups' fixation ratios, adding to the quantity breads novelty debate. Finally, the study also provided further evidence of the hypothesis by Agogué et al (2011) that example solutions constructed from restrictive partitions have a greater fixation affect....

  18. Percutaneous anterior C1/2 transarticular screw fixation: salvage of failed percutaneous odontoid screw fixation for odontoid fracture

    Wu, Ai-Min; Jin, Hai-Ming; Lin, Zhong-Ke; Chi, Yong-Long; Wang, Xiang-Yang

    2017-01-01

    Background The objective of this study is to investigate the outcomes and safety of using percutaneous anterior C1/2 transarticular screw fixation as a salvage technique for odontoid fracture if percutaneous odontoid screw fixation fails. Methods Fifteen in 108 odontoid fracture patients (planned to be treated by percutaneous anterior odontoid screw fixation) were failed to introduce satisfactory odontoid screw trajectory. To salvage this problem, we chose the percutaneous anterior C1/2 trans...

  19. Biomechanical rationale and evaluation of an implant system for rib fracture fixation

    Bottlang, M.; Walleser, S.; Noll, M.; Honold, S.; Madey, S. M.; Fitzpatrick, D.; Long, W. B.

    2010-01-01

    Background Biomechanical research directed at developing customized implant solutions for rib fracture fixation is essential to reduce the complexity and to increase the reliability of rib osteosynthesis. Without a simple and reliable implant solution, surgical stabilization of rib fractures will remain underutilized despite proven benefits for select indications. This article summarizes the research, development, and testing of a specialized and comprehensive implant solution for rib fractur...

  20. EXTERNAL FIXATION OF METACARPAL AND PHALANGAL FRACTURES

    Krunoslav Margić

    2001-11-01

    Full Text Available Background. In past three years we have used smallexternal fixator in the treatment of: 18 closed fractures of metacarpalbones, 15 phalangeal fractures, four dislocated fracturesof MCP and five of PIP joint, ten arthrodesis, five replantations/revascularisations, two pathological fractures, and infew post-traumatic infection of bones and joints.Results. Results were graded as excellent (completely normalfunction, very good (15° deficit of total ROM, good (30° deficitof total ROM; can flex the fingers to the palm, and poor.Excellent result was obtained in the treatment of all 18 metacarpalfractures. The final results in the treatment of 12 closedfragmentated fractures of phalanges were as follows: excellent3, very good 2, good 2 and five poor results (three patientsin this group have fallen on their hands causing refractureand reoperation. Three of four fractures of MCP joint andfour of five fractures involving PIP joint have good mobility.In eight of ten patients arthrodeses are stable and withoutpain. In two cases pathological fractures were first stabilizedand than the tumor was evacuated and grafted with minimaldissection; booth have good results.Conclusion. Author suggests that, in selected cases, with applicationof small external fixator reasonable good results can beobtained.

  1. Internal Versus External Fixation of Charcot Midfoot Deformity Realignment.

    Lee, Daniel J; Schaffer, Joseph; Chen, Tien; Oh, Irvin

    2016-07-01

    Internal and external fixation techniques have been described for realignment and arthrodesis of Charcot midfoot deformity. There currently is no consensus on the optimal method of surgical reconstruction. This systematic review compared the clinical results of surgical realignment with internal and external fixation, specifically in regard to return to functional ambulation, ulcer occurrence, nonunion, extremity amputation, unplanned further surgery, deep infection, wound healing problems, peri- or intraoperative fractures, and total cases with any complication. A search of multiple databases for all relevant articles published from January 1, 1990, to March 22, 2014, was performed. A logistic regression model evaluated each of the outcomes and its association with the type of fixation method. The odds of returning to functional ambulation were 25% higher for internal fixation (odds ratio [OR], 1.259). Internal fixation had a 42% reduced rate of ulcer occurrence (OR, 0.578). External fixation was 8 times more likely to develop radiographic nonunion than internal fixation (OR, 8.2). Internal fixation resulted in a 1.5-fold increase in extremity amputation (OR, 1.488), a 2-fold increase in deep infection (OR, 2.068), a 3.4-fold increase in wound healing complications (OR, 3.405), and a 1.5-fold increase in the total number of cases experiencing any complication (OR, 1.525). This was associated with a 20% increase in the need for unplanned further surgery with internal fixation (OR, 1.221). Although internal fixation may decrease the risk of nonunion and increase return to functional ambulation, it had a higher rate of overall complications than external fixation for realignment and arthrodesis of Charcot midfoot deformity. [Orthopedics. 2016; 39(4):e595-e601.]. Copyright 2016, SLACK Incorporated.

  2. STUDY ON SPANNING EXTERNAL FIXATORS FOR PERIARTICULAR OPEN FRACTURES

    Prasanth Maddila

    2017-04-01

    Full Text Available BACKGROUND Open fractures which occur close to any fracture need immobilisation for the soft tissues to heal. Some open fractures are even fixed with provisional fixations to maintain the alignment of the fractures. The provisional fixation needs to be augmented with external support, which can be given by spanning external fixators across a joint. MATERIALS AND METHODS Our study consists of 38 open fractures of the lower limbs, which are of Gustilo-Anderson’s type IIIB, an MT4 of AO-ASIF soft tissue injury classification essentially requiring open wound management as well as fracture fixation. Wound lavage and debridements are carried out till the soft tissues show granulations. The position in which joint is immobilised is functional and with access to open wound for dressings and inspection without any displacement of the fracture as well as creeping granulation tissue. RESULTS All the cases in our study are maintained with functional position till soft tissue cover is achieved and provisional fixation is done with definitive fixation after soft tissue cover with skin grafting. CONCLUSION Spanning external fixators are useful in maintaining functional positions as well as augmenting the provisional fixation of the compound fractures.

  3. Sacroiliac screw fixation: A mini review of surgical technique

    Hernando Raphael Alvis-Miranda

    2014-01-01

    Full Text Available The sacral percutaneous fixation has many advantages but can be associated with a significant exposure to X-ray radiation. Currently, sacroiliac screw fixation represents the only minimally invasive technique to stabilize the posterior pelvic ring. It is a technique that should be used by experienced surgeons. We present a practical review of important aspects of this technique.

  4. Biomechanical analysis of titanium fixation plates and screws in ...

    Conclusions: It was concluded that the use of double 4-hole straight plates provided the sufficient stability on the osteotomy site when compared with the other rigid fixation methods used in this study. Key words: Bone plates, bone screws, finite element analysis, jaw fixation techniques, mandible, mandibular osteotomy ...

  5. Indications and outcome of Open Reduction and Internal Fixation of ...

    Background: Open reduction and internal fixation (ORIF) is a well-established surgical treatment of fractures worldwide. However, the indications and modes of stabilization of long bone fractures vary and are evolving .The general trend now is towards fixation with locked intramedullary nail (i.m nail) rather than plate and ...

  6. Predicting Eye Fixations on Complex Visual Stimuli Using Local Symmetry.

    Kootstra, Gert; de Boer, Bart; Schomaker, Lambert R B

    2011-03-01

    Most bottom-up models that predict human eye fixations are based on contrast features. The saliency model of Itti, Koch and Niebur is an example of such contrast-saliency models. Although the model has been successfully compared to human eye fixations, we show that it lacks preciseness in the prediction of fixations on mirror-symmetrical forms. The contrast model gives high response at the borders, whereas human observers consistently look at the symmetrical center of these forms. We propose a saliency model that predicts eye fixations using local mirror symmetry. To test the model, we performed an eye-tracking experiment with participants viewing complex photographic images and compared the data with our symmetry model and the contrast model. The results show that our symmetry model predicts human eye fixations significantly better on a wide variety of images including many that are not selected for their symmetrical content. Moreover, our results show that especially early fixations are on highly symmetrical areas of the images. We conclude that symmetry is a strong predictor of human eye fixations and that it can be used as a predictor of the order of fixation.

  7. Femoral fractures : indications an[d] biomechanics of external fixation

    A.H. Broekhuizen (Tom); B. van Linge

    1988-01-01

    textabstractInternal fixation can be carried out in various ways. For femoral shaft fractures, an (interlocking) nail is becoming increasingly popular, instead of open realignment of the fracture. External fixation, which has become a generally accepted method of treating fractures of the lower

  8. Application of monorail fixator for femoral gap nonunion.

    Agrawal, Hemendra-Kumar; Jaiman, Ashish; Khatkar, Vipin; Sharma, Vinod-Kumar

    2014-01-01

    Difficult femoral nonunion takes account of infective nonunion and aseptic gap nonunion. Limb length discrepancy and nonunion need to be tackled simultaneously. Conventionally Ilizarov ring fixator is in vogue but it has some limitations. To overcome these, monorail fixator is an effective alternative. Persistent good results can be obtained if we can get a perfect anatomical alignment and good regeneration.

  9. Predicting Eye Fixations on Complex Visual Stimuli Using Local Symmetry

    Kootstra, Geert; de Boer, Bart; Schomaker, Lambertus

    Most bottom-up models that predict human eye fixations are based on contrast features. The saliency model of Itti, Koch and Niebur is an example of such contrast-saliency models. Although the model has been successfully compared to human eye fixations, we show that it lacks preciseness in the

  10. Predicting eye fixations on complex visual stimuli using local symmetry

    Kootstra, G.; de Boer, B.; Schomaker, L.R.B.

    2011-01-01

    Most bottom-up models that predict human eye fixations are based on contrast features. The saliency model of Itti, Koch and Niebur is an example of such contrast-saliency models. Although the model has been successfully compared to human eye fixations, we show that it lacks preciseness in the

  11. [Treatment of femoral neck fracture--preference to internal fixation].

    Minato, Izumi

    2011-03-01

    In the guidelines for the treatment of femoral neck fracture, prosthetic replacement is recommended in displaced one and internal fixation is in undisplaced one. However, in the long view, survived femoral head after internal fixation can be superior to prosthesis which will deteriorate as time goes by. Surgical method should be considered not only by type of fracture but general status of the patient.

  12. Tightrope fixation of ankle syndesmosis injuries: clinical outcome, complications and technique modification.

    Naqvi, Gohar A

    2012-06-01

    Ankle syndesmotic injuries are complex and require anatomic reduction and fixation. Tightrope fixation is a relatively new technique and we present the largest series of syndesmosis fixation using Arthrex Tightrope™ (Naples, FL, USA).

  13. Fixation and escape times in stochastic game learning

    Realpe-Gomez, John; Szczesny, Bartosz; Galla, Tobias; Dall’Asta, Luca

    2012-01-01

    Evolutionary dynamics in finite populations is known to fixate eventually in the absence of mutation. We here show that a similar phenomenon can be found in stochastic game dynamical batch learning, and investigate fixation in learning processes in a simple 2×2 game, for two-player games with cyclic interaction, and in the context of the best-shot network game. The analogues of finite populations in evolution are here finite batches of observations between strategy updates. We study when and how such fixation can occur, and present results on the average time-to-fixation from numerical simulations. Simple cases are also amenable to analytical approaches and we provide estimates of the behaviour of so-called escape times as a function of the batch size. The differences and similarities with escape and fixation in evolutionary dynamics are discussed. (paper)

  14. Les aciers inoxydables dans les fixations

    CETIM

    2010-01-01

    Cet ouvrage, qui fait la synthèse de plusieurs travaux menés par le Cetim, propose une vue d'ensemble sur les aciers inoxydables utilisés pour les fixations. Au sommaire : les normes EN, ISO et ATSM qui s'y rapportent , les désignations symboliques , les nuances et caractéristiques mécaniques , les différentes formes de corrosion, les méthodes pour les détecter , les règles du métier , les mises en oeuvre. L'ouvrage comprend plusieurs fiches matériaux et des tableaux qui présentent les équivalences entre les désignations.

  15. Nitrogen fixation by legumes in retorted shale

    Hersman, L E; Molitoris, E; Klein, D A

    1981-01-01

    Although a soil-shale mixture was employed as the growth medium in this experiment, the results presentd are applicable to the proposed method of disposal mentioned earlier. Under field conditions, when covering the retorted shale with topsoil, some mixing of these materials might occur in the plant root region. In addition, it has been demonstrated that buried shale negatively affects enzyme activities in overburden surface soil. The occurrence of either of those events could affect symbiotic N/sub 2/ fixation in a manner similar to that reported in this paper. Researchers conclude that due to the varied effects of retorted shale on the legumes tested, further evaluation of other legumes may be necessary. Additional research would be required to determine which legumes have potential use for reclamation of retorted shale.

  16. A Nearly Lethal Screw: An Unusual Cause of Recurrent Bradycardia and Asystole Episodes after Fixation of the Cervical Spine

    Amit Frenkel

    2017-01-01

    Full Text Available We present a case of a 51-year-old man who was injured in a bicycle accident. His main injury was an unstable fracture of the cervical and thoracic vertebral column. Several hours after his arrival to the hospital the patient underwent open reduction and internal fixation (ORIF of the cervical and thoracic spine. The patient was hospitalized in our critical care unit for 99 days. During this time patient had several episodes of severe bradycardia and asystole; some were short with spontaneous return to sinus and some required pharmacological treatment and even Cardiopulmonary Resuscitation (CPR. Initially, these episodes were attributed to the high cervical spine injury, but, later on, CT scan suggested that a fixation screw abutted on the esophagus and activated the vagus nerve by direct pressure. After repositioning of the cervical fixation, the bradycardia and asystole episodes were no longer observed and the patient was released to a rehabilitation ward. This case is presented in order to alert practitioners to the possibility that, after operative fixation of cervical spine injuries, recurrent episodes of bradyarrhythmia can be caused by incorrect placement of the fixation screws and might be confused with the natural history of the high cervical cord injury.

  17. Fiscal 1995 investigation on biological fixation of carbon dioxide; 1995 nendo seibutsuteki CO2 kotei ni kansuru chosa hokokusho

    NONE

    1996-03-01

    To cope with the global warming caused by CO2, an investigation was conducted into biological fixation. It is necessary to make a many-sided and comprehensive study on the mechanism of CO2 fixation, the scale (area and carbon holding density), the rate and the environmental impact of the introduction of the technology and the technical problems, and to make a quantitative evaluation of each of the methods in order to make them practical proposals. The global ecosystem is classified into the land biota and ocean biota, and each typical ecosystem was surveyed in terms of the surface area, the carbon holding amount (presently existing amount), the net primary production amount, the required nutrient salt amount, the transpiration rate, etc. Next, a discussion was made on the increasing effect of the carbon fixation amount by changing the present ecosystem from the aspect of scale and rate. At the same time, a study was carried out of energy efficiency, economical efficiency and problems. Last, elementary technology was taken up which seems to be important for implementing measures for the biological carbon fixation. As to the ocean, it is necessary to obtain information, which is not sufficient to utilize marine biota for CO2 fixation, especially on the mechanism of depth-direction transfer of organism and its quantitative grasp. As to the land, one of the measures is conversion of the ecosystem where the amount of carbon fixed is small to the ecosystem where the amount is large. 249 refs., 58 figs., 51 tabs.

  18. Do you like what you see? The role of first fixation and total fixation duration in consumer choice

    Laan, van der L.N.; Hooge, I.T.C.; Ridder, de D.T.D.; Viergever, M.A.; Smeets, P.A.M.

    2015-01-01

    Although there has been recent growing interest in the associations between measures of visual attention and consumer choice, there is still uncertainty about the role of the first fixation in consumer choice and the factors that drive total fixation duration. The study aimed (1) to investigate the

  19. External Fixation versus two-stage Open Reduction Internal Fixation of distal intra-articular Tibia fractures; a Systematic Review

    Ladeby Erichsen, Julie; Jensen, Carsten; Damborg, Frank Lindhøj

    Internal Fixation (ORIF) or External Fixation (EF). Method : A search was conducted using PUBMED, Embase, Cochrane Central, Open Grey, Orthopaedic Proceedings and WHO International Clinical Trials Registry Platform. Studies with level of evidence I-IV comparing EF with two-stage ORIF of DIATF in patients...

  20. Do you like what you see? : The role of first fixation and total fixation duration in consumer choice

    van der Laan, Laura N.; Hooge, Ignace T C; De Ridder, Denise T D; Viergever, Max A.; Smeets, Paul A M

    2015-01-01

    Although there has been recent growing interest in the associations between measures of visual attention and consumer choice, there is still uncertainty about the role of the first fixation in consumer choice and the factors that drive total fixation duration. The study aimed (1) to investigate the

  1. A Meta-Analysis for Postoperative Complications in Tibial Plafond Fracture: Open Reduction and Internal Fixation Versus Limited Internal Fixation Combined With External Fixator.

    Wang, Dong; Xiang, Jian-Ping; Chen, Xiao-Hu; Zhu, Qing-Tang

    2015-01-01

    The treatment of tibial plafond fractures is challenging to foot and ankle surgeons. Open reduction and internal fixation and limited internal fixation combined with an external fixator are 2 of the most commonly used methods of tibial plafond fracture repair. However, conclusions regarding the superior choice remain controversial. The present meta-analysis aimed to quantitatively compare the postoperative complications between open reduction and internal fixation and limited internal fixation combined with an external fixator for tibial plafond fractures. Nine studies with 498 fractures in 494 patients were included in the present study. The meta-analysis found no significant differences in bone healing complications (risk ratio [RR] 1.17, 95% confidence interval [CI] 0.68 to 2.01, p = .58], nonunion (RR 1.09, 95% CI 0.51 to 2.36, p = .82), malunion or delayed union (RR 1.24, 95% CI 0.57 to 2.69, p = .59), superficial (RR 1.56, 95% CI 0.43 to 5.61, p = .50) and deep (RR 1.89, 95% CI 0.62 to 5.80) infections, arthritis symptoms (RR 1.20, 95% CI 0.92 to 1.58, p = .18), or chronic osteomyelitis (RR 0.31, 95% CI 0.05 to 1.84, p = .20) between the 2 groups. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  2. Mini-Fragment Fixation Is Equivalent to Bicortical Screw Fixation for Horizontal Medial Malleolus Fractures.

    Wegner, Adam M; Wolinsky, Philip R; Robbins, Michael A; Garcia, Tanya C; Amanatullah, Derek F

    2018-05-01

    Horizontal fractures of the medial malleolus occur through application of valgus or abduction force through the ankle that creates a tension failure of the medial malleolus. The authors hypothesize that mini-fragment T-plates may offer improved fixation, but the optimal fixation construct for these fractures remains unclear. Forty synthetic distal tibiae with identical osteotomies were randomized into 4 fixation constructs: (1) two parallel unicortical cancellous screws; (2) two parallel bicortical cortical screws; (3) a contoured mini-fragment T-plate with 2 unicortical screws in the fragment and 2 bicortical screws in the shaft; and (4) a contoured mini-fragment T-plate with 2 bicortical screws in the fragment and 2 unicortical screws in the shaft. Specimens were subjected to offset axial tension loading on a servohydraulic testing system and tracked using high-resolution video. Failure was defined as 2 mm of articular displacement. Analysis of variance followed by a Tukey-Kramer post hoc test was used to assess for differences between groups, with significance defined as Pfragment T-plate constructs (239±83 N/mm and 190±37 N/mm) and the bicortical screw construct (240±17 N/mm) were not statistically different. The mean stiffness values of both mini-fragment T-plate constructs and the bicortical screw construct were higher than that of a parallel unicortical screw construct (102±20 N/mm). Contoured T-plate constructs provide stiffer initial fixation than a unicortical cancellous screw construct. The T-plate is biomechanically equivalent to a bicortical screw construct, but may be superior in capturing small fragments of bone. [Orthopedics. 2018; 41(3):e395-e399.]. Copyright 2018, SLACK Incorporated.

  3. Reconstruction of Oryza sativa indica Genome Scale Metabolic Model and Its Responses to Varying RuBisCO Activity, Light Intensity, and Enzymatic Cost Conditions

    Ankita Chatterjee

    2017-11-01

    Full Text Available To combat decrease in rice productivity under different stresses, an understanding of rice metabolism is needed. Though there are different genome scale metabolic models (GSMs of Oryza sativa japonica, no GSM with gene-protein-reaction association exist for Oryza sativa indica. Here, we report a GSM, OSI1136 of O.s. indica, which includes 3602 genes and 1136 metabolic reactions and transporters distributed across the cytosol, mitochondrion, peroxisome, and chloroplast compartments. Flux balance analysis of the model showed that for varying RuBisCO activity (Vc/Vo (i the activity of the chloroplastic malate valve increases to transport reducing equivalents out of the chloroplast under increased photorespiratory conditions and (ii glyceraldehyde-3-phosphate dehydrogenase and phosphoglycerate kinase can act as source of cytosolic ATP under decreased photorespiration. Under increasing light conditions we observed metabolic flexibility, involving photorespiration, chloroplastic triose phosphate and the dicarboxylate transporters of the chloroplast and mitochondrion for redox and ATP exchanges across the intracellular compartments. Simulations under different enzymatic cost conditions revealed (i participation of peroxisomal glutathione-ascorbate cycle in photorespiratory H2O2 metabolism (ii different modes of the chloroplastic triose phosphate transporters and malate valve, and (iii two possible modes of chloroplastic Glu–Gln transporter which were related with the activity of chloroplastic and cytosolic isoforms of glutamine synthetase. Altogether, our results provide new insights into plant metabolism.

  4. Phase-Contrast Hounsfield Units of Fixated and Non-Fixated Soft-Tissue Samples

    Willner, Marian; Fior, Gabriel; Marschner, Mathias; Birnbacher, Lorenz; Schock, Jonathan; Braun, Christian; Fingerle, Alexander A.; Noël, Peter B.; Rummeny, Ernst J.; Pfeiffer, Franz; Herzen, Julia

    2015-01-01

    X-ray phase-contrast imaging is a novel technology that achieves high soft-tissue contrast. Although its clinical impact is still under investigation, the technique may potentially improve clinical diagnostics. In conventional attenuation-based X-ray computed tomography, radiological diagnostics are quantified by Hounsfield units. Corresponding Hounsfield units for phase-contrast imaging have been recently introduced, enabling a setup-independent comparison and standardized interpretation of imaging results. Thus far, the experimental values of few tissue types have been reported; these values have been determined from fixated tissue samples. This study presents phase-contrast Hounsfield units for various types of non-fixated human soft tissues. A large variety of tissue specimens ranging from adipose, muscle and connective tissues to liver, kidney and pancreas tissues were imaged by a grating interferometer with a rotating-anode X-ray tube and a photon-counting detector. Furthermore, we investigated the effects of formalin fixation on the quantitative phase-contrast imaging results. PMID:26322638

  5. "Cold" Fixation: Reconciliation of Nitrogen Fixation Rates and Diazotroph Assemblages in the Arctic Ocean

    Fong, A. A.; Waite, A.; Rost, B.; Richter, K. U.

    2016-02-01

    Measurements of biological nitrogen fixation are typically conducted in oligotrophic subtropical and tropical marine environments where concentrations of fixed inorganic nitrogen are low. To date, only a handful of nitrogen fixation studies have been conducted in high latitude marine environments, but further investigation is needed to resolve the distribution of cold ocean diazotrophic assemblages. Nitrogen fixation rates and nifH gene distributions were measured at seven stations from 5°E to 20°E, north of 81°N in the Arctic Ocean at the onset of summer 2015. Discrete water samples in ice-covered regions were collected from the sea surface to 200 m for 15N2-tracer additions and targeted nifH gene and transcript analyses. Previous work suggests that heterotrophic bacteria dominate diazotrophic communities in the Arctic Ocean. Therefore, additional nifH gene surveys of sinking particles were conducted to test for enrichment on organic matter-rich microenvironments. Together, these measurements aim to reconcile diazotrophic activity with microbial community composition, further elucidating how nitrogen fixers could impact current concepts in polar carbon and nutrient cycling.

  6. Five-year experience with modified Fogli (Loré's fascia fixation) platysmaplasty.

    Hodgkinson, Darryl J

    2012-02-01

    Over a 5-year period, my technique of approaching and modifying the aging neck has changed from direct suturing of the medial platysma bands and strong posterior traction of the platysma to superior elevation of the posterior platysma and strong fixation to the tympanoparotid fascia. When indicated, redundant anterior platysmal bands are resected instead of approximated. Evaluation of these anterior bands preoperatively for thickness and degree of descent allows more precise decision-making regarding the need to resect redundant and excessively thick or long anterior platysmal bands. The added advantage of the strong fixation of the platysma in a vertical fashion to Loré's fascia (the tympanoparotid fascia) leads not only to an improvement in the contour of the jawline and submental area but also to the undervalued aesthetic feature of a defined contour and visually increased length of the sternomastoid muscle.

  7. Osseointegration: a review of the fundamentals for assuring cementless skeletal fixation

    Isaacson BM

    2014-04-01

    Full Text Available Brad M Isaacson,1,2 Sujee Jeyapalina3,4 1Henry M Jackson Foundation for the Advancement of Military Medicine, 2The Center for Rehabilitation Sciences Research, Department of Physical Medicine and Rehabilitation, Uniformed Services University of Health Sciences, Bethesda, MD, USA; 3Department of Orthopedics, 4Orthopedic Research Laboratory, University of Utah, Salt Lake City, UT, USA Abstract: Direct skeletal fixation, termed osseointegration, has expanded in the last century and includes use in total joint replacements, the edentulous mandible and maxilla, and percutaneous osseointegrated prosthetics. Although it is well known that titanium and bone have the ability to form a durable bone–implant interface, new applications have emerged in the field of orthopedics, which requires a more thorough assessment of the literature. This review aims to introduce the basic biological principles for attaining osseointegration and discusses the major factors for assuring successful cementless fixation. Keywords: osseointegration, bone, skeletal attachment, total joint replacements, dental implants, percutaneous

  8. Fixation of petroleum contaminated soils via cold-mix asphalt for use as a liner

    Testa, S.M.; Patton, D.L.; Conca, J.L.

    1992-01-01

    This paper reports on several methodologies which are available for the remediation of petroleum hydrocarbon-affected soils (PHAS) including bioremediation vapor extraction, chemical fixation and direct disposal. A proven alternative for the fixation of petroleum-contaminated soils is via combination with cold-mix asphalt. One viable and creative use which is within the intent and spirit of current regulations is producing, in lieu of a landfill waste, an end-product for use as a cap, liner or other site-specific application. Consideration of certain factors including durability, aging, permeability and leachability suggests that cold-mix asphalt incorporation petroleum-contaminated soils will perform more than adequately under normal conditions for a long period of time - probably more than 1,000 years

  9. Free flap reconstructions of tibial fractures complicated after internal fixation.

    Nieminen, H; Kuokkanen, H; Tukiainen, E; Asko-Seljavaara, S

    1995-04-01

    The cases of 15 patients are presented where microvascular soft-tissue reconstructions became necessary after internal fixation of tibial fractures. Primarily, seven of the fractures were closed. Eleven fractures had originally been treated by open reduction and internal fixation using plates and screws, and four by intramedullary nailing. All of the patients suffered from postoperative complications leading to exposure of the bone or fixation material. The internal fixation material was removed and radical revision of dead and infected tissue was carried out in all cases. Soft tissue reconstruction was performed using a free microvascular muscle flap (11 latissimus dorsi, three rectus abdominis, and one gracilis). In eight cases the nonunion of the fracture indicated external fixation. The microvascular reconstruction was successful in all 15 patients. In one case the recurrence of deep infection finally indicated a below-knee amputation. In another case, chronic infection with fistulation recurred postoperatively. After a mean follow-up of 26 months the soft tissue coverage was good in all the remaining 13 cases. All the fractures united. Microvascular free muscle flap reconstruction of the leg is regarded as a reliable method for salvaging legs with large soft-tissue defects or defects in the distal leg. If after internal fixation of the tibial fracture the osteosynthesis material or fracture is exposed, reconstruction of the soft-tissue can successfully be performed by free flap transfer. By radical revision, external fixation, bone grafting, and a free flap the healing of the fracture can be achieved.

  10. Skin Graft Fixation Using Hydrofiber (Aquacel® Extra).

    Yen, Ya-Hui; Lin, Chih-Ming; Hsu, Honda; Chen, Ying-Chen; Chen, Yi-Wen; Li, Wan-Yu; Hsieh, Chia-Nan; Huang, Chieh-Chi

    2018-06-01

    The traditional method of skin graft fixation is with tie-over bollus dressing. The use of splints in the extremities for skin graft fixation is a common practice. However, these splints are heavy and uncomfortable and contribute considerably to our overall medical waste. Hydrofiber (Aquacel Extra) has a strong fluid absorption property and fixates well to the underlying wound once applied. In this study, we used hydrofiber for fixation, avoiding the use of splints after skin grafting. A total of 56 patients reconstructed with split-thickness skin graft that was fixated only with hydrofiber between March 2015 and March 2016 were included in this retrospective study. There were 44 men and 12 women with a mean age of 61 ± 18 years. The defect size ranged from 1 × 1 cm for fingertips to 30 × 12 cm for lower limb defects. The average defect size was 61 ± 78 cm. The mean skin graft take was 96% ± 6%. Because splints were not required, we saved around 48 kg of medical waste over the space of 1 year. The use of hydrofiber for skin graft fixation was effective and technically very simple. Splints were not required with this method, decreasing the medical waste created and increasing patient comfort. We suggest that this is an excellent alternative for skin graft fixation while at the same time decreasing our carbon footprint as surgeons.

  11. Fracture healing using degradable magnesium fixation plates and screws.

    Chaya, Amy; Yoshizawa, Sayuri; Verdelis, Kostas; Noorani, Sabrina; Costello, Bernard J; Sfeir, Charles

    2015-02-01

    Internal bone fixation devices made with permanent metals are associated with numerous long-term complications and may require removal. We hypothesized that fixation devices made with degradable magnesium alloys could provide an ideal combination of strength and degradation, facilitating fracture fixation and healing while eliminating the need for implant removal surgery. Fixation plates and screws were machined from 99.9% pure magnesium and compared with titanium devices in a rabbit ulnar fracture model. Magnesium device degradation and the effect on fracture healing and bone formation were assessed after 4 weeks. Fracture healing with magnesium device fixation was compared with that of titanium devices using qualitative histologic analysis and quantitative histomorphometry. Micro-computed tomography showed device degradation after 4 weeks in vivo. In addition, 2-dimensional micro-computed tomography slices and histologic staining showed that magnesium degradation did not inhibit fracture healing or bone formation. Histomorphology showed no difference in bone-bridging fractures fixed with magnesium and titanium devices. Interestingly, abundant new bone was formed around magnesium devices, suggesting a connection between magnesium degradation and bone formation. Our results show potential for magnesium fixation devices in a loaded fracture environment. Furthermore, these results suggest that magnesium fixation devices may enhance fracture healing by encouraging localized new bone formation. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  12. Design and Optimization of Resorbable Silk Internal Fixation Devices

    Haas, Dylan S.

    Limitations of current material options for internal fracture fixation devices have resulted in a large gap between user needs and hardware function. Metal systems offer robust mechanical strength and ease of implantation but require secondary surgery for removal and/or result in long-term complications (infection, palpability, sensitivity, etc.). Current resorbable devices eliminate the need for second surgery and long-term complications but are still associated with negative host response as well as limited functionality and more difficult implantation. There is a definitive need for orthopedic hardware that is mechanically capable of immediate fracture stabilization and fracture fixation during healing, can safely biodegrade while allowing complete bone remodeling, can be resterilized for reuse, and is easily implantable (self-tapping). Previous work investigated the use of silk protein to produce resorbable orthopedic hardware for non- load bearing fracture fixation. In this study, silk orthopedic hardware was further investigated and optimized in order to better understand the ability of silk as a fracture fixation system and more closely meet the unfulfilled market needs. Solvent-based and aqueous-based silk processing formulations were cross-linked with methanol to induce beta sheet structure, dried, autoclaved and then machined to the desired device/geometry. Silk hardware was evaluated for dry, hydrated and fatigued (cyclic) mechanical properties, in vitro degradation, resterilization, functionalization with osteoinductive molecules and implantation technique for fracture fixation. Mechanical strength showed minor improvements from previous results, but remains comparable to current resorbable fixation systems with the advantages of self-tapping ability for ease of implantation, full degradation in 10 months, ability to be resterilized and reused, and ability to release molecules for osteoinudction. In vivo assessment confirmed biocompatibility, showed

  13. Early Experience with Biodegradable Fixation of Pediatric Mandibular Fractures

    Mazeed, Ahmed Salah; Shoeib, Mohammed Abdel-Raheem; Saied, Samia Mohammed Ahmed; Elsherbiny, Ahmed

    2014-01-01

    This clinical study aims to evaluate the stability and efficiency of biodegradable self-reinforced poly-l/dl-lactide (SR-PLDLA) plates and screws for fixation of pediatric mandibular fractures. The study included 12 patients (3–12 years old) with 14 mandibular fractures. They were treated by open reduction and internal fixation by SR-PLDLA plates and screws. Maxillomandibular fixation was maintained for 1 week postoperatively. Clinical follow-up was performed at 1 week, 6 weeks, 3 months, and...

  14. Operative Fixation Options for Elective and Diabetic Ankle Arthrodesis.

    Ramanujam, Crystal L; Stapleton, John J; Zgonis, Thomas

    2017-07-01

    Ankle arthrodesis remains one of the most definitive treatment options for end-stage arthritis, paralysis, posttraumatic and postinfectious conditions, failed total ankle arthroplasty, and severe deformities. The general aims of ankle arthrodesis are to decrease pain and instability, correct the accompanying deformity, and create a stable plantigrade foot. Several surgical approaches have been reported for ankle arthrodesis with internal fixation options. External fixation has also evolved for ankle arthrodesis in certain clinical scenarios. This article provides a comprehensive analysis of midterm to long-term outcomes for ankle arthrodesis using internal and/or external fixation each for elective and diabetic conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Carbon Dioxide Fixation in Isolated Kalanchoe Chloroplasts 1

    Levi, Carolyn; Gibbs, Martin

    1975-01-01

    Chloroplasts isolated from Kalanchoe diagremontiana leaves were capable of photosynthesizing at a rate of 5.4 μmoles of CO2 per milligram of chlorophyll per hour. The dark rate of fixation was about 1% of the light rate. A high photosynthetic rate was associated with low starch content of the leaves. Ribose 5-phosphate, fructose 1,6-diphosphate, and dithiothreitol stimulated fixation, whereas phosphoenolpyruvate and azide were inhibitors. The products of CO2 fixation were primarily those of the photosynthetic carbon reduction cycle. PMID:16659249

  16. Modeling the impact of iron and phosphorus limitations on nitrogen fixation in the Atlantic Ocean

    R. R. Hood

    2007-07-01

    Full Text Available The overarching goal of this study is to simulate subsurface N* (sensu, Gruber and Sarmiento, 1997; GS97 anomaly patterns in the North Atlantic Ocean and determine the basin wide rates of N2-fixation that are required to do so. We present results from a new Atlantic implementation of a coupled physical-biogeochemical model that includes an explicit, dynamic representation of N2-fixation with light, nitrogen, phosphorus and iron limitations, and variable stoichiometric ratios. The model is able to reproduce nitrogen, phosphorus and iron concentration variability to first order. The latter is achieved by incorporating iron deposition directly into the model's detrital iron compartment which allows the model to reproduce sharp near surface gradients in dissolved iron concentration off the west coast of Africa and deep dissolved iron concentrations that have been observed in recent observational studies. The model can reproduce the large scale N* anomaly patterns but requires relatively high rates of surface nitrogen fixation to do so (1.8×1012 moles N yr−1 from 10° N–30° N, 3.4×1012 moles N yr−1 from 25° S–65° N. In the model the surface nitrogen fixation rate patterns are not co-located with subsurface gradients in N*. Rather, the fixed nitrogen is advected away from its source prior to generating a subsurface N* anomaly. Changes in the phosphorus remineralization rate (relative to nitrogen linearly determine the surface nitrogen fixation rate because they change the degree of phosphorus limitation, which is the dominant limitation in the Atlantic in the model. Phosphorus remineralization rate must be increased by about a factor of 2 (relative to nitrogen in order to generate subsurface N* anomalies that are comparable to the observations. We conclude that N2-fixation rate estimates for the Atlantic (and globally may need to be revised upward, which

  17. Biomechanical stability of a supra-acetabular pedicle screw internal fixation device (INFIX) vs external fixation and plates for vertically unstable pelvic fractures.

    Vigdorchik, Jonathan M; Esquivel, Amanda O; Jin, Xin; Yang, King H; Onwudiwe, Ndidi A; Vaidya, Rahul

    2012-09-27

    We have recently developed a subcutaneous anterior pelvic fixation technique (INFIX). This internal fixator permits patients to sit, roll over in bed and lie on their sides without the cumbersome external appliances or their complications. The purpose of this study was to evaluate the biomechanical stability of this novel supraacetabular pedicle screw internal fixation construct (INFIX) and compare it to standard internal fixation and external fixation techniques in a single stance pelvic fracture model. Nine synthetic pelves with a simulated anterior posterior compression type III injury were placed into three groups (External Fixator, INFIX and Internal Fixation). Displacement, total axial stiffness, and the stiffness at the pubic symphysis and SI joint were calculated. Displacement and stiffness were compared by ANOVA with a Bonferroni adjustment for multiple comparisons The mean displacement at the pubic symphysis was 20, 9 and 0.8 mm for external fixation, INFIX and internal fixation, respectively. Plate fixation was significantly stiffer than the INFIX and external Fixator (P = 0.01) at the symphysis pubis. The INFIX device was significantly stiffer than external fixation (P = 0.017) at the symphysis pubis. There was no significant difference in SI joint displacement between any of the groups. Anterior plate fixation is stiffer than both the INFIX and external fixation in single stance pelvic fracture model. The INFIX was stiffer than external fixation for both overall axial stiffness, and stiffness at the pubic symphysis. Combined with the presumed benefit of minimizing the complications associated with external fixation, the INFIX may be a more preferable option for temporary anterior pelvic fixation in situations where external fixation may have otherwise been used.

  18. [Odontoid bending stiffness after anterior fixation with a single lag screw: biomechanical study].

    Buchvald, P; Čapek, L; Barsa, P

    2015-01-01

    PURPOSE OF THE STUDY The aim of the experiment was to compare the bending stiffness of an intact odontoid process with bending stiffness after its simulated type II fracture was fixed with a single lag screw. The experiment was done with a desire to answer the question of whether a single osteosynthetic screw is sufficient for good fixation of a type II odontoid fracture. MATERIAL AND METHODS The C2 vertebrae of six cadavers were used. With simultaneous measurement of odontoid bending stiffness, the occurrence of a fracture (type IIA, Grauer's modification of the Anderson- D'Alonzo classification) was simulated using action exerted by a tearing machine in the direction perpendicular to the odontoid axis. Each odontoid fracture was subsequently treated by direct osteosynthesis with a single lag screw inserted in the axial direction by a standard surgical procedure in order to provide conditions similar to those achieved by routine surgical management. The treated odontoid process was subsequently subjected to the same tearing machine loading as applied to it at the start of the experiment. The bending stiffness measured was then compared with that found before the fracture occurred. The results were statistically evaluated by the t-test for paired samples at the level of significance α = 0.05. RESULTS The average value of bending stiffness for odontoid processes of intact vertebrae at the moment of fracture occurrence was 318.3 N/mm. After single axial lag screw fixation of the fracture, the average bending stiffness for the odontoid processes treated was 331.3 N/mm. DISCUSSION Higher values of bending stiffness after screw fixation were found in all specimens and, in comparison with the values recorded before simulated fractures, the increase was statistically significant. CONCLUSIONS The results of our measurements suggest that the single lag screw fixation of a type IIA odontoid fracture will provide better stability for the fracture fragment-C2 body complex on

  19. Eye fixations indicate men's preference for female breasts or buttocks.

    Dagnino, Bruno; Navajas, Joaquin; Sigman, Mariano

    2012-08-01

    Evolutionary psychologists have been interested in male preferences for particular female traits that are thought to signal health and reproductive potential. While the majority of studies have focused on what makes specific body traits attractive-such as the waist-to-hip ratio, the body mass index, and breasts shape and size-there is little empirical research that has examined individual differences in male preferences for specific traits (e.g., favoring breasts over buttocks). The current study begins to fill this empirical gap. In the first experiment (Study 1), 184 male participants were asked to report their preference between breasts and buttocks on a continuous scale. We found that (1) the distribution of preference was bimodal, indicating that Argentinean males tended to define themselves as favoring breasts or buttocks but rarely thinking that these traits contributed equally to their choice and (2) the distribution was biased towards buttocks. In a second experiment (Study 2), 19 male participants were asked to rate pictures of female breasts and buttocks. This study was necessary to generate three categories of pictures with statistically different ratings (high, medium, and low). In a third experiment (Study 3), we recorded eye-movements of 25 male participants while they chose the more attractive between two women, only seeing their breasts and buttock. We found that the first and last fixations were systematically directed towards the self-reported preferred trait.

  20. Fixation not required: characterizing oculomotor attention capture for looming stimuli.

    Lewis, Joanna E; Neider, Mark B

    2015-10-01

    A stimulus moving toward us, such as a ball being thrown in our direction or a vehicle braking suddenly in front of ours, often represents a stimulus that requires a rapid response. Using a visual search task in which target and distractor items were systematically associated with a looming object, we explored whether this sort of looming motion captures attention, the nature of such capture using eye movement measures (overt/covert), and the extent to which such capture effects are more closely tied to motion onset or the motion itself. We replicated previous findings indicating that looming motion induces response time benefits and costs during visual search Lin, Franconeri, & Enns(Psychological Science 19(7): 686-693, 2008). These differences in response times were independent of fixation, indicating that these capture effects did not necessitate overt attentional shifts to a looming object for search benefits or costs to occur. Interestingly, we found no differences in capture benefits and costs associated with differences in looming motion type. Combined, our results suggest that capture effects associated with looming motion are more likely subserved by covert attentional mechanisms rather than overt mechanisms, and attention capture for looming motion is likely related to motion itself rather than the onset of motion.

  1. Regulation of Development and Nitrogen Fixation in Anabaena

    James W. Golden

    2008-10-17

    The regulation of development and cellular differentiation is important for all multicellular organisms. The nitrogen-fixing filamentous cyanobacterium Anabaena (also Nostoc) sp. PCC 7120 (hereafter Anabaena) provides a model of multicellular microbial development and pattern formation. Anabaena reduces N2 to ammonia in specialized terminally differentiated cells called heterocysts. A one-dimensional developmental pattern of single heterocysts regularly spaced along filaments of photosynthetic vegetative cells is established to form a multicellular organism composed of these two interdependent cell types. This multicellular growth pattern, the distinct phylogeny of cyanobacteria, and the suspected antiquity of heterocyst development make this an important model system. Our long-term goal is to understand the regulatory network required for heterocyst development and nitrogen fixation. This project is focused on two key aspects of heterocyst regulation: one, the mechanism by which HetR controls the initiation of differentiation, and two, the cis and trans acting factors required for expression of the nitrogen-fixation (nif) genes. HetR is thought to be a central regulator of heterocyst development but the partners and mechanisms involved in this regulation are unknown. Our recent results indicate that PatS and other signals that regulate heterocyst pattern cannot interact, directly or indirectly, with a R223W mutant of HetR. We plan to use biochemical and genetic approaches to identify proteins that interact with the HetR protein, which will help reveal the mechanisms underlying its regulation of development. Our second goal is to determine how the nif genes are expressed. It is important to understand the mechanisms controlling nif genes since they represent the culmination of the differentiation process and the essence of heterocyst function. The Anabaena genome lacks the genes required for expression of nif genes present in other organisms such as rpoN (sigma 54

  2. Necrotizing fasciitis after internal fixation of fracture of femoral trochanteric ? ??

    Santos, Leandro Em?lio Nascimento; Pires, Robinson Esteves Santos; Figueiredo, Leonardo Brand?o; Soares, Eduardo Augusto Marques

    2014-01-01

    Necrotizing fasciitis is a rare and potentially lethal soft tissue infection. We report a case of trochanteric femur fracture in a patient who underwent fracture fixation and developed necrotizing fasciitis. A literature review on the topic will be addressed.

  3. Use of 15N methodology to assess biological nitrogen fixation

    Hardarson, G.

    1990-01-01

    One of the most important characteristics of legumes are their ability in symbiosis with Rhizobium bacteria to fix atmospheric nitrogen for growth. For proper management and a full realization of the benefits of this plant-microbial association, it is necessary to estimate how much nitrogen is fixed under different conditions in the field. It is only after this is known that various factors can be manipulated so as to increase the amount and proportion of N a plant derives from biological fixation. A suitable method for accurately measuring the amount of N crops derive from fixation is therefore an important requirement in any programme aimed at maximizing biological nitrogen fixation. There are several methods available to measure N 2 fixation (Bergersen, 1980) based on (1) increment in N yield and plant growth, (2) nitrogen balance (3) acetylene reduction and (4) the use of isotopes of N. Only isotopic methods will be illustrated here. 20 refs, 2 figs, 9 tabs

  4. Outcome of complex tibial plateau fractures treated with external fixator

    Sushil H Mankar

    2012-01-01

    Conclusion: We believe that minimally invasive treatment by percutaneous techniques and external fixation is a fairly reasonable treatment alternative, if near anatomical reduction of joint surface can be confirmed on fluoroscopy.

  5. Biomechanical analysis of titanium fixation plates and screws in ...

    hole Y plates with monocortical screws. 150 N incisal occlusal loads were simulated on the models. The commercial ANSYS software was utilized to calculate the Von Mises stresses on fixative appliances. Results: The highest Von Mises stress ...

  6. Cyanobacteria Occurrence and Nitrogen Fixation Rates in the ...

    Keywords: Cyanobacteria, Nitrogen Fixation, Seagrass, Seaweed Farming. Abstract—The .... during every sampling period, using a mercury thermometer and a ..... Capone, D.G. (1993) Determination of nitrogenase activity in aquatic samples ...

  7. A new 3-dimensional head fixation device for brain imaging

    Goto, Ryoi; Kawashima, Ryuta; Yoshioka, Seiro; Ono, Shuichi; Ito, Hiroshi; Sato, Kazunori; Akaizawa, Takashi; Koyama, Masamichi; Fukuda, Hiroshi

    1995-01-01

    We have developed a new head fixation device for studies of brain function. This device was designed to immobilize subject's heads during image scanning and to precisely reproduce the head position for two different imaging modalities such as MRI and PET. The device consists of a plastic frame, a pillow filled with beads of styrene foam, and a face mask of thermoplastic resin which was originally intended for application in radiotherapy. A bridge for biting was incorporated into the mask for stable fixation. The device enables immobilization of subject's heads with good reproducibility of position at the practical level. Our results indicate that this head fixation system is useful for fixation of head during activation studies using PET. (author)

  8. Nitrogen fixation rates in the eastern Arabian Sea

    Ahmed, A.; Gauns, M.; Kurian, S.; Bardhan, P.; Pratihary, A.K.; Naik, H.; Shenoy, D.M.; Naqvi, S.W.A.

    The Arabian Sea experiences bloom of the diazotroph Trichodesmium during certain times of the year when optimal sea surface temperature and oligotrophic condition favour their growth. We measured nitrogen fixation rates in the euphotic zone during...

  9. Symbiotic N fixation of several soybean varieties and mutants

    Soertini, G.; Hendratno

    1988-01-01

    Symbiotic N fixation of several soybean varieties and mutants. Research activities comprising of three experiments were carried out to screen several soybean varieties and mutants for symbiotic N fixation potential. The first two experiments involved screening of seven rhizobium strains/isolate for effective N fixation. Depending on the medium used, plant response to strains was different. In sterile medium, rhizobium strain USDA 136, 142 and TAL 102 showed a high nitrogen fixation potential. In soil only rhizobium strain USDA 110 had better performance and proved to be competitive to the native strains. Nitrogen-15 dilution method was used to screen nitrogen fixing ability of several soybean varieties and mutants. Guntur variety showed a better response to high dose of N fertilizer without disturbance in its fixing ability. This variety then was considered good to be introduced in the cropping system. (author). 8 refs

  10. Fixation of tritium in a highly stable polymer form

    Steinberg, M.; Colombo, P.; Pruzansky, J.

    1977-01-01

    A method for the fixation of tritium comprises reacting tritiated water with calcium carbide to produce calcium hydroxide and tritiated acetylene, polymerizing the acetylene, and then incorporating the polymer in a solidifying matrix. 2 claims

  11. Improving food and agricultural production. Thailand. Biological nitrogen fixation

    Bowen, G.D.

    1991-01-01

    The aim of the mission was to assist the counterpart scientists in the analysis and interpretation of data relating to nitrogen fixation studies on grain legumes. The report briefly summarizes the discussions that were held with the counterparts

  12. Meniscal allograft transplantation. Part 1: systematic review of graft biology, graft shrinkage, graft extrusion, graft sizing, and graft fixation.

    Samitier, Gonzalo; Alentorn-Geli, Eduard; Taylor, Dean C; Rill, Brian; Lock, Terrence; Moutzouros, Vasilius; Kolowich, Patricia

    2015-01-01

    To provide a systematic review of the literature regarding five topics in meniscal allograft transplantation: graft biology, shrinkage, extrusion, sizing, and fixation. A systematic literature search was conducted using the PubMed (MEDLINE), ScienceDirect, and EBSCO-CINAHL databases. Articles were classified only in one topic, but information contained could be reported into other topics. Information was classified according to type of study (animal, in vitro human, and in vivo human) and level of evidence (for in vivo human studies). Sixty-two studies were finally included: 30 biology, 3 graft shrinkage, 11 graft extrusion, 17 graft size, and 6 graft fixation (some studies were categorized in more than one topic). These studies corresponded to 22 animal studies, 22 in vitro human studies, and 23 in vivo human studies (7 level II, 10 level III, and 6 level IV). The principal conclusions were as follows: (a) Donor cells decrease after MAT and grafts are repopulated with host cells form synovium; (b) graft preservation alters collagen network (deep freezing) and causes cell apoptosis with loss of viable cells (cryopreservation); (c) graft shrinkage occurs mainly in lyophilized and gamma-irradiated grafts (less with cryopreservation); (d) graft extrusion is common but has no clinical/functional implications; (e) overall, MRI is not superior to plain radiograph for graft sizing; (f) graft width size matching is more important than length size matching; (g) height appears to be the most important factor influencing meniscal size; (h) bone fixation better restores contact mechanics than suture fixation, but there are no differences for pullout strength or functional results; and (i) suture fixation has more risk of graft extrusion compared to bone fixation. Systematic review of level II-IV studies, Level IV.

  13. Incidence of infection after early intramedullary nailing of open tibial shaft fractures stabilized with pinless external fixators

    Kulshrestha Vikas

    2008-01-01

    Full Text Available Background: A major drawback of conventional fixator system is the penetration of fixator pins into the medullary canal. The pins create a direct link between the medullary cavity and outer environment, leading to higher infection rates on conversion to intramedullary nailing. This disadvantage is overcome by the AO pinless fixator, in which the trocar points are clamped onto the outer cortex without penetrating it. This study was designed to evaluate the role of AO pinless fixators in primary stabilization of open diaphyseal tibial fractures that received staged treatment because of delayed presentation or poor general condition. We also analyzed the rate of infection on early conversion to intramedullary nail. Materials and Methods: This study is a retrospective review of 30 open diaphyseal fractures of tibia, which were managed with primary stabilization with pinless fixator and early exchange nailing. Outcome was evaluated in terms of fracture union and rate of residual infection. The data were compared with that available in the literature. Results: All the cases were followed up for a period of 2 years. The study includes Gustilo type 1 (n=10, 14 Gustilo type 2 (n=14, and type3 (n=6 cases. 6 cases (20% had clamp site infection, 2 cases (6.7% had deep infection, and in 28 cases (93% the fracture healed and consolidated well. Conclusion: This study has highlighted the valuable role of pinless external fixator in the management of open tibial fractures in terms of safety and ease of application as well as the advantage of early conversion to intramedullary implant without the risk of deep infection.

  14. CT simulation in stereotactic brain radiotherapy - analysis of isocenter reproducibility with mask fixation

    Willner, Jochen; Flentje, Michael; Bratengeier, Klaus

    1997-01-01

    Background and purpose: CT verification and measurement of isocenter deviation using repeated mask fixation in linac-based stereotactic high dose radiotherapy of brain metastases were performed in this study. Materials and methods: For stereotactic radiotherapy of brain metastases a commercial head mask fixation device based on thermoplastic materials (BrainLAB) was used. A two-step planning-treatment procedure was performed. Immediately before treatment the patient was relocated in the mask and a verification CT scan of the radiopaque marked isocenter was performed and if necessary its position was corrected. The verification procedure is described in detail. Twenty-two CT verifications in 16 patients were analyzed. Deviations were measured separately for each direction. A 3D-deviation vector was calculated. Additionally the average amount of deviation in each of the three dimensions was calculated. Results: The mean deviation and standard deviation (SD) of the isocenter was 0.4 mm (SD 1.5 mm) in the longitudinal direction, -0.1 mm (SD 1.8 mm) in the lateral direction and 0.1 mm (SD 1.2 mm) in the anterior-posterior direction. The mean three-dimensional distance (3D-vector) between the verified and the corrected isocenter was 2.4 mm (SD 1.3 mm). The average deviation (without consideration of direction) was 1.1 mm (SD 1.1 mm), 1.3 mm (SD 1.3 mm) and 0.8 mm (SD 0.9 mm) in the longitudinal, lateral and sagittal directions, respectively. No correlation was found between 3D-deviation and the distance of the isocenter from the reference plane nor between deviation and the position of metastases in the brain (central versus peripheral or between different lobes), or the date of treatment. Conclusion: Reproducibility of the isocenter using the presented mask fixation is in the range of positioning reproducibility reported for other non-invasive fixation devices for stereotactic brain treatment. Our results underline the importance of CT verification as a quality

  15. The Role of Personality and Team-Based Product Dissection on Fixation Effects

    Toh, Christine; Miller, Scarlett; Kremer, Gül E. Okudan

    2013-01-01

    Design fixation has been found to be complex in its definition and expression, but it plays an important role in design idea generation. Identifying the factors that influence fixation is crucial in understanding how to enhance the design process and reduce the negative effects of fixation. One way to potentially mitigate fixation is through…

  16. Rubisco Activase Is Required for Optimal Photosynthesis in the Green Alga Chlamydomonas reinhardtii in a Low-CO2 Atmosphere1

    Pollock, Steve V.; Colombo, Sergio L.; Prout, Davey L.; Godfrey, Ashley C.; Moroney, James V.

    2003-01-01

    This report describes a Chlamydomonas reinhardtii mutant that lacks Rubisco activase (Rca). Using the BleR (bleomycin resistance) gene as a positive selectable marker for nuclear transformation, an insertional mutagenesis screen was performed to select for cells that required a high-CO2 atmosphere for optimal growth. The DNA flanking the BleR insert of one of the high-CO2-requiring strains was cloned using thermal asymmetric interlaced-polymerase chain reaction and inverse polymerase chain reaction and sequenced. The flanking sequence matched the C. reinhardtii Rca cDNA sequence previously deposited in the National Center for Biotechnology Information database. The loss of a functional Rca in the strain was confirmed by the absence of Rca mRNA and protein. The open reading frame for Rca was cloned and expressed in pSL18, a C. reinhardtii expression vector conferring paromomycin resistance. This construct partially complemented the mutant phenotype, supporting the hypothesis that the loss of Rca was the reason the mutant grew poorly in a low-CO2 atmosphere. Sequencing of the C. reinhardtii Rca gene revealed that it contains 10 exons ranging in size from 18 to 470 bp. Low-CO2-grown rca1 cultures had a growth rate and maximum rate of photosynthesis 60% of wild-type cells. Results obtained from experiments on a cia5 rca1 double mutant also suggest that the CO2-concentrating mechanism partially compensates for the absence of an active Rca in the green alga C. reinhardtii. PMID:14605215

  17. Diversity and Transcriptional Levels of RuBisCO Form II of Sulfur-Oxidizing γ-Proteobacteria in Coastal-Upwelling Waters with Seasonal Anoxia

    Bárbara Léniz

    2017-07-01

    Full Text Available Seasonal wind-driven upwelling, high primary production in surface waters, and oxygen deficiency in subsurface waters characterize the coastal ecosystem of the subtropical eastern South Pacific (ESP, and shape the nature and dynamics of the microbial community structure and function. We investigated the diversity, abundance, and transcriptional levels of the gene encoding the large subunit form II of the RuBisCO enzyme (cbbM in the pelagic microbial community at a continental-shelf site off central Chile over 2 years. We focused on cbbM genes affiliated with the sulfur-oxidizing γ-proteobacteria cluster, whose members are known to dominate in oxygen-deficient marine environments and are highly abundant in the study area. Phylogenetic analysis of cbbM sequences suggests the presence of a novel group of chemolithoautotrophs, closely related to the SUP05/ARCTIC96BD-19 clade. Through (RT-qPCR, we studied the cbbM gene abundance and transcript dynamics over an annual cycle, finding a significantly higher number of cbbM copies per unit volume in months of active upwelling and at depths in which oxygen was scarce or absent. The same temporal pattern was observed at the transcriptional level. We also analyzed the relative expression of key genes for carbon, nitrogen and sulfur cycling in six metatranscriptomic datasets, for two characteristic periods within the annual cycle: the anoxic upwelling and the suboxic downwelling. Our results indicate that coastal waters of the subtropical ESP contain transcriptionally active populations of carbon fixing pelagic bacteria, whose dynamics is controlled, in large part, by fluctuations in oxygen levels. They also suggest that chemolithoautotrophic processes coupled to the sulfur and nitrogen cycles become increasingly important for the carbon economy of marine coastal waters as oxygen concentrations decline.

  18. Tandem repeats, high copy number and remarkable diel expression rhythm of form II RuBisCO in Prorocentrum donghaiense (Dinophyceae.

    Xinguo Shi

    Full Text Available Gene structure and expression regulation of form II RuBisCO (rbcII in dinoflagellates are still poorly understood. Here we isolated this gene (Pdrbc and investigated its diel expression pattern in a harmful algal bloom forming dinoflagellate Prorocentrum donghaiense. We obtained cDNA sequences with triple tandem repeats of the coding unit (CU; the 5' region has the sequence of a typical dinoflagellate plastid gene, encoding an N-terminus with two transmembrane regions separated by a plastid transit peptide. The CUs (1,455 bp except 1464 bp in last CU are connected through a 63 bp spacer. Phylogenetic analysis showed that rbcII CUs within species formed monophyletic clusters, indicative of intraspecific gene duplication or purifying evolution. Using quantitative PCR (qPCR we estimated 117±40 CUs of Pdrbc in the P. donghaiense genome. Although it is commonly believed that most dinoflagellate genes lack transcriptional regulation, our RT-qPCR analysis on synchronized cultures revealed remarkable diel rhythm of Pdrbc expression, showing significant correlations of transcript abundance with the timing of the dark-to-light transition and cell cycle G2M-phase. When the cultures were shifted to continuous light, Pdrbc expression remained significantly correlated with the G2M-phase. Under continuous darkness the cell cycle was arrested at the G1 phase, and the rhythm of Pdrbc transcription disappeared. Our results suggest that dinoflagellate rbcII 1 undergoes duplication or sequence purification within species, 2 is organized in tandem arrays in most species probably to facilitate efficient translation and import of the encoded enzyme, and 3 is regulated transcriptionally in a cell cycle-dependent fashion at least in some dinoflagellates.

  19. Nitrogen supply of crops by biological nitrogen fixation. 2

    Jensen, E.S.; Andersen, A.J.; Soerensen, H.; Thomsen, J.D.

    1985-02-01

    In the present work the contributions from combined N-sources and symbiotic nitrogen fixation to the nitrogen supply of field-grown peas and field beans were evaluated by means of 15 N fertilizer dilution. The effect of N-fertilizer, supplied at sowing and at different stages of plant development, on nitrogen fixation, yield and protein production in peas, was studied in pot experiments. (author)

  20. A Novel Handmade External Fixator for Phalangeal and Metacarpal Fractures

    Davod Jafari

    2016-12-01

    Full Text Available Background The value of external fixation in complex hand injuries is well established. Expenses and technical difficulties of commercial mini external fixator sets have led to the innovation of handmade external fixators. These fixators are used as versatile facilities to treat certain hand fractures. Usually, these structures are made by k-wires crossed filled with cement plastic tube. However, these fixators have multiple deficiencies that should be addressed. Objectives In this study, we described in detail the surgical technique of a handmade concrete like mini external fixator and report its clinical use and results. Methods Our handmade external fixator was applied for 52 patients with 56 fractures. Only 5% of the fractures were closed, non-comminuted extra-articular, and the other 51 fractures were more complex injuries. The mean follow up time was 9.3 months. At the end of the follow up, radiologic and functional assessment (DASH: Disability of arm, shoulder and hand and TAM: Total active motion was evaluated. Results All 56 fractures were united completely. None of the cases experienced pin loosening or reduction loss. Of the fractures, 8.9% malunited due to fracture complexity. The mean dash score was 3.76. TAM was excellent in 45% of the fractures; it was good in 7% and fair in 4%. Conclusions This type of handmade external fixator is simple, lightweight, and cheap. Furthermore, all implements are readily available in most operating fields. The probability of loosening has been greatly diminished because of the concrete like structure. Easy and fast assembly and good clinical and functional results are the other advantages of this technique. Due to the less complication and benefits, this technique could be used for many phalangeal and metacarpal fractures with confidence.

  1. Postinflammatory ossicular fixation: CT analysis with surgical correlation

    Swartz, J.D.; Wolfson, R.J.; Marlowe, F.I.; Popky, G.L.

    1985-01-01

    Postinflammatory ossicular fixation is a common problem encountered by the otologic surgeon upon exploration because of conductive hearing loss in patients with chronic otitis media. These nonotosclerotic noncongenital lesions take three pathologic forms: fibrous tissue fixation (chronic adhesive otitis media), hyalinization of collagen (tympanosclerosis), and new bone formation (fibro-osseous sclerosis). More than 300 patients with the clinical diagnosis of chronic otitis media have been examined. This study encompasses 23 proved cases

  2. External fixation of tibial pilon fractures and fracture healing.

    Ristiniemi, Jukka

    2007-06-01

    Distal tibial fractures are rare and difficult to treat because the bones are subcutaneous. External fixation is commonly used, but the method often results in delayed union. The aim of the present study was to find out the factors that affect fracture union in tibial pilon fractures. For this purpose, prospective data collection of tibial pilon fractures was carried out in 1998-2004, resulting in 159 fractures, of which 83 were treated with external fixation. Additionally, 23 open tibial fractures with significant > 3 cm bone defect that were treated with a staged method in 2000-2004 were retrospectively evaluated. The specific questions to be answered were: What are the risk factors for delayed union associated with two-ring hybrid external fixation? Does human recombinant BMP-7 accelerate healing? What is the role of temporary ankle-spanning external fixation? What is the healing potential of distal tibial bone loss treated with a staged method using antibiotic beads and subsequent autogenous cancellous grafting compared to other locations of the tibia? The following risk factors for delayed healing after external fixation were identified: post-reduction fracture gap of >3 mm and fixation of the associated fibula fracture. Fracture displacement could be better controlled with initial temporary external fixation than with early definitive fixation, but it had no significant effect on healing time, functional outcome or complication rate. Osteoinduction with rhBMP-7 was found to accelerate fracture healing and to shorten the sick leave. A staged method using antibiotic beads and subsequent autogenous cancellous grafting proved to be effective in the treatment of tibial bone loss. Healing potential of the bone loss in distal tibia was at least equally good as in other locations of the tibia.

  3. Bilateral spontaneous subluxation of scleral-fixated intraocular lenses.

    Assia, Ehud I; Nemet, Arie; Sachs, Dani

    2002-12-01

    Two young men with primary ectopic lenses had intracapsular cataract extraction and scleral fixation of posterior chamber intraocular lenses (PC IOLs) using 10-0 polypropylene sutures tied to the IOL eyelets. Three to 9 years after implantation, spontaneous IOL vertical subluxation occurred in all 4 eyes (5 IOL loops), probably because of suture breakage. Late subluxation of a sutured IOL may occur several years after implantation. Double fixation and thicker sutures should be considered, especially in young patients.

  4. Extent and Morbidity of Lateralization of a Trochanteric Fixation Nail Blade.

    Sandifer, Phillip A; Hulick, Robert M; Graves, Matthew L; Spitler, Clay A; Russell, George V; Hydrick, Josie M; Jones, LaRita C; Bergin, Patrick F

    2017-09-01

    This study examined the incidence and risk factors associated with lateral helical blade migration and trochanteric pain with the trochanteric fixation nail. A retrospective review was performed of 141 cases of pertrochanteric femur fracture treated with a trochanteric fixation nail at a level I trauma center over a period of 42 months. Exclusion criteria included follow-up of less than 60 days, preexisting osteonecrosis of the femoral head, and prophylactic trochanteric fixation nail treatment. Patient demographics, operative findings, and radiographic findings were recorded. Medical records were reviewed to identify symptomatic hardware. Overall, 27 patients (19.1%) were symptomatic, and 3 (2.1%) required revision surgery for blade prominence. Of the patients, 42 (30%) had lateralization of greater than 1 cm, and 16 of these (38.1%) were symptomatic (Pfractures showing lateralization of greater than 1 cm. The quality of calcar reduction nearly reached statistical significance, and 44.8% of patients who had inadequate reduction had lateralization of greater than 1 cm compared with 26.4% of patients who had adequate reduction (P=.054). Lateralization of greater than 1 cm was directly associated with the presence of symptoms (Ptrochanteric pain (P=.007). Multivariate analysis showed that increasing tip-apex distance, inadequate calcar reduction, and greater fracture severity were predictive of excessive lateralization of greater than 1 cm. Nearly 20% of patients had lateral hip pain associated with cephalomedullary fixation. Final lateralization of the helical blade of greater than 1 cm was a very strong predictor of symptoms. During preoperative counseling, surgeons should caution patients about this relatively frequent and likely underreported complication. [Orthopedics. 2017; 40(5):e886-e891.]. Copyright 2017, SLACK Incorporated.

  5. Plant densities and modulation of symbiotic nitrogen fixation in soybean

    Marcos Javier de Luca

    2014-06-01

    Full Text Available Soybean nitrogen (N demands can be supplied to a large extent via biological nitrogen fixation, but the mechanisms of source/sink regulating photosynthesis/nitrogen fixation in high yielding cultivars and current crop management arrangements need to be investigated. We investigated the modulation of symbiotic nitrogen fixation in soybean [Glycine max (L. Merrill] at different plant densities. A field trial was performed in southern Brazil with six treatments, including non-inoculated controls without and with N-fertilizer, both at a density of 320,000 plants ha−1, and plants inoculated with Bradyrhizobium elkanii at four densities, ranging from 40,000 to 320,000 plants ha−1. Differences in nodulation, biomass production, N accumulation and partition were observed at stage R5, but not at stage V4, indicating that quantitative and qualitative factors (such as sunlight infrared/red ratio assume increasing importance during the later stages of plant growth. Decreases in density in the inoculated treatments stimulated photosynthesis and nitrogen fixation per plant. Similar yields were obtained at the different plant densities, with decreases only at the very low density level of 40,000 plants ha−1, which was also the only treatment to show differences in seed protein and oil contents. Results confirm a fine tuning of the mechanisms of source/sink, photosynthesis/nitrogen fixation under lower plant densities. Higher photosynthesis and nitrogen fixation rates are capable of sustaining increased plant growth.

  6. Effects of tissue fixation and dehydration on tendon collagen nanostructure.

    Turunen, Mikael J; Khayyeri, Hanifeh; Guizar-Sicairos, Manuel; Isaksson, Hanna

    2017-09-01

    Collagen is the most prominent protein in biological tissues. Tissue fixation is often required for preservation or sectioning of the tissue. This may affect collagen nanostructure and potentially provide incorrect information when analyzed after fixation. We aimed to unravel the effect of 1) ethanol and formalin fixation and 2) 24h air-dehydration on the organization and structure of collagen fibers at the nano-scale using small and wide angle X-ray scattering. Samples were divided into 4 groups: ethanol fixed, formalin fixed, and two untreated sample groups. Samples were allowed to air-dehydrate in handmade Kapton pockets during the measurements (24h) except for one untreated group. Ethanol fixation affected the collagen organization and nanostructure substantially and during 24h of dehydration dramatic changes were evident. Formalin fixation had minor effects on the collagen organization but after 12h of air-dehydration the spatial variation increased substantially, not evident in the untreated samples. Generally, collagen shrinkage and loss of alignment was evident in all samples during 24h of dehydration but the changes were subtle in all groups except the ethanol fixed samples. This study shows that tissue fixation needs to be chosen carefully in order to preserve the features of interest in the tissue. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Fractures of the proximal fifth metatarsal: percutaneous bicortical fixation.

    Mahajan, Vivek; Chung, Hyun Wook; Suh, Jin Soo

    2011-06-01

    Displaced intraarticular zone I and displaced zone II fractures of the proximal fifth metatarsal bone are frequently complicated by delayed nonunion due to a vascular watershed. Many complications have been reported with the commonly used intramedullary screw fixation for these fractures. The optimal surgical procedure for these fractures has not been determined. All these observations led us to evaluate the effectiveness of percutaneous bicortical screw fixation for treating these fractures. Twenty-three fractures were operatively treated by bicortical screw fixation. All the fractures were evaluated both clinically and radiologically for the healing. All the patients were followed at 2 or 3 week intervals till fracture union. The patients were followed for an average of 22.5 months. Twenty-three fractures healed uneventfully following bicortical fixation, with a mean healing time of 6.3 weeks (range, 4 to 10 weeks). The average American Orthopaedic Foot & Ankle Society (AOFAS) score was 94 (range, 90 to 99). All the patients reported no pain at rest or during athletic activity. We removed the implant in all cases at a mean of 23.2 weeks (range, 18 to 32 weeks). There was no refracture in any of our cases. The current study shows the effectiveness of bicortical screw fixation for displaced intraarticular zone I fractures and displaced zone II fractures. We recommend it as one of the useful techniques for fixation of displaced zone I and II fractures.

  8. Geochemical fixation of carbon dioxide in the environment. Chikyu kagakuteki kenchi kara no tansan'en ni yoru nisanka tanso no kotei

    Ishikawa, M [Mitsubishi Research Institute, Inc., Tokyo (Japan)

    1993-06-15

    The Mitsubishi Research Institute has investigated and discussed the current situation and the future direction of the studies on geochemical fixation of carbon dioxide by means of carbonates. This paper summarizes the results thereof. The discussion items are listed as follows: The current status of land areas active in carbonate fixation (lake-bottom deposits, sabkha, dry areas, carbonate rock areas); investigation on sea areas active in carbonate fixation (coral reef areas, land shelf areas, open sea areas, and mantle); development of environmental change analyzing technologies (measurement of ancient environments, measurement of fixation ages, development of local area analysis, measurement of diagenetic structures, origin and behavior of trace elements in carbonate substances, and measurement of the current environments); evaluation on fixation ability of carbon sinks (circulation and fixation in coral reef ecosystems, calcification mechanisms in calcareous algae, dissolution processes at ocean bottoms, and inorganic chemical measurement); and investigation on simulation models (solution chemistry equilibrium model and global carbonate circulation model). 4 refs., 1 tab.

  9. Evaluation of functional outcome of pilon fractures managed with limited internal fixation and external fixation: A prospective clinical study.

    Meena, Umesh Kumar; Bansal, Mahesh Chand; Behera, Prateek; Upadhyay, Rahul; Gothwal, Gyan Chand

    2017-11-01

    The management of pilon fractures is controversial primarily due to the high rate of complications irrespective of the mode of treatment. Limited internal fixation with external fixation is associated with minimal soft tissue handling. This may reduce the chances of wound dehiscence and infection. This study was designed to evaluate the functional and clinical outcomes in patients treated with limited internal fixation combined with external fixation in pilon fractures. This study was conducted as a prospective clinical study on 56 skeletally mature patients with closed fractures with poor skin condition, and with open grade 1 and grade 2 distal tibial intra-articular fractures. All patients were treated with combined limited internal fixation and ankle spanning external fixation. All fractures in this series united with an average time period of union of 18.3weeks (ranging from 13 weeks to 30 weeks). There was no non-union in any case. There was malunion in 4 cases, varus malunion (>5 degree) in 2 cases and recurvatum in another 2 cases). Excellent to good functional results were observed in 88% cases based on the modified Ovadia and Beals score. The mean ankle dorsiflexion and planter flexion movements were 10.2±5.3 degrees and 27.4±7.2 degrees respectively. infections occurred in 6 patients which included 4 pin tract infections and 2 superficial wound infection, all 6 healed after removal of pin tract and with oral antibiotics. The technique of combined external fixation with internal fixation is safe and effective management option for intra-articular distal tibial fractures.

  10. The importance of regulation of nitrogen fixation

    Menge, D. N.

    2012-12-01

    I am not a proponent of including more detail in models simply because it makes them more realistic. More complexity increases the difficulty of model interpretation, so it only makes sense to include complexity if its benefit exceeds its costs. Biological nitrogen (N) fixation (BNF) is one process for which I feel the benefits of including greater complexity far outweigh the costs. I don't think that just because I work on BNF; I work on BNF because I think that. BNF, a microbial process carried out by free-living and symbiotic microbes, is the dominant N input to many ecosystems, the primary mechanism by which N deficiency can feed back to N inputs, and a main mechanism by which N surplus can develop. The dynamics of BNF, therefore, have huge implications for the rate of carbon uptake and the extent of CO2 fertilization, as well as N export to waterways and N2O emissions to the atmosphere. Unfortunately, there are serious deficiencies in our understanding of BNF. One main deficiency in our understanding is the extent to which various symbiotic N fixing organisms respond to imbalanced nutrition. Theory suggests that these responses, which I will call "strategies," have fundamental consequences for N fixer niches and ecosystem-level N and C cycling. Organisms that fix N regardless of whether they need it, a strategy that I will call "obligate," occupy post-disturbance niches and rapidly lead to N surplus. On the contrary, organisms that only fix as much N as they need, a "facultative" strategy, can occupy a wider range of successional niches, do not produce surplus N, and respond more rapidly to increased atmospheric CO2. In this talk I will show new results showing that consideration of these strategies could on its own explain the latitudinal distribution of symbiotic N fixing trees in North America. Specifically, the transition in N-fixing tree abundance from ~10% of basal area south of 35° latitude to ~1% of basal area north of 35° latitude that we observe

  11. Comparison of Monolateral External Fixation and Internal Fixation for Skeletal Stabilisation in the Management of Small Tibial Bone Defects following Successful Treatment of Chronic Osteomyelitis.

    Wang, Yicun; Jiang, Hui; Deng, Zhantao; Jin, Jiewen; Meng, Jia; Wang, Jun; Zhao, Jianning; Sun, Guojing; Qian, Hongbo

    2017-01-01

    To compare the salvage rate and complication between internal fixation and external fixation in patients with small bone defects caused by chronic infectious osteomyelitis debridement. 125 patients with chronic infectious osteomyelitis of tibia fracture who underwent multiple irrigation, debridement procedure, and local/systemic antibiotics were enrolled. Bone defects, which were less than 4 cm, were treated with bone grafting using either internal fixation or monolateral external fixation. 12-month follow-up was conducted with an interval of 3 months to evaluate union of bone defect. Patients who underwent monolateral external fixation had higher body mass index and fasting blood glucose, longer time since injury, and larger bone defect compared with internal fixation. No significant difference was observed in incidence of complications (23.5% versus 19.3%), surgery time (156 ± 23 minutes versus 162 ± 21 minutes), and time to union (11.1 ± 3.0 months versus 10.9 ± 3.1 months) between external fixation and internal fixation. Internal fixation had no significant influence on the occurrence of postoperation complications after multivariate adjustment when compared with external fixation. Furthermore, patients who underwent internal fixation experienced higher level of daily living scales and lower level of anxiety. It was relatively safe to use internal fixation for stabilization in osteomyelitis patients whose bone defects were less than 4 cm and infection was well controlled.

  12. The emergence and early evolution of biological carbon-fixation.

    Braakman, Rogier; Smith, Eric

    2012-01-01

    The fixation of CO₂ into living matter sustains all life on Earth, and embeds the biosphere within geochemistry. The six known chemical pathways used by extant organisms for this function are recognized to have overlaps, but their evolution is incompletely understood. Here we reconstruct the complete early evolutionary history of biological carbon-fixation, relating all modern pathways to a single ancestral form. We find that innovations in carbon-fixation were the foundation for most major early divergences in the tree of life. These findings are based on a novel method that fully integrates metabolic and phylogenetic constraints. Comparing gene-profiles across the metabolic cores of deep-branching organisms and requiring that they are capable of synthesizing all their biomass components leads to the surprising conclusion that the most common form for deep-branching autotrophic carbon-fixation combines two disconnected sub-networks, each supplying carbon to distinct biomass components. One of these is a linear folate-based pathway of CO₂ reduction previously only recognized as a fixation route in the complete Wood-Ljungdahl pathway, but which more generally may exclude the final step of synthesizing acetyl-CoA. Using metabolic constraints we then reconstruct a "phylometabolic" tree with a high degree of parsimony that traces the evolution of complete carbon-fixation pathways, and has a clear structure down to the root. This tree requires few instances of lateral gene transfer or convergence, and instead suggests a simple evolutionary dynamic in which all divergences have primary environmental causes. Energy optimization and oxygen toxicity are the two strongest forces of selection. The root of this tree combines the reductive citric acid cycle and the Wood-Ljungdahl pathway into a single connected network. This linked network lacks the selective optimization of modern fixation pathways but its redundancy leads to a more robust topology, making it more

  13. The emergence and early evolution of biological carbon-fixation.

    Rogier Braakman

    Full Text Available The fixation of CO₂ into living matter sustains all life on Earth, and embeds the biosphere within geochemistry. The six known chemical pathways used by extant organisms for this function are recognized to have overlaps, but their evolution is incompletely understood. Here we reconstruct the complete early evolutionary history of biological carbon-fixation, relating all modern pathways to a single ancestral form. We find that innovations in carbon-fixation were the foundation for most major early divergences in the tree of life. These findings are based on a novel method that fully integrates metabolic and phylogenetic constraints. Comparing gene-profiles across the metabolic cores of deep-branching organisms and requiring that they are capable of synthesizing all their biomass components leads to the surprising conclusion that the most common form for deep-branching autotrophic carbon-fixation combines two disconnected sub-networks, each supplying carbon to distinct biomass components. One of these is a linear folate-based pathway of CO₂ reduction previously only recognized as a fixation route in the complete Wood-Ljungdahl pathway, but which more generally may exclude the final step of synthesizing acetyl-CoA. Using metabolic constraints we then reconstruct a "phylometabolic" tree with a high degree of parsimony that traces the evolution of complete carbon-fixation pathways, and has a clear structure down to the root. This tree requires few instances of lateral gene transfer or convergence, and instead suggests a simple evolutionary dynamic in which all divergences have primary environmental causes. Energy optimization and oxygen toxicity are the two strongest forces of selection. The root of this tree combines the reductive citric acid cycle and the Wood-Ljungdahl pathway into a single connected network. This linked network lacks the selective optimization of modern fixation pathways but its redundancy leads to a more robust topology

  14. Reduction and temporary stabilization of Tile C pelvic ring injuries using a posteriorly based external fixation system.

    Martin, Murphy P; Rojas, David; Mauffrey, Cyril

    2017-12-05

    Tile C pelvic ring injuries are challenging to manage even in the most experienced hands. The majority of such injuries can be managed using percutaneous reduction techniques, and the posterior ring can be stabilized using percutaneous transiliac-transsacral screw fixation. However, a subgroup of patients present with inadequate bony corridors, significant sacral zone 2 comminution or significant lateral/vertical displacement of the hemipelvis through a complete sacral fracture. Percutaneous strategies in such circumstances can be dangerous. Those patients may benefit from prone positioning and open reduction of the sacral fracture with fixation through tension band plating or lumbo-pelvic fixation. Soft tissue handling is critical, and direct reduction techniques around the sacrum can be difficult due to the complex anatomy and the fragile nature of the sacrum making clamp placement and tightening a challenge. In this paper, we propose a mini-invasive technique of indirect reduction and temporary stabilization, which is soft tissue friendly and permits maintenance of reduction during definitive fixation surgical.

  15. Dosimetric evaluation of using in-house BoS Frame Fixation Tool for the Head and Neck Cancer Patient

    Kim, Kwang Suk; Jo, Kwang Hyun; Choi, Byeon Ki

    2016-01-01

    BoS(Base of Skull) Frame, the fixation tool which is used for the proton of brain cancer increases the lateral penumbra by increasing the airgap (the distance between patient and beam jet), due to the collision of the beam of the posterior oblique direction. Thus, we manufactured the fixation tool per se for improving the limits of BoS frame, and we'd like to evaluate the utility of the manufactured fixation tool throughout this study. We've selected the 3 patients of brain cancer who have received the proton therapy from our hospital, and also selected the 6 beam angles; for this, we've selected the beam angle of the posterior oblique direction. We've measured the planned BoS frame and the distance of Snout for each beam which are planned for the treatment of the patient using the BoS frame. After this, we've proceeded with the set-up that is above the location which was recommended by the manufacturer of the BoS frame, at the same beam angle of the same patient, by using our in-house Bos frame fixation tool. The set-up was above 21 cm toward the superior direction, compared to the situation when the BoS frame was only used with the basic couch. After that, we've stacked the snout to the BoS frame as much as possible, and measured the distance of snout. We've also measured the airgap, based on the gap of that snout distance; and we've proceeded the normalization based on each dose (100% of each dose), after that, we've conducted the comparative analysis of lateral penumbra. Moreover, we've established the treatment plan according to the changed airgap which has been transformed to the Raystation 5.0 proton therapy planning system, and we've conducted the comparative analysis of DVH(Dose Volume Histogram). When comparing the result before using the in-house Bos frame fixation tool which was manufactured for each beam angle with the result after using the fixation tool, we could figure out that airgap than when not used in accordance with the use of the in-house Bos

  16. Dosimetric evaluation of using in-house BoS Frame Fixation Tool for the Head and Neck Cancer Patient

    Kim, Kwang Suk; Jo, Kwang Hyun; Choi, Byeon Ki [Dept. of Radiation Oncology, Samsung Seoul Hospital, Seoul (Korea, Republic of)

    2016-06-15

    BoS(Base of Skull) Frame, the fixation tool which is used for the proton of brain cancer increases the lateral penumbra by increasing the airgap (the distance between patient and beam jet), due to the collision of the beam of the posterior oblique direction. Thus, we manufactured the fixation tool per se for improving the limits of BoS frame, and we'd like to evaluate the utility of the manufactured fixation tool throughout this study. We've selected the 3 patients of brain cancer who have received the proton therapy from our hospital, and also selected the 6 beam angles; for this, we've selected the beam angle of the posterior oblique direction. We've measured the planned BoS frame and the distance of Snout for each beam which are planned for the treatment of the patient using the BoS frame. After this, we've proceeded with the set-up that is above the location which was recommended by the manufacturer of the BoS frame, at the same beam angle of the same patient, by using our in-house Bos frame fixation tool. The set-up was above 21 cm toward the superior direction, compared to the situation when the BoS frame was only used with the basic couch. After that, we've stacked the snout to the BoS frame as much as possible, and measured the distance of snout. We've also measured the airgap, based on the gap of that snout distance; and we've proceeded the normalization based on each dose (100% of each dose), after that, we've conducted the comparative analysis of lateral penumbra. Moreover, we've established the treatment plan according to the changed airgap which has been transformed to the Raystation 5.0 proton therapy planning system, and we've conducted the comparative analysis of DVH(Dose Volume Histogram). When comparing the result before using the in-house Bos frame fixation tool which was manufactured for each beam angle with the result after using the fixation tool, we could figure out that airgap than when

  17. Insertion and fixation of fiducial markers for setup and tracking of lung tumors in radiotherapy

    Imura, Mikado; Yamazaki, Koichi; Shirato, Hiroki; Onimaru, Rikiya; Fujino, Masaharu; Shimizu, Shinichi; Harada, Toshiyuki; Ogura, Shigeaki; Dosaka-Akita, Hirotoshi; Miyasaka, Kazuo; Nishimura, Masaharu

    2005-01-01

    Purpose: Internal 1.5-mm fiducial markers were used in real-time tumor-tracking radiotherapy (RT) for lung cancer. The fixation rate of the markers using the bronchial insertion technique, reliability of the setup using markers around the target volume, dislocation of the markers after real-time tumor-tracking RT, and long-term toxicity of marker insertion were investigated. Methods and Materials: Between July 2000 and April 2004, 154 gold markers were inserted into 57 patients with peripheral lung cancer. The distances between the implanted markers in 198 measurements in 71 setups in 11 patients were measured using two sets of orthogonal diagnostic X-ray images of the real-time tumor-tracking RT system. The distance between the markers and the chest wall was also measured in a transaxial CT image on 186 occasions in 48 patients during treatment planning and during follow-up. The median treatment time was 6 days (range, 4-14 days). Results: In 115 (75%) of the 154 inserted markers, the gold marker was detected throughout the treatment period. In 122 markers detected at CT planning, 115 (94%) were detected until the end of treatment. The variation in the distances between the implanted markers was within ±2 mm in 95% and ±1 mm in 80% during treatment. The variation in the distances between the implanted markers was >2 mm in at least one direction in 9% of the setups for which reexamination with a CT scan was indicated. The fixation rate in the left upper lobe was lower than in the other lobes. A statistically significant relationship was found between a shorter distance between the markers and the chest wall and the fixation rate, suggesting that the markers in the smaller bronchial lumens fixed better than those in the larger lumens. A learning curve among the endoscopists was suggested in the fixation rate. The distance between the markers and the chest wall changed significantly within a median of 44 days (range, 16-181 days) after treatment. Conclusion: The

  18. Optimizing pediatric interdental fixation by use of a paramedian palatal fixation site.

    McNichols, Colton H; Hatef, Daniel A; Cole, Patrick D; Hollier, Larry H

    2012-03-01

    Condylar fractures are the most common injury seen in pediatric mandibular trauma. These injuries often cannot be adequately stabilized by conservative techniques such as splinting. The pediatric condyle fracture often requires a period of intermaxillary fixation. Because of the characteristics of the developing dentition, circumdental wiring is often not possible. Surgeons commonly achieve interdental stabilization by the connection of a circum-mandibular wire and a second wire placed through a drill hole in the piriform aperture. This method can be problematic in the young patient whose palatal suture is still patent. In this brief technical note, the use of a paramedian drill hole through the palate posterior to the maxillary incisors is described. It is believed that this method is superior to other techniques because it avoids injury to the deciduous tooth buds and allows for the maxillary wire to be seated in more structurally sound tissues.

  19. [Staple fixation for the treatment of hamate metacarpal joint injury].

    Tang, Yang-Hua; Zeng, Lin-Ru; Huang, Zhong-Ming; Yue, Zhen-Shuang; Xin, Da-Wei; Xu, Can-Da

    2014-03-01

    To investigate the effcacy of the staple fixation for the treatment of hamate metacarpal joint injury. From May 2009 to November 2012,16 patients with hamate metacarpal joint injury were treated with staple fixation including 10 males and 6 females with an average age of 33.6 years old ranging from 21 to 57 years. Among them, 11 cases were on the fourth or fifth metacarpal base dislocation without fractures, 5 cases were the fourth or fifth metacarpal base dislocation with avulsion fractures of the back of hamatum. Regular X-ray review was used to observe the fracture healing, joint replacement and position of staple fixation. The function of carpometacarpal joint and metacarpophalangeal joint were evaluated according to ASIA (TAM) system evaluation method. All incision were healed well with no infection. All patients were followed up from 16 to 24 months with an average of (10.0 +/- 2.7) months. No dislocation recurred, the position of internal fixator was good,no broken nail and screw withdrawal were occurred. Five patients with avulsion fracture of the back of hamatum achieved bone healing. The function of carpometacarpal joint and metacarpophalangeal was excellent in 10 cases,good in 5 cases, moderate in 1 case. The application of the staple for the treatment of hamatometacarpal joint injury has the advantages of simple operation, small trauma, reliable fixation, early postoperative function exercise and other advantages, which is the ideal operation mode for hamatometacarpal joint injury.

  20. Relative strength of tailor's bunion osteotomies and fixation techniques.

    Haddon, Todd B; LaPointe, Stephan J

    2013-01-01

    A paucity of data is available on the mechanical strength of fifth metatarsal osteotomies. The present study was designed to provide that information. Five osteotomies were mechanically tested to failure using a materials testing machine and compared with an intact fifth metatarsal using a hollow saw bone model with a sample size of 10 for each construct. The osteotomies tested were the distal reverse chevron fixated with a Kirschner wire, the long plantar reverse chevron osteotomy fixated with 2 screws, a mid-diaphyseal sagittal plane osteotomy fixated with 2 screws, the mid-diaphyseal sagittal plane osteotomy fixated with 2 screws, and an additional cerclage wire and a transverse closing wedge osteotomy fixated with a box wire technique. Analysis of variance was performed, resulting in a statistically significant difference among the data at p chevron was statistically the strongest construct at 130 N, followed by the long plantar osteotomy at 78 N. The chevron compared well with the control at 114 N, and they both fractured at the proximal model to fixture interface. The other osteotomies were statistically and significantly weaker than both the chevron and the long plantar constructs, with no statistically significant difference among them at 36, 39, and 48 N. In conclusion, the chevron osteotomy was superior in strength to the sagittal and transverse plane osteotomies and similar in strength and failure to the intact model. Copyright © 2013 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  1. Comparison of cemented and uncemented fixation in total knee arthroplasty.

    Brown, Thomas E; Harper, Benjamin L; Bjorgul, Kristian

    2013-05-01

    As a result of reading this article, physicians should be able to :1. Understand the rationale behind using uncemented fixation in total knee arthroplasty.2.Discuss the current literature comparing cemented and uncemented total knee arthroplasty3. Describe the value of radiostereographic analysis in assessing implant stability.4. Appreciate the limitations in the available literature advocating 1 mode of fixation in total knee arthroplasty. Total knee arthroplasty performed worldwide uses either cemented, cementless, or hybrid (cementless femur with a cemented tibia) fixation of the components. No recent literature review concerning the outcomes of cemented vs noncemented components has been performed. Noncemented components offer the potential advantage of a biologic interface between the bone and implants, which could demonstrate the greatest advantage in long-term durable fixation in the follow-up of young patients undergoing arthroplasty. Several advances have been made in the backing of the tibial components that have not been available long enough to yield long-term comparative follow-up studies. Short-term radiostereographic analysis studies have yielded differing results. Although long-term, high-quality studies are still needed, material advances in biologic fixation surfaces, such as trabecular metal and hydroxyapatite, may offer promising results for young and active patients undergoing total knee arthroplasty when compared with traditional cemented options. Copyright 2013, SLACK Incorporated.

  2. Immunohistochemistry of colorectal cancer biomarker phosphorylation requires controlled tissue fixation.

    Abbey P Theiss

    Full Text Available Phosphorylated signaling molecules are biomarkers of cancer pathophysiology and resistance to therapy, but because phosphoprotein analytes are often labile, poorly controlled clinical laboratory practices could prevent translation of research findings in this area from the bench to the bedside. We therefore compared multiple biomarker and phosphoprotein immunohistochemistry (IHC results in 23 clinical colorectal carcinoma samples after either a novel, rapid tissue fixation protocol or a standard tissue fixation protocol employed by clinical laboratories, and we also investigated the effect of a defined post-operative "cold" ischemia period on these IHC results. We found that a one-hour cold ischemia interval, allowed by ASCO/CAP guidelines for certain cancer biomarker assays, is highly deleterious to certain phosphoprotein analytes, specifically the phosphorylated epidermal growth factor receptor (pEGFR, but shorter ischemic intervals (less than 17 minutes facilitate preservation of phosphoproteins. Second, we found that a rapid 4-hour, two temperature, formalin fixation yielded superior staining in several cases with select markers (pEGFR, pBAD, pAKT compared to a standard overnight room temperature fixation protocol, despite taking less time. These findings indicate that the future research and clinical utilities of phosphoprotein IHC for assessing colorectal carcinoma pathophysiology absolutely depend upon attention to preanalytical factors and rigorously controlled tissue fixation protocols.

  3. Fixation Probability in a Haploid-Diploid Population.

    Bessho, Kazuhiro; Otto, Sarah P

    2017-01-01

    Classical population genetic theory generally assumes either a fully haploid or fully diploid life cycle. However, many organisms exhibit more complex life cycles, with both free-living haploid and diploid stages. Here we ask what the probability of fixation is for selected alleles in organisms with haploid-diploid life cycles. We develop a genetic model that considers the population dynamics using both the Moran model and Wright-Fisher model. Applying a branching process approximation, we obtain an accurate fixation probability assuming that the population is large and the net effect of the mutation is beneficial. We also find the diffusion approximation for the fixation probability, which is accurate even in small populations and for deleterious alleles, as long as selection is weak. These fixation probabilities from branching process and diffusion approximations are similar when selection is weak for beneficial mutations that are not fully recessive. In many cases, particularly when one phase predominates, the fixation probability differs substantially for haploid-diploid organisms compared to either fully haploid or diploid species. Copyright © 2017 by the Genetics Society of America.

  4. Fixation orientation in ankle fractures with syndesmosis injury.

    Nimick, Craig J; Collman, David R; Lagaay, Pieter

    2013-01-01

    Accurate reduction of the syndesmosis has been shown to be an important prognostic factor for functional outcome in ankle injuries that disrupt the syndesmosis. The purpose of the present case series was to assess the fixation orientation and the position of the fibula within the tibial incisura after open reduction and internal fixation of ankle fractures with syndesmosis injury. Computed tomography was used to assess the accuracy of the reduction. Twelve patients were included in the present case series. A ratio representing the relationship between the tibia and fibula and the orientation of the syndesmotic fixation was measured preoperatively and postoperatively and compared with the uninjured contralateral ankle, representing the patient's normal anatomy. The measurements were accomplished electronically to one tenth of 1 mm using Stentor Intelligent Informatics, I-site, version 3.3.1 (Phillips Electronics; Andover, MA). Posteriorly oriented syndesmotic fixation caused posterior translation of the fibula with respect to the tibia and anteriorly oriented syndesmotic fixation caused anterior translation. Copyright © 2013. Published by Elsevier Inc.

  5. New insights into the evolutionary history of biological nitrogen fixation

    Eric eBoyd

    2013-08-01

    Full Text Available Nitrogenase, which catalyzes the ATP-dependent reduction of dinitrogen (N2 to ammonia (NH3, accounts for roughly half of the bioavailable nitrogen supporting extant life. The fundamental requirement for fixed forms of nitrogen for life on Earth, both at present and in the past, has led to broad and significant interest in the origin and evolution of this fundamental biological process. One key question is whether the limited availability of fixed nitrogen was a factor in life’s origin or whether there were ample sources of fixed nitrogen produced by abiotic processes or delivered through the weathering of bolide impact materials to support this early life. If the latter, the key questions become what were the characteristics of the environment that precipitated the evolution of this oxygen sensitive process, when did this occur, and how was its subsequent evolutionary history impacted by the advent of oxygenic photosynthesis and the rise of oxygen in the Earth’s biosphere. Since the availability of fixed sources of nitrogen capable of supporting early life is difficult to glean from the geologic record, there are limited means to get direct insights into these questions. Indirect insights, however, can be gained by deep phylogenetic studies of nitrogenase structural gene products and additional gene products involved in the biosynthesis of the complex metal-containing prosthetic groups associated with this enzyme complex. Insights gained from such studies, as reviewed herein, challenge traditional models for the evolution of biological nitrogen fixation and provide the basis for the development of new conceptual models that explain the stepwise evolution of this highly complex and life sustaining process.

  6. Chromate reduction and heavy metal fixation in soil

    Schwitzgebel, K.

    1992-06-01

    In situ reduction of chromates and the fixation of the metals Cr, Pb, Zn, Cu, Cd and Ni in soil was investigated using Fe II and soluble silica. Fe II fulfills two functions. It reduces chromates (CrVI) at soil pH to CrIII and the reaction products, Fe(OH) 3 and Cr(OH) 3 , coprecipitate/adsorb heavy metals. In the absence of CrVI iron is added as FeIII. Destabilized silica also fulfills two functions. It reacts with the metal and metal hydroxides and reduces the soil permeability. The leaching rate (mg/m 2 s) of a metal is the product of leachate flow rate (ell/M 2 s) and the leachate concentration (mg/ell). The leachate flow rate is directly proportional to the hydraulic coefficient (Darcy's Law). Treatment with destabilized silica reduces the hydraulic coefficient of virgin soil (K h = 10 -2 ...10 -4 ) to K h =10 -7 (cm/s) resulting in a flow rate reduction of 3--5 orders of magnitude. Iron plus silica treatment results in a leachate concentration reduction of up to 2 orders of magnitude (Cr:95--99%;Pb:99%;Zn 95--99%; Cd:93--99%; Ni:75--94%). Combined effect of flow rate reduction and leachate concentration reduction results in a potential leaching rate reduction of five to seven orders of magnitude. Iron-silica treatment may be developed into an efficient containment technology, provided the silica gel integrity does not change with time

  7. Pediatric mandibular fractures treated by rigid internal fixation.

    Wong, G B

    1993-09-01

    Mandibular fractures in the pediatric patient population are relatively uncommon. These patients present with their own unique treatment requirements. Most fractures have been treated conservatively by dental splints. Closed reduction techniques with maxillomandibular fixation (MMF) in very young children can pose several concerns, including cooperation, compliance and adequate nutritional intake. Rigid internal fixation of unstable mandibular fractures using miniplates and screws circumvents the need for MMF and allows immediate jaw mobilization. At major pediatric trauma institutions, there has been an increasing trend toward the use of this treatment when open reduction is necessary. This article presents a report of a five-year-old child who presented with bilateral mandibular fractures and was treated by rigid internal fixation and immediate mandibular mobilization.

  8. Operative Fixation of Rib Fractures Indications, Techniques, and Outcomes.

    Galos, David; Taylor, Benjamin; McLaurin, Toni

    2017-01-01

    Rib fractures are extremely common injuries and vary in there severity from single nondisplaced fractures to multiple segmental fractures resulting in flail chest and respiratory compromise. Historically, rib fractures have been treated conservatively with pain control and respiratory therapy. However this method may not be the best treatment modality in all situations. Operative fixation of select rib fractures has been increasing in popularity especially in patients with flail chest and respiratory compromise. Newer techniques use muscle sparing approaches and precontoured locking plate technology to obtain stable fixation and allow improved respiration. Current reports shows that rib fracture fixation offers the benefits of improved respiratory mechanics and improved pain control in the severe chest wall injury with resultant improvement in patient outcomes by decreasing time on the ventilator, time in the intensive care unit, and overall hospital length of stay.

  9. Single absorbable polydioxanone pin fixation for distal chevron bunion osteotomies.

    Deorio, J K; Ware, A W

    2001-10-01

    The distal chevron osteotomy is a well-established technique for correction of symptomatic mild to moderate metatarsus primus varus with hallux valgus deformity. Fixation of the osteotomy ranges from none to bone pegs, Kirschner wires, screws, or absorbable pins. We evaluated one surgeon's (J.K.D.) results of distal chevron osteotomy fixation with a single, nonpredrilled, 1.3-mm poly-p-dioxanone pin and analyzed any differences in patients with unilateral or bilateral symptomatic metatarsus primus varus with hallux valgus deformities. All osteotomies healed without evidence of infection, osteolysis, nonunion, or necrosis. Equal correction was achieved in unilateral and bilateral procedures. The technique is quick and easy, and adequate fixation is achieved.

  10. Can we improve fixation and outcomes? Use of bone substitutes.

    Moroni, Antonio; Larsson, Sune; Hoang Kim, Amy; Gelsomini, Letizia; Giannoudis, Peter V

    2009-07-01

    Hip fractures secondary to osteoporosis are common in the elderly. Stabilizing these fractures until union is achieved is a challenge due to poor bone stock and insufficient purchase of the implant to the bone. The reported high rate of complications has prompted extensive research in the development of fixation techniques. Furthermore, manipulation of both the local fracture environment in terms of application of growth factors, scaffolds, and mesenchymal cells and the systemic administration of agents promoting bone formation and bone strength has been considered as a treatment option with promising results. There are only a few evidence-based studies reporting on fixation augmentation techniques. This article reports on the efficacy of bone graft substitutes for the fixation of hip fractures, in particular calcium phosphates, which have been used as granules, cements, and implant coatings.

  11. How Life History Can Sway the Fixation Probability of Mutants

    Li, Xiang-Yi; Kurokawa, Shun; Giaimo, Stefano; Traulsen, Arne

    2016-01-01

    In this work, we study the effects of demographic structure on evolutionary dynamics when selection acts on reproduction, survival, or both. In contrast to the previously discovered pattern that the fixation probability of a neutral mutant decreases while the population becomes younger, we show that a mutant with a constant selective advantage may have a maximum or a minimum of the fixation probability in populations with an intermediate fraction of young individuals. This highlights the importance of life history and demographic structure in studying evolutionary dynamics. We also illustrate the fundamental differences between selection on reproduction and selection on survival when age structure is present. In addition, we evaluate the relative importance of size and structure of the population in determining the fixation probability of the mutant. Our work lays the foundation for also studying density- and frequency-dependent effects in populations when demographic structures cannot be neglected. PMID:27129737

  12. Photosynthetic and nitrogen fixation capability in several soybean mutant lines

    Gandanegara, S.; Hendratno, K.

    1987-01-01

    Photosynthetic and nitrogen fixation capability in several soybean mutant lines. A greenhouse experiment has been carried out to study photosynthetic and nitrogen fixation capability of five mutant lines and two soybean varieties. An amount of 330 uCi of 14 CO 2 was fed to the plants including of the non-fixing reference crop (Chippewa non-nodulating isoline). Nitrogen fixation measurements was carried out using 15 N isotope dilution technique according to A-value concept. Results showed that beside variety/mutant lines, plant growth also has important role in photosynthetic and N fixing capability. Better growth and a higher photosynthetic capability in Orba, mutant lines nos. 63 and 65 resulted in a greater amount of N 2 fixed (mg N/plant) than other mutant lines. (author). 12 refs.; 5 figs

  13. Biomechanical Strength of Retrograde Fixation in Proximal Third Scaphoid Fractures.

    Daly, Charles A; Boden, Allison L; Hutton, William C; Gottschalk, Michael B

    2018-04-01

    Current techniques for fixation of proximal pole scaphoid fractures utilize antegrade fixation via a dorsal approach endangering the delicate vascular supply of the dorsal scaphoid. Volar and dorsal approaches demonstrate equivalent clinical outcomes in scaphoid wrist fractures, but no study has evaluated the biomechanical strength for fractures of the proximal pole. This study compares biomechanical strength of antegrade and retrograde fixation for fractures of the proximal pole of the scaphoid. A simulated proximal pole scaphoid fracture was produced in 22 matched cadaveric scaphoids, which were then assigned randomly to either antegrade or retrograde fixation with a cannulated headless compression screw. Cyclic loading and load to failure testing were performed and screw length, number of cycles, and maximum load sustained were recorded. There were no significant differences in average screw length (25.5 mm vs 25.6 mm, P = .934), average number of cyclic loading cycles (3738 vs 3847, P = .552), average load to failure (348 N vs 371 N, P = .357), and number of catastrophic failures observed between the antegrade and retrograde fixation groups (3 in each). Practical equivalence between the 2 groups was calculated and the 2 groups were demonstrated to be practically equivalent (upper threshold P = .010). For this model of proximal pole scaphoid wrist fractures, antegrade and retrograde screw configuration have been proven to be equivalent in terms of biomechanical strength. With further clinical study, we hope surgeons will be able to make their decision for fixation technique based on approaches to bone grafting, concern for tenuous blood supply, and surgeon preference without fear of poor biomechanical properties.

  14. Dependence of carbon dioxide concentration on microalgal carbon dioxide fixation

    Yun, Yeoung Sang; Park, Song Moon [Department of Chemical Engineering, School of Environmental Engineering, Pohang University of Science and Technology, Pohang (Korea); Bolesky, Bohumil [Department of Chemical Engineering, McGill University (Canada)

    1999-10-01

    Batch cultivation of chlorella vulgaris was carried out under various CO{sub 2} concentrations in order to understand and describe mathematically the CO{sub 2} inhibition of microalgal CO{sub 2} fixation. The volumetric CO{sub 2} transfer coefficient from mixture gas to culture medium was estimated from the volumetric O{sub 2} transfer coefficient obtained experimentally. Using this transfer coefficient and aquatic equilibrium relationship between dissolved inorganic carbons, the behavior of dissolved CO{sub 2} was calculated during microalgal culture. When air containing 0.035%(v/v) CO{sub 2} was supplied into microalgal culture, the fixation rate was limited by CO{sub 2} transfer rate. However, the limitation was disappeared by supplying mixture gas containing above 2%(v/v) CO{sub 2} and the dissolved CO{sub 2} concentration was maintained at the saturated value. In the range of CO{sub 2} partial pressure in the flue gases from thermal power sations and steel-making plants, the microalgal CO{sub 2} fixation rate was inhibited. The CO{sub 2} fixation rate was successfully formulated by a new empirical equation as a function of dissolved CO{sub 2} concentration, which could be useful for modeling and simulating the performance of photobioreaction with enriched CO{sub 2}. Also, it was found that the CO{sub 2} inhibition of microalgal CO{sub 2} fixation was reversible and that microalgal CO{sub 2} fixation process could be stable against a shock of unusually high CO{sub 2} concentration. 29 refs., 8 figs.

  15. Internal fixation of mandibular angle fractures: a meta-analysis.

    Regev, Eran; Shiff, Jacob S; Kiss, Alex; Fialkov, Jeffrey A

    2010-06-01

    The degree of rigidity of internal fixation required for the treatment of mandibular angle fractures has long been at the center of debate in the literature. A statistical comparison between rigid fixation and monocortical fixation has been difficult because of multiple terms, definitions, and technical variations. The purpose of this study was to use the meta-analysis tool to combine information from multiple studies and to compare complication rates for different fixation methods. An English language literature search was conducted for articles on mandibular angle fractures. Information was collected on four variables of interest: compression/noncompression technique, monocortical/bicortical screws, number of plates, and location of plates. Five outcome rates were analyzed: infection, reoperation, hardware removal, malunion, and nonunion. Meta-analyses were run using Comprehensive Meta Analysis, version 2.2.03. Twenty-four studies with relevant data on the variables and outcomes of interest met the inclusion criteria. Significantly higher rates of infection, reoperation, and hardware removal were found for compression compared with noncompression, two plates compared with one plate, and for plates located on both the inferior and superior borders as compared with superior or inferior only. There were also significantly higher infection rates for bicortical screws compared with monocortical screws and higher malunion rates for compression compared with noncompression plating techniques. The results of this meta-analysis found lower complication rates with the use of noncompression, monocortical, and single-plate fixation, supporting the trend toward a single, superiorly placed, monocortical miniplate for fixation of mandibular angle fractures.

  16. Fixations on objects in natural scenes: dissociating importance from salience

    Bernard Marius e’t Hart

    2013-07-01

    Full Text Available The relation of selective attention to understanding of natural scenes has been subject to intense behavioral research and computational modeling, and gaze is often used as a proxy for such attention. The probability of an image region to be fixated typically correlates with its contrast. However, this relation does not imply a causal role of contrast. Rather, contrast may relate to an object’s importance for a scene, which in turn drives attention. Here we operationalize importance by the probability that an observer names the object as characteristic for a scene. We modify luminance contrast of either a frequently named (common/important or a rarely named (rare/unimportant object, track the observers’ eye movements during scene viewing and ask them to provide keywords describing the scene immediately after.When no object is modified relative to the background, important objects draw more fixations than unimportant ones. Increases of contrast make an object more likely to be fixated, irrespective of whether it was important for the original scene, while decreases in contrast have little effect on fixations. Any contrast modification makes originally unimportant objects more important for the scene. Finally, important objects are fixated more centrally than unimportant objects, irrespective of contrast.Our data suggest a dissociation between object importance (relevance for the scene and salience (relevance for attention. If an object obeys natural scene statistics, important objects are also salient. However, when natural scene statistics are violated, importance and salience are differentially affected. Object salience is modulated by the expectation about object properties (e.g., formed by context or gist, and importance by the violation of such expectations. In addition, the dependence of fixated locations within an object on the object’s importance suggests an analogy to the effects of word frequency on landing positions in reading.

  17. Preliminary experience with biodegradable implants for fracture fixation

    Dhillon Mandeep

    2008-01-01

    Full Text Available Background: Biodegradable implants were designed to overcome the disadvantages of metal-based internal fixation devices. Although they have been in use for four decades internationally, many surgeons in India continue to be skeptical about the mechanical strength of biodegradable implants, hence this study. Materials and Methods: A prospective study was done to assess the feasibility and surgeon confidence level with biodegradable implants over a 12-month period in an Indian hospital. Fifteen fractures (intra-articular, metaphyseal or small bone fractures were fixed with biodegradable implants. The surgeries were randomly scheduled so that different surgeons with different levels of experience could use the implants for fixation. Results: Three fractures (one humeral condyle, two capitulum, were supplemented by additional K-wires fixation. Trans-articular fixator was applied in two distal radius and two pilon fractures where bio-pins alone were used. All fractures united, but in two cases the fracture displaced partially during the healing phase; one fibula due to early walking, and one radius was deemed unstable even after bio-pin and external fixator. Conclusions: Biodegradable -implants are excellent for carefully selected cases of intra-articular fractures and some small bone fractures. However, limitations for use in long bone fractures persist and no great advantage is gained if a "hybrid" composite is employed. The mechanical properties of biopins and screws in isolation are perceived to be inferior to those of conventional metal implants, leading to low confidence levels regarding the stability of reduced fractures; these implants should be used predominantly in fracture patterns in which internal fixation is subjected to minimal stress.

  18. Biomechanical and morphometric evaluation of occipital condyle for occipitocervical segmental fixation

    Hong, Jae-Taek; Takigaya, Tomoyuki; Sugisaki, Keizo; Orias, A.A.E.; Inoue, Nozomu; An, H.S.

    2011-01-01

    Two recent novel techniques of occipital fixation are the occipitoatlantal (C0-C1) transarticular screw technique and the direct occipital condyle screw technique. The present study evaluated and compared the biomechanical stability of the direct occipital condyle screw and C0-C1 transarticular screw with the established method for craniocervical spine fixation using the midline occipital keel screw and C1 lateral mass screw. Morphometric evaluation of the occipital condyle and the hypoglossal canal was performed to avoid hypoglossal nerve injury during the screw placement. Thirteen recently frozen cadaveric specimens were used. The occipital condyle anatomy and the hypoglossal canal dimension were measured using reconstructed computed tomography images. Insertion torque and pullout strength were evaluated to compare the midline occipital keel screw, C0-C1 transarticular screw, C1 lateral mass screw, and direct occipital condyle screw. The dimensions of the occipital condyle allow use of a 3.5 or 4.0-mm diameter screw. Mean pullout strength was 1619.6 N for the midline occipital keel screw, 870.7 N for the C0-C1 transarticular screw, 707.0 N for the C1 lateral mass screw, and 431.7 N for the direct occipital condyle screw. Mean insertion torque was 0.55 Nm for the midline occipital keel screw, 0.32 Nm for the C0-C1 transarticular screw, 0.14 Nm for the C1 lateral mass screw, and 0.11 Nm for the direct occipital condyle screw. The condylar anatomy allows direct insertion of the occipital condyle screw and C0-C1 transarticular screw. These techniques are suitable options for the treatment of craniovertebral junction instabilities in selected patients. (author)

  19. Database of diazotrophs in global ocean: abundance, biomass and nitrogen fixation rates

    Y.-W. Luo

    2012-08-01

    Full Text Available Marine N2 fixing microorganisms, termed diazotrophs, are a key functional group in marine pelagic ecosystems. The biological fixation of dinitrogen (N2 to bioavailable nitrogen provides an important new source of nitrogen for pelagic marine ecosystems and influences primary productivity and organic matter export to the deep ocean. As one of a series of efforts to collect biomass and rates specific to different phytoplankton functional groups, we have constructed a database on diazotrophic organisms in the global pelagic upper ocean by compiling about 12 000 direct field measurements of cyanobacterial diazotroph abundances (based on microscopic cell counts or qPCR assays targeting the nifH genes and N2 fixation rates. Biomass conversion factors are estimated based on cell sizes to convert abundance data to diazotrophic biomass. The database is limited spatially, lacking large regions of the ocean especially in the Indian Ocean. The data are approximately log-normal distributed, and large variances exist in most sub-databases with non-zero values differing 5 to 8 orders of magnitude. Reporting the geometric mean and the range of one geometric standard error below and above the geometric mean, the pelagic N2 fixation rate in the global ocean is estimated to be 62 (52–73 Tg N yr−1 and the pelagic diazotrophic biomass in the global ocean is estimated to be 2.1 (1.4–3.1 Tg C from cell counts and to 89 (43–150 Tg C from nifH-based abundances. Reporting the arithmetic mean and one standard error instead, these three global estimates are 140 ± 9.2 Tg N yr−1, 18 ± 1.8 Tg C and 590 ± 70 Tg C, respectively. Uncertainties related to biomass conversion factors can change the estimate of geometric mean pelagic diazotrophic biomass in the global ocean by about ±70%. It was recently established that the most commonly applied method used to measure N2

  20. Soaking morselized allograft in bisphosphonate can impair implant fixation

    Jakobsen, Thomas; Baas, Jørgen; Bechtold, Joan E

    2007-01-01

    biomechanical implant fixation and graft incorporation. In 10 dogs, a pair of titanium implants surrounded by a 2.5-mm gap was inserted into the proximal part of each humerus during two separate surgeries to allow two observation periods. The gap was filled with impacted, morselized allograft soaked in either...... of implants was observed for 12 weeks and the second pair for 4 weeks. Implants were evaluated by histomorphometry and biomechanical pushout test. We found substantially decreased biomechanical implant fixation for all implants surrounded by impacted, morselized allograft that had been soaked in alendronate...

  1. [Usefullness of intrasacral fixation in an extremely unstable lumbosacral spine].

    Nishiura, Tsukasa; Nishiguchi, Mitsuhisa; Kusaka, Noboru; Takayama, Kazuhiro; Maeda, Yasuhiko; Ogihara, Kotaro; Nakagawa, Minoru

    2007-04-01

    Intrasacral fixation technique devised by Jackson is said to provide rigid lumbosacral fixation. We treated 3 cases of lumbosacral lesions using this technique in which lumbosacral segment had become extremely unstable during surgical intervention adding to the effect of original lesions. In all cases, surgeries were performed in 2 stages, intrasacral fixation and anterior stabilization. Case 1: A 52-year-old male was diagnosed fungal discitis and spondylitis at L4 and L5. X-ray showed destruction of the vertebral bodies. L2, L3 and sacrum were fixed posteriorly using the intrasacral fixation technique. One week after the first operation, L4 and L5 vertebral bodies were replaced by long fibula grafts through the extraperitoneal approach. Case 2: A 25-year-old female with cauda equina syndrome and abnormal body form diagnosed as having spondyloptosis in which the entire vertebral body of L5 had descended below the endplate of S1. MR imaging revealed marked canal stenosis at the S1 level. In the first surgery, L5 vertebral body was resected through the transperitoneal approach. After 1 week of bed rest, posterior segments of L5 were resected, L4 was affixed to the sacrum and anterior stabilization was achieved with 2 mesh cages and lumbosacral spine was fixed using the intrasacral fixation technique. Case 3: A 64-year-old female was diagnosed as having pyogenic discitis and osteomyelitis at the L5-S1 level. In spite of successful medical treatment for infection, low back pain continued. Radiologically, L5 vertebral body was shown to have collapsed and slipped anteriorly over the sacrum. L3, L4 and sacrum were fixed by intrasacral fixation. One week after the first operation, the L5/S1 disc and the suppurtive vertebral bodies were resected through the extraperitoneal approach and anterior stabilization was performed with iliac bone grafts. At follow-up for a minimum of 6 months, initial fixation was maintained in all 3 cases and bony fusion was obtained. The

  2. The use of titanium and stainless steel in fracture fixation.

    Hayes, J S; Richards, R G

    2010-11-01

    The use of metal in fracture fixation has demonstrated unrivalled success for many years owing to its high stiffness, strength, biological toleration and overall reliable function. The most prominent materials used are electropolished stainless steel and commercially pure titanium, along with the more recent emergence of titanium alloys. Despite the many differences between electropolished stainless steel and titanium, both materials provide a relatively predictable clinical outcome, and offer similar success for fulfilling the main biomechanical and biological requirements of fracture fixation despite distinctive differences in implant properties and biological responses. This article explores these differences by highlighting the limitations and advantages of both materials, and addresses how this translates to clinical success.

  3. Dinitrogen fixation by blue-green algae from paddy fields

    Thomas, Joseph

    1977-01-01

    Recent work using radioactive nitrogen on the blue-green algae of paddy fields has been reviewed. These algae fix dinitrogen and photoassimilate carbon evolving oxygen, thereby augmenting nitrogen and carbon status of the soil and also providing oxygen to the water-logged rice paddies. Further studies using radioactive isotopes 13 N, 24 Na and 22 Na on their nitrogen fixation, nitrogen assimilation pathways; regulation of nitrogenase, heterocysts production and sporulation and sodium transport and metabolism have been carried out and reported. The field application of blue green algae for N 2 fixation was found to increase the status of soil nitrogen and yield of paddy. (M.G.B.)

  4. Determination of symbiotic nitrogen fixation by labelling the soil atmosphere with sup(15)N sub(2) at low isotope enrichment

    Trivelin, P.C.O.

    1982-01-01

    A direct method to determine the total symbiotic nitrogen fixation during the leguminous plants cycles has been, developed, by labelling the soil atmosphere with sup(15)N sub(2) at low isotope enrichment, of about 1 atom % excess. The soil explored by the root system of leguminous plants was confined by means of a chamber in the field and by sealed pots in greenhouse experiments in order to maintain the soil air labelled with sup(15)N sub(2). The average sup(15)N concentration in the soil atmosphere, necessary to calculate dinitrogen fixation, was obtained by integration of the exponential functions of isotope dilution. Those functions were obtained by periodic sampling and analysis of the N sub(2) in the soil atmosphere. The field experiment with labelled atmosphere was carried out from the 22 sup(nd) to the 31 sup(st) day of the bean crop cycle and 5.5 mg N/plant (24% of total plant N) was derived from fixation. In pot experiments, under greenhouse conditions, integrated determination of fixation was made in Phaseolus beans (from the 19 sup(th) to the 67 sup(th) day from planting) and in soybeans (from the 24 sup(th) to the 70 sup(th) day from planting). The soil atmosphere was labelled with sup(15)N sub(2) in both cases. Average fixation obtained for Phaseolus beans was 80 mg N/plant (65% of total plant N) and for soybeans 265 mg N/plant (71% of total plant N). Evaluation of the basic concept of the isotope dilution method to determine nitrogen fixation in pots experiments, as proposed by Fried and Middelboe (1977) has also been made in the present paper. Simultaneous determinations of fixation in soybeans, using the isotope dilution method of Fried and Middelboe, natural variation of the sup(15)N/ sup(14)N ratios, and total-N differences, indicated the same results for pot experiments, harvested at the end of the plant cycle. (author)

  5. Abiotic nitrogen fixation on terrestrial planets: reduction of NO to ammonia by FeS.

    Summers, David P; Basa, Ranor C B; Khare, Bishun; Rodoni, David

    2012-02-01

    Understanding the abiotic fixation of nitrogen and how such fixation can be a supply of prebiotic nitrogen is critical for understanding both the planetary evolution of, and the potential origin of life on, terrestrial planets. As nitrogen is a biochemically essential element, sources of biochemically accessible nitrogen, especially reduced nitrogen, are critical to prebiotic chemistry and the origin of life. Loss of atmospheric nitrogen can result in loss of the ability to sustain liquid water on a planetary surface, which would impact planetary habitability and hydrological processes that shape the surface. It is known that NO can be photochemically converted through a chain of reactions to form nitrate and nitrite, which can be subsequently reduced to ammonia. Here, we show that NO can also be directly reduced, by FeS, to ammonia. In addition to removing nitrogen from the atmosphere, this reaction is particularly important as a source of reduced nitrogen on an early terrestrial planet. By converting NO directly to ammonia in a single step, ammonia is formed with a higher product yield (~50%) than would be possible through the formation of nitrate/nitrite and subsequent conversion to ammonia. In conjunction with the reduction of NO, there is also a catalytic disproportionation at the mineral surface that converts NO to NO₂ and N₂O. The NO₂ is then converted to ammonia, while the N₂O is released back in the gas phase, which provides an abiotic source of nitrous oxide.

  6. Modified fixation with pinning and external fixation components for feline femur multiple-lined fracture: A case report

    Okamoto, Y.; Minami, S.; Matuhashi, A.

    1992-01-01

    A 3-year-old female Japanese domestic cat, weighing 3kg, was referred to us because of right hind leg lameness occuring for 3 days' duration. Radiography of the affected leg revealed severe femoral diaphysial comminuted fracture. The affected leg was treated using wire with an intramedullary Stainman pin being placed completely through the femur. After suturing the wound, both ends of the intramedullary pin exposed both proximally and distally were fixed with external fixation components (two double clamps, two single clamps, two short rods and one long rod) to prevent the pin from rotation. There was a slight gait problem due to the external apparatus and no post-operative infection. The function of the right hind leg gradually recovered. The intramedullary pin and external fixative apparatus were removed on the 52nd day after surgery. This modified fixation appears to offer versatility in the treatment of various fractures in smaller dogs and cats

  7. Consequences of altering rubisco regulation

    Salvucci, Michael [US Dept. of Agriculture (USDA)., Ames, IA (United States)

    2013-12-31

    Research examined the thermal stability and propensity for aggregation of wild type and the C- and N-terminally modified forms of activase to determine if loss of activity under heat stress is dependent on protein aggregation. The results showed that 1) loss of activity at high temperature is independent of aggregation; 2) activase with both C- and N-terminal S-Tags are more susceptible to aggregation than wild type activase, 3) aggregation is highly dependent on the concentration of Mg2+ and 4) the ATP analog, ATPgammaS, protects against both thermal inactivation and aggregation.

  8. Comparative study of thyroid fixation of different iodine compounds; Etude comparative de la fixation thyroidienne de differents composes iodes

    Rinaldi, R; Coeur, A; Raynfeld, Ch [Commissariat a l' Energie Atomique, Grenoble (France).Centre d' Etudes Nucleaires

    1961-07-01

    The aim of this work is to study the thyroid fixation of various iodine compounds in mineral or organic form. The animals (rats) are given therapeutic doses of the derivative orally with the object of saturating the thyroid, and then receive a determined dose of radio-iodine 131 by intra-peritoneal injection; any fixation of this latter is then measured under anaesthetic by means of a scintillation counter. Whatever form of iodine derivative was used whether in ionic (potassium iodide type) or organic form (iodo-tannic syrup) or in the form of elementary iodine (iodinated water), thyroid saturation was always obtained, as shown by practically zero fixation of the 4 {mu}curies of iodine 131 administered by intra-peritoneal injection. (author) [French] Notre travail a pour but l'etude de la fixation thyroidienne de differents composes iodes sous forme minerale ou organique. Les animaux (rats), apres absorption orale de doses therapeutiques de derives destines a saturer leur thyroide recoivent par voie intra-peritoneale une dose determinee de radio-iode {sup 131}I, la fixation eventuelle de ce dernier est ensuite mesuree sous anesthesie en utilisant un compteur a scintillation. Quelle que soit la forme utilisee, c'est-a-dire derive iode sous forme ionique (type iodure de potassium) ou sous forme organique (sirop iodotanique) ou encore sous forme d'iode metalloidique (eau iodee), nous avons obtenu chaque fois une saturation thyroidienne mise en evidence par une fixation pratiquement nulle des 4 {mu}curies de l'iode 131 injectes par voie intraperitoneale. (auteur)

  9. A cell shrinkage artefact in growth plate chondrocytes with common fixative solutions: importance of fixative osmolarity for maintaining morphology

    MY Loqman

    2010-05-01

    Full Text Available The remarkable increase in chondrocyte volume is a major determinant in the longitudinal growth of mammalian bones. To permit a detailed morphological study of hypertrophic chondrocytes using standard histological techniques, the preservation of normal chondrocyte morphology is essential. We noticed that during fixation of growth plates with conventional fixative solutions, there was a marked morphological (shrinkage artifact, and we postulated that this arose from the hyper-osmotic nature of these solutions. To test this, we fixed proximal tibia growth plates of 7-day-old rat bones in either (a paraformaldehyde (PFA; 4%, (b glutaraldehyde (GA; 2% with PFA (2% with ruthenium hexamine trichloride (RHT; 0.7%, (c GA (2% with RHT (0.7%, or (d GA (1.3% with RHT (0.5% and osmolarity adjusted to a ‘physiological’ level of ~280mOsm. Using conventional histological methods, confocal microscopy, and image analysis on fluorescently-labelled fixed and living chondrocytes, we then quantified the extent of cell shrinkage and volume change. Our data showed that the high osmolarity of conventional fixatives caused a shrinkage artefact to chondrocytes. This was particularly evident when whole bones were fixed, but could be markedly reduced if bones were sagittally bisected prior to fixation. The shrinkage artefact could be avoided by adjusting the osmolarity of the fixatives to the osmotic pressure of normal extracellular fluids (~280mOsm. These results emphasize the importance of fixative osmolarity, in order to accurately preserve the normal volume/morphology of cells within tissues.

  10. A financial analysis of maxillomandibular fixation versus rigid internal fixation for treatment of mandibular fractures.

    Schmidt, B L; Kearns, G; Gordon, N; Kaban, L B

    2000-11-01

    The aim of this study was to compare the cost-effectiveness of mandibular fracture treatment by closed reduction with maxillomandibular fixation (CRF) with open reduction and rigid internal fixation (ORIF). This was a retrospective study of 85 patients admitted to the Oral and Maxillofacial Surgery Service at San Francisco General Hospital and treated for mandibular fractures from January 1 to December 31, 1993. The patients were divided into 2 groups: 1) those treated with CRF and 2) those treated with ORIF. The outcome variables were length of hospital stay, duration of anesthesia, and time in operating room. The charge for primary fracture treatment included the fees for the operation and hospitalization without any complications. Within the group of 85 patients treated for mandibular fractures in 1993, 10 patients treated with CRF and 10 patients treated with ORIF were randomly selected, and hospital billing statements were used to estimate the average charge of primary treatment. The average charge to manage a major postoperative infection also was estimated based on the billing statements of 10 randomly selected patients treated in 1992 (5 treated with CRF, 5 with ORIF) who required hospital admission for the management of a complication. The average total charge was computed by using the average charge for primary treatment plus the incidence of postoperative infection multiplied by the average charge for management of that complication. Eighty-five patients were included in the study. The average charge for primary treatment was $10,100 for the CRF group and $28,362 for the ORIF group. The average charge for the inpatient management of a major postoperative infection was $26,671 for the CRF group and $39,213 for the ORIF group. The average total charge for management of a mandible fracture with CRF was $10,927; the total charge for the ORIF group was $34,636. The results of this retrospective study suggest that the use of CRF in the management of mandibular

  11. Short Segment Fixation Versus Short Segment Fixation With Pedicle Screws at the Fracture Level for Thoracolumbar Burst Fracture

    Anghel S

    2014-04-01

    Full Text Available Objective: The most prevailing surgical procedure in the treatment of thoracolumbar burst fractures, Short Segment Fixation (SSF, is often followed by loss of correction or hardware failure which may be significant enough to require another surgical intervention. In order to take advantage of its benefits but to avoid or diminish the risk and impact of associated drawbacks, some other alternatives have been lately developed among which we refer to short segment fixation with intermediate screws (SSF+IS. This article provides a comparative picture over the effectiveness of the two above-mentioned surgical treatments, focusing on their potential to prevent the loss of correction.

  12. Impact of Crab Bioturbation on Nitrogen-Fixation Rates in Red Sea Mangrove Sediment

    Qashqari, Maryam S.

    2017-01-01

    be uptaken by plants. Hence, biological nitrogen fixation increases the input of nitrogen in the mangrove ecosystem. In this project, we focus on measuring the rates of nitrogen fixation on Red Sea mangrove (Avicennia marina) located at Thuwal, Saudi Arabia

  13. Stress and stability of plate-screw fixation and screw fixation in the treatment of Schatzker type IV medial tibial plateau fracture: a comparative finite element study.

    Huang, Xiaowei; Zhi, Zhongzheng; Yu, Baoqing; Chen, Fancheng

    2015-11-25

    The purpose of this study is to compare the stress and stability of plate-screw fixation and screw fixation in the treatment of Schatzker type IV medial tibial plateau fracture. A three-dimensional (3D) finite element model of the medial tibial plateau fracture (Schatzker type IV fracture) was created. An axial force of 2500 N with a distribution of 60% to the medial compartment was applied to simulate the axial compressive load on an adult knee during single-limb stance. The equivalent von Mises stress, displacement of the model relative to the distal tibia, and displacement of the implants were used as the output measures. The mean stress value of the plate-screw fixation system was 18.78 MPa, which was significantly (P stress value of the triangular fragment in the plate-screw fixation system model was 42.04 MPa, which was higher than that in the screw fixation model (24.18 MPa). But the mean stress of the triangular fractured fragment in the screw fixation model was significantly higher in terms of equivalent von Mises stress (EVMS), x-axis, and z-axis (P < 0.001). This study demonstrated that the load transmission mechanism between plate-screw fixation system and screw fixation system was different and the stability provided by the plate-screw fixation system was superior to the screw fixation system.

  14. Percutaneous Pin Fixation of Gartland Type I11 Supraconylar ...

    S G Lungu M.Med (Orth). Specialist Orthopaedic Surgeon. Zambian Italian Orthopaedic Hospital, Lusaka. Key words: Percutaneous, pin fixation, Gartland type Ill, supracondylar, fractures, and humerus. This was a prospective study of 40 children with severely displaced (Gartland Type 111) supracondylar fractures of the ...

  15. Nitrogen fixation and nodulation of soybean as affected by rhizobial ...

    The study evaluated the efficacy of different adhesives added to rhizobial seed inoculum on soybean nodulation and biological nitrogen fixation in a screen house and under field conditions. The experiment was a 6×3 factorial arranged in Completely Randomized Design and Randomized Complete Block Design for the pot ...

  16. Breeding for traits supportive of nitrogen fixation in legumes

    Herridge, David F.

    2001-01-01

    As the potential economic benefits of enhancing dinitrogen (N 2 ) fixation of crop, pasture and forage legumes are substantial, the idea that legume breeding could play a role in enhancing N 2 fixation was advanced more than 50 years ago. Various programmes have sought to genetically improve a wide range of species, from pasture legumes such as red clover (Trifolium pratense) to the crop legumes like soybean (Glycine max) and common bean (Phaseolus vulgaris). In some the selection trait was yield, whilst in others it was high plant reliance on N 2 fixation (%Ndfa). A third strategy was to optimise legume nodulation through specific nodulation traits, e.g. mass, duration, promiscuous and selective nodulation. Plant genetic variation was sought from natural populations or created through mutagenesis. Although methods for assessing single plants and populations of plants for yield and %Ndfa varied over the years, it is now clear that measurements based on either 15 N or xylem solute analysis are the most reliable. Methodological issues as well as poor focus plagued many of the earlier programmes, since enhancing N 2 fixation essentially involves adapting legumes to fix more N when growing in N-poor soils. Programmes in which plant genotypes are inoculated with effective rhizobia and screened under conditions of low soil N maximise the symbiotic potential of the legume. (author)

  17. Ender’s Nail fixation in paediatric femoral shaft fractures.

    Rajeev Dwivedi

    2013-12-01

    Flynn criteria 34 had excellent and 6 had satisfactory results. No poor results were seen. Conclusion: Ender’s nail fixation can be preferred method of treatment for femoral shaft fractures in age group 5 -15 years as the results are excellent and satisfactory. It is technically simple and can be done in a closed manner. It spares the vascularity and growth plate.

  18. Management and quantification of nitrogen fixation in Leucaena leucocephala

    Safo, E.Y.

    1998-01-01

    The effects of pruning and age on N 2 fixation were studied using Leucaena leucocephala isoline K28, with Cassia siamea as the non-N 2 -fixing reference species, at a site of degraded soil fertility typical of much of the farming land in Ghana. The 15 N-dilution method was used to estimate N2 fixation. Cassia siamea consistently produced higher total biomass and total N yields than did L. leucocephala. The mean value for the fraction of N derived from fixation (%Ndfa) was higher for pruned L. leucocephala (36%) than for unpruned trees (18%). There was some underestimation of N 2 fixation as a result of using C. siamea as the reference, and because root N-contents were not determined. Strong, significant linear correlations were observed between foliar and whole-tree (weighted average) percent 15 N atom excess in unpruned L. leucocephala and C. siamea, suggesting that foliar 15 N enrichment can be used to accurately estimate %Ndfa. The results demonstrated that the 15 N-enrichment methodology can provide meaningful estimates of %Ndfa and total N 2 fixed for mixed tree plantations under field conditions, when adequate spacing is provided. (author)

  19. Two isotopic methods for estimation of soybean nitrogen fixation

    Domenach, A.-M.; Chalamet, Alain; Pachiaudi, Christiane

    1979-01-01

    Measurements of rate of nitrogen symbiotic fixation by Soybean were determined by two different methods: variations in the natural abundance of 15 N in plants; use of 'A' value determined from labelled nitrogen applications to the soil. The results from both methods were in good agreement. Rates of fixed nitrogen were similar when using non nodulated Soybean or Ray-Grass as reference [fr

  20. Role of symbiotic nitrogen fixation in the improvement of legume ...

    Role of symbiotic nitrogen fixation in the improvement of legume productivity under stressed environments. R Serraj, J Adu-Gyamfi. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · http://dx.doi.org/10.4314/wajae.v6i1.45613.

  1. Capsule-Fixated Intraocular Lens Implantation in Small Pupil Cases.

    Schojai, Merita; Schultz, Tim; Burkhard Dick, H

    2017-08-01

    To describe a new technique for implantation of capsule-fixated intraocular lenses (IOLs) (FEMTIS; Oculentis, Berlin, Germany) in patients with small pupils. In 4 eyes with small pupils, an anterior capsule-fixated IOL was implanted into the capsular bag after femtosecond laser treatment. The two large and two small flaps of the IOL were elevated to the front of the iris and the anterior capsule. Finally, the iris was flipped over the flaps to ensure a fixation of the capsule inside of the capsulotomy. In all cases, the implantation of anterior capsule-fixated IOLs was possible. No complications occurred during surgery or within the first months after surgery. With the described technique, capsulefixated IOLs can be implanted in eyes with small pupil easily and safely. This type of IOL has great potential to improve the refractive outcome by better prediction of the postoperative IOL position and eliminating IOL rotation after cataract surgery. [J Refract Surg. 2017;33(8):568-570.]. Copyright 2017, SLACK Incorporated.

  2. Operative fixation of chest wall fractures: an underused procedure?

    Richardson, J David; Franklin, Glen A; Heffley, Susan; Seligson, David

    2007-06-01

    Chest wall fractures, including injuries to the ribs and sternum, usually heal spontaneously without specific treatment. However, a small subset of patients have fractures that produce overlying bone fragments that may produce severe pain, respiratory compromise, and, if untreated mechanically, result in nonunion. We performed open reduction and internal fixation on seven patients with multiple rib fractures-five in the initial hospitalization and two delayed--as well as 35 sternal fractures (19 immediate fixation and 16 delayed). Operative fixation was accomplished using titanium plates and screws in both groups of patients. All patients with rib fractures did well; there were no major complications or infections, and no plates required removal. Clinical results were excellent. There was one death in the sternal fracture group in a patient who was ventilator-dependent preoperatively and extubated himself in the early postoperative period. Otherwise, the results were excellent, with no complications occurring in this group. Three patients had their plates removed after boney union was achieved. No evidence of infection or nonunion occurred. The excellent results achieved in the subset of patients with severe chest wall deformities treated initially at our institution and those referred from outside suggest that operative fixation is a useful modality that is likely underused.

  3. Cyanobacteria Occurrence and Nitrogen Fixation Rates in the ...

    The occurrence and biological nitrogen fixation rates of epiphytic and benthic diazotrophs were studied in seagrass meadows at sites with seaweed farms and at a control site without seaweed farms from two locations, Chwaka Bay and Jambiani, along the east coast of. Zanzibar. Ten species of cyanobacteria were ...

  4. Biomechanical analysis of titanium fixation plates and screws in ...

    2015-08-10

    Aug 10, 2015 ... values on fixative appliances were predicted by means of. 3D FEA. The highest ... such as poor resistance to torsional forces, poor rigidity, and poor stability in ... the adequacy of mathematical models to relate mechanical factors such as ... the risk of bacterial contamination, scarring, postoperative edema ...

  5. Nitrogen fixation and nitrogenase activity of Azotobacter chroococcum

    Brotonegoro, S.

    1974-01-01

    The purpose of the present investigation was to study the effect of some chemical, physical and biological factors on growth, efficiency of nitrogen fixation and nitrogenase activity of Azotobacter chroococcum.

    From biochemical studies with cell-free

  6. Resorbable screws for fixation of autologous bone grafts

    Raghoebar, GM; Liem, RSB; Bos, RRM; van der Wal, JE; Vissink, A

    The aim of this study was to evaluate the suitability of resorbable screws made of poly (D,L-lactide) acid (PDLLA) for fixation of autologous bone grafts related to graft regeneration and osseointegration of dental implants. In eight edentulous patients suffering from insufficient retention of their

  7. Serious complication 1?year after sacrospinous ligament fixation

    Faber, Violet J.; van der Vaart, Huub C.; Heggelman, Ben G. F.; Schraffordt Koops, Steven E.

    2008-01-01

    Myositis of the gluteal region caused by group A streptococci 1 year after a sacrospinous ligament fixation was recognised as a serious complication of this procedure. Most likely, the infection was spread to the gluteal region through a port d’entree caused by vaginal atrophy, via the non-resorbable sutures. The patient was treated successfully with antibiotics intravenous and local estrogens.

  8. Button fixation technique for Achilles tendon reinsertion: a biomechanical study.

    Awogni, David; Chauvette, Guillaume; Lemieux, Marie-Line; Balg, Frédéric; Langelier, Ève; Allard, Jean-Pascal

    2014-01-01

    Chronic insertional tendinopathy of the Achilles tendon is a frequent and disabling pathologic entity. Operative treatment is indicated for patients for whom nonoperative management has failed. The treatment can consist of the complete detachment of the tendon insertion and extensive debridement. We biomechanically tested a new operative technique that uses buttons for fixation of the Achilles tendon insertion on the posterior calcaneal tuberosity and compared it with 2 standard bone anchor techniques. A total of 40 fresh-frozen cadaver specimens were used to compare 3 fixation techniques for reinserting the Achilles tendon: single row anchors, double row anchors, and buttons. The ultimate loads and failure mechanisms were recorded. The button assembly (median load 764 N, range 713 to 888) yielded a median fixation strength equal to 202% (range 137% to 251%) of that obtained with the double row anchors (median load 412 N, range 301 to 571) and 255% (range 213% to 317%) of that obtained with the single row anchors (median load 338 N, range 241 to 433N). The most common failure mechanisms were suture breakage with the buttons (55%) and pull out of the implant with the double row (70%) and single row (85%) anchors. The results of the present biomechanical cadaver study have shown that Achilles tendon reinsertion fixation using the button technique provides superior pull out strength than the bone anchors tested. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  9. Estimates of biological nitrogen fixation by Pterocarpus lucens in a ...

    Nitrogen (N2) fixation by Pterocarpus lucens in a natural semi arid ecosystem, in Ferlo, Senegal was estimated using 15N natural abundance (15N) procedure. Other non-fixing trees accompanying P. lucens in the same area were also investigated as control. Results showed an important variation of 15N in leaves between ...

  10. Nodulation and nitrogen fixation in common bean (Phaseolus vulgaris)

    Mamadou Gueye

    Nodulation and nitrogen fixation of field grown common bean (Phaseolus vulgaris) as influenced by fungicide seed treatment. Ndeye Fatou Diaw GUENE, Adama DIOUF and Mamadou GUEYE*. MIRCEN/ Laboratoire commun de microbiologie IRD-ISRA-UCAD, BP 1386, DAKAR, Senegal. Accepted 23 June 2003.

  11. variability in olecranon ao fracture fixation: a radiological study

    ABSTRACT. Background: Tension Band Wire(TBW) fixation of olecranon fracture is a commonly used technique by ... There are many classification systems of this injury of which the Mayo is ... backing out by as much as three times in comparison with those ..... “K” wire. A blinded randomized control outcome based clinical.

  12. Differences in fixations between grasping and viewing objects

    Brouwer, A.M.; Franz, V.H.; Gegenfurtner, K.R.

    2009-01-01

    Where exactly do people look when they grasp an object? An object is usually contacted at two locations, whereas the gaze can only be at one location at the time. We investigated participants' fixation locations when they grasp objects with the contact positions of both index finger and thumb being

  13. Ad gist : Ad communication in a single eye fixation

    Pieters, R.; Wedel, M.

    2012-01-01

    Most ads in practice receive no more than a single eye fixation. This study investigates the limits of what ads can communicate under such adverse exposure conditions. We find that consumers already know at maximum levels of accuracy and with high degree of certainty whether something is an ad or is

  14. Adaptation and fixation in entrepreneurial approaches of a dental laboratory

    Cornelia M. Ferreira

    2014-08-01

    Research purpose: The study described how the dental laboratory adapted its entrepreneurial approaches over time in response to critical changes that occurred and how aspects in the managerial approach became fixated and proved to be essential to success. Motivation for the study: The study provided insight into how the dental laboratory transformed into a stable and prosperous laboratory by the integration of strategic, economic, cultural and social capital through a process of business decision making. Research design, approach and method: A cohort survey research design, based upon the compilation of longitudinal data over three selected time periods, was employed. The design of the measuring instruments and the interpretation of research results were derived from an adapted entrepreneurial-in-network theoretical framework. A triangulation data compilation approach was followed. Main findings: The results revealed that cultural capital in the dental laboratory became fixated on three value principles, whilst the other critical capitals prescribed exist in sufficient volumes and improve to adapt to changing circumstances in the dental market. Practical/managerial implications: Fixated cultural values acted as a ‘parent’-actor in order to guide the righteousness of behaviour, whereas adaptation required sufficient critical capitals and the proper integration thereof. Contribution/value-added: By adopting the entrepreneurship-in-network approach, the researchers incorporated the dynamic and interactive processes of entrepreneurship. Future studies may employ the same design and use multi-varied analyses to show how a business adapt or fixate its approaches in response to crises or changes in the business environment.

  15. Improved coating and fixation methods for scanning electron microscope autoradiography

    Weiss, R.L.

    1984-01-01

    A simple apparatus for emulsion coating is described. The apparatus is inexpensive and easily assembled in a standard glass shop. Emulsion coating for scanning electron microscope autoradiography with this apparatus consistently yields uniform layers. When used in conjunction with newly described fixation methods, this new approach produces reliable autoradiographs of undamaged specimens

  16. N-2 fixation by non-heterocystous cyanobacteria

    Bergman, B.; Gallon, J.R.; Rai, A.N.; Stal, L.J.

    1997-01-01

    Many, though not all, non-heterocystous cyanobacteria can fix N-2. However, very few strains can fix N-2 aerobically. Nevertheless, these organisms may make a substantial contribution to the global nitrogen cycle. In this general review, N-2 fixation by laboratory cultures and natural populations of

  17. Functional Outcome of Internal Fixation of Radial and Ulna Fracture

    mehrdad Mansouri

    2006-02-01

    Conclusion: Anatomic reduction and internal fixation is the standard method for treatment of fractures by displacing radios and ulna in adults. According to results, it seems more intension to motions specially pronation and muscle strengthening foream after surgery will have affect on improving patients’ function specially pronation and Grip strength.

  18. Single-suture scleral fixation of subluxated foldable intraocular lenses.

    Yarangumeli, Alper; Alp, Mehmet Numan; Kural, Gulcan

    2012-01-01

    To evaluate the results of single-suture scleral fixation of subluxated foldable intraocular lenses (IOL) in eyes with sufficient residual capsular support. The results of IOL repositioning by single-suture scleral fixation in 6 eyes of 6 patients with IOL subluxation were included. All subluxated IOLs were single-piece hydrophilic acrylic. Subluxation resulted from posterior capsule tears in 3 eyes, zonular dialyses in 2 eyes, and zonular dialysis with a capsulorhexis tear in 1 eye. A similar technique was used in all eyes in which one haptic was externalized through a superior clear corneal incision and tied with a Pair-PAK 10-0 polypropylene suture, and was finally retracted and fixated behind the iris close to the ciliary sulcus at the 12:00 meridian. All patients were followed up for at least 6 months. Best-corrected visual acuities ranged between finger counting and 20/70 (mean logMAR 1.02±0.64) preoperatively, and between 20/100 and 20/20 (mean logMAR 0.22±0.26) at the final postoperative visit. All IOLs remained centered and no significant postoperative complications were encountered except for an IOL tilt which resulted in a considerable oblique astigmatism in one eye. Subluxated foldable IOLs may safely be repositioned and secured with a single scleral fixation suture in selected cases with adequate amount of capsular remnants.

  19. Intraocular lens iris fixation. Clinical and macular OCT outcomes

    2012-01-01

    Background To assess the efficacy, clinical outcomes, visual acuity (VA), incidence of adverse effects, and complications of peripheral iris fixation of 3-piece acrylic IOLs in eyes lacking capsular support. Thirteen patients who underwent implantation and peripheral iris fixation of a 3-piece foldable acrylic PC IOL for aphakia in the absence of capsular support were followed after surgery. Clinical outcomes and macular SD-OCT (Cirrus OCT; Carl Zeiss Meditec, Germany) were analyzed. Findings The final CDVA was 20/40 or better in 8 eyes (62%), 20/60 or better in 12 eyes (92%), and one case of 20/80 due to corneal astigmatism and mild persistent edema. No intraoperative complications were reported. There were seven cases of medically controlled ocular hypertension after surgery due to the presence of viscoelastic in the AC. There were no cases of cystoid macular edema, chronic iridocyclitis, IOL subluxation, pigment dispersion, or glaucoma. Macular edema did not develop in any case by means of SD-OCT. Conclusions We think that this technique for iris suture fixation provides safe and effective results. Patients had substantial improvements in UDVA and CDVA. This surgical strategy may be individualized however; age, cornea status, angle structures, iris anatomy, and glaucoma are important considerations in selecting candidates for an appropriate IOL fixation method. PMID:23050659

  20. Intermediate results of sutureless intrascleral posterior chamber intraocular lens fixation.

    Scharioth, Gabor B; Prasad, Som; Georgalas, Ilias; Tataru, Calin; Pavlidis, Mitrofanis

    2010-02-01

    To report the intermediate multicenter results of a technique of sutureless intrascleral fixation of a standard 3-piece posterior chamber intraocular lens (PC IOL) in the ciliary sulcus. Four European ophthalmology centers. A technique for sutureless intrascleral fixation of the haptics of a standard 3-piece PC IOL was retrospectively evaluated. The technique uses standardized maneuvers to fixate the PC IOL without need for special haptic architecture or preparation or haptic suturing. All patients having IOL implantation by the technique were evaluated for preoperative status (visual acuity, refractive error, preexisting ocular conditions, optical biometry), postoperative status, complications, and need for further surgery. The study evaluated 63 consecutive patients from 4 institutions (4 surgeons). The median follow-up was 7 months. Two dislocated PC IOLs (3.6%) were decentered; the other 61 IOLs (96.8%) were stable and well centered. There were no cases of recurrent dislocation, endophthalmitis, retinal detachment, or glaucoma. Fixation of PC IOL haptics in a limbus-parallel scleral tunnel provided exact centration and axial stability of the IOL and prevented distortion and subluxation in most cases. Copyright 2010 ASCRS and ESCRS. All rights reserved.

  1. Intraocular lens iris fixation. Clinical and macular OCT outcomes

    Garcia-Rojas Leonardo

    2012-10-01

    Full Text Available Abstract Background To assess the efficacy, clinical outcomes, visual acuity (VA, incidence of adverse effects, and complications of peripheral iris fixation of 3-piece acrylic IOLs in eyes lacking capsular support. Thirteen patients who underwent implantation and peripheral iris fixation of a 3-piece foldable acrylic PC IOL for aphakia in the absence of capsular support were followed after surgery. Clinical outcomes and macular SD-OCT (Cirrus OCT; Carl Zeiss Meditec, Germany were analyzed. Findings The final CDVA was 20/40 or better in 8 eyes (62%, 20/60 or better in 12 eyes (92%, and one case of 20/80 due to corneal astigmatism and mild persistent edema. No intraoperative complications were reported. There were seven cases of medically controlled ocular hypertension after surgery due to the presence of viscoelastic in the AC. There were no cases of cystoid macular edema, chronic iridocyclitis, IOL subluxation, pigment dispersion, or glaucoma. Macular edema did not develop in any case by means of SD-OCT. Conclusions We think that this technique for iris suture fixation provides safe and effective results. Patients had substantial improvements in UDVA and CDVA. This surgical strategy may be individualized however; age, cornea status, angle structures, iris anatomy, and glaucoma are important considerations in selecting candidates for an appropriate IOL fixation method.

  2. Two isotopic methods for estimation of soybean nitrogen fixation

    Domenach, A M; Chalamet, A; Pachiaudi, C [Lyon-1 Univ., 69 - Villeurbanne (France)

    1979-07-16

    Measurements of rate of nitrogen symbiotic fixation by Soybean were determined by two different methods: variations in the natural abundance of /sup 15/N in plants; use of 'A' value determined from labelled nitrogen applications to the soil. The results from both methods were in good agreement. Rates of fixed nitrogen were similar when using non nodulated Soybean or Ray-Grass as reference.

  3. The clinical outcome of lateral mass fixation after decompressive ...

    Ahmed Yehya

    2014-10-11

    Oct 11, 2014 ... Abstract Lateral mass cervical fixation is the technique of choice for posterior cervical stabiliza- tion of the lower ... In group I, neck pain improved in 68.8% and brachialgia improved in 83.3% .... a p value for Student t-test.

  4. Paediatric tibial shaft fractures treated by open reduction and stabilization with monolateral external fixation.

    Simon, A-L; Apostolou, N; Vidal, C; Ferrero, E; Mazda, K; Ilharreborde, B

    2018-02-01

    Elastic stable intramedullary nailing is increasingly used for surgical treatment of tibial shaft fractures, but frequently requires immobilization and delayed full weight-bearing. Therefore, external fixation remains interesting. The aim was to report clinico-radiological outcomes of monolateral external fixation for displaced and unstable tibial shaft fractures in children. All tibial fractures consecutively treated by monolateral external fixation between 2008 and 2013 were followed. Inclusion criteria included skeletal immaturity and closed and open Gustilo I fractures caused by a direct impact. Patients were seen until two years postoperatively. Demographics, mechanism of injury, surgical data and complications were recorded. Anteroposterior and lateral side radiographs were performed at each visit. Full-limb 3D reconstructions using biplanar stereroradiography was performed for final limb length and alignment measures. A total of 45 patients (mean age 9.7 years ± 0.5) were included. In all, 17 were Gustilo I fractures, with no difference between open and closed fractures for any data. Mean time to full weight bearing was 18.2 days ± 0.7. After 15 days, 39 patients returned to school. Hardware removal (mean time to union 15.6 weeks ± 0.8) was performed during consultation under analgesic gas. There were no cases of nonunion. No fracture healed with > 10° of angulation (mean 5.1° ± 0.4°). Leg-length discrepancy > 10 mm was found for six patients. This procedure can be a safe and simple surgical treatment for children with tibial shaft fractures. Few complications and early return to school were reported, with the limitations of non-comparative study. IV.

  5. Paediatric tibial shaft fractures treated by open reduction and stabilization with monolateral external fixation

    Simon, A.-L.; Apostolou, N.; Vidal, C.; Ferrero, E.; Mazda, K.; Ilharreborde, B.

    2018-01-01

    Abstract Purpose Elastic stable intramedullary nailing is increasingly used for surgical treatment of tibial shaft fractures, but frequently requires immobilization and delayed full weight-bearing. Therefore, external fixation remains interesting. The aim was to report clinico-radiological outcomes of monolateral external fixation for displaced and unstable tibial shaft fractures in children. Methods All tibial fractures consecutively treated by monolateral external fixation between 2008 and 2013 were followed. Inclusion criteria included skeletal immaturity and closed and open Gustilo I fractures caused by a direct impact. Patients were seen until two years postoperatively. Demographics, mechanism of injury, surgical data and complications were recorded. Anteroposterior and lateral side radiographs were performed at each visit. Full-limb 3D reconstructions using biplanar stereroradiography was performed for final limb length and alignment measures. Results A total of 45 patients (mean age 9.7 years ± 0.5) were included. In all, 17 were Gustilo I fractures, with no difference between open and closed fractures for any data. Mean time to full weight bearing was 18.2 days ± 0.7. After 15 days, 39 patients returned to school. Hardware removal (mean time to union 15.6 weeks ± 0.8) was performed during consultation under analgesic gas. There were no cases of nonunion. No fracture healed with > 10° of angulation (mean 5.1° ± 0.4°). Leg-length discrepancy > 10 mm was found for six patients. Conclusions This procedure can be a safe and simple surgical treatment for children with tibial shaft fractures. Few complications and early return to school were reported, with the limitations of non-comparative study. Level of Evidence IV PMID:29456750

  6. Elevated CO2 concentration around alfalfa nodules increases N2 fixation

    Fischinger, Stephanie A.; Hristozkova, Marieta; Mainassara, Zaman-Allah; Schulze, Joachim

    2009-01-01

    Nodule CO2 fixation via PEPC provides malate for bacteroids and oxaloacetate for N assimilation. The process is therefore of central importance for efficient nitrogen fixation. Nodule CO2 fixation is known to depend on external CO2 concentration. The hypothesis of the present paper was that nitrogen fixation in alfalfa plants is enhanced when the nodules are exposed to elevated CO2 concentrations. Therefore nodulated plants of alfalfa were grown in a hydroponic system that allowed separate ae...

  7. Porcine intestinal mast cells. Evaluation of different fixatives for histochemical staining techniques considering tissue shrinkage

    J. Rieger

    2013-07-01

    Full Text Available Staining of mast cells (MCs, including porcine ones, is critically dependent upon the fixation and staining technique. In the pig, mucosal and submucosal MCs do not stain or stain only faintly after formalin fixation. Some fixation methods are particularly recommended for MC staining, for example the fixation with Carnoy or lead salts. Zinc salt fixation (ZSF has been reported to work excellently for the preservation of fixation-sensitive antigens. The aim of this study was to establish a reliable histological method for counting of MCs in the porcine intestinum. For this purpose, different tissue fixation and staining methods that also allow potential subsequent immunohistochemical investigations were evaluated in the porcine mucosa, as well as submucosa of small and large intestine. Tissues were fixed in Carnoy, lead acetate, lead nitrate, Zamboni and ZSF and stained subsequently with either polychromatic methylene blue, alcian blue or toluidine blue. For the first time our study reveals that ZSF, a heavy metal fixative, preserves metachromatic staining of porcine MCs. Zamboni fixation was not suitable for histochemical visualization of MCs in the pig intestine. All other tested fixatives were suitable. Alcian blue and toluidine blue co-stained intestinal goblet cells which made a prima facie identification of MCs difficult. The polychromatic methylene blue proved to be the optimal staining. In order to compare MC counting results of the different fixation methods, tissue shrinkage was taken into account. As even the same fixation caused shrinkage-differences between tissue from small and large intestine, different factors for each single fixation and intestinal localization had to be calculated. Tissue shrinkage varied between 19% and 57%, the highest tissue shrinkage was found after fixation with ZSF in the large intestine, the lowest one in the small intestine after lead acetate fixation. Our study emphasizes that MC counting results from

  8. Adjacent-segment disease after thoracic pedicle screw fixation.

    Agarwal, Nitin; Heary, Robert F; Agarwal, Prateek

    2018-03-01

    OBJECTIVE Pedicle screw fixation is a technique widely used to treat conditions ranging from spine deformity to fracture stabilization. Pedicle screws have been used traditionally in the lumbar spine; however, they are now being used with increasing frequency in the thoracic spine as a more favorable alternative to hooks, wires, or cables. Although safety concerns, such as the incidence of adjacent-segment disease (ASD) after cervical and lumbar fusions, have been reported, such issues in the thoracic spine have yet to be addressed thoroughly. Here, the authors review the literature on ASD after thoracic pedicle screw fixation and report their own experience specifically involving the use of pedicle screws in the thoracic spine. METHODS Select references from online databases, such as PubMed (provided by the US National Library of Medicine at the National Institutes of Health), were used to survey the literature concerning ASD after thoracic pedicle screw fixation. To include the authors' experience at Rutgers New Jersey Medical School, a retrospective review of a prospectively maintained database was performed to determine the incidence of complications over a 13-year period in 123 consecutive adult patients who underwent thoracic pedicle screw fixation. Children, pregnant or lactating women, and prisoners were excluded from the review. By comparing preoperative and postoperative radiographic images, the occurrence of thoracic ASD and disease within the surgical construct was determined. RESULTS Definitive radiographic fusion was detected in 115 (93.5%) patients. Seven incidences of instrumentation failure and 8 lucencies surrounding the screws were observed. One patient was observed to have ASD of the thoracic spine. The mean follow-up duration was 50 months. CONCLUSIONS This long-term radiographic evaluation revealed the use of pedicle screws for thoracic fixation to be an effective stabilization modality. In particular, ASD seems to be less of a problem in the

  9. Fixation of Soil Using PEC and Separation of Fixed Soil

    Choi, Yong Suk; Yang, Hee-Man; Lee, Kune Woo; Seo, Bum-Kyoung; Moon, Jei Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    Radioactive cesium (Cs-137) is the most apprehensive element due to its long half-lives, high solubility in water, and strong radiation emission in the form of gamma rays. Because the radioactivity is localized within topsoil, soil surface on topsoil should be fixed to prevent the spreading of the contaminated soils by wind and water erosion. Many methods have been developing for soil fixation to remove radioactive contaminants in soil and prevent to diffuse radioactive materials. Various materials have been used as fixatives such as clays, molecular sieves, polymer, and petroleum based products. One of the methods is a soil fixation or solidification using polyelectrolyte. Polyelectrolytes have many ionic groups and form the polyelectrolyte complex (PEC) due to electrostatic interaction of anion and cation in an aqueous solution. polyelectrolyte complex can fix soil particles by flocculation and formation of crust between soil. The method can prevent a spread of radioactive material by floating on a soil surface. The decontamination efficiency of the surface soils reached about 90%, and dust release was effectively suppressed during the removal of surface soils. However it has a problem that the removed soil must separate soil and polymer to treat as the waste. In this study, the fixation of soil by polyelectrolyte complex to suppress the spread of contaminant and the separation method of soil and polymer was investigated. The properties of polyelectrolyte complex solution and the stability of fixed soil by polyelectrolyte complex were investigated. The concentration of salt in the polyelectrolyte complex solution is a very important parameter for the soil fixation.

  10. Surface fixation of dried blood by glutaraldehyde and peracetic acid.

    Kampf, G; Bloss, R; Martiny, H

    2004-06-01

    The difficulties of successful prion inactivation by chemical agents has led to changes in recommendations regarding the reprocessing of instruments including flexible endoscopes. One of the changes is the preference for peracetic acid instead of glutaraldehyde in order to avoid fixation of organic material, but the surface fixation by various active agents has not been fully investigated. We used a standardized amount of dried blood soil on metal carriers (on average 22 mg). One part of the carriers was exposed to different disinfectants (four based on peracetic acid, three based on glutaraldehyde, two based on quaternary ammonium compounds (QAC), one based on QAC and amines, one based on phenols and one cleaning agent) and air dried. The difference compared with the non-exposed soiled carrier was taken as the measure of blood removal by exposure to the disinfectants. In addition the other part of the carriers was exposed to a cleaning agent and air dried. The cleaning agent itself was capable of removing more than 99% of the dried blood and served as a control for non-fixation. The rate of fixation of dried blood was calculated as the ratio of the weight of residual soil on 'soiled, disinfected and cleaned' carriers and on 'soiled and disinfected' carriers. All experiments were repeated eight times. Blood removal varied between 90.3% +/- 1.5% (phenol-based disinfectant) and peracetic acid. No other preparations showed a potential for blood fixation (peracetic acid, and support the evidence that effective cleaning should precede the chemical disinfection. Copyright 2004 The Hospital Infection Society

  11. Surgical treatment of neglected clubfoot using external fixator

    Rodrigo Mota Pacheco Fernandes

    Full Text Available ABSTRACT The definition of neglected clubfoot (NC includes a variable range of complex deformities of the foot that are refractory to conventional treatments or are treated inappropriately. Several etiologies may be related to this. The Ilizarov method has become established as a tool for treating these deformities. It minimizes soft-tissue damage through gradual correction of the deformity, with a high success rate in relation to achieving a plantigrade foot, with low incidence of recurrence. The indications for treatment include severe rigid deformities (Dimeglio III and IV, or adverse skin conditions. Careful clinical and radiological examination is fundamental for proper planning and installation of the external fixator. The techniques used include selection of external fixation assemblies, which can be closed when there is a connection between the leg, hindfoot and forefoot. This closed assembly may or may not be constricted, according to whether hinges are provided or whether use of the natural anatomical hinges during correction of the deformity is envisaged. An open assembly makes it possible to add flexibility to the foot through histogenesis, while allowing closed corrections of greater precision later on. Hexapod fixators are an innovation with high potential for accuracy in correcting deformities. Procedures associated with external fixation include soft-tissue release and bone procedures. These procedures enable corrections that are more anatomical, for different degrees of severity and stiffness of deformity. It can be concluded from analyzing this case series that treatment of neglected clubfoot using an external fixator has a high rate of good and excellent results, with low frequency of complications.

  12. Flanged Intrascleral Intraocular Lens Fixation with Double-Needle Technique.

    Yamane, Shin; Sato, Shimpei; Maruyama-Inoue, Maiko; Kadonosono, Kazuaki

    2017-08-01

    To report the clinical outcomes of a new technique for transconjunctival intrascleral fixation of an intraocular lens (IOL). Prospective, noncomparative, interventional case series. One hundred eyes of 97 consecutive patients with aphakia, dislocated IOL, or subluxated crystalline lens who underwent posterior chamber sutureless implantation of an IOL were studied. Two angled incisions parallel to the limbus were made by 30-gauge thin-wall needles. Haptics of an IOL were externalized with the needles and cauterized to make a flange of the haptics. The flange of the haptics were pushed back and fixed into the scleral tunnels. Best-corrected visual acuity (VA), corneal endothelial cell density, IOL tilt, and complications were determined. The IOLs were fixed with exact centration and axial stability. The mean preoperative best-corrected VA was 0.25 logarithm of the minimum angle of resolution (logMAR) units; after surgery, it improved significantly to 0.11 logMAR, 0.09 logMAR, 0.12 logMAR, and 0.04 logMAR at 6, 12, 24, and 36 months, respectively (P IOL tilt was 3.4°±2.5°. The postoperative complications included iris capture by the IOL in 8 eyes (8%), vitreous hemorrhage in 5 eyes (5%), and cystoid macular edema in 1 eye (1%). There were no incidents of postoperative retinal detachment, endophthalmitis, or IOL dislocation. We have developed a new technique for intrascleral IOL fixation. The flanged IOL fixation technique is a simple and minimally invasive method for achieving good IOL fixation with firm haptic fixation. Copyright © 2017 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  13. Ethanol-Glycerin Fixation with Thymol Conservation: A Potential Alternative to Formaldehyde and Phenol Embalming

    Hammer, Niels; Loffler, Sabine; Feja, Christine; Sandrock, Mara; Schmidt, Wolfgang; Bechmann, Ingo; Steinke, Hanno

    2012-01-01

    Anatomical fixation and conservation are required to prevent specimens from undergoing autolysis and decomposition. While fixation is the primary arrest of the structures responsible for autolysis and decomposition, conservation preserves the state of fixation. Although commonly used, formaldehyde has been classified as carcinogenic to humans. For…

  14. The effect of hubs and shortcuts on fixation time in evolutionary graphs

    Askari, Marziyeh; Moradi Miraghaei, Zeinab; Aghababaei Samani, Keivan

    2017-07-01

    How can a new species (like a gene, an idea, or a strategy) take over the whole of a population? This process, which is called fixation, is considerably affected by the structure of the population. There are two key quantities to quantify the fixation process, namely fixation probability and fixation time. Fixation probability has been vastly studied in recent years, but fixation time has not been completely explored, yet. This is because the discovery of a relationship between fixation time and network structure is quite challenging. In this paper we investigate this relationship for a number of well-known complex networks. We show that the existence of a few high-degree nodes (hubs) in the network results in a longer fixation time, while the existence of a few short-cuts decreases the fixation time. Furthermore we investigate the effect of network parameters, such as connection probability, on fixation time. We show that by increasing the density of edges, fixation time decreases for all types of studied networks. Finally, we survey the effect of rewiring probability in a Watts-Strogatz network on fixation time.

  15. The role of minimally invasive plate osteosynthesis in rib fixation : A review

    Bemelman, Michael; Van Baal, Mark; Yuan, Jian Zhang; Leenen, Luke

    2016-01-01

    More than a century ago, the first scientific report was published about fracture fixation with plates. During the 1950's, open reduction and plate fixation for fractures were standardized by the founders of Arbeitsgemeinschaft für osteosynthesefragen/Association for the Study of Internal Fixation.

  16. The interactive effects of temperature and moisture on nitrogen fixation in two temperate-arctic mosses

    Rousk, Kathrin; Pedersen, Pia Agerlund; Dyrnum, Kristine

    2017-01-01

    fixation in mosses under controlled conditions have rarely been investigated separately, rendering the interactive effects of the two climatic factors on N2 fixation unknown. Here, we tested the interactive effects of temperature and moisture on N2 fixation in the two most dominant moss species...

  17. Comparison of /sup 15/N-aided methods for determining symbiotic dinitrogen fixation

    Rennie, R J [International Atomic Energy Agency, Vienna (Austria). Joint FAO/IAEA Div. of Atomic Energy in Food and Agriculture

    1979-01-01

    Three methods of calculating the amount of symbiotic dinitrogen fixation in navy beans (Phaseolus vulgaris cv. Sanilac) were compared in a greenhouse experiment. /sup 15/N-isotope dilution procedures yielded the most logical estimation of dinitrogen fixation. The classical difference method was not in agreement. Potential errors of the 'A'-value procedure to calculate dinitrogen fixation are discussed.

  18. Four quadrant parallel peripheral screw fixation for displaced femoral neck fractures in elderly patients

    Bhava RJ Satish

    2013-01-01

    Conclusion: Closed reduction and cannulated cancellous screw fixation gives satisfactory functional results in large group of elderly patients. The four quadrant parallel peripheral (FQPP screw fixation technique gives good stability, allows controlled collapse, avoids fixation failure and achieves predictable bone healing in displaced femoral neck fracture in patients ≥50 years of age.

  19. Interpretation of Post-operative Distal Humerus Radiographs After Internal Fixation: Prediction of Later Loss of Fixation

    Claessen, F.M.; Stoop, N.; Doornberg, J.N.; Guitton, T.G.; Bekerom, M.P. van den; Ring, D.; Biert, J.; et al.,

    2016-01-01

    PURPOSE: Stable fixation of distal humerus fracture fragments is necessary for adequate healing and maintenance of reduction. The purpose of this study was to measure the reliability and accuracy of interpretation of postoperative radiographs to predict which implants will loosen or break after

  20. Anatomical evidence for the anterior plate fixation of sacroiliac joint.

    Bai, Zhibiao; Gao, Shichang; Liu, Jia; Liang, Anlin; Yu, Weihua

    2018-01-01

    The iatrogenic injuries to the lumbar nerves during the fixation the sacroiliac (SI) joint fractures with anterior plates were often reported. No specific method had been reported to avoid it. This study was done to find a safer way of placing the anterior plates and screws for treating the sacroiliac (SI) joint fracture and/or dislocation. The research was performed using 8 male and 7 female normal corpse pelvic specimens preserved by 10% formalin solution. Try by measuring the horizontal distance from L4, L5 nerve roots to the sacroiliac joint and perpendicular distance from L4, L5 nerve roots to the ala sacralis, the length of L4, L5 nerve roots from intervertebral foramen to the edge of true pelvis, the diameter of L4, L5 nerve roots. The angles between the sacroiliac joint and sagittal plane were measured on the CT images. The horizontal distance between the lateral side of the anterior branches of L4, L5 nerve roots and the sacroiliac joint decreased gradually from the top to the bottom. The widest distances for L4,5 were 2.1 cm (range, 1.74-2.40) and 2.7 cm (range, 2.34-3.02 cm), respectively. The smallest distances for L4, 5 were 1.2 cm (range, 0.82-1.48 cm) and 1.5 cm (range, 1.08-1.74 cm), respectively. On CT images, the angle between the sacroiliac joint and sagittal plane was about 30°. If we use two anterior plates to fix the sacroiliac joint, It is recommended to place one plate on the superior one third part of the joint, with exposing medially no more than 2.5 cm and the other in the middle one third part of the joint, with elevating periosteum medially no more than 1.5 cm. The screws in the sacrum are advised to incline medially about 30° directing to the true pelvis. Copyright © 2017. Published by Elsevier B.V.

  1. Measurement of dinitrogen fixation by Biological soil crust (BSC) from the Sahelian zone: an isotopic method.

    Ehrhardt, F.; Alavoine, G.; Bertrand, I.

    2012-04-01

    Amongst the described ecological roles of Biological Soil Crust, N fixation is of importance for soil fertility, especially in arid and semi-arid ecosystems with low inputs. In BSC, the quantification of N fixation fluxes using an indirect method is widespread, usually with the Acetylene Reduction Assay (ARA) which consists in measuring the nitrogenase activity through the process of acetylene reduction into ethylene. A converting factor, still discussed in the literature and greatly depending of the constitutive organisms of the BSC, is the tool used to convert the amount of reduced ethylene into quantitative fixed Nitrogen. The aim of this poster is to describe an isotopic direct method to quantify the atmospheric dinitrogen fixation fluxes in BSC, while minimizing the variability due to manipulations. Nine different BSC from the Sahelian zone were selected and placed in an incubation room at 28° C in dark and light conditions during three days, while moisture equivalent to pF=2 was regularly adjusted using the gravimetric method with needles and deionized water, in order to activate and reach a dynamic stability of their metabolisms. Subsequently, each crust was placed into a gas-tight glass vial for incubation with a reconstituted 15N2 enriched atmosphere (31.61 % atom 15N, while the proportion of each main gas present in the air was conserved, i.e. 78% N2, 21% O2 and 0.04% CO2). Principal difficulties are to guarantee the airtighness of the system, to avoid crust desiccation and to keep the crust metabolically active under stable conditions for six hours. Several tests were performed to determine the optimum time for 15N2 incubation. Three replicated control samples per crust were also stabilized for three days and then dried at 105° C, without any incubation with 15N2 enriched atmosphere. Total N and 15N were then measured in the grounded (80μm) and dried (105° C) crust, using a Flash EA elemental analyzer (Eurovector, Milan, Italy) coupled to a Delta

  2. Knee stabiligy after ACL reconstruction through graft fixation in femoral tunnel: transfemoral pinning versus endobutton techniques

    Tahmasebi MN

    2011-05-01

    Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 st1":*{behavior:url(#ieooui } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} Background: One of the most common orthopedic complaints is direct or indirect trauma to the knee with torn anterior cruciate ligament (ACL. Reconstruction of the torn ACL is emphatically offered in active individuals as by this operation, we prevent osteoarthritis, knee instability and injury to the meniscus. There are numerous methods for graft fixation in the femoral tunnel in ACL reconstruction. If the graft proves to be stable after the operation, patients would not complain of giving way knee joints. In this clinical trial, we compared transfemoral pinning with endobutton fixation of hamstring graft in arthroscopic ACL reconstruction by examining knee stability and use of other relevant functional tests. "n"nMethods : Fourteen Patients who had undergone arthroscopic ACL reconstruction in Shariati Hospital during the years 2008-2009 and were being followed up were evaluated at least 15 months post-operatively by physical examination and the use of an arthrometer made by the Faculty of Mechanics of Sharif Technical University."n"nResults : The results showed that two out of seven patients in which their ACL had been reconstructed by hamstring graft fixation by endobutton technique, and

  3. Soybean seed treatment with nickel improves biological nitrogen fixation and urease activity

    José eLavres Junior

    2016-05-01

    Full Text Available Nickel (Ni is an essential micronutrient required for plants’ metabolism due to its role as a structural component of urease and hydrogenase, which in turn perform nitrogen (N metabolism in many legume species. Seed treatment with cobalt, molybdenum and Bradyrhizobium strains has been widely practiced to improve crops. Additionally, seed treatment together with Ni fertilization of soybean might improve the efficiency of biological nitrogen fixation (BNF, boosting grain dry matter yield and N content. The objective of this study was to evaluate the effect of soybean seed treatment with Ni rates (0, 45, 90,135, 180, 360 and 540 mg kg-1 on biological nitrogen fixation (BNF, directly by the 15N natural abundance method (δ15N‰ and by measurement of urease [E.C. 3.5.1.5] activity, as well as indirectly by nitrogenase (N-ase activity [E.C. 1.18.6.1]. Soybean plants (cultivar BMX Potência RR were grown in a sandy soil up to the R7 developmental stage (grain maturity, at which point the nutrient content in the leaves, chlorophyll content, urease and N-ase activities, Ni and N content in the grains, nodulation (at R1 - flowering stage, as well as the contribution of biological nitrogen fixation (δ15N ‰, were evaluated. The proportion of N derived from N2 fixation varied from 77 to 99% using the natural 15N abundance method and non-nodulating Panicum miliaceum and Phalaris canariensis as references. A Ni rate of 45 mg kg-1 increased BNF by 12% compared to the control. The increased N uptake in the grains was closely correlated with chlorophyll content in the leaves, urease and N-ase activities, as well as with nodulation. Grain dry matter yield and aerial part dry matter yield increased, respectively, by 84% and 51% in relation to the control plants at 45 mg kg-1 Ni via seed treatment. Despite, Ni concentration was increased with Ni-seed treatment, Ni rates higher than 135 mg kg-1 promoted negative effects on plant growth and yield. In these

  4. EEG Negativity in Fixations Used for Gaze-Based Control: Toward Converting Intentions into Actions with an Eye-Brain-Computer Interface

    Shishkin, Sergei L.; Nuzhdin, Yuri O.; Svirin, Evgeny P.; Trofimov, Alexander G.; Fedorova, Anastasia A.; Kozyrskiy, Bogdan L.; Velichkovsky, Boris M.

    2016-01-01

    We usually look at an object when we are going to manipulate it. Thus, eye tracking can be used to communicate intended actions. An effective human-machine interface, however, should be able to differentiate intentional and spontaneous eye movements. We report an electroencephalogram (EEG) marker that differentiates gaze fixations used for control from spontaneous fixations involved in visual exploration. Eight healthy participants played a game with their eye movements only. Their gaze-synchronized EEG data (fixation-related potentials, FRPs) were collected during game's control-on and control-off conditions. A slow negative wave with a maximum in the parietooccipital region was present in each participant's averaged FRPs in the control-on conditions and was absent or had much lower amplitude in the control-off condition. This wave was similar but not identical to stimulus-preceding negativity, a slow negative wave that can be observed during feedback expectation. Classification of intentional vs. spontaneous fixations was based on amplitude features from 13 EEG channels using 300 ms length segments free from electrooculogram contamination (200–500 ms relative to the fixation onset). For the first fixations in the fixation triplets required to make moves in the game, classified against control-off data, a committee of greedy classifiers provided 0.90 ± 0.07 specificity and 0.38 ± 0.14 sensitivity. Similar (slightly lower) results were obtained for the shrinkage Linear Discriminate Analysis (LDA) classifier. The second and third fixations in the triplets were classified at lower rate. We expect that, with improved feature sets and classifiers, a hybrid dwell-based Eye-Brain-Computer Interface (EBCI) can be built using the FRP difference between the intended and spontaneous fixations. If this direction of BCI development will be successful, such a multimodal interface may improve the fluency of interaction and can possibly become the basis for a new input device

  5. EEG Negativity in Fixations Used for Gaze-Based Control: Toward Converting Intentions into Actions with an Eye-Brain-Computer Interface

    Sergei L. Shishkin

    2016-11-01

    Full Text Available We usually look at an object when we are going to manipulate it. Thus, eye tracking can be used to communicate intended actions. An effective human-machine interface, however, should be able to differentiate intentional and spontaneous eye movements. We report an electroencephalogram (EEG marker that differentiates gaze fixations used for control from spontaneous fixations involved in visual exploration. Eight healthy participants played a game with their eye movements only. Their gaze-synchronized EEG data (fixation-related potentials, FRPs were collected during game’s control-on and control-off conditions. A slow negative wave with a maximum in the parietooccipital region was present in each participant’s averaged FRPs in the control-on conditions and was absent or had much lower amplitude in the control-off condition. This wave was similar but not identical to stimulus-preceding negativity, a slow negative wave that can be observed during feedback expectation. Classification of intentional vs. spontaneous fixations was based on amplitude features from 13 EEG channels using 300 ms length segments free from electrooculogram contamination (200..500 ms relative to the fixation onset. For the first fixations in the fixation triplets required to make moves in the game, classified against control-off data, a committee of greedy classifiers provided 0.90 ± 0.07 specificity and 0.38 ± 0.14 sensitivity. Similar (slightly lower results were obtained for the shrinkage LDA classifier. The second and third fixations in the triplets were classified at lower rate. We expect that, with improved feature sets and classifiers, a hybrid dwell-based Eye-Brain-Computer Interface (EBCI can be built using the FRP difference between the intended and spontaneous fixations. If this direction of BCI development will be successful, such a multimodal interface may improve the fluency of interaction and can possibly become the basis for a new input device for

  6. Clinical efficacy and safety of limited internal fixation combined with external fixation for Pilon fracture: A systematic review and meta-analysis

    Zhang, Shaobo; Zhang, Yibao; Wang, Shenghong; Zhang, Hua; Liu, Peng; Zhang, Wei; Ma, Jing-Lin; Wang, Jing

    2017-01-01

    Purpose: To compare the clinical efficacy and complications of limited internal fixation combined with external fixation (LIFEF) and open reduction and internal fixation (ORIF) in the treatment of Pilon fracture. Methods: We searched databases including Pubmed, Embase, Web of science, Cochrane Library and China Biology Medicine disc for the studies comparing clinical efficacy and complications of LIFEF and ORIF in the treatment of Pilon fracture. The clinical efficacy was evaluated by the ...

  7. Analysis and an overview of fixators in medicine and the methods of processing materials for producing fixators

    Dalibor Milojko Đenadić

    2013-06-01

    Full Text Available The fixator is a medical device that provides support to fractured biological structures. Metal biomaterials are mainly used for replacing broken or damaged hard tissues such as bones because of their high strenght, toughness and corrosion resistance. Materials such as stainless steel, titanium and aluminium alloys (Ti-6Al-4V, cobalt and chromium alloys, composite materials and other biocompatible materials are used in orthopedy for the stabilization of connective tissue injuries or as a substitute for the bone tissues. Fixators are classified according to the place of installation to external and internal fixators. Widely used medical fixators are pins, rods plates, screws, pipes, wires, nails and external fixators. Conventional and non-conventional methods of processing are used in the production process for all types of fixators. Introduction Fixators are medical devices manufactured to support damaged biological structures. In the field of orthopedic surgery that deals with skeletal disorders such as bone, spine, joints, muscles and tendons injuries and diseases, various metals, titanium and cobalt alloys etc. are used to stabilize the supporting tissue injuries or as a substitute for bone tissues. Metallic implants are frequently used in orthopedic surgery as joint prosthesis (hip, knee and elbow fracture fixation devices (plates, screws, external fixators and devices for the fixation of the spine. In principle, fixators are devided into external and internal ones, depending on the place of installation (outside or inside the body. The most common types of medical fixators are pins, rods and plates. This paper presents some of the most common materials used for the production of fixators, their processing and possibilties of use in medicine for various purposes. Types of fixators and materials used for their production Nowadays, biocompatible materials are usually used for the production of fixators and implants. These materials show good

  8. Glue versus suture for mesh fixation in inguinal hernia repair.

    Chandrasekar, Shruthi; Jeyakumar, S; Ganapathy, Tharun

    2018-03-22

    Inguinal hernia is one of the most common surgical problem presenting to the surgical OPD. Surgery is the mainstay of treatment for inguinal hernia today. Surgery for inguinal hernia has undergone a great evolution over a period of several centuries. Lichenstein's tension free hernioplasty is the one of the first surgeries taught to a surgical resident. The main aim of surgeries in this era is to give the best possible results with the least possible pain, scar and time. This has given rise to so many modifications to the classical Lichenstein's procedure and also to laparoscopic hernioplasty. Pain after inguinal hernia surgery is found to be debilitating and altering the quality of life in several patients, which has been attributed to the traumatic fixation of the mesh with sutures. This has paved way to the development of various atraumatic methods of fixation, tissue glue is one such development. Hence this study, to compare traumatic and atraumatic methods of mesh fixation in inguinal hernia repair. The aim of this study was to compare suture fixation versus tissue glue fixation of the mesh in inguinal hernia repair. Primary objective was to compare the immediate and chronic post-operative pain. Secondary objective was to compare the time taken for the procedure by the two methods in use and also to compare the presence of any complications. and methodology: This study was done in the General Surgery department of XXX hospital, medical college and research centre, kattangulathur after Ethics committee clearance. It is a single blinded study. The study was done on 51 patients consenting for the study and meeting the inclusion criterias from the period of March 2016 to August 2017 out of which 26 were selected for glue mesh fixation and 25 for suture mesh fixation according to simple randomization. The suture group patients underwent classical Lichenstein's tension free hernioplasty and the glue group underwent Lichenstein's hernioplasty with glue where dots of

  9. Root contact with maxillomandibular fixation screws in orthognathic surgery: incidence and consequences.

    Camargo, I B; Van Sickels, J E; Laureano Filho, J R; Cunningham, L L

    2016-08-01

    The use of maxillomandibular fixation (MMF) screws in orthognathic surgery has become common in recent years. The risk of injury to adjacent roots with their placement in this population has not been studied extensively. The aim of this study was to review the incidence and consequences of root contact/injury in patients undergoing orthognathic surgery. A retrospective analysis of the treatment and radiographic records of patients who underwent orthognathic surgery between January 2013 and September 2014 at a university in Kentucky, USA was performed. The mean number of screws used was correlated to the mean number of roots affected using Spearman's test, set to a level of significance of 5%. Of 125 patients who underwent orthognathic surgery, 15 (12%) had evidence of root contact. Subsequent radiographs showed resolution of the bone defects. There was no clinical evidence of pulpal necrosis or pain during follow-up. The average number of screws used was 3.14±0.35 per patient, with an average of 0.17±0.52 root contacts per patient. There was no correlation between the number of screws used and the number of roots injured (P=0.279). Based on these results, MMF screws can safely be used to establish interim fixation during orthognathic surgery. Caution should be taken during placement to avoid direct injury to the roots of teeth. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  10. C-2 anterior plate-screw fixation: a quantitative anatomical and morphometric evaluation.

    Senoglu, M; Ozbag, D; Gumusalan, Y

    2010-01-01

    Discectomy and inter-vertebral body fusion combined with the anterior plate-screw fixa tion is the common procedure in cervical spine surgery. But the anterior plate-screw fixation of the C2 spine has been the uncommon surgical procedure. In this study, we analyze the anatomy of the C2 body relevant to C2 anterior plate-screw fixation. Eighty-six dried C2 spines were evaluated directly for this study. Measurements were made on the C2 body width and midsagittal anteroposterior (AP) depth and the anteroposterior parasagittal depth 5 mm lateral to midline on the inferior endplates, in addition to on the middle body. Measurements also were made of anteroposterior parasagittal vertebral depth with both medial and lateral inclination of 10 degrees, with respect to the parasagittal plane of the vertebral body. The ideal maximum screw length and trajectory was found to be AP medial parasagittal depth of inferior surface of the C2 body [Right: 13.7 +/- 1.4 mm (11.0-17.9), Left: 13.6 +/- 1.5 mm (10.7-17.8)]. We report the measurements of the vertebral body of the C2. We think these measurements provide guidelines for operating on the anterior C2 spine, and enhance the confidence interval for the surgeon (Tab. 3, Fig. 1, Ref. 24).

  11. Clinical use of computed tomography and surface markers to assist internal fixation within the equine hoof.

    Gasiorowski, Janik C; Richardson, Dean W

    2015-02-01

    To describe clinical use of computed tomography (CT) and hoof surface markers to facilitate internal fixation within the confines of the hoof wall. Retrospective case series. Horses (n = 16) that had CT-guided internal fixation of the distal phalanx (DP) or distal sesamoid bone (DSB). Drill bit entry point and direction were planned from CT image series performed on hooves with grids of barium paste dots at proposed entry and projected exit sites. Post-implantation CT images were obtained to check screw position and length as well as fracture reduction. Imaging, reduction, and surgical and general anesthesia times were evaluated. Outcome was recorded. Screw position and length were considered near optimal in all horses, with no consequential malposition of bits or screws. Fracture reduction was evident in all cases. Preoperative planning times (at least 2 CT image acquisitions and grid creation) ranged from 10 to 20 minutes. Surgery time ranged from 45 to 90 minutes (mean, 61 minutes) and general anesthesia time ranged from 115 to 220 minutes (mean, 171 minutes). The combination of CT and surface marker grids allowed accurate positioning of screws in clinical DP and DSB fractures. The technique was simple and rapid. An aiming device is useful for the technique. © Copyright 2014 by The American College of Veterinary Surgeons.

  12. Results of operative fixation of unstable ankle fractures in geriatric patients.

    Pagliaro, A J; Michelson, J D; Mizel, M S

    2001-05-01

    It is widely accepted that operative fixation of unstable ankle fractures yields predictably good outcomes in the general population. The current literature, however reports less acceptable results in the geriatric population age 65 years and older. The current study analyzes the outcome of the surgical treatment of unstable ankle fractures in patients at least 65 years old. Twenty three patient over 65 years old were surgically treated after sustaining 21 (91%) closed and 2 (9%) open grade II unstable ankle fractures. Fractures were classified according to the Danis-Weber and Lauge-Hansen schemes. Fracture type was predominantly Weber B (21/23, 91%), or supination external rotation stage IV (21/23, 91%). Fracture union rate was 100%. There were three significant complications including a lateral wound dehiscence with delayed fibular union in an open fracture dislocation, and two below knee amputations, neither of which was directly related to the fracture treatment. There were three minor complications; one superficial wound infection and two cases of prolonged incision drainage, all of which resolved without further surgical intervention. Complications were associated with open fractures and preexisting systemic disease. These results indicate that open reduction and internal fixation of unstable ankle fractures in geriatric patients is an efficacious treatment regime that with results that are comparable to the general population.

  13. Visual scan-path analysis with feature space transient fixation moments

    Dempere-Marco, Laura; Hu, Xiao-Peng; Yang, Guang-Zhong

    2003-05-01

    The study of eye movements provides useful insight into the cognitive processes underlying visual search tasks. The analysis of the dynamics of eye movements has often been approached from a purely spatial perspective. In many cases, however, it may not be possible to define meaningful or consistent dynamics without considering the features underlying the scan paths. In this paper, the definition of the feature space has been attempted through the concept of visual similarity and non-linear low dimensional embedding, which defines a mapping from the image space into a low dimensional feature manifold that preserves the intrinsic similarity of image patterns. This has enabled the definition of perceptually meaningful features without the use of domain specific knowledge. Based on this, this paper introduces a new concept called Feature Space Transient Fixation Moments (TFM). The approach presented tackles the problem of feature space representation of visual search through the use of TFM. We demonstrate the practical values of this concept for characterizing the dynamics of eye movements in goal directed visual search tasks. We also illustrate how this model can be used to elucidate the fundamental steps involved in skilled search tasks through the evolution of transient fixation moments.

  14. A New Paradigm for Tissue Diagnostics: Tools and Techniques to Standardize Tissue Collection, Transport, and Fixation.

    Bauer, Daniel R; Otter, Michael; Chafin, David R

    2018-01-01

    Studying and developing preanalytical tools and technologies for the purpose of obtaining high-quality samples for histological assays is a growing field. Currently, there does not exist a standard practice for collecting, fixing, and monitoring these precious samples. There has been some advancement in standardizing collection for the highest profile tumor types, such as breast, where HER2 testing drives therapeutic decisions. This review examines the area of tissue collection, transport, and monitoring of formalin diffusion and details a prototype system that could be used to help standardize tissue collection efforts. We have surveyed recent primary literature sources and conducted several site visits to understand the most error-prone processes in histology laboratories. This effort identified errors that resulted from sample collection techniques and subsequent transport delays from the operating room (OR) to the histology laboratories. We have therefore devised a prototype sample collection and transport concept. The system consists of a custom data logger and cold transport box and takes advantage of a novel cold + warm (named 2 + 2) fixation method. This review highlights the beneficial aspects of standardizing tissue collection, fixation, and monitoring. In addition, a prototype system is introduced that could help standardize these processes and is compatible with use directly in the OR and from remote sites.

  15. Robust biological nitrogen fixation in a model grass-bacterial association.

    Pankievicz, Vânia C S; do Amaral, Fernanda P; Santos, Karina F D N; Agtuca, Beverly; Xu, Youwen; Schueller, Michael J; Arisi, Ana Carolina M; Steffens, Maria B R; de Souza, Emanuel M; Pedrosa, Fábio O; Stacey, Gary; Ferrieri, Richard A

    2015-03-01

    Nitrogen-fixing rhizobacteria can promote plant growth; however, it is controversial whether biological nitrogen fixation (BNF) from associative interaction contributes to growth promotion. The roots of Setaria viridis, a model C4 grass, were effectively colonized by bacterial inoculants resulting in a significant enhancement of growth. Nitrogen-13 tracer studies provided direct evidence for tracer uptake by the host plant and incorporation into protein. Indeed, plants showed robust growth under nitrogen-limiting conditions when inoculated with an ammonium-excreting strain of Azospirillum brasilense. (11)C-labeling experiments showed that patterns in central carbon metabolism and resource allocation exhibited by nitrogen-starved plants were largely reversed by bacterial inoculation, such that they resembled plants grown under nitrogen-sufficient conditions. Adoption of S. viridis as a model should promote research into the mechanisms of associative nitrogen fixation with the ultimate goal of greater adoption of BNF for sustainable crop production. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

  16. Minimally invasive mini open split-muscular percutaneous pedicle screw fixation of the thoracolumbar spine

    Murat Ulutaş

    2015-03-01

    Full Text Available We prospectively assessed the feasibility and safety of a new percutaneous pedicle screw (PPS fixation technique for instrumentation of the thoracic and lumbar spine in this study. All patients were operated in the prone position under general anesthesia. A 6 to 8 cm midline skin incision was made and wide sub-cutaneous dissection was performed. The paravertebral muscles were first dissected subperiosteally into the midline incision of the fascia for lumbar microdiscectomy with transforaminal lumbar interbody fusion cage implantation. After the secondary paramedian incisions on the fascia, the PPSs were inserted via cleavage of the multifidus muscles directly into the pedicles under fluoroscopy visualization. A total of 35 patients underwent surgery with this new surgical technique. The control group for operative time, blood loss and analgesic usage consisted of 35 randomly selected cases from our department. The control group underwent surgery via conventional pedicle screw instrumentation with paramedian fusion. All patients in the minimal invasive surgery series were ambulatory with minimal pain on the first postoperative day. The operation time and blood loss and the postoperative analgesic consumption were significantly less with this new technique. In conclusion, the minimal invasive mini open split-muscular percutaneous pedicle screw fixation technique is safe and feasible. It can be performed via a short midline skin incision and can also be combined with interbody fusion, causing minimal pain without severe muscle damage.

  17. The influence on the contact condition and initial fixation stability of the main design parameters of a self-expansion type anterior cruciate ligament fixation device

    Kim, Jong Dae; Oh, Chae Youn; Kim, Cheol Sang

    2008-01-01

    This paper proposes a self-expansion type anterior cruciate ligament fixation device. The proposed fixation device provides graft fixation force by maintaining contact with the bone tunnel. Since the device maintains contact with the bone tunnel by the force that expands by the self-driven elastic force of the device, the main design parameters that determine the performance of this device are the ring thickness and expansion angle. This paper develops the three-dimensional finite element models of the fixation device and bone. By simulation with the developed finite element model, this paper studies the influence of the main design parameters of the device on the maximum stress around the ring when grasping the fixation device. Through the analysis of the stress on the bone tunnel wall when the fixation device comes in contact with the bone tunnel, this paper shows the influence of the main design parameters of the fixation device on the contact condition. In addition, through the analysis of the migration that occur upon application of the pull-out force, this paper studies the influence of the main design parameters on the initial fixation stability of the fixation device

  18. The influence on the contact condition and initial fixation stability of the main design parameters of a self-expansion type anterior cruciate ligament fixation device

    Kim, Jong Dae [Jeonju University, Jeonju (Korea, Republic of); Oh, Chae Youn; Kim, Cheol Sang [Chonbuk National University, Jeonju (Korea, Republic of)

    2008-12-15

    This paper proposes a self-expansion type anterior cruciate ligament fixation device. The proposed fixation device provides graft fixation force by maintaining contact with the bone tunnel. Since the device maintains contact with the bone tunnel by the force that expands by the self-driven elastic force of the device, the main design parameters that determine the performance of this device are the ring thickness and expansion angle. This paper develops the three-dimensional finite element models of the fixation device and bone. By simulation with the developed finite element model, this paper studies the influence of the main design parameters of the device on the maximum stress around the ring when grasping the fixation device. Through the analysis of the stress on the bone tunnel wall when the fixation device comes in contact with the bone tunnel, this paper shows the influence of the main design parameters of the fixation device on the contact condition. In addition, through the analysis of the migration that occur upon application of the pull-out force, this paper studies the influence of the main design parameters on the initial fixation stability of the fixation device

  19. Complications Using Bioabsorbable Cross-Pin Femoral Fixation: A Case Report and Review of the Literature

    Saqib Hasan

    2011-01-01

    Full Text Available The use of bioabsorbable cross-pin transcondylar fixation has remained a viable option for femoral fixation in anterior cruciate ligament reconstruction. Although numerous biomechanical studies have demonstrated high fixation strength and minimal slippage with use of this method of fixation, there have been increasing reports of a variety of clinical complications associated with these implants. We reviewed the literature for all complications associated with the Bio-TransFix implant and present a case report of a patient status after ACL reconstruction using Bio-TransFix cross-pin femoral fixation with iliotibial band friction syndrome from a broken cross-pin four month post-operatively.

  20. Fixation of a human rib by an intramedullary telescoping splint anchored by bone cement.

    Liovic, Petar; Šutalo, Ilija D; Marasco, Silvana F

    2016-09-01

    A novel concept for rib fixation is presented that involves the use of a bioresorbable polymer intramedullary telescoping splint. Bone cement is used to anchor each end of the splint inside the medullary canal on each side of the fracture site. In this manner, rib fixation is achieved without fixation device protrusion from the rib, making the splint completely intramedullary. Finite element analysis is used to demonstrate that such a splint/cement composite can preserve rib fixation subjected to cough-intensity force loadings. Computational fluid dynamics and porcine rib experiments were used to study the anchor formation process required to complete the fixation.

  1. Novel anterior cruciate ligament graft fixation device reduces slippage

    Lopez MJ

    2013-05-01

    Full Text Available Mandi J Lopez,1 Allen Borne,2 W Todd Monroe,3 Prakash Bommala,1 Laura Kelly,1 Nan Zhang11Laboratory for Equine and Comparative Orthopedic Research, Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, 2Louisiana State University, New Orleans Health Sciences Center, School of Medicine, New Orleans, 3Department of Biological and Agricultural Engineering, Agricultural Center, Louisiana State University, Baton Rouge, LA, USAAbstract: Clinically significant laxity occurs in 10%–30% of knees after anterior cruciate ligament reconstruction. Graft slippage and tension loss at the hamstring graft tibial fixation site during and after reconstruction surgery contribute to postoperative joint laxity and are detrimental to long-term knee stability and graft properties. Limiting graft slippage will reduce associated complications. We sought to compare the in vitro mechanical properties and in vivo joint stabilization, postoperative limb use, and graft incorporation of the novel GraftGrab™ (GG device designed to reduce hamstring graft tibial fixation slippage with the commercially available bioabsorbable Bio-Post™ and spiked washer (BP. Mechanical testing was performed on canine tibia-hamstring graft constructs to quantify initial fixation properties. In vivo joint stabilization, postoperative limb use and graft incorporation of hamstring graft reconstructions were determined in a canine model. Outcomes included tibial translation and ground reaction forces preoperatively and 4 and 8 weeks postoperatively, three-dimensional graft and bone tunnel dimensions at the latter two time points, and graft-bone microstructure, as well as mechanical properties 8 weeks after implantation. Immediately after fixation, all grafts slipped from the BP constructs versus about 30% of GG constructs. In vivo limb use remained low, and tibial translation increased with time in the BP cohort. These results together

  2. EXPERIMENTAL APPROVAL OF COMBINED FIXATION FOR FEMUR LENGTHENING

    M. A. Stepanov

    2017-01-01

    Full Text Available Elimination of congenital shortening of lower limb still remains a complex and unsolved orthopaedic task which requires an improved fixation technique as well as adjusted tactics of treatment and rehabilitation procedures.Purpose of the study — experimental approval of femur lengthening technique by external fixation with Ilizarov apparatus and internal fixation by plate.Materials and methods. Femur lengthening was performed in 6 mongrel dogs. Average animal age was 1,5±0,3 years, average weight — 20±5 kg, femur length — 22±2 sm. External apparatus with two supports and a titanium plate of an original design were applied under general anesthesia on the right femur of animals. Lengthening was performed manually at a rate of1 mm per day in 4 stages at a distance of 10% from initial segment length. External apparatus was removed on the last day of distraction after locking the plate. X-ray examination was done on the day of surgery, in 7, 14 and 25 days from the onset of distraction as well as in 14, 30, 60 and 90 days after completion of distraction and removal of external apparatus. Three animals were taken out of experiment in 30 days of fixation, remaining three animals — in 90 days. After euthanasia the authors performed autopsy of the organic femur complex and tissues contacting the plate.Results. The use of operated limb was not restricted during the whole distraction period. The authors observed first roentgenological signs of distraction osteogenesis on 7th day of lengthening. By the end of distraction period, at 25th day, shadows of regenerates demonstrated longitudinal striated structures in all cases. Median lucency area of 1–5 mm was located diagonally and across the regenerate or was intermittent. In 60 days of fixation X-rays demonstrated homogeneous regenerate. External fixation index was 13,9±1,5 days/sm (p≤0,05. The authors observed no cases of implants fracture or deformity during the experiment

  3. Deepwater Nitrogen Fixation: Who's Doing it, Where, and Why?

    Montoya, J. P.; Weber, S.; Vogts, A.; Voss, M.; Saxton, M.; Joye, S. B.

    2016-02-01

    Nitrogen availability frequently limits marine primary production and N2-fixation plays an important role in supporting biological production in surface waters of many oligotrophic regions. Although subsurface waters typically contain high concentrations of nitrate and other nutrients, measurements from a variety of oceanic settings show measurable, and at times high rates of N2-fixation in deep, dark waters below the mixed layer. We have explored the distribution of N2-fixation throughout the water column of the Gulf of Mexico (GoM) during a series of cruises beginning shortly after the Deepwater Horizon (DWH) spill in 2010 and continuing at roughly annual intervals. These cruises allowed us to sample oligotrophic waters across a range of depths, and to explore the connections between the C and N cycles mediated by release of oil and gas (petrocarbon) from natural seeps as well as anthropogenic sources (e.g., the DWH). We used stable isotope abundances (15N and 13C) in particles and zooplankton in combination with experimental measurements of N2-fixation and CH4 assimilation to assess the contribution of oil- and gas-derived C to the pelagic food web, and the impact of CH4 releases on the pelagic C and N cycles. Our isotopic measurements document the movement of petrocarbon into the pelagic food web, and our experiments revealed that high rates of N2-fixation were widespread in deep water immediately after the DWH incident, and restricted to the vicinity of natural seeps in subsequent years. Unfortunately, these approaches provided no insight into the organisms actually responsible for N2-fixation and CH4-assimilation. We used nano-scale Secondary Ion Mass Spectrometry (nanoSIMS) to image the organisms responsible for these processes, and molecular approaches to explore the diversity of methanotrophs and diazotrophs present in the system. The ability to resolve isotopic distributions on the scale of individual cells is a critical part of bridging the gap between

  4. Seasonal patterns of periphyton nitrogen fixation in calcareous wetlands

    Liao, X.; Inglett, P.

    2011-12-01

    Periphyton mats are an ecologically important component of the Everglades ecosystem and plays various vital ecological functions. However, nitrogen fixation of periphyton, has received little attention throughout much of the Everglades system. The objective of this study was to characterize the seasonal pattern of periphyton N2 fixation in the Hole-in-the-Donut (HID) of Florida Everglades, where farmed marl prairie wetlands have been restored through complete soil removal (CSR) to reduce nutrient levels. Two restored areas (i.e., cleared in 2000 and 2003) and a reference (natural and unfarmed) marl prairie wetland sites were selected in the HID. Seven times of sampling were performed across the wet and dry season during the 2010 and 2011. The annual fixed nitrogen was approximately 0.4gN m-2 yr-1 in the restored sites which was higher in the reference site (~0.2gN m-2 yr-1). All the three sites showed similar seasonal patterns of N2 fixation that is higher values were observed in the wet season; but the peak value was one month later in reference sits (i.e., September) comparing to the restored areas (i.e., July). The peak of periphyton AR rates in the 2000- and 2003-restored areas appeared in July (i.e., wet season) within the range of 20-79 nmols g-1dw h-1 and 31-53nmols g-1dw h-1, respectively. In contrast, the peak of reference site was observed in September with the range of 2-5 nmols g-1dw h-1. Stable N isotopic ratios (i.e., δ15N) also varied with time but didn't show consistent seasonal pattern as nitrogen fixation. N2 fixation positively correlated with periphyton total phosphorus (TP) and negatively correlated with total nitrogen and phosphorus molar ratios (TN:TP), indicating that N2 fixation would be a indicator of nutrient limitation. In general, δ15N was negatively correlated with nitrogenase activity but the correlation became weakened in the wet season, especially in the flooded July and September, which would be explained by other environmental

  5. Directional Positive Selection on an Allele of Arbitrary Dominance

    Teshima, Kosuke M.; Przeworski, Molly

    2006-01-01

    Most models of positive directional selection assume codominance of the beneficial allele. We examine the importance of this assumption by implementing a coalescent model of positive directional selection with arbitrary dominance. We find that, for a given mean fixation time, a beneficial allele has a much weaker effect on diversity at linked neutral sites when the allele is recessive.

  6. Enzymatic regulation of photosynthetic and light-independent carbon fixation in Laminaria setchellii (Phaeophyta, Ulva lactuca (Chlorophyta and Iridaea cordata (Rhodophyta Regulación enzimática de la fotosíntesis y la fijación de carbono en obscuridad por Laminaria setchellii (Phaeophyta, Ulva lactuca (Chlorophyta e Iridaea cordata (Rhodophyta

    ALEJANDRO CABELLO-PASINI

    2001-06-01

    Full Text Available Carbon is acquired through photosynthetic and non-photosynthetic processes in marine algae. However, little is known about the biochemical regulation of these metabolic pathways along the thallus of seaweeds. Consequently, the objective of this study was to assess the distribution of in vivo carboxylation pathways and to relate them to the in vitro activity of ribulose 1,5-bisphosphate carboxylase/oxygenase (RUBISCO, phosphoenolpyruvate carboxykinase (PEPCK, and phosphoenolpyruvate carboxylase (PEPC in the Phaeophyte Laminaria setchellii, the Chlorophyte Ulva lactuca, and the Rhodophyte Iridaea cordata. Chlorophyll-a levels did not vary in U. lactuca and I. cordata. However, pigment levels were significantly lower in the meristematic region of L. setchellii probably as a result of a lack of differentiation of the chloroplasts in this region. Similarly, net photosynthesis did not vary in the thallus of U. lactuca and I. cordata, while it increased from the stipe and meristem towards the lamina of L. setchellii. In contrast to photosynthesis, light-independent carbon fixation rates were significantly greater in the meristematic region of L. setchellii suggesting a compensating mechanism for carbon incorporation in photosynthetically limited tissue. The activity of RUBISCO and PEPCK followed a pattern similar to that of in vivo carboxylation processes indicating that in vivo carbon assimilation is regulated by the activity of the carboxylating enzymes throughout the thallus of L. setchelliiLa incorporación de carbono en algas marinas se lleva a cabo mediante procesos fotosintéticos y no-fotosintéticos. Sin embargo, poco se sabe sobre la regulación bioquímica de estas rutas metabólicas en el tejido de algas marinas. En consecuencia, el objetivo de este estudio fue el de evaluar la distribución de la carboxilación in vivo y relacionarlas a la actividad in vitro de ribulosa 1,5-bisfosfato carboxilasa/oxigenasa (RUBISCO, fosfoenolpiruvato

  7. Regulation of methanol oxidation and carbon dioxide fixation in Xanthobacter strain 25a grown in continuous culture

    Croes, L.M.; Meijer, Wilhelmus; Dijkhuizen, L.

    The regulation of C1-metabolism in Xanthobacter strain 25a was studied during growth of the organism on acetate, formate and methanol in chemostat cultures. No activity of methanol dehydrogenase (MDH), formate dehydrogenase (FDS) or ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisC/O) could be

  8. Ball-joint versus single monolateral external fixators for definitive treatment of tibial shaft fractures.

    Beltsios, Michail; Mavrogenis, Andreas F; Savvidou, Olga D; Karamanis, Eirineos; Kokkalis, Zinon T; Papagelopoulos, Panayiotis J

    2014-07-01

    To compare modular monolateral external fixators with single monolateral external fixators for the treatment of open and complex tibial shaft fractures, to determine the optimal construct for fracture union. A total of 223 tibial shaft fractures in 212 patients were treated with a monolateral external fixator from 2005 to 2011; 112 fractures were treated with a modular external fixator with ball-joints (group A), and 111 fractures were treated with a single external fixator without ball-joints (group B). The mean follow-up was 2.9 years. We retrospectively evaluated the operative time for fracture reduction with the external fixator, pain and range of motion of the knee and ankle joints, time to union, rate of malunion, reoperations and revisions of the external fixators, and complications. The time for fracture reduction was statistically higher in group B; the rate of union was statistically higher in group B; the rate of nonunion was statistically higher in group A; the mean time to union was statistically higher in group A; the rate of reoperations was statistically higher in group A; and the rate of revision of the external fixator was statistically higher in group A. Pain, range of motion of the knee and ankle joints, rates of delayed union, malunion and complications were similar. Although modular external fixators are associated with faster intraoperative fracture reduction with the external fixator, single external fixators are associated with significantly better rates of union and reoperations; the rates of delayed union, malunion and complications are similar.

  9. Time Savings and Surgery Task Load Reduction in Open Intraperitoneal Onlay Mesh Fixation Procedure

    Sanjoy Roy

    2015-01-01

    Full Text Available Background. This study assessed the reduction in surgeon stress associated with savings in procedure time for mechanical fixation of an intraperitoneal onlay mesh (IPOM compared to a traditional suture fixation in open ventral hernia repair. Study Design. Nine general surgeons performed 36 open IPOM fixation procedures in porcine model. Each surgeon conducted two mechanical (using ETHICON SECURESTRAPTM Open and two suture fixation procedures. Fixation time was measured using a stopwatch, and related surgeon stress was assessed using the validated SURG-TLX questionnaire. T-tests were used to compare between-group differences, and a two-sided 95% confidence interval for the difference in stress levels was established using nonparametric methodology. Results. The mechanical fixation group demonstrated an 89.1% mean reduction in fixation time, as compared to the suture group (p<0.00001. Surgeon stress scores measured using SURG-TLX were 55.5% lower in the mechanical compared to the suture fixation group (p<0.001. Scores in five of the six sources of stress were significantly lower for mechanical fixation. Conclusions. Mechanical fixation with ETHICON SECURESTRAPTM Open demonstrated a significant reduction in fixation time and surgeon stress, which may translate into improved operating efficiency, improved performance, improved surgeon quality of life, and reduced overall costs of the procedure.

  10. Small bowel obstruction in percutaneous fixation of traumatic pelvic fractures

    Roberto Bini

    2013-01-01

    Full Text Available The use of external fixation for the initial treatment of unstable, complex pelvic injuries with hemodynamic instability remains an effective treatment for multiply injured patients. Bowel entrapment within a pelvic fracture is a rarely reported, potentially fatal complication. Here, we report a polytrauma patient with pelvic fractures who developed an intestinal obstruction after an external fixation. At an explorative laparotomy, we found an ileum segment trapped in the sacral fracture. Reported cases of bowel entrapment in pelvic fractures, especially in sacral fractures, are exceedingly rare. The diagnosis is often delayed due to difficulty distinguishing entrapment from the more common adynamic ileus. In conclusion, clinicians and radiologists should be aware of this potentially lethal complication of pelvic fractures treatment. To exclude bowel entrapment, patients with persistent ileus or sepsis should undergo early investigations.

  11. Molecular nitrogen fixation and nitrogen cycle in nature

    Virtanen, A I

    1952-01-01

    The origin of nitrogen oxides in the atmosphere is discussed. Evidently only a small proportion of the nitrate-and nitrite-nitrogen found in the precipitation is formed through electric discharges from molecular nitrogen, photochemical nitrogen fixation being probably of greater importance. Formation of nitrate nitrogen through atmospheric oxidation of nitrous oxide (N/sub 2/O) evaporating from the soil is also considered likely. Determination of nitrogen compounds at different altitudes is indispensable for gaining information of the N/sub 2/-fixation in the atmosphere and, in general, of the origin of nitrogen oxides and their decomposition. International cooperation is needed for this as well as for the quantitative determination of the nitrogen compounds removed from the soil by leaching and brought by waters into the seas.

  12. CO2 Fixation by Membrane Separated NaCl Electrolysis

    Park, Hyun Sic; Lee, Ju Sung; Han, Junyoung

    2015-01-01

    for converting CO2 into CaCO3 requires high temperature and high pressure as reaction conditions. This study proposes a method to fixate CaCO3 stably by using relatively less energy than existing methods. After forming NaOH absorbent solution through electrolysis of NaCl in seawater, CaCO3 was precipitated...... crystal product was high-purity calcite. The study shows a successful method for fixating CO2 by reducing carbon dioxide released into the atmosphere while forming high-purity CaCO3.......Atmospheric concentrations of carbon dioxide (CO2), a major cause of global warming, have been rising due to industrial development. Carbon capture and storage (CCS), which is regarded as the most effective way to reduce such atmospheric CO2 concentrations, has several environmental and technical...

  13. Bone graft materials in fixation of orthopaedic implants in sheep

    Babiker, Hassan

    2013-01-01

    Bone graft is widely used within orthopaedic surgery especially in revision joint arthroplasty and spine fusion. The early implant fixation in the revision situation of loose joint prostheses is important for the long-term survival. Bone autograft has been considered as gold standard in many...... orthopaedic procedures, whereas allograft is the gold standard by replacement of extensive bone loss. However, the use of autograft is associated with donor site morbidity, especially chronic pain. In addition, the limited supply is a significant clinical challenge. Limitations in the use of allograft include...... the risk of bacterial contamination and disease transmission as well as non-union and poor bone quality. Other bone graft and substitutes have been considered as alternative in order to improve implant fixation. Hydroxyapatite and collagen type I composite (HA/Collagen) have the potential in mimicking...

  14. Optimising biological N2 fixation by legumes in farming systems

    Hardarson, Gudni; Atkins, Craig

    2001-01-01

    Whether grown as pulses for grain, as green manure, as pastures or as the tree components of agro-forestry systems, the value of leguminous crops lies in their ability to fix atmospheric N 2 , so reducing the use of expensive fertiliser N and enhancing soil fertility. N 2 fixing legumes provide the basis for developing sustainable farming systems that incorporate integrated nutrient management. By exploiting the stable nitrogen isotope 15 N, it has been possible to reliably measure rates of N 2 fixation in a wide range of agro-ecological field situations involving many leguminous species. The accumulated data demonstrate that there is a wealth of genetic diversity among legumes and their Rhizobium symbionts which can be used to enhance N 2 fixation. Practical agronomic and microbiological means to maximise N inputs by legumes have also been identified. (author)

  15. Fixation Of Mo In Uranium Leach Liquor By Activated Carbon

    Mainar, S.; Guswita, A.; Erni, R.A.; Susilaningtyas

    1996-01-01

    The use of activated carbon for Mo fixation by bulk system is reported. Several factors influencing the fixation process were examined, including contact time, carbon particle size, carbon porosity and the effect of other elements present in Mo containing solutions. Experimental data showed that an adsorption equilibrium of Mo on of activated carbon and 0,85 to 1,18 mm of carbon particle size under forced-convection mass transfer in 100 ml solution that contains + 0,56 m mol of Mo and +. 0,25 m mol Of U was reached after 6 hours period. Under those conditions, about 0,50 m mol of Mo and 0,026 m mol of U were adsorbed into carbon. High concentration of rare earth elements decreased Mo adsorption, hence, the use of activated carbon was not effective to separate Mo from the digestion liquor of Rirang are where Mo was adsorbed, into the carbon + 34,5 %

  16. Monotest in the complement fixation test: the Chorus system

    Laura Meli

    2009-06-01

    Full Text Available The complement fixation test (CFT is a method used for the detection of antibodies against pathogens of infectious diseases, it has been proved to be a useful diagnostic method in the detection of acute disease in many medical laboratories.The test performed manually is time consuming and needs very skilled personnel.This study evaluates the automated Chorus CFT system with 87 serum samples in comparison with manual method using Virion-Serion reagents, against a panel of antigens, such as Adenovirus, Influenza A and B virus, Respiratory Syncythial Virus, Parainfluenza Mix, Mycoplasma Pneumoniae, and Echinococcus. The Chorus system includes standardized reagents and a monotest device to perform the single assay. In comparison to the manual CFT method, the correlation is 91.6% (7/83.The results obtained show that the automated Chorus system can be applied for detecting complement fixation antibodies against different infectious disease agents.

  17. Scleral fixation of a single-piece multifocal intraocular lens.

    Can, Ertugrul; Basaran, M Resat; Gül, Adem

    2013-01-01

    We describe an ab interno technique for injector implantation of a one-piece multifocal intraocular lens (IOL). Transscleral fixation of multifocal posterior chamber IOL implantation using an injector with ab interno technique was performed in an eye of a 9-year-old girl who had undergone pars plana lensectomy 2 years before for bilateral lens subluxation with unknown etiology. No major complications were encountered during a 3-month follow-up of the patient and excellent centration was observed during the follow-up period. Her preoperative best spectacle-corrected distance visual acuity of 20/32 improved to uncorrected distance visual acuity of 20/25. Closed-loop design of IOL served the function of eyelets and position of the IOL was provided using only a 2-point fixation. Intraoperative position adjustment of the IOL provided an excellent centralization of multifocal IOL.

  18. Fixational eye movement: a negligible source of dynamic aberration.

    Mecê, Pedro; Jarosz, Jessica; Conan, Jean-Marc; Petit, Cyril; Grieve, Kate; Paques, Michel; Meimon, Serge

    2018-02-01

    To evaluate the contribution of fixational eye movements to dynamic aberration, 50 healthy eyes were examined with an original custom-built Shack-Hartmann aberrometer, running at a temporal frequency of 236Hz, with 22 lenslets across a 5mm pupil, synchronized with a 236Hz pupil tracker. A comparison of the dynamic behavior of the first 21 Zernike modes (starting from defocus) with and without digital pupil stabilization, on a 3.4s sequence between blinks, showed that the contribution of fixational eye movements to dynamic aberration is negligible. Therefore we highlighted the fact that a pupil tracker coupled to an Adaptive Optics Ophthalmoscope is not essential to achieve diffraction-limited resolution.

  19. [Effectiveness comparison of flexible fixation and rigid fixation in treatment of ankle pronation-external rotation fractures with distal tibiofibular syndesmosis].

    Li, Yuewei; Zhang, Minghui; Li, Xiaorong; Chen, Xiaoyong; Deng, Jianlong

    2017-07-01

    To compare the effectiveness of flexible fixation and rigid fixation in the treatment of ankle pronation-external rotation fractures with distal tibiofibular syndesmosis. A retrospective analysis was made on the clinical data of 50 patients with ankle pronation-external rotation fractures and distal tibiofibular syndesmosis treated between January 2013 and December 2015. Suture-button fixation was used in 23 patients (flexible fixation group) and cortical screw fixation in 27 patients (rigid fixation group). There was no significant difference in age, gender, weight, side, fracture type, and time from trauma to surgery between 2 groups ( P >0.05). The operation time, medial clear space (MCS), tibiofibular clear space (TFCS), tibiofibular overlap (TFO), American Orthopaedic Foot and Ankle Society (AOFAS) score, and Foot and Ankle Disability Index (FADI) score were compared between 2 groups. The operation time was (83.0±9.1) minutes in the flexible fixation group and was (79.6±13.1) minutes in the rigid fixation group, showing no significant difference ( t =1.052, P =0.265). All patients achieved healing of incision by first intention. The patients were followed up 12-20 months (mean, 14 months). The X-ray films showed good healing of fracture in 2 groups. There was no screw fracture, delayed union or nounion. The fracture healing time was (12.1±2.5) months in the flexible fixation group and was (11.3±3.2) months in the rigid fixation group, showing no significant difference between 2 groups ( t =1.024, P =0.192). Reduction loss occurred after removal of screw in 2 cases of the rigid fixation group. At last follow-up, there was no significant difference in MCS, TFCS, TFO, AOFAS score and FADI score between 2 groups ( P >0.05). Suture-button fixation has similar effectiveness to screw fixation in ankle function and imaging findings, and flexible fixation has lower risk of reduction loss of distal tibiofibular syndesmosis than rigid fixation.

  20. Nitrogen fixation in the tissues of ruminant

    Buttery, P.J.

    1990-01-01

    Protein metabolism in animals is in a constant state of flux, the processes of protein synthesis and protein breakdown acting against each other, and the balance between the two processes causing changes in the mass of protein in a tissue. Reduction in the diet reduces both protein synthesis and protein degradation unless the dietary depletion is severe and prolonged, when there is a marked increase in protein catabolism. The synthesis and degradation of protein can be manipulated by anabolic agents, thus increasing the efficiency of animals. While the use of these agents has met with success in many countries, it remains to be seen whether they will be useful in harsh environments. Lactation and pregnancy put an extra demand on the nitrogen economy of animals. Evidence indicates that the extra amino acids needed for milk production do not come from muscle protein breakdown. Many animals in harsh environments are infected with parasites; intestinal parasites reduce food intake and cause blood loss into the intestines. Associated with this is a general disruption of protein metabolism. In all these studies, isotopic techniques have played a vital role. Few studies have been conducted on nitrogen metabolism in the tissue of ruminants exposed to harsh environments (with one notable exception: rumen function studies, some of which are described elsewhere in the Proceedings of this Seminar). This lack of work on nitrogen metabolism of animals from the harsher environments has often made it necessary to extrapolate data obtained from animals found and maintained in the temperate zones to quite different environments and to animals maintained on quite different dietary regimens. Several examples of the use of isotopes in metabolic studies with animals to yield information of direct or potential relevance to the harsh environments are presented. (author). 23 refs. 1 fig. 6 tabs

  1. Fixation of zygomatic and mandibular fractures with biodegradable plates

    Degala, Saikrishna; Shetty, Sujeeth; Ramya, S

    2013-01-01

    Context: In this prospective study, 13 randomly selected patients underwent treatment for zygomatic?complex fractures (2 site fractures) and mandibular fractures using 1.5 / 2 / 2.5-mm INION CPS biodegradable plates and screws. Aims: To assess the fixation of zygomatic-complex and mandibular fractures with biodegradable copolymer osteosynthesis system. Materials and Methods: In randomly selected 13 patients, zygomatic-complex and mandibular fractures were plated using resorbable plates and sc...

  2. Fixation of zygomatic and mandibular fractures with biodegradable plates.

    Degala, Saikrishna; Shetty, Sujeeth; Ramya, S

    2013-01-01

    In this prospective study, 13 randomly selected patients underwent treatment for zygomatic-complex fractures (2 site fractures) and mandibular fractures using 1.5 / 2 / 2.5-mm INION CPS biodegradable plates and screws. To assess the fixation of zygomatic-complex and mandibular fractures with biodegradable copolymer osteosynthesis system. In randomly selected 13 patients, zygomatic-complex and mandibular fractures were plated using resorbable plates and screws using Champy's principle. All the cases were evaluated clinically and radiologically for the type of fracture, need for the intermaxillary fixation (IMF) and its duration, duration of surgery, fixation at operation, state of reduction at operation, state of bone union after operation, anatomic reduction, paresthesia, occlusal discrepancies, soft tissue infection, immediate and late inflammatory reactions related to biodegradation process, and any need for the removal of the plates. Descriptives, Frequencies, and Chi-square test were used. In our study, the age group range was 5 to 55 years. Road traffic accidents accounted for the majority of patients six, (46.2%). Postoperative occlusal discrepancies were found in seven patients as mild to moderate, which resolved with IMF for 1-8 weeks. There were minimal complications seen and only as soft tissue infection. Use of biodegradable osteosynthesis system is a reliable alternative method for the fixation of zygomatic-complex and mandibular fractures. The biodegradable system still needs to be refined in material quality and handling to match the stability achieved with metal system. Biodegradable plates and screws is an ideal system for pediatric fractures with favorable outcome.

  3. POSSIBILITIES OF CARBON DIOXIDE FIXATION BY MICROALGAE IN REFINERY

    Šingliar, Michal; Mikulec, Jozef; Kušnir, Patrik; Polakovičova, Gabriela

    2013-01-01

    Capture and sequestration of carbon dioxide is one of the most critical challenges today for businesses and governments worldwide. Thousands of emitting power plants and industries worldwide face this costly challenge – reduce the CO2 emissions or pay penalties. One possibility for carbon dioxide sequestration is its fixation in microalgae. Microalgae can sequester CO2 from flue gases emitted from fossil fuel-fired refinery plants and units, thereby reducing emissions of a major greenhouse ga...

  4. Measures and limits of models of fixation selection.

    Niklas Wilming

    Full Text Available Models of fixation selection are a central tool in the quest to understand how the human mind selects relevant information. Using this tool in the evaluation of competing claims often requires comparing different models' relative performance in predicting eye movements. However, studies use a wide variety of performance measures with markedly different properties, which makes a comparison difficult. We make three main contributions to this line of research: First we argue for a set of desirable properties, review commonly used measures, and conclude that no single measure unites all desirable properties. However the area under the ROC curve (a classification measure and the KL-divergence (a distance measure of probability distributions combine many desirable properties and allow a meaningful comparison of critical model performance. We give an analytical proof of the linearity of the ROC measure with respect to averaging over subjects and demonstrate an appropriate correction of entropy-based measures like KL-divergence for small sample sizes in the context of eye-tracking data. Second, we provide a lower bound and an upper bound of these measures, based on image-independent properties of fixation data and between subject consistency respectively. Based on these bounds it is possible to give a reference frame to judge the predictive power of a model of fixation selection. We provide open-source python code to compute the reference frame. Third, we show that the upper, between subject consistency bound holds only for models that predict averages of subject populations. Departing from this we show that incorporating subject-specific viewing behavior can generate predictions which surpass that upper bound. Taken together, these findings lay out the required information that allow a well-founded judgment of the quality of any model of fixation selection and should therefore be reported when a new model is introduced.

  5. Development of cermets for high-level radioactive waste fixation

    Aaron, W.S.; Quinby, T.C.; Kobisk, E.H.

    1979-01-01

    A method is currently under development for the solidification and fixation of commercial and defense high-level radioactive wastes in the form of ceramic particles encapsulated by metal, i.e., a cermet. The chemical and physical processing techniques which have been developed and the properties of the resulting cermet bodies are described in this paper. These cermets have the advantages of high thermal conductivity and low leach rates

  6. Salvage of infected total knee arthroplasty with Ilizarov external fixator

    Venkata Gurava Reddy

    2011-01-01

    Full Text Available Background: Knee arthrodesis may be the only option of treatment in cases of chronic infected total knee arthroplasty (TKA with concomitant irreparable extensor mechanism disruption, extensive bone loss or severe systemic morbidities. Circular external fixation offers possible progressive adjustment to stimulate the bony fusion and to make corrections in alignment. We evaluated the results of knee arthrodesis with one or two stage circular external fixator for infected TKA. Materials and Methods: 16 cases of femoro-tibial fusion were retrospectively evaluated. Male-to-female ratio was 10:6. Mean age of the patients was 62.2 years. Cierney-Mader classification was used for anatomical and physiological evaluation while the bone stock deficiency was classified into mild, moderate and severe. Surgical technique involved either single or two stage arthrodesis using circular external fixator. Results: Union was achieved in 15 patients (93.75%. The mean duration for union (frame application time in these patients was 28.33 weeks (range 22 to 36 weeks. Analysis showed that in the group with frame application time of less than 28 weeks, the incidence of mild to moderate bone deficiency was 83.33%, while in the frame application time more than 28 weeks group the incidence was 20% (P-value 0.034. Similarly the incidence of Cierney-Mader 4B (Bl, Bs, Bls was found to be 33.33% in the group of frame application time of less than 28 weeks, while it was 90% in the group with frame application time more than 28 weeks (P-value 0.035. Conclusion: Circular external fixator is a safe and reliable method to achieve knee arthrodesis in cases of deep infection following TKA. Severe bone stock deficiency and Cierney- Mader type B host are likely risk factors for prolonged frame application time. We recommend a two-stage procedure especially when there is compromised host or severe bone loss.

  7. Complications associated with distraction plate fixation of wrist fractures.

    Hanel, Douglas P; Ruhlman, Scott David; Katolik, Leo I; Allan, Christopher H

    2010-05-01

    This article discusses the major and minor complications of distal plating in the light of a cohort study carried out by the authors, who reviewed all patients undergoing bridge distraction plate fixation of distal radius fractures by three surgeons in a single level I trauma center. The article discusses the effectiveness and the complication rates associated with the technique. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  8. Failure analysis of stainless steel femur fixation plate.

    Hussain, P B; Mohammad, M

    2004-05-01

    Failure analysis was performed to investigate the failure of the femur fixation plate which was previously fixed on the femur of a girl. Radiography, metallography, fractography and mechanical testing were conducted in this study. The results show that the failure was due to the formation of notches on the femur plate. These notches act as stress raisers from where the cracks start to propagate. Finally fracture occurred on the femur plate and subsequently, the plate failed.

  9. A tricalcium phosphate/polyether ether ketone anchor bionic fixation device for anterior cruciate ligament reconstruction: Safety and efficacy in a beagle model.

    Mao, Genwen; Qin, Zili; Li, Zheng; Li, Xiang; Qiu, Yusheng; Bian, Weiguo

    2018-05-02

    The goal of this study was to develop a bionic fixation device based on the use of a tricalcium phosphate/polyether ether ketone anchor and harvesting of the ulnar carpal flexor muscle tendon for application as a ligament graft in a beagle anterior cruciate ligament (ACL) reconstruction model, with the goal of accelerating the ligament graft-to-bone tunnel healing and providing a robust stability through exploration of this new kind of autologous ligament graft. The safety and efficacy of this fixation device were explored 3 and 6 months after surgery in a beagle ACL reconstruction model using biomechanical tests and comprehensive histological observation. The data were compared using a two-tailed Student's t test and a paired t test. A p value <0.05 was defined as statistically significant. All the models were successfully established. This fixation device possessed the excellent mechanical properties for ACL reconstruction. A comprehensive histological observation revealed that a cartilage layer was visible in the transition zone between the tendon and bone interface at both 3 and 6 months postoperation. The trabecular of the new bone was observed six months after surgery and was found to be similar to a direct connection. This fixation technique provided not only a robust primary mechanical fixation but also a bionic fixation for long-term knee joint stability by accelerating the healing of the tendon to the bone tunnel, showing a high potential for use in clinical practice. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2018. © 2018 Wiley Periodicals, Inc.

  10. Early Experience with Biodegradable Fixation of Pediatric Mandibular Fractures.

    Mazeed, Ahmed Salah; Shoeib, Mohammed Abdel-Raheem; Saied, Samia Mohammed Ahmed; Elsherbiny, Ahmed

    2015-09-01

    This clinical study aims to evaluate the stability and efficiency of biodegradable self-reinforced poly-l/dl-lactide (SR-PLDLA) plates and screws for fixation of pediatric mandibular fractures. The study included 12 patients (3-12 years old) with 14 mandibular fractures. They were treated by open reduction and internal fixation by SR-PLDLA plates and screws. Maxillomandibular fixation was maintained for 1 week postoperatively. Clinical follow-up was performed at 1 week, 6 weeks, 3 months, and 12 months postoperatively. Radiographs were done at 1 week, 3 months, and 12 months postoperatively to observe any displacement and fracture healing. All fractures healed both clinically and radiologically. No serious complications were reported in the patients. Normal occlusion was achieved in all cases. Biodegradable osteofixation of mandibular fractures offers a valuable clinical solution for pediatric patients getting the benefit of avoiding secondary surgery to remove plates, decreasing the hospital stay, further painful procedures, and psychological impact.

  11. Sorption and fixation of large cations by shale formations

    Brindley, G.W.

    1977-01-01

    Large cations such as Cs + are preferentially sorbed and partially fixed by fine-grained 2 : 1 type layer silicates such as micas, vermiculites, smectites and various mixed-layer minerals. Since these minerals are common constituents of many shale formations, these formations may provide suitable location for the burial of radioactive waste containers. However, the usual investigations of cation sorption and fixation must be extended to the conditions likely to develop in the vicinity of buried radioactive waste. Prior to possible leakage from buried containers, elevated temperatures around the burial site will develop leading to hydrothermal modification of the surrounding mineralogy. A range of temperature and of mineralogy must be envisaged. If and when leakage occurs, an outward diffusion of radioactive ions will occur by solvation in the fluids in the shale. The ratio of radioactive ions/normal ions will diminish outwards from the source. At near distances from the source high temperature modifications of the clay minerals and high concentrations of radioactive cations may lead to saturation of the fixation capacity. At greater distances, little or no thermal modification of the clay minerals and lower concentrations of ions will permit maximum sorption and fixation

  12. New fixation method for maxillary distraction osteogenesis using locking attachments.

    Suzuki, Eduardo Yugo; Buranastidporn, Boonsiva; Ishii, Masatoshi

    2006-10-01

    The external traction hooks of the intraoral splint used in the rigid external distraction (RED) system for maxillary distraction osteogenesis interfere with the surgical procedures. The purpose of this study is to introduce an innovative splint fixation method for maxillary distraction osteogenesis with Locking Attachments and evaluate their advantages, such as reduction of operating time compared with the traditional intraoral splint method. Retrospective comparison of operative times of maxillary Le Fort I osteotomy procedures was carried out with the traditional protocol using the intraoral splint cemented to the maxillary dentition (n = 14), and a removable intraoral splint that is inserted postsurgically (n = 14). Operative procedure times were compared and analyzed statistically using the data extracted from the surgical records. There were no complications inserting the removable splint postsurgically, including pain, discomfort, or time-consuming procedure. Stable and secure splint fixation was obtained before the distraction procedure and the desired treatment goals were obtained in all patients. The total operative procedure times were significantly reduced in the Locking Attachments group by 24% to 41% (approximately 65 minutes) compared with earlier operations involving the conventional splints (P Maxillary distraction osteogenesis with the Locking Attachments is a highly effective fixation approach to manage severe hypoplastic maxilla, eliminating lip constraints resulting from scarring and allowing for easier, more deliberate and careful dissection. The use of the Locking Attachments is reliable in craniofacial surgery and has proved to be advantageous in the reduction of the operating time and surgical risks.

  13. Stress Fractures of Tibia Treated with Ilizarov External Fixator.

    Górski, Radosław; Żarek, Sławomir; Modzelewski, Piotr; Górski, Ryszard; Małdyk, Paweł

    2016-08-30

    Stress fractures are the result of cyclic loading of the bone, which gradually becomes damaged. Most often they are treated by rest or plaster cast and, in rare cases, by internal fixation. There is little published data on initial reposition followed by stabilization with the Ilizarov apparatus in such fractures. Six patients were treated with an external fixator according to the Ilizarov method for a stress fracture of the tibia between 2007 and 2015. Three patients were initially treated conservatively. Due to increasing tibial deformation, they were qualified for surgical treatment with external stabilization. In the other patients, surgery was the first-line treatment. All patients demonstrated risk factors for a stress fracture. After the surgery, they fully loaded the operated limb. No patient developed malunion, nonunion, infection or venous thrombosis. The average time from the first operation to the removal of the external fixator was 19 weeks. Radiographic and clinical outcomes were satisfactory in all patients. 1. The Ilizarov method allows for successful stabilization of stress fractures of the tibia. 2. It may be a good alternative to internal stabilization, especially in patients with multiple comorbidities which affect bone quality and may impair soft tissue healing.

  14. Rib fractures in trauma patients: does operative fixation improve outcome?

    Majak, Peter; Næss, Pål A

    2016-12-01

    Renewed interest in surgical fixation of rib fractures has emerged. However, conservative treatment is still preferred at most surgical departments. We wanted to evaluate whether operative treatment of rib fractures may benefit severely injured patients. Several studies report a reduction in mechanical ventilation time, ICU length of stay (LOS), hospital LOS, pneumonia, need for tracheostomy, pain and costs in operatively treated patients with multiple rib fractures compared with patients treated nonoperatively. Although patient selection and timing of the operation seem crucial for successful outcome, no consensus exists. Mortality reduction has only been shown in a few studies. Most studies are retrospective cohort and case-control studies. Only four randomized control trials exist. Conservative treatment, consisting of respiratory assistance and pain control, is still the treatment of choice in the vast majority of patients with multiple rib fractures. In selected patients, operative fixation of fractured ribs within 72 h postinjury may lead to better outcome. More randomized control trials are needed to further determine who benefits from surgical fixation of rib fractures.

  15. Nitrogen fixation in four dryland tree species in central Chile

    Ovalle, C.; Arredondo, S.; Aronson, J.; Longeri, L.; Avendano, J.

    1998-01-01

    Results are presented from a 5-year experiment using 15 N-enriched fertilizer to determine N 2 fixation in four tree species on degraded soils in a Mediterranean-climate region of central Chile in which there are 5 months of drought. Species tested included three slow-growing but long-lived savannah trees native to southers South America, (acacia caven, Prosopic alba and P. chilensis; Mimosoideae), and Tagasaste (Chamaecytisus proliferus ssp. palmensis; Papilonoideae), a fast-growing but medium-lived tree from the Canary Islands. Tagasaste produced four- to twenty-fold more biomass than the other species, but showed declining N 2 fixation and biomass accumulation during the 5th year, corresponding to the juvenile-to-adult developmental transition. Nitrogen content was significantly higher in Tagasaste and Acacia caven than in the other species. The data revealed inter-specific differences in resource allocation and phenology of N 2 fixation rarely detailed for woody plants in dryland regions. (author)

  16. Treatment Approach for Infection of Healed Fractures After Internal Fixation.

    Lawrenz, Joshua M; Frangiamore, Salvatore J; Rane, Ajinkya A; Cantrell, William Alex; Vallier, Heather A

    2017-11-01

    To review the efficacy of a treatment approach for patients with infection and colonized implants after open reduction and internal fixation of fractures. Retrospective case series. Level one trauma center. Twenty patients were treated for wound infection with colonized implants after open reduction and internal fixation. Surgical debridement, removal of implants, and a short postoperative oral antibiotic course. The course of patients after surgical debridement and removal of implants, including culture results, antibiotic administration, and presence of recurrent clinical infection and radiographic union. Twenty patients had clinical presentations, including skin breakdown, serous drainage, purulent drainage and/or exposed implants, most commonly of the tibia (15 of 20). Mean time from index procedure to debridement with implant removal was 19.7 months. At the time of debridement and implant removal, 18 of 20 (90%) patients had a positive intraoperative culture (16 routine cultures and 2 broth cultures). The most common bacteria were Enterobacter cloacae (5/17) and methicillin-sensitive Staphylococcus aureus (4/17). All patients had soft tissue healing without signs of recurrent infection after mean follow up of 40 months after implant removal. Surgical debridement with implant removal plus a short oral antibiotic course is effective to resolve wound infection with a colonized implant in the setting of healed fracture after internal fixation. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

  17. Awake craniotomy using electromagnetic navigation technology without rigid pin fixation.

    Morsy, Ahmed A; Ng, Wai Hoe

    2015-11-01

    We report our institutional experience using an electromagnetic navigation system, without rigid head fixation, for awake craniotomy patients. The StealthStation® S7 AxiEM™ navigation system (Medtronic, Inc.) was used for this technique. Detailed preoperative clinical and neuropsychological evaluations, patient education and contrast-enhanced MRI (thickness 1.5mm) were performed for each patient. The AxiEM Mobile Emitter was typically placed in a holder, which was mounted to the operating room table, and a non-invasive patient tracker was used as the patient reference device. A monitored conscious sedation technique was used in all awake craniotomy patients, and the AxiEM Navigation Pointer was used for navigation during the procedure. This offers the same accuracy as optical navigation, but without head pin fixation or interference with intraoperative neurophysiological techniques and surgical instruments. The application of the electromagnetic neuronavigation technology without rigid head fixation during an awake craniotomy is accurate, and offers superior patient comfort. It is recommended as an effective adjunctive technique for the conduct of awake surgery. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Tissue fixation and autoradiographic negative chemography in rat oral epithelium

    Prime, S.S.; MacDonald, D.G. (Glasgow Dental Hospital (UK))

    1983-01-01

    The effect of routine methods of tissue fixation on autoradiographic negative chemography was investigated in adult rat palatal and tongue epithelia following the incorporation of /sup 3/H thymidine in vivo. Tissues fixed in formalin or Bouin's without acetic acid demonstrated more negative chemography than those fixed in Bouin's fluid, formol-acetic-methanol or Carnoy's solutions. These findings were associated with the lowest silver grain counts per nucleus in the formalin fixed tissues, low grain counts in tissues fixed in Bouin's without acetic acid, but the addition of acetic acid to make complete Bouin's fluid gave results similar to those following fixation with Carnoy's solution. The highest silver grain counts were obtained with tissues fixed in formol-acetic-methanol. The relationship between negative chemography and the labelling indices of tissues was unclear except where the negative chemographic effects were severe. Formalin fixed tissues showed the maximum negative chemographic effects and the lowest labelling indices. Carnoy's solution appeared to be the fixative of choice for cell kinetic studies of oral epithelium.

  19. Liquifying PLDLLA Anchor Fixation in Achilles Reconstruction for Insertional Tendinopathy.

    Boden, Stephanie A; Boden, Allison L; Mignemi, Danielle; Bariteau, Jason T

    2018-04-01

    Insertional Achilles tendinopathy (IAT) is a frequent cause of posterior heel pain and is often associated with Haglund's deformity. Surgical correction for refractory cases of IAT has been well studied; however, the method of tendon fixation to bone in these procedures remains controversial, and to date, no standard technique has been identified for tendon fixation in these surgeries. Often, after Haglund's resection, there is large exposed cancellous surface for Achilles reattachment, which may require unique fixation to optimize outcomes. Previous studies have consistently demonstrated improved patient outcomes after Achilles tendon reconstruction with early rehabilitation with protected weight bearing, evidencing the need for a strong and stable anchoring of the Achilles tendon that allows early weight bearing without tendon morbidity. In this report, we highlight the design, biomechanics, and surgical technique of Achilles tendon reconstruction with Haglund's deformity using a novel technique that utilizes ultrasonic energy to liquefy the suture anchor, allowing it to incorporate into surrounding bone. Biomechanical studies have demonstrated superior strength of the suture anchor utilizing this novel technique as compared with prior techniques. However, future research is needed to ensure that outcomes of this technique are favorable when compared with outcomes using traditional suture anchoring methods. Level V: Operative technique.

  20. Photosynthate partitioning and nitrogen fixation of alfalfa and birdsfoot trefoil

    Shieh, W.J.

    1985-01-01

    Nodule mass and number are usually correlated with rates of nitrogen fixation in legumes. Birdsfoot trefoil (Lotus corniculatus L.) with more than twice the nodule number and mass, however, fixes far less nitrogen than alfalfa (Medicago sativa L.) at the same age. In this research, photosynthesis and photosynthate partitioning and utilization in relation to nitrogen fixation of alfalfa and birdsfoot trefoil were examined in order to determine their relationship to nitrogen fixation potential. Photosynthate to nodules was studied using 14 CO 2 labeling techniques. Partitioning patterns were altered by shading and dark depletion treatments. Efficiency of photosynthate utilization was examined by determining turnover of 14 C photosynthate in nodule metabolites and by studying rates of cyanide-resistant and cyanide-sensitive O 2 uptake. Alfalfa nodule activity was greater than trefoil expressed on a hole pot or nodule dry weight basis. Both shading and dark treatments significantly reduced nodule activity as estimated by the acetylene reduction assay. Shoots of both species were found to be the dominant sinks for photosynthate. Percentage 14 C recovered in alfalfa roots was more than twice that of trefoil at 1,2,3,4 and 24 h after labeling. Greater relative specific radioactivity (RSA) in nodules of both species suggests that they were stronger sinks for current photosynthate than roots

  1. Fixation probability in a two-locus intersexual selection model.

    Durand, Guillermo; Lessard, Sabin

    2016-06-01

    We study a two-locus model of intersexual selection in a finite haploid population reproducing according to a discrete-time Moran model with a trait locus expressed in males and a preference locus expressed in females. We show that the probability of ultimate fixation of a single mutant allele for a male ornament introduced at random at the trait locus given any initial frequency state at the preference locus is increased by weak intersexual selection and recombination, weak or strong. Moreover, this probability exceeds the initial frequency of the mutant allele even in the case of a costly male ornament if intersexual selection is not too weak. On the other hand, the probability of ultimate fixation of a single mutant allele for a female preference towards a male ornament introduced at random at the preference locus is increased by weak intersexual selection and weak recombination if the female preference is not costly, and is strong enough in the case of a costly male ornament. The analysis relies on an extension of the ancestral recombination-selection graph for samples of haplotypes to take into account events of intersexual selection, while the symbolic calculation of the fixation probabilities is made possible in a reasonable time by an optimizing algorithm. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Tissue fixation and autoradiographic negative chemography in rat oral epithelium

    Prime, S.S.; MacDonald, D.G.

    1983-01-01

    The effect of routine methods of tissue fixation on autoradiographic negative chemography was investigated in adult rat palatal and tongue epithelia following the incorporation of 3 H thymidine in vivo. Tissues fixed in formalin or Bouin's without acetic acid demonstrated more negative chemography than those fixed in Bouin's fluid, formol-acetic-methanol or Carnoy's solutions. These findings were associated with the lowest silver grain counts per nucleus in the formalin fixed tissues, low grain counts in tissues fixed in Bouin's without acetic acid, but the addition of acetic acid to make complete Bouin's fluid gave results similar to those following fixation with Carnoy's solution. The highest silver grain counts were obtained with tissues fixed in formol-acetic-methanol. The relationship between negative chemography and the labelling indices of tissues was unclear except where the negative chemographic effects were severe. Formalin fixed tissues showed the maximum negative chemographic effects and the lowest labelling indices. Carnoy's solution appeared to be the fixative of choice for cell kinetic studies of oral epithelium. (author)

  3. Anterior cervical decompression and fusion with caspar plate fixation

    Rehman, L.; Akbar, H.; Das, G.; Hashim, A.S.M.

    2013-01-01

    Objective: To evaluate the role of anterior cervical decompression and fixation with Caspar plating in cervical spine injury on neurological outcome. Study Design: A case series. Place and Duration of Study: Department of Neurosurgery, Jinnah Postgraduate Medical Centre, Karachi, from July 2008 to March 2011. Methodology: Thirty patients admitted with cervical spine injuries were inducted in the study. All cases were evaluated for their clinical features, level of injury and degree of neurological injury was assessed using Frankel grading. Pre and postoperative record with X-rays and MRI were maintained. Cervical traction was applied to patients with sub-luxation. All patients underwent anterior cervical decompression, fusion and Caspar plate fixation. The follow-up period was 6 months with clinical and radiological assessment. Results: Among 30 patients, 24 (80%) were males and 6 (20%) were females. Age ranged from 15 to 55 years. Causes of injury were road traffic accident (n = 20), fall (n = 8) and assault (n = 2). Commonest mode of injury was road traffic accident (66.6%). Postoperative follow-up showed that pain and neurological deficit were improved in 21 patients. There was no improvement in 7 patients, one patient deteriorated and one expired. All patients developed pain at donor site. Conclusion: Anterior decompression, fusion and fixation with Caspar plate is an effective method with good neurological and radiological outcome. However, it is associated with pain at donor site. (author)

  4. Three-dimensional accuracy and interfractional reproducibility of patient fixation and positioning using a stereotactic head mask system

    Karger, Christian P.; Jaekel, Oliver; Debus, Juergen; Kuhn, Sabine; Hartmann, Guenther H.

    2001-01-01

    Purpose: Conformal radiotherapy in the head and neck region requires precise and reproducible patient setup. The definition of safety margins around the clinical target volume has to take into account uncertainties of fixation and positioning. Data are presented to quantify the involved uncertainties for the system used. Methods and Materials: Interfractional reproducibility of fixation and positioning of a target point in the brain was evaluated by biplanar films. 118 film pairs obtained at 52 fractions in 4 patients were analyzed. The setup was verified at the actual treatment table position by diagnostic X-ray units aligned to the isocenter and by a stereotactic X-ray localization technique. The stereotactic coordinates of the treated isocenter, of fiducials on the mask, and of implanted internal markers within the patient were measured to determine systematic and random errors. The data are corrected for uncertainty of the localization method. Results: Displacements in target point positioning were 0.35±0.41 mm, 1.22±0.25 mm, and -0.74±0.32 mm in the x, y, and z direction, respectively. The reproducibility of the fixation of the patient's head within the mask was 0.48 mm (x), 0.67 mm (y), and 0.72 mm (z). Rotational uncertainties around an axis parallel to the x, y, and z axis were 0.72 deg., 0.43 deg., and 0.70 deg., respectively. A simulation, based on the acquired data, yields a typical radial overall uncertainty for positioning and fixation of 1.80±0.60 mm. Conclusions: The applied setup technique showed to be highly reproducible. The data suggest that for the applied technique, a safety margin between clinical and planning target volume of 1-2 mm along one axis is sufficient for a target at the base of skull

  5. Optimization of northern analysis by vacuum-blotting, RNA-transfer visualization, and ultraviolet fixation

    Kroczek, R.A.; Siebert, E.

    1990-01-01

    We have optimized Northern analysis at several steps. Overnight electrophoresis was replaced by short gel runs and overnight capillary transfer by rapid vacuum-blotting adapted to Northern analysis. Short uv irradiation was used as a substitute for the usual RNA fixation by baking. Direct staining of RNA before electrophoresis made it possible to check RNA integrity and to evaluate the quality of the size separation immediately after electrophoresis. In this system, RNA transfer onto the membrane support could also be quickly assessed after the blotting step. The net result of all modifications was a doubling of the autoradiography signal compared with that obtained by modern Northern protocols. At the same time, the duration of the procedure was shortened drastically, allowing an autoradiography signal to be obtained within 24 h

  6. Modifying bone scaffold architecture in vivo with permanent magnets to facilitate fixation of magnetic scaffolds.

    Panseri, S; Russo, A; Sartori, M; Giavaresi, G; Sandri, M; Fini, M; Maltarello, M C; Shelyakova, T; Ortolani, A; Visani, A; Dediu, V; Tampieri, A; Marcacci, M

    2013-10-01

    The fundamental elements of tissue regeneration are cells, biochemical signals and the three-dimensional microenvironment. In the described approach, biomineralized-collagen biomaterial functions as a scaffold and provides biochemical stimuli for tissue regeneration. In addition superparamagnetic nanoparticles were used to magnetize the biomaterials with direct nucleation on collagen fibres or impregnation techniques. Minimally invasive surgery was performed on 12 rabbits to implant cylindrical NdFeB magnets in close proximity to magnetic scaffolds within the lateral condyles of the distal femoral epiphyses. Under this static magnetic field we demonstrated, for the first time in vivo, that the ability to modify the scaffold architecture could influence tissue regeneration obtaining a well-ordered tissue. Moreover, the association between NdFeB magnet and magnetic scaffolds represents a potential technique to ensure scaffold fixation avoiding micromotion at the tissue/biomaterial interface. © 2013.

  7. Management of paediatric tibial fractures using two types of circular external fixator: Taylor spatial frame and Ilizarov circular fixator.

    Tafazal, Suhayl; Madan, Sanjeev S; Ali, Farhan; Padman, Manoj; Swift, Simone; Jones, Stanley; Fernandes, James A

    2014-05-01

    The use of circular fixators for the treatment of tibial fractures is well established in the literature. The aim of this study was to compare the Ilizarov circular fixator (ICF) with the Taylor spatial frame (TSF) in terms of treatment results in consecutive patients with tibial fractures that required operative management. A retrospective analysis of patient records and radiographs was performed to obtain patient data, information on injury sustained, the operative technique used, time duration in frame, healing time and complications of treatment. The minimum follow-up was 24 months. Ten patients were treated with ICF between 2000 and 2005, while 15 patients have been treated with TSF since 2005. Two of the 10 treated with ICF and 5 of the 15 treated with TSF were open fractures. All patients went on to achieve complete union. Mean duration in the frame was 12.7 weeks for ICF and 14.8 weeks for the TSF group. Two patients in the TSF group had delayed union and required additional procedures including adjustment of fixator and bone grafting. There was one malunion in the TSF group that required osteotomy and reapplication of frame. There were seven and nine pin-site infections in the ICF and TSF groups, respectively, all of which responded to antibiotics. There were no refractures in either group. In an appropriate patient, both types of circular fixator are equally effective but have different characteristics, with TSF allowing for postoperative deformity correction. Of concern are the two cases of delayed union in the TSF group, all in patients with high-energy injuries. We feel another larger study is required to provide further clarity in this matter. Level II-comparative study.

  8. Biomechanical Comparison of External Fixation and Compression Screws for Transverse Tarsal Joint Arthrodesis.

    Latt, L Daniel; Glisson, Richard R; Adams, Samuel B; Schuh, Reinhard; Narron, John A; Easley, Mark E

    2015-10-01

    Transverse tarsal joint arthrodesis is commonly performed in the operative treatment of hindfoot arthritis and acquired flatfoot deformity. While fixation is typically achieved using screws, failure to obtain and maintain joint compression sometimes occurs, potentially leading to nonunion. External fixation is an alternate method of achieving arthrodesis site compression and has the advantage of allowing postoperative compression adjustment when necessary. However, its performance relative to standard screw fixation has not been quantified in this application. We hypothesized that external fixation could provide transverse tarsal joint compression exceeding that possible with screw fixation. Transverse tarsal joint fixation was performed sequentially, first with a circular external fixator and then with compression screws, on 9 fresh-frozen cadaveric legs. The external fixator was attached in abutting rings fixed to the tibia and the hindfoot and a third anterior ring parallel to the hindfoot ring using transverse wires and half-pins in the tibial diaphysis, calcaneus, and metatarsals. Screw fixation comprised two 4.3 mm headless compression screws traversing the talonavicular joint and 1 across the calcaneocuboid joint. Compressive forces generated during incremental fixator foot ring displacement to 20 mm and incremental screw tightening were measured using a custom-fabricated instrumented miniature external fixator spanning the transverse tarsal joint. The maximum compressive force generated by the external fixator averaged 186% of that produced by the screws (range, 104%-391%). Fixator compression surpassed that obtainable with screws at 12 mm of ring displacement and decreased when the tibial ring was detached. No correlation was found between bone density and the compressive force achievable by either fusion method. The compression across the transverse tarsal joint that can be obtained with a circular external fixator including a tibial ring exceeds that

  9. Capture of fixation by rotational flow; a deterministic hypothesis regarding scaling and stochasticity in fixational eye movements

    Nicholas Mansel Wilkinson

    2014-02-01

    Full Text Available Visual scan paths exhibit complex, stochastic dynamics. Even during visual fixation, the eye is in constant motion. Fixational drift and tremor are thought to reflect fluctuations in the persistent neural activity of neural integrators in the oculomotor brainstem, which integrate sequences of transient saccadic velocity signals into a short term memory of eye position. Despite intensive research and much progress, the precise mechanisms by which oculomotor posture is maintained remain elusive. Drift exhibits a stochastic statistical profile which has been modelled using random walk formalisms. Tremor is widely dismissed as noise. Here we focus on the dynamical profile of fixational tremor, and argue that tremor may be a signal which usefully reflects the workings of the oculomotor postural control. We identify signatures reminiscent of a certain flavour of transient neurodynamics; toric travelling waves which rotate around a central phase singularity. Spiral waves play an organisational role in dynamical systems at many scales throughout nature, though their potential functional role in brain activity remains a matter of educated speculation. Spiral waves have a repertoire of functionally interesting dynamical properties, including persistence, which suggest that they could in theory contribute to persistent neural activity in the oculomotor postural control system. Whilst speculative, the singularity hypothesis of oculomotor postural control implies testable predictions, and could provide the beginnings of an integrated dynamical framework for eye movements across scales.

  10. Transforaminal lumbar interbody fusion using unilateral pedicle screw fixation plus contralateral translaminar facet screw fixation in lumbar degenerative diseases.

    Liu, Fubing; Jiang, Chun; Cao, Yuanwu; Jiang, Xiaoxing; Feng, Zhenzhou

    2014-07-01

    Transforaminal lumbar interbody fusion (TLIF) has been used in lumbar degenerative diseases. Some researchers have applied unilateral fixation in TLIF to reduce operational trauma without compromising the clinical outcome, but it is always suspected biomechanically unstable. The supplementary contralateral translaminar facet screw (cTLFS) seemed to be able to overcome the inherent drawbacks of unilateral pedicle screw (uPS) fixation theoretically. This study evaluates the safety, feasibility and efficacy of TLIF using uPS with cTLFS fixation in the treatment of lumbar degenerative diseases (LDD). 50 patients (29 male) underwent the aforementioned surgical technique for their LDD between December 2009 and April 2012. The results were evaluated based on visual analogue scale (VAS) of the leg and back, Japanese Orthopedic Association (JOA) score and Oswestry Disability Index (ODI) were recorded. The radiographic examinations in form of X-ray, computed tomography (CT) or magnetic resonance imaging was done preoperatively and 1 week, 3 months, 6 months, 12 months and 24 months postoperatively. The student t-test was used for comparison between the preoperative values and postoperative counterparts. P degenerative diseases short termly.

  11. Comparison of two-staged ORIF and limited internal fixation with external fixator for closed tibial plafond fractures.

    Wang, Cheng; Li, Ying; Huang, Lei; Wang, Manyi

    2010-10-01

    To compare the results of two-staged open reduction and internal fixation (ORIF) and limited internal fixation with external fixator (LIFEF) for closed tibial plafond fractures. From January 2005 to June 2007, 56 patients with closed type B3 or C Pilon fractures were randomly allocated into groups I and II. Two-staged ORIF was performed in group I and LIFEF in group II. The outcome measures included bone union, nonunion, malunion, pin-tract infection, wound infection, osteomyelitis, ankle joint function, etc. These postoperative data were analyzed with Statistical Package for Social Sciences (SPSS) 13.0. Incidence of superficial soft tissue infection (involved in wound infection or pin-tract infection) in group I was lower than that in group II (P delayed union, and arthritis symptoms, with no statistical significance. Both groups resulted similar ankle joint function. Logistic regression analysis indicated that smoking and fracture pattern were the two factors significantly influencing the final outcomes. In the treatment of closed tibial plafond fractures, both two-staged ORIF and LIFEF offer similar results. Patients undergo LIFEF carry significantly greater radiation exposure and higher superficial soft tissue infection rate (usually occurs on pin tract and does not affect the final outcomes).

  12. [DESIGN AND CLINICAL APPLICATION OF LESSER TROCHANTERIC REDUCTION FIXATION SYSTEM].

    Guo, Xiaoze; Zhang, Ying; Xiao, Jin; Xie, Huibin; Yu, Jiefeng

    2015-02-01

    To design and produce a lesser trochanteric reduction fixation system and verify its value and effectiveness. A lesser trochanteric reduction fixation system was designed and produced according to the anatomical features of the lesser trochanteric fractures. Sixty-six patients with intertrochanteric fractures of Evans type III were included between January 2010 and July 2012. Of 66 patients, 32 were treated with dynamic hip screw (DHS) assisted with the lesser trochanteric reduction fixation system (study group), and 34 cases were treated with DHS only (control group). The 2 groups were comparable with no significant difference in gender, age, the reasons, and the types of the fractures (P > 0.05). The operation time, intraoperative blood loss, neck-shaft angle, bone healing time, ratio of successful fixations, and the functional evaluation of the hip joint after operation were compared between 2 groups. The study group had shorter operation time [(58.4 ± 5.3) minutes] and less intraoperative blood loss [(186.3 ± 6.6) mL than the control group [(78.5 ± 6.2)minutes and (246.2 ± 8.7) mL], showing significant differences (t = -14.040, P = 0.000; t = -31.145, P = 0.000). There was no significant difference in neck-shaft angle between study group [(138.6 ± 3.0)] and control group [(139.4 ± 2.9) degrees] (t = -1.044, P = 0.301). The wounds healed by first intention in both groups. The 30 and 31 patients were followed up 12 to 24 months (mean, 15 months) in the study group, and 13 to 25 months (mean, 16 months) in the control group, respectively. All fractures healed well in 2 groups. The study group had significantly shorter healing time [(8.8 ± 2.0) weeks] than the control group [(10.7 ± 3.4) weeks] (t = -2.871, P = 0.006). At 12 months after operation, coxa vara happened in 2 cases of the study group with a successful fixation ratio of 93.3% and in 10 cases of the control group with a successful fixation ratio of 67.7%, showing significant difference (Χ2 = 6

  13. Changes in biomolecular profile in a single nucleolus during cell fixation.

    Kuzmin, Andrey N; Pliss, Artem; Prasad, Paras N

    2014-11-04

    Fixation of biological sample is an essential technique applied in order to "freeze" in time the intracellular molecular content. However, fixation induces changes of the cellular molecular structure, which mask physiological distribution of biomolecules and bias interpretation of results. Accurate, sensitive, and comprehensive characterization of changes in biomolecular composition, occurring during fixation, is crucial for proper analysis of experimental data. Here we apply biomolecular component analysis for Raman spectra measured in the same nucleoli of HeLa cells before and after fixation by either formaldehyde solution or by chilled ethanol. It is found that fixation in formaldehyde does not strongly affect the Raman spectra of nucleolar biomolecular components, but may significantly decrease the nucleolar RNA concentration. At the same time, ethanol fixation leads to a proportional increase (up to 40%) in concentrations of nucleolar proteins and RNA, most likely due to cell shrinkage occurring in the presence of coagulant fixative. Ethanol fixation also triggers changes in composition of nucleolar proteome, as indicated by an overall reduction of the α-helical structure of proteins and increase in the concentration of proteins containing the β-sheet conformation. We conclude that cross-linking fixation is a more appropriate protocol for mapping of proteins in situ. At the same time, ethanol fixation is preferential for studies of RNA-containing macromolecules. We supplemented our quantitative Raman spectroscopic measurements with mapping of the protein and lipid macromolecular groups in live and fixed cells using coherent anti-Stokes Raman scattering nonlinear optical imaging.

  14. The importance of nodule CO2 fixation for the efficiency of symbiotic nitrogen fixation in pea at vegetative growth and during pod formation.

    Fischinger, Stephanie Anastasia; Schulze, Joachim

    2010-05-01

    Nodule CO2 fixation is of pivotal importance for N2 fixation. The process provides malate for bacteroids and oxaloacetate for nitrogen assimilation. The hypothesis of the present paper was that grain legume nodules would adapt to higher plant N demand and more restricted carbon availability at pod formation through increased nodule CO2 fixation and a more efficient N2 fixation. Growth, N2 fixation, and nodule composition during vegetative growth and at pod formation were studied in pea plants (Pisum sativum L.). In parallel experiments, 15N2 and 13CO2 uptake, as well as nodule hydrogen and CO2 release, was measured. Plants at pod formation showed higher growth rates and N2 fixation per plant when compared with vegetative growth. The specific activity of active nodules was about 25% higher at pod formation. The higher nodule activity was accompanied by higher amino acid concentration in nodules and xylem sap with a higher share of asparagine. Nodule 13CO2 fixation was increased at pod formation, both per plant and per 15N2 fixed unit. However, malate concentration in nodules was only 40% of that during vegetative growth and succinate was no longer detectable. The data indicate that increased N2 fixation at pod formation is connected with strongly increased nodule CO2 fixation. While the sugar concentration in nodules at pod formation was not altered, the concentration of organic acids, namely malate and succinate, was significantly lower. It is concluded that strategies to improve the capability of nodules to fix CO2 and form organic acids might prolong intensive N2 fixation into the later stages of pod formation and pod filling in grain legumes.

  15. [Case-control study on effects of external fixation combined with limited internal fixation for the treatment of Pilon fractures of Rüedi-Allgower type III].

    Duan, Da-Peng; You, Wu-Lin; Ji, Le; Zhang, Yong-Tao; Dang, Xiao-Qian; Wang, Kun-Zheng

    2014-01-01

    To analyze the effects of three surgical operations in the treatment of Pilon fracture of Rüedi-Allgower type III, and put forward the best therapeutic method. The clinical data of 33 patients with Pilon fracture who received surgical operations (plaster immobilization group, 10 cases; distal tibia anatomical plate group, 11 cases; external fixation with limited internal fixation group, 12 cases) from October 2009 to January 2012 were analyzed. There were 5 males and 5 females, ranging in age from 24 to 61 years in the plaster immobilization group. There were 7 males and 4 females, ranging in age from 21 to 64 years in the distal tibia anatomical plate group. There were 7 males and 5 females, ranging in age from 23 to 67 years in the external fixation with limited internal fixation group. The Ankle X-ray of Pilon fracture after operation, ankle score, early and late complications were collected. Bourne system was used to evaluate ankle joint function. After 8 months to 3 years follow-up, it was found that three kinds of treatment had significant differences in the outcomes and complications (P external fixation with limited internal fixation group got the best results. The number of anatomic reduction cases in the external fixation with limited internal fixation group (7 cases) and the distal tibia anatomical plate group (8 cases) was more than the plaster immobilization group (2 cases). According to the ankle score, 8 patients got an excellent result, 3 good and 1 poor in the limited internal fixation group ,which was better than those of distal tibia anatomical plate group (5 excellent, 4 good and 2 poor) and the plaster immobilization group (3 excellent, 4 good and 3 poor). The number of early and late complications in the external fixation with limited internal fixation group was more than those in the plaster immobilization group and the distal tibia anatomical plate group (Pexternal fixation with limited internal fixation in the treatment of Pilon fracture

  16. Emergency department external fixation for provisional treatment of pilon and unstable ankle fractures

    Craig R Lareau

    2015-01-01

    Full Text Available Unstable ankle fractures and impacted tibial pilon fractures often benefit from provisional external fixation as a temporizing measure prior to definitive fixation. Benefits of external fixation include improved articular alignment, decreased articular impaction, and soft tissue rest. Uniplanar external fixator placement in the Emergency Department (ED ex-fix is a reliable and safe technique for achieving ankle reduction and stability while awaiting definitive fixation. This procedure involves placing transverse proximal tibial and calcaneal traction pins and connecting the pins with two external fixator rods. This technique is particularly useful in austere environments or when the operating room is not immediately available. Additionally, this bedside intervention prevents the patient from requiring general anesthesia and may be a cost-effective strategy for decreasing valuable operating time. The ED ex-fix is an especially valuable procedure in busy trauma centers and during mass casualty events, in which resources may be limited.

  17. Effects of Long-term Fertilization on Potassium Fixation Capacity in Brown Soil

    Li, Na; Guo, Chunlei; Wang, Yue; Gao, Tianyi; Yang, Jinfeng; Han, Xiaori

    2018-01-01

    This study concentrated on the research of features of fixation. The objective of this study was to provide theoretical foundation of rational application of potassium fertilizer along with improving fertilizer availability ratio. A 32 years long-term experiment was conducted to evaluate the effects of fertilizer application on potassium changes and the factors affecting K fixation on brown soil by simulation in laboratory. When the concentration of exogenous potassium was in range of 400∼4000 mg·kg-1, potassium fixation capacity increased along with the rise of concentration of exogenous potassium, whereas K fixation rate reduced; Compared with no-potassium fertilizer, application of potassium fertilizer and organic fertilizer reduced soil potassium fixation capacity. Potassium rate and fixation-release of potassium character in soil should be taken into comprehensive consideration for rational fertilization to maintain or improve soil fertility for increasing potassium fertilizers efficiency in agriculture.

  18. When the mean is not enough: Calculating fixation time distributions in birth-death processes.

    Ashcroft, Peter; Traulsen, Arne; Galla, Tobias

    2015-10-01

    Studies of fixation dynamics in Markov processes predominantly focus on the mean time to absorption. This may be inadequate if the distribution is broad and skewed. We compute the distribution of fixation times in one-step birth-death processes with two absorbing states. These are expressed in terms of the spectrum of the process, and we provide different representations as forward-only processes in eigenspace. These allow efficient sampling of fixation time distributions. As an application we study evolutionary game dynamics, where invading mutants can reach fixation or go extinct. We also highlight the median fixation time as a possible analog of mixing times in systems with small mutation rates and no absorbing states, whereas the mean fixation time has no such interpretation.

  19. Improved patient repositioning accuracy by integrating an additional jaw fixation into a high precision face mask system in stereotactic radiotherapy of the head

    Lopatta, E.; Liesenfeld, S.M.; Bank, P.; Guenther, R.; Wiezorek, T.; Wendt, T.G.; Wurm, R.

    2003-01-01

    Background: For high precision radiotherapy of the neurocranium a precise, reproducible positioning technique is the basic pre-requisite. The aim of this study was to assess the influence of a modification of the commercially available stereotactical BrainLab trademark -head mask system on accuracy in patient positioning during fractionated radiotherapy. Material and Methods: 29 patients were treated with stereotactic radiotherapy of the head. Immobilization was provided by a two layer thermoplastic mask system (BrainLab trademark). 18 of these patients received an additional custom made fixation either of the upper jaw (OKF) or of the mandibula (UKF). The positioning accuracy was assessed by measurements of the shifting of anatomical landmarks in relation to therigid mask system on biplanar simulator films using a digital imaging system. Before each measurement a fine adjustment of the simulator to an optical ring system was performed. The reference radiographs were done just before CT-planning. During a 2-7 weeks lasting course of radiotherapy displacement measurements in relation to the reference images for all three dimensions (z, y and x) were done once a week. In 29 patients 844 measurements were analyzed. Results: An additional jaw fixation improves the reproducibility of patient positioning significantly in all three spatial dimensions. The standard deviation in lateral direction (x) was 0.6 mm with jaw fixation vs. 0.7 mm without jaw fixation (p [de

  20. Determination of the most appropriate stress distribution by Finite Element Analysis in fixation with resorbable screws after Bilateral Sagittal Split Ramus Osteotomy surgery

    Sarkarat F.

    2009-12-01

    Full Text Available "nBackground and Aim: Due to the complications associated with fixation by Titanium screws and plates in Bilateral Sagittal Split Ramus Osteotomy (BSSRO surgery, the use of resorbable polymers has been increasingly recommended. Since there are not enough studies on this issue, this study aimed to assess the most appropriate stress distribution in fixation with resorbable screws after BSSRO surgery by Fnite Element Analysis (FEA."nMaterials and Methods: This experimental study was performed on simulated human mandible using Ansys and Catia softwares. The osteotomy line was applied to the simulated model and experimental loads of 75, 135 and 600 N were respectively exerted according to the natural direction of occlusal force. The distribution pattern of stress was assessed and compared for fixation with one resorbable screw, two resorbable screws in vertical pattern, two resorbable screws in horizontal pattern, three resorbable screws in L pattern and three resorbable screws in inverted backward L pattern using Ansys software."nResults: Among the four simulated fixations, L pattern showed the highest primary stability. Two screws in vertical pattern were also associated with sufficient primary stability and less trauma and cost for patients. One screw did not provide enough stability under 600 N."nConclusion: Polymer-based resorbable screws (polyglycolic acid and D, L polylactide acid provided satisfactory primary stability in BSSRO surgery.

  1. [Analysis of tension-distraction state in the shin bones fractures in conditions of external fixation with application of apparatuses with different spatially oriented supports].

    Hutsuliak, V I

    2014-09-01

    In Autodesk Inventor 11 program, using method of end-capping elements, a three- dimensional computeric modelling of biomechanical systems of two models was conducted: I - "tibia - Ilizarov's apparatus with concentric location of supports"; II - "tibia - Ilizarov's apparatus with excentric location of supports". The loading, which was applied towards distal fragment in 6 standard degrees of freedom, was modelled for studying of the fixation rigidity of tibial fragments in these systems. Determination of the loading value in various directions, in which the fragment have had shifted by 1 mm, have constituted the main task of the investigation. In a model II a rigidity of the fragments fixation, in comparison with such in a model I, is bigger by 631.43% - while applying a compression loading, by 8.35 - 31.75% - the transversal one and by 19.72% - the rotation loading. While choosing the method of transosteal osteosynthesis of the shin bones the advantage, have the apparatuses with excentric location of supports, what secures the enhanced rigidity of the fragments fixation in comparison with such in apparatuses with concentric location of supports. Although, even in excentric location of supports in the apparatus the fixation rigidity is insufficient for early full loading of the traumatized extremity while walking. It is necessary to elaborate such apparatus, the form of which may be adopted toanatomic configuration of segment.

  2. Contributions of retinal input and phenomenal representation of a fixation object to the saccadic gap effect.

    Ueda, Hiroshi; Takahashi, Kohske; Watanabe, Katsumi

    2013-04-19

    The saccadic "gap effect" refers to a phenomenon whereby saccadic reaction times (SRTs) are shortened by the removal of a visual fixation stimulus prior to target presentation. In the current study, we investigated whether the gap effect was influenced by retinal input of a fixation stimulus, as well as phenomenal permanence and/or expectation of the re-emergence of a fixation stimulus. In Experiment 1, we used an occluded fixation stimulus that was gradually hidden by a moving plate prior to the target presentation, which produced the impression that the fixation stimulus still remained and would reappear from behind the plate. We found that the gap effect was significantly weakened with the occluded fixation stimulus. However, the SRT with the occluded fixation stimulus was still shorter in comparison to when the fixation stimulus physically remained on the screen. In Experiment 2, we investigated whether this effect was due to phenomenal maintenance or expectation of the reappearance of the fixation stimulus; this was achieved by using occluding plates that were an identical color to the background screen, giving the impression of reappearance of the fixation stimulus but not of its maintenance. The result showed that the gap effect was still weakened by the same degree even without phenomenal maintenance of the fixation stimulus. These results suggest that the saccadic gap effect is modulated by both retinal input and subjective expectation of re-emergence of the fixation stimulus. In addition to oculomotor mechanisms, other components, such as attentional mechanisms, likely contribute to facilitation of the subsequent action. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. [Automated analysis of bacterial preparations manufactured on automatic heat fixation and staining equipment].

    2012-01-01

    Heat fixation of preparations was made in the fixation bath designed by EMKO (Russia). Programmable "Emkosteiner" (EMKO, Russia) was used for trial staining. Reagents set Micko-GRAM-NITsF was applied for Gram's method of staining. It was demostrated that automatic smear fixation equipment and programmable staining ensure high-quality imaging (1% chromaticity variation) good enough for standardization of Gram's staining of microbial preparations.

  4. Nitrogen fixation by free-living organisms in rice soils. Studies with 15N

    Rao, V.R.; Charyulu, P.B.B.N.; Nayak, D.N.; Ramakrishna, C.

    1979-01-01

    Heterotrophic nitrogen fixation as influenced by water regime, organic matter, combined nitrogen and pesticides was investigated in several Indian rice soils by means of the 15 N 2 tracer technique. Soil submergence accelerated nitrogen fixation. Addition of cellulose to both non-flooded and flooded soils enhanced nitrogen fixation. Under submerged conditions, addition of sucrose, glucose and malate in that order stimulated nitrogen fixation in alluvial soil, while only sucrose enhanced nitrogen fixation in laterite soil. Nitrogen fixation in flooded alluvial and laterite soils decreased with increasing concentration of combined nitrogen. Nitrogen fixation was appreciable in acid sulphate and saline soils under both flooded and non-flooded conditions, despite high salinity and acidity. Application of certain pesticides at rates equivalent to recommended field level greatly influenced nitrogen fixation in flooded rice soils. Additions of benomyl (carbamate fungicide) and carbofuran (methyl carbamate insecticide) to alluvial and laterite soils resulted in significant stimulation of nitrogen fixation. Gamma-BHC stimulated nitrogen fixation only in alluvial soil, with considerable inhibition in a laterite soil. Nitrogen fixation by Azospirillum lipoferum was investigated by 15 N 2 . Large variations in 15 N 2 incorporation by A. lipoferum isolated from the roots of several rice cultivars was observed. Specific lines of rice harbouring A. lipoferum with high nitrogenase activity might be selected. Nitrogen fixed by heterotrophic organisms in a complex system such as soil could not be evaluated precisely. Indigenous nitrogen fixation in a flooded soil would be in the range of 5-10 kg N/ha, increasable 3 to 4-fold by appropriate fertilizers and cultural practices

  5. Report About the Design of External Fixator for Treatment of Pelvis and Acetabulum Fractures

    Martin JANEČKA

    2012-06-01

    Full Text Available Main point in this contribution is the design of external fixators applied in traumatology and orthopaedics. These fixators can be used in the treatment of open and unstable (i.e. complicated fractures of pelvis and its acetabulum. Numerical modelling (i.e. Finite Element Method, together with CAD modelling, experiments, material engineering, and nanotechnology are presented as a support for developing of a new design of external fixators.

  6. [Results of femoral lengthening over an intramedullary nail and external fixator].

    Jasiewicz, Barbara; Kacki, Wojciech; Tesiorowski, Maciej; Potaczek, Tomasz

    2008-01-01

    Current techniques of operative limb lengthening usually are based on distraction osteogenesis. One of the techniques is limb lengthening over an intramedullary nail. The goal of this study is to evaluate the results of femoral lengthening over an intramedullary nail. Between 1999 and 200619 femoral "over nail" lengthenings were performed. There were 7 males and 12 females. Mean patients' age at surgery was 15.8 years, and mean initial femoral shortening was 5.1 cm. Operative technique consisted of one-stage implantation of intramedullary nail and external fixator. Ilizarov apparatus was used in 9 patients, monolateral fixator in 10 cases--ORTHOFIX in 9 patients, Wagner fixator--in 1 patient. Intramedullary nail was locked proximally with screws or Schanz pins from external fixator. After distraction phase, external fixator was removed and distal locking screws were applied. Evaluation criteria: obtained lengthening, time of external fixator, treatment time, healing index, external fixation index, range of motion in hip and knee joints and complications according to Paley. The mean lengthening was 4.6 cm, and mean distraction time was 66.6 days. Mean time of external fixation was 115.5 days, and external fixation index was 26.2 days for centimeter. Healing index was 36.9 days for centimeter. In cases with monolateral fixator, healing index did not differ with the whole group. During treatment 18 complications occurred, for a rate of 0.9 complication per segment. Lengthening over an intramedullary nail reduces the time of external fixator. Over nail femoral lengthening can prevent axis deviation following regenerate bending. Complication rate is similar to lengthenings with the classic Ilizarov technique. There are no differences in the treatment time in relation to the type of external fixator.

  7. Effects of macro nutrient concentration on biological N2 fixation by Azotobacter vinelandii ATCC 12837

    Liew Pauline Woan Ying; Nazalan Najimudin; Jong Bor Chyan; Latiffah Noordin; Khairuddin Abdul Rahim; Amir Hamzah Ahmad Ghazali

    2010-01-01

    The dynamic changes of biological N 2 fixation by Azotobacter vinelandii ATCC 12837 under the influence of various macro nutrients, specifically phosphorus (P) and potassium (K), was investigated. In this attempt, Oryza sativa L. var. MR 219 was used as the model plant. Results obtained showed changes in the biological N 2 fixation activities with different macro nutrient(s) manipulations. The research activity enables optimisation of macro nutrients concentration for optimal/ enhanced biological N 2 fixation by A. vinelandii ATCC 12837. (author)

  8. Symbiotic nitrogen fixation and nitrate uptake by the pea crop

    Jensen, E.S.

    1986-08-01

    Symbiotic nitrogen fixation and nitrate uptake by pea plants (Pisum sativum L.) were studied in field and pot experiments using the 15 N isotope dilution technique and spring barley as a non-fixing reference crop. Barley, although not ideal, seemed to be a suitable reference for pea in the 15 N-technique. Maximum N 2 fixation activity of 10 kg N fixed per ha per day was reached around the flat pod growth stage, and the activity decreased rapidly during pod-filling. The pea crop fixed between 100 and 250 kg N ha -1 , corresponding to from 45 to 80 per cent of total crop N. The amount of symbiotically fixed N 2 depended on the climatic conditions in the experimental year, the level of soil mineral N and the pea cultivar. Field-grown pea took up 60 to 70 per cent of the N-fertilizer supplied. The supply of 50 kg NO 3 -N ha -1 inhibited the N 2 fixation approximately 15 per cent. Small amounts of fertilizer N, supplied at sowing (starter-N), slightly stimulated the vegetative growth of pea, but the yields of seed dry matter and protein were not significantly influenced. In the present field experiments the environmental conditions, especially the distribution of rainfall during the growth season, seemed to be more important in determining the protein and dry matter yield of the dry pea crop, than the ability of pea to fix nitrogen symbiotically. However, fertilizer N supplied to pot-grown pea plants at the flat pod growth stage or as split applications significantly increased the yield of seed dry matter and protein. (author)

  9. Fixation of the Achilles tendon insertion using suture button technology.

    Fanter, Nathan J; Davis, Edward W; Baker, Champ L

    2012-09-01

    In the operative treatment of Achilles insertional tendinopathy, no guidelines exist concerning which form of fixation of the Achilles tendon insertion is superior. Transcalcaneal drill pin passage does not place any major plantar structures at risk, and the addition of a Krackow stitch and suture button to the fixation technique provides a significant increase in ultimate load to failure in Achilles tendon insertional repairs. Controlled laboratory study. The Achilles tendon insertions in 6 fresh-frozen cadaveric ankles were detached, and transcalcaneal drill pins were passed. Plantar dissection took place to evaluate the drill pin relationship to the plantar fascia, lateral plantar nerve and artery, flexor digitorum longus tendon, and master knot of Henry. The Achilles tendons were then repaired with a double-row suture anchor construct alone or with a suture button and Krackow stitch added to the double-row suture anchor construct. The repairs were then tested to maximum load to failure at 20 mm/min. The mode of failure was recorded, and the mean maximum load to failure was assessed using the Student t test for distributions with equal variance. Transcalcaneal drill pin passage did not place any selected anatomic structures at risk. The mean maximum load to failure for the suture bridge group was 239.2 N; it was 391.4 N for the group with the suture button (P = .014). The lateral plantar artery was the structure placed at greatest risk from drill pin placement, with a mean distance of 22.7 mm (range, 16.5-29.2 mm) between the pin and artery. In this laboratory study, transcalcaneal drill pin passage appeared to be anatomically safe, and the use of suture button technology with a Krackow stitch for Achilles tendon insertional repair significantly increased repair strength. Achilles tendon insertional repair with suture button fixation and a Krackow stitch may facilitate the earlier institution of postoperative rehabilitation and improve clinical outcomes.

  10. Mechanical design optimization of bioabsorbable fixation devices for bone fractures.

    Lovald, Scott T; Khraishi, Tariq; Wagner, Jon; Baack, Bret

    2009-03-01

    Bioabsorbable bone plates can eliminate the necessity for a permanent implant when used to fixate fractures of the human mandible. They are currently not in widespread use because of the low strength of the materials and the requisite large volume of the resulting bone plate. The aim of the current study was to discover a minimally invasive bioabsorbable bone plate design that can provide the same mechanical stability as a standard titanium bone plate. A finite element model of a mandible with a fracture in the body region is subjected to bite loads that are common to patients postsurgery. The model is used first to determine benchmark stress and strain values for a titanium plate. These values are then set as the limits within which the bioabsorbable bone plate must comply. The model is then modified to consider a bone plate made of the polymer poly-L/DL-lactide 70/30. An optimization routine is run to determine the smallest volume of bioabsorbable bone plate that can perform and a titanium bone plate when fixating fractures of this considered type. Two design parameters are varied for the bone plate design during the optimization analysis. The analysis determined that a strut style poly-L-lactide-co-DL-lactide plate of 690 mm2 can provide as much mechanical stability as a similar titanium design structure of 172 mm2. The model has determined a bioabsorbable bone plate design that is as strong as a titanium plate when fixating fractures of the load-bearing mandible. This is an intriguing outcome, considering that the polymer material has only 6% of the stiffness of titanium.

  11. Laser-assisted fixation of a nitinol stapes prosthesis.

    Schrötzlmair, Florian; Suchan, Fabian; Pongratz, Thomas; Krause, Eike; Müller, Joachim; Sroka, Ronald

    2018-02-01

    Otosclerosis is an inner ear bone disease characterized by fixation of the stapes and consequently progressive hearing loss. One treatment option is the surgical replacement of the stapes by a prosthesis. When so called "smart materials" like nitinol are used, prosthesis fixation can be performed using a laser without manual crimping on the incus. However, specific laser-prosthesis interactions have not been described yet. The aim of the present study was to elucidate the thermo-mechanical properties of the NiTiBOND® prosthesis as a basis for handling instructions for laser-assisted prosthesis fixation. Closure of the NiTiBOND® prosthesis was induced ex vivo by either a diode laser emitting at λ = 940 nm or a CO 2 laser (λ = 10,600 nm). Total energy for closure was determined. Suitable laser parameters (pulse duration, power per pulse, distance between tip of the laser fiber and prosthesis) were assessed. Specific laser-prosthesis interactions were recorded. Especially the diode laser was found to be an appropriate energy source. A total energy deposit of 60 mJ by pulses in near contact application was found to be sufficient for prosthesis closure ex vivo. Energy should be transmitted through a laser fiber equipollent to the prosthesis band diameter. Specific deformation characteristics due to the zonal prosthesis composition have to be taken into account. NiTiBOND® stapes prosthesis can be closed by very little energy when appropriate energy sources like diode lasers are used, suggesting a relatively safe application in vivo. Lasers Surg. Med. 50:153-157, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  12. Assessment of modified gold surfaced titanium implants on skeletal fixation

    Zainali, Kasra; Danscher, Gorm; Jakobsen, Thomas

    2013-01-01

    shown to liberate gold ions through the process termed dissolucytosis. Furthermore, gold ions are known to act in an anti-inflammatory manner by inhibiting cellular NF-κB-DNA binding. The present study investigated whether partial coating of titanium implants could augment early osseointegration...... and increase mechanical fixation. Cylindrical porous coated Ti-6Al4V implants partially coated with metallic gold were inserted in the proximal region of the humerus in ten canines and control implants without gold were inserted in contralateral humerus. Observation time was 4 weeks. Biomechanical push out...

  13. Effects of gold coating on experimental implant fixation

    Zainali, Kasra; Danscher, Gorm; Jakobsen, Thomas

    2009-01-01

    Insertions of orthopedic implants are traumatic procedures that trigger an inflammatory response. Macrophages have been shown to liberate gold ions from metallic gold. Gold ions are known to act in an antiinflammatory manner by inhibiting cellular NF-kappa B-DNA binding and suppressing I-kappa B......-kinase activation. The present study investigated whether gilding implant Surfaces augmented early implant osseointegration and implant fixation by its modulatory effect on the local inflammatory response. Ion release was traced by autometallographic silver enhancement. Gold-coated cylindrical porous coated Ti6Al4V...

  14. Fixation of metallic sulfosalicylate complexes on an anionic exchange resin

    Cahuzac, S.

    1969-06-01

    Since sulfosalicylate ions have acid-base properties, sulfosalicylate complexes have an apparent stability which varies with the ph. As a result, the fixation of sulfo-salicylates on an anionic exchange resin depends on the ph of the solution in equilibrium with the resin. This research has been aimed at studying the influence of the ph on the fixation on an anionic exchange resin (Dowex 1 x 4) of sulfosalicylate anions on the one hand, and of metallic sulfosalicylate complexes on the other hand. In the first part of this work, a determination has been made, by frontal analysis of the distribution of sulfosalicylate ions in the resin according to the total sulfosalicylate I concentration in the aqueous solution in equilibrium with the resin. The exchange constants of these ions between the resin and the solution have been calculated. In the second part, a study has been made of the fixation of anionic sulfosalicylate complexes of Fe(III), Al(III), Cr(III), Cu(II), Ni(II), Co(II), Zn(II), Mn(II), Cd(II), Fe(II) and UO 2 2+ . By measuring the partition coefficients of these different elements between the resin and the solution it has been possible to give interpretation for the modes of fixation of the metallic ions, and to calculate their exchange constant between the resin and the solution. The relationship has been established for each metallic element studied, between its partition coefficient, the ph and the total concentration of the complexing agent in solution. Such a relationship makes it possible to predict, for given conditions, the nature of the species in solution and in the resin, as well as the partition coefficient of a metallic, element. Finally, in the third part of the work, use has been made of results obtained previously, to carry out some separations (Ni 2+ - Co 2+ ; Ni 2+ - Co 2+ - Cu 2+ ; UO 2 2+ - Fe 3+ ; UO 2 2+ - Cr 3+ ; UO 2 2+ - Cu 2+ ; UO 2 2+ - Ni 2+ ; UO 2 2+ - Co 2+ ; UO 2 2+ - Mn 2+ and UO 2 2+ - Cd 2+ ), as well as the purification

  15. Seed protein and nitrogen fixation in chickpea mutant variety Hyprosola

    Schroeder, H E; Gibson, A H; Oram, R N [CSIRO, Division of Plant Industry, Canberra ACT (Australia); Shaikh, M A.Q. [Bangladesh Institute of Nuclear Agriculture, Mymensingh (Bangladesh)

    1989-01-01

    Full text: 'Hyprosola' is a high yielding, high protein mutant cultivar obtained after gamma irradiation from the variety 'Faridpur-1'. The mutant yields 45 % more protein per unit area. The essential amino acid index is unchanged. It is likely that the high nutritional value in 'Hyprosola' seed protein arises from an increase in the albumin:globulin ratio. Nitrogen fixation rates of the mutant during the first 7 weeks of growth were found to be similar to 'Faridpur-1'. Under field conditions, the mutant may be able to nodulate more rapidly and more extensively than the parent variety. (author)

  16. Abnormalities of fixation, saccade and pursuit in posterior cortical atrophy.

    Shakespeare, Timothy J; Kaski, Diego; Yong, Keir X X; Paterson, Ross W; Slattery, Catherine F; Ryan, Natalie S; Schott, Jonathan M; Crutch, Sebastian J

    2015-07-01

    The clinico-neuroradiological syndrome posterior cortical atrophy is the cardinal 'visual dementia' and most common atypical Alzheimer's disease phenotype, offering insights into mechanisms underlying clinical heterogeneity, pathological propagation and basic visual phenomena (e.g. visual crowding). Given the extensive attention paid to patients' (higher order) perceptual function, it is surprising that there have been no systematic analyses of basic oculomotor function in this population. Here 20 patients with posterior cortical atrophy, 17 patients with typical Alzheimer's disease and 22 healthy controls completed tests of fixation, saccade (including fixation/target gap and overlap conditions) and smooth pursuit eye movements using an infrared pupil-tracking system. Participants underwent detailed neuropsychological and neurological examinations, with a proportion also undertaking brain imaging and analysis of molecular pathology. In contrast to informal clinical evaluations of oculomotor dysfunction frequency (previous studies: 38%, current clinical examination: 33%), detailed eyetracking investigations revealed eye movement abnormalities in 80% of patients with posterior cortical atrophy (compared to 17% typical Alzheimer's disease, 5% controls). The greatest differences between posterior cortical atrophy and typical Alzheimer's disease were seen in saccadic performance. Patients with posterior cortical atrophy made significantly shorter saccades especially for distant targets. They also exhibited a significant exacerbation of the normal gap/overlap effect, consistent with 'sticky fixation'. Time to reach saccadic targets was significantly associated with parietal and occipital cortical thickness measures. On fixation stability tasks, patients with typical Alzheimer's disease showed more square wave jerks whose frequency was associated with lower cerebellar grey matter volume, while patients with posterior cortical atrophy showed large saccadic intrusions

  17. Nitrogen fixation and induction of pseudo-nodules in grass

    Rasul, G.; Hassan, U.; Mehnaz, S.; Malik, K.A.

    1993-01-01

    The rice grown nitrogen depleted saline sols showed higher values for in-situ ARA. Isolations of N/sub 2/ fixing bacteria were carried out on soil Azotobacter was observed in plant rhizosphere. The 2,4-D (0.5 and 1 ppm) with diazo trophic bacteria induced nodule like structure on the wheat roots. The bacteria were found in nodules in the form of micro colonies or bacterial aggregates which were responsible for nitrogen fixation providing optimum 02 concentrations was incorporations /sup 15/N dilution data indicated that 125-46.5% atmosphere N was incorporated in nitrogen pool of inoculated plants. (author)

  18. Fixation in laparoscopic incisional hernia repair: Suture versus tacks

    Adil Bangash

    2013-01-01

    Full Text Available Aims and Objectives: To compare the frequency of complications of laparoscopic repair of incisional hernia using fixation of mesh with transabdominal sutures tacks. Materials and Methods: This study was conducted as part of an interventional multicenter trial at the Rehman Medical Institute, Peshawar, Peshawar Institute of Medical Sciences, and Pakistan Institute of Medical Science, Islamabad, from the 1 st of November 2008 till 31 st October 2011. The frequency of complications was calculated as the measure of comparing two methods of fixation in laparoscopic repair of incisional hernia using the IPOM technique. These patients were admitted via the outpatient department and their demographic data were collected on a pro forma basis. Forty-five patients were alternately placed in either group, and group I comprised patients with a ventral hernia that was fixed using spiral tacks whereas the other group was fixed with transabdominal sutures. A polytetraflouroethylene (Dual R mesh was applied in all cases. All data were collected onthe individual pro forma of each patient and was loaded on the SPSS R version 13.0. Results: The BMI in both groups was similar (P=0.94 The mean hospital stay was higher in the PTFE mesh group but the values were not significant (P=1.22.No perioperative death was observed in either group. One patient (2.2% from group I was readmitted with varying complaints and was diagnosed as having subacute intestinal obstruction (P>0.05. A higher but insignificant recurrence rate was observed in the polyester group over a one-year period of follow-up. Three patients (6.6% were diagnosed with recurrences in group I. Instead the PTFE group had a similar recurrence rate recurrence (P=1.00. Conclusion: The rate of recurrence in this study showed no significant difference by either mode of fixation. But statistically significant pain scores and increased operative time to fixation favors the use of tacks that limits to the few inner

  19. A new fixation aid for the radiotherapy of eye tumors

    Buchgeister, Markus; Grisanti, Salvatore; Suesskind, Daniela; Bamberg, Michael; Paulsen, Frank

    2007-01-01

    A modified swim goggle holding a light spot as an optical guide for actively aligning the eye in a reproducible orientation has been constructed to perform radiotherapy of ocular tumors. This device is compatible with computed tomography (CT) and magnetic resonance imaging systems. Image fusion of these data sets yielded clinically acceptable results. The reproducibility of the eye's positioning is tested by repeated CT. The eye's alignment during radiotherapy is monitored by an infrared TV camera with individual markings of the eye's position on the TV-monitor screen. From 2003-2006, 50 patients were treated with this fixation aid by radiosurgery with good patient compliance

  20. Stress state during fixation determines susceptibility to fatigue-linked biodegradation in bioprosthetic heart valve materials.

    Margueratt, Sean D; Lee, J Michael

    2002-01-01

    Mechanical loading contributes to the structural deterioration of bioprosthetic heart valves. The influence of stress state during fixation may play a substantial role in their failure, linking fatigue damage caused by buckling and tension and the enzymatic degradation of glutaraldehyde-crosslinked collagen. Bovine pericardia were obtained immediately postmortem and 100 mm x 15 mm samples were cut in the base-to-apex direction. Half the samples were subjected to a uniaxial tensile stress of 250 kPa and half remained unloaded during a crosslinking treatment in 0.5% glutaraldehyde. Tissue samples were rinsed and cut into 16 mm x 4 mm test strips. Half of these strips were exposed to cyclic compressive buckling and alternating tension at 30 Hz for 20 million cycles (approx. 7.5 days) using a custom-built multi-sample fatigue system. Fatigue-damaged and non-damaged samples were subsequently incubated at 37 C for 48 hrs in: (i) Type I bacterial collagenase (20 U/ml) buffered in 0.05 M Tris, 10 mM CaCl2 2H2O (pH 7.4) or (ii) 0.05 M Tris buffer (pH 7.4) only. In both cases, the samples were loaded sinusoidally between 40 and 80 g using a previously described microtensile culture system. Tissue removed from the bath was rinsed in 0.1 M EDTA solution and mounted in a servo-hydraulic mechanical testing system (MTS). Ultimate tensile strength (UTS), maximum tissue modulus, and fracture strain were determined. The percent collagen solubilized was assessed by a colourmetric hydroxyproline assay of the enzyme bath and tissue sample. All data were analyzed by analysis of variance (ANOVA). The results confirmed the synergy between fatigue damage and collagenase proteolysis in these materials; however, there were no significant differences in this effect between simple fixation and stress-fixation up to 20 million cycles. There were significant decreases in the mechanical properties and an increase in the amount of collagen solubilized with increased exposure to fatigue cycling.

  1. An improvement of the fixation method for preimplantation genetic diagnosis by fluorescent in situ hybridization%植入前遗传学诊断中单卵裂球固定方法的相关研究

    张敏敏; 章志国; 周平; 曹云霞

    2012-01-01

    目的 以人类受精胚胎单卵裂球为对象,对传统低渗固定法进行改良,探讨一种更简便效率更高的固定方法.方法 收集30枚人类多精受精胚胎激光打孔后去除透明带,将获得的完整卵裂球按传统低渗固定法和直接固定法进行固定后行X,Y染色体双色荧光原位杂交,比较固定率和杂交率.结果 固定卵裂球共171枚.低渗固定法(A组)固定80枚,成功68枚,成功率为85.0%.直接固定法(B)组固定91枚,成功82枚,成功率为90.1%.两组差异有显著性.A组杂交率为77.5%(每卵裂球数),91.2%(每核数),B组杂交率为83.5%(每卵裂球数)92.7%(每核数).两组差异无显著性.结论 直接固定法简化了固定步骤,降低了细胞丢失率,为较理想的单个卵裂球间期核固定技术.%Objective To improve current preimplantation genetic diagnosis fixation techniques in order to find a more efficient fixation method by using polyspermy embryos. Methods At first,to remove the zona pellucida by laser. The Integrity Blastomeres were distributed into two groups: conventional hypotonic- fixationgroup and direct-fixation group. Fluorescence in situ hybridization was accomplished after fixation using chromosome X and Y probes,and then the fixation rate and the fluorescent signals were analyzed. Result 1. A total of 30 Blastomeres were analyzed and 171 Blastomeres fixated. Of the 80 Blastomeres in conventional group (A group) ,68 got fine fixation, the successful rate was 85.0%. Among 91 Blastomeres in direct-fixation group (B group) ,82 got fine fixation, the successful rate was 90. 1% . 2. In conventional group, the hybridization rate was 77. 5% (/ Blastomere) or 91. 2% (/Nuclear) . The rate were 83. 5% and 92.7% respectively with hypotonic-fixation group and the direct-fixation group. There was no Significant difference. Conclusion This improved fixation technique essentially eliminates the possibility of losing a cell during fixation and simplifies the process of

  2. [Domestic external fixator application in the treatment of limb deformities: 7 289 cases application report].

    Qin, S H; Guo, B F; Zheng, X J; Jiao, S F; Xia, H T; Peng, A M; Pan, Q; Zang, J C; Wang, Z J

    2017-09-01

    Objective: To discuss the clinical application and effects of domestic external fixator in the treatment of patients with malformations of limbs. Methods: A total of 7 289 patients with malformation of limbs who had been operated in Qin Sihe orthopedic surgery team from January 1989 to June 2016 were retrospective analyzed. The patients were treated with domestic external fixator, including 4 033 males and 3 256 females, aging from 2 to 82 years with a mean age of 23.4 years. There were 2 732 patients using Ilizarov external fixator, 4 713 patients using hybrid external fixator, 57 patients using monobrachial external fixator, 232 patients using Ilizarov external fixator and hybrid external fixator. The Ilizarov, hybrid and monobrachial external fixator were used in 67, 65 and 0 patients on the upper limbs and in 2 665, 4 616 and 57 patients on the lower limbs. There were 3 028 patients operated on the left limbs, 3 260 patients operated on the right limbs and 1 001 patients operated on the bilateral limbs. The top three types of diseases were sequelae of poliomyelitis, cerebral palsy and post-traumatic stress disorder peromely. Deformity types inclued talipes equinovarus, knee flexion deformity, cavus foot and so on. Results: All the patients were followed up for a period of 2.5 months to 22.4 years, with an average follow-up time of 5.4 years. All of the external fixators were used for single once, and there was no substitute for external fixator quality problem. All the patients were completed surgery goal until removing external fixation except 1 patient gave up treatment and 1 removed the fixator because of metal allergy. The common complications included wire or pin infection and joint movement limitation and so on. Conclusions: The domestic external fixator developed and produced based on the characteristics of Chinese limb deformity disability. The domestic external fixator can be used to treat kinds of limb deformities with the advantages of practical

  3. Fractionated stereotactic radiotherapy for skull base tumors: analysis of treatment accuracy using a stereotactic mask fixation system

    Montagnoli Roberto

    2010-01-01

    Full Text Available Abstract Background To assess the accuracy of fractionated stereotactic radiotherapy (FSRT using a stereotactic mask fixation system. Patients and Methods Sixteen patients treated with FSRT were involved in the study. A commercial stereotactic mask fixation system (BrainLAB AG was used for patient immobilization. Serial CT scans obtained before and during FSRT were used to assess the accuracy of patient immobilization by comparing the isocenter position. Daily portal imaging were acquired to establish day to day patient position variation. Displacement errors along the different directions were calculated as combination of systematic and random errors. Results The mean isocenter displacements based on localization and verification CT imaging were 0.1 mm (SD 0.3 mm in the lateral direction, 0.1 mm (SD 0.4 mm in the anteroposterior, and 0.3 mm (SD 0.4 mm in craniocaudal direction. The mean 3D displacement was 0.5 mm (SD 0.4 mm, being maximum 1.4 mm. No significant differences were found during the treatment (P = 0.4. The overall isocenter displacement as calculated by 456 anterior and lateral portal images were 0.3 mm (SD 0.9 mm in the mediolateral direction, -0.2 mm (SD 1 mm in the anteroposterior direction, and 0.2 mm (SD 1.1 mm in the craniocaudal direction. The largest displacement of 2.7 mm was seen in the cranio-caudal direction, with 95% of displacements Conclusions The results indicate that the setup error of the presented mask system evaluated by CT verification scans and portal imaging are minimal. Reproducibility of the isocenter position is in the best range of positioning reproducibility reported for other stereotactic systems.

  4. Removal of internal fixation--the effect on patients' complaints: a study of 66 cases of removal of internal fixation after malleolar fractures

    Jacobsen, S; Honnens de Lichtenberg, M; Jensen, C M

    1994-01-01

    To estimate the effect of removal of internal fixation after treatment of malleolar fractures on postoperatively presented complaints, we retrospectively evaluated 66 patients by their records and by personal questionnaires. Of all the patients, 89.4% had one or more complaints. These were...... typically soreness over implant and cicatrix, reduced movement of the ankle joint, and strain-related pain. About 75% of these patients reported improvement after removal. The AO mode of fixation, i.e., typically by lateral semitubular plating and transsyndesmotic screw and a medial screw or pins...... period. We conclude that removal of internal fixation after malleolar fractures is indicated when common types of complaints are presented....

  5. Effectiveness of a step-by-step oral recount before a practical simulation of fracture fixation.

    Abagge, Marcelo; Uliana, Christiano Saliba; Fischer, Sergei Taggesell; Kojima, Kodi Edson

    2017-10-01

    To evaluate the effectiveness of a step-by-step oral recount by residents before the final execution of a practical exercise simulating a surgical fixation of a radial diaphyseal fracture. The study included 10 residents of orthopaedics and traumatology (four second- year and six first-year residents) divided into two groups with five residents each. All participants initially gathered in a room in which a video was presented demonstrating the practical exercise to be performed. One group (Group A) was referred directly to the practical exercise room. The other group (Group B) attended an extra session before the practical exercise, in which they were invited by instructors to recount all the steps that they would perform during the practical exercise. During this session, the instructors corrected the residents if any errors in the step-by-step recount were identified, and clarified questions from them. After this session, both Groups A and B gathered in a room in which they proceeded to the practical exercise, while being video recorded and evaluated using a 20-point checklist. Group A achieved a 57% accuracy, with results in this group ranging from 7 to 15 points out of a total of a possible 20 points. Group B achieved an 89% accuracy, with results in this group ranging from 15 to 20 points out of 20. An oral step-by-step recount by the residents before the final execution of a practical simulation exercise of surgical fixation of a diaphyseal radial fracture improved the technique and reduced the execution time of the exercise. © 2017 Elsevier Ltd. All rights reserved.

  6. [Comparison study on locking compress plate external fixator and standard external fixator for treatment of tibial open fractures].

    Wu, Gang; Luo, Xiaozhong; Tan, Lun; Lin, Xu; Wu, Chao; Guo, Yong; Zhong, Zewei

    2013-11-01

    To compare the clinical results of locking compress plate (LCP) as an external fixator and standard external fixator for treatment of tibial open fractures. Between May 2009 and June 2012, 59 patients with tibial open fractures were treated with LCP as an external fixator in 36 patients (group A), and with standard external fixator in 23 patients (group B). There was no significant difference in gender, age, cause of injury, affected side, type of fracture, location, and interval between injury and surgery between 2 groups (P > 0.05). The time of fracture healing and incision healing, the time of partial weight-bearing, the range of motion (ROM) of knee and ankle, and complications were compared between 2 groups. The incidence of pin-track infection in group A (0) was significantly lower than that in group B (21.7%) (P=0.007). No significant difference was found in the incidence of superficial infection and deep infection of incision, and the time of incision healing between 2 groups (P > 0.05). Deep vein thrombosis occurred in 5 cases of group A and 2 cases of group B, showing no significant difference (Chi(2)=0.036, P=0.085). All patients were followed up 15.2 months on average (range, 9-28 months) in group A, and 18.6 months on average (range, 9-47 months) in group B. The malunion rate and nonunion rate showed no significant difference between groups A and B (0 versus 13.0% and 0 versus 8.7%, P > 0.05); the delayed union rate of group A (2.8%) was significantly lower than that of group B (21.7%) (Chi(2)=5.573, P=0.018). Group A had shorter time of fracture healing, quicker partial weight-bearing, greater ROM of the knee and ankle than group B (P fracture, and has good patients' compliance, so it is helpful to do functional exercise, improve fracture healing and function recovery, and reduce the complication incidence.

  7. Web pages: What can you see in a single fixation?

    Jahanian, Ali; Keshvari, Shaiyan; Rosenholtz, Ruth

    2018-01-01

    Research in human vision suggests that in a single fixation, humans can extract a significant amount of information from a natural scene, e.g. the semantic category, spatial layout, and object identities. This ability is useful, for example, for quickly determining location, navigating around obstacles, detecting threats, and guiding eye movements to gather more information. In this paper, we ask a new question: What can we see at a glance at a web page - an artificial yet complex "real world" stimulus? Is it possible to notice the type of website, or where the relevant elements are, with only a glimpse? We find that observers, fixating at the center of a web page shown for only 120 milliseconds, are well above chance at classifying the page into one of ten categories. Furthermore, this ability is supported in part by text that they can read at a glance. Users can also understand the spatial layout well enough to reliably localize the menu bar and to detect ads, even though the latter are often camouflaged among other graphical elements. We discuss the parallels between web page gist and scene gist, and the implications of our findings for both vision science and human-computer interaction.

  8. Navicular stress fractures treated with minimally invasive fixation

    Korula Mani Jacob

    2013-01-01

    Early intervention with minimally invasive surgery has significantly less morbidity and a reliable early return to active sports and is therefore the best option in high-performance athletes. Materials and Methods: Nine athletes with ten stress fractures of the navicular treated at our institution between April 1991 and October 2000. The mean age of the patients was 22.8 years (range 18-50 years. All patients were treated by minimally invasive screw fixation and early weight bearing mobilization without a cast. The average followup was 7 years (range 2-11 years. Results: Seven of the nine patients returned to their pre-fracture level of sporting activity at an average of 5 months (range 3-9 months. One patient returned to full sporting activity following a delay of 2 years due to an associated tibial stress fracture and one patient had an unsatisfactory result. Long term review at an average of 7 years showed that six of these eight patients who returned to sports remained symptom free with two patients experiencing minimal intermittent discomfort after prolonged activity. Conclusions: We recommend percutaneous screw fixation as a reliable, low morbidity procedure allowing early return to full sporting activity without long term complications or recurrences.

  9. Energy Considerations for Plasma-Assisted N-Fixation Reactions

    Aikaterini Anastasopoulou

    2014-09-01

    Full Text Available In a time of increasing concerns about the immense energy consumption and poor environmental performance of contemporary processes in the chemical industry, there is great need to develop novel sustainable technologies that enhance energy efficiency. There is abundant chemical literature on process innovations (laboratory-scale around the plasma reactor itself, which, naturally, is the essential part to be intensified to achieve a satisfactory process. In essence, a plasma process needs attention beyond reaction engineering towards the process integration side and also with strong electrical engineering focus. In this mini-review, we have detailed our future focus on the process and energy intensification of plasma-based N-fixation. Three focal points are mainly stressed throughout the review: (I the integration of renewable energy; (II the power supply system of plasma reactors and (III process design of industrial plasma-assisted nitrogen fixation. These different enabling strategies will be set in a holistic and synergetic picture so as to improve process performance.

  10. Feasibility of purely endoscopic intramedullary fixation of mandibular condyle fractures.

    Frake, Paul C; Goodman, Joseph F; Joshi, Arjun S

    2015-01-01

    The investigators of this study hypothesized that fractures of the mandibular condyle can be repaired using short-segment intramedullary implants and purely endoscopic surgical technique, using a basic science, human cadaver model in an academic center. Endoscopic instrumentation was used through a transoral mucosal incision to place intramedullary implants of 2 cm in length into osteotomized mandibular condyles. The surgical maneuvers that required to insert these implants, including condyle positioning, reaming, implant insertion, and seating of the mandibular ramus, are described herein. Primary outcome was considered as successful completion of the procedure. Ten cadaveric mandibular condyles were successfully repaired with rigid intramedullary internal fixation without the use of external incisions. Both insertion of a peg-type implant and screwing a threaded implant into the condylar head were possible. The inferior portion of the implant remained exposed, and the ramus of the mandible was manipulated into position on the implant using retraction at the sigmoid notch. The results of this study suggest that purely endoscopic repair of fractures of the mandibular condyle is possible by using short-segment intramedullary titanium implants and a transoral endoscopic approach without the need for facial incisions or punctures. The biomechanical advantages of these intramedullary implants, including improved strength and resistance to mechanical failure compared with miniplates, have been recently established. The combination of improved implant design and purely endoscopic technique may allow for improved fixation and reduced surgical- and implant-related morbidity in the treatment of condylar fractures.

  11. Functional outcome of knee arthrodesis with a monorail external fixator.

    Roy, Alfred Cyril; Albert, Sandeep; Gouse, Mohamad; Inja, Dan Barnabas

    2016-04-01

    Several methods for obtaining knee arthrodesis have been described in the literature and world; over, the commonest cause for arthrodesis is a failed arthroplasty. Less commonly, as in this series, post-infective or traumatic causes may also require a knee fusion wherein arthroplasty may not be indicated. We present salient advantages along with the radiological and functional outcome of twenty four patients treated with a single monorail external fixator. All patients went on develop fusion at an average of 5.4 months with an average limb length discrepancy of 3 cm (1.5-6 cm). Improvements in functional outcome as assessed by the lower extremity functional score (LEFS), and the SF-36 was significant (p = 0.000). Knee arthrodesis with a single monorail external fixator is a reasonable single-staged salvage option in patients wherein arthroplasty may not be the ideal choice. The outcome, though far from ideal, is definitely positive and predictable.

  12. Internal Fixation of Cervical Fractures in Three Horses.

    Rossignol, Fabrice; Brandenberger, Olivier; Mespoulhes-Rivière, Céline

    2016-01-01

    To describe the surgical treatment outcome of cervical fractures in 3 horses. Case report. Three client-owned horses with cervical vertebral fractures. Three horses were refered for neck stiffness, pain, and ataxia after a cervical trauma because of a fall. Radiographic examination showed an oblique displaced fracture of the caudal aspect of the body of the second cervical vertebra (C2) in horse 1, an oblique displaced fracture of the caudal aspect of C4 involving the disc between C4 and C5 in horse 2, and a displaced transverse fracture of the body of the axis (C2) extending to the lateral arches and involving the vertebral canal in horse 3. In horse 1, the fracture was reduced and stabilized using a 14-hole narrow DCP plate, applied ventrally, and fixed with cancellous screws. A cervical fusion was performed. In horses 2 and 3, fracture fixation was performed using a 5-hole narrow LCP and 5 mm locking screws. All horses showed improvement and returned to full activity. The fracture healed in all horses. Internal fixation of cervical fracture in these horses was associated with minimal complications, and was associated with healing and a highly functional outcome in all horses. The LCP was preferred and would be recommended for ventral stabilization of selected cases of vertebral fractures. © Copyright 2015 by The American College of Veterinary Surgeons.

  13. Postoperative complications associated with external skeletal fixators in cats.

    Beever, Lee; Giles, Kirsty; Meeson, Richard

    2017-07-01

    The objective of this study was to quantify complications associated with external skeletal fixators (ESFs) in cats and to identify potential risk factors. A retrospective review of medical records and radiographs following ESF placement was performed. Case records of 140 cats were reviewed; fixator-associated complications (FACs) occurred in 19% of cats. The region of ESF placement was significantly associated with complication development. Complications developed most frequently in the femur (50%), tarsus (35%) and radius/ulna (33%). Superficial pin tract infection (SPTI) and implant failure accounted for 45% and 41% of all FACs, respectively. SPTI occurred more frequently in the femur, humerus and tibia, with implant failure more frequent in the tarsus. No association between breed, age, sex, weight, fracture type (open vs closed), ESF classification, number of pins per bone segment, degree of fracture load sharing, and the incidence or type of FAC was identified. No association between region of placement, breed, age, sex, weight, fracture type (open vs closed), ESF classification, number of pins per bone segment, fracture load sharing and the time to complication development was identified. Complication development is not uncommon in cats following ESF placement. The higher complication rate in the femur, tarsus and radius/ulna should be considered when reviewing options for fracture management. However, cats appear to have a lower rate of pin tract infections than dogs.

  14. Magnetoactive elastomer as an element of a magnetic retina fixator

    Makarova, L. A.; Nadzharyan, T. A.; Alekhina, Yu A.; Stepanov, G. V.; Kazimirova, E. G.; Perov, N. S.; Kramarenko, E. Yu

    2017-09-01

    We explore the possibility of creating an effective retinal fixator on the basis of magnetoactive elastomers (MAEs) and systems of permanent magnets. MAEs consist of silicone elastomer matrix with embedded magnetic iron microparticles. We study theoretically and experimentally magnetic forces acting between MAE samples and permanent magnets in various configurations. The theoretical model is based around classical magnetostatics and Maxwell equations with different parameters accounting for peculiarities of the material and the setup. Approximation of the experimentally measured magnetization curves for MAE samples was used to find input parameters for the theoretical model. To test the model, we conducted a series of experimental measurements of magnetic forces accompanied by model predictions for the system of one cylindrical magnet and a cuboid MAE sample. Calculated dependences of the average pressure arising from magnetic interactions on the distance between the closest faces of MAE samples and a permanent magnet are in a good agreement with the experimental data. The proof on concept for smaller magnetic systems required for eye surgery includes data for 10 magnets configuration and a thin MAE band. This research demonstrates high prospects of using MAE as an element of a magnetic fixator for treatment of complicated retinal detachments.

  15. Biological nitrogen fixation in non-legume plants.

    Santi, Carole; Bogusz, Didier; Franche, Claudine

    2013-05-01

    Nitrogen is an essential nutrient in plant growth. The ability of a plant to supply all or part of its requirements from biological nitrogen fixation (BNF) thanks to interactions with endosymbiotic, associative and endophytic symbionts, confers a great competitive advantage over non-nitrogen-fixing plants. Because BNF in legumes is well documented, this review focuses on BNF in non-legume plants. Despite the phylogenic and ecological diversity among diazotrophic bacteria and their hosts, tightly regulated communication is always necessary between the microorganisms and the host plant to achieve a successful interaction. Ongoing research efforts to improve knowledge of the molecular mechanisms underlying these original relationships and some common strategies leading to a successful relationship between the nitrogen-fixing microorganisms and their hosts are presented. Understanding the molecular mechanism of BNF outside the legume-rhizobium symbiosis could have important agronomic implications and enable the use of N-fertilizers to be reduced or even avoided. Indeed, in the short term, improved understanding could lead to more sustainable exploitation of the biodiversity of nitrogen-fixing organisms and, in the longer term, to the transfer of endosymbiotic nitrogen-fixation capacities to major non-legume crops.

  16. Surgical Site Infection Following Fixation of Acetabular Fractures.

    Iqbal, Faizan; Younus, Sajid; Asmatullah; Zia, Osama Bin; Khan, Naveed

    2017-09-01

    Acetabular fractures are mainly caused by high energy trauma. Surgical fixation of these fractures requires extensive surgical exposure which increases the length of operation and blood loss as well. This may increase the risk of surgical site infection. Our aim is to evaluate the prevalence of surgical site infections and the risk factors associated with it so as to minimize its chances. A total of 261 patients who underwent acetabular fracture surgery were retrospectively reviewed. Patients were divided into 2 groups, with or without surgical site infection. Factors examined include patients' gender, age, body mass index (BMI), time between injury and surgery, operative time, estimated blood loss, number of packed red blood cell transfused, length of total intensive care unit (ICU) stay, fracture type, surgical approach, smoking status, patients' comorbids and associated injuries. Fourteen patients (5.4%) developed surgical site infection. Out of 14 infections, 4 were superficial and 10 were deep. The factors that were found to be associated with surgical site infection following acetabular fracture fixation were prolonged operation time, increased BMI, prolonged ICU stay, larger amount of packed red blood cell transfused and associated genitourinary and abdominal trauma. In our study, we conclude that measures should be undertaken to attenuate the chances of surgical site infection in this major surgery by considering the risk factors significantly associated with it.

  17. Fixation and transport of uranium by humic substances (1962)

    Martin, J.

    1962-03-01

    One enter upon the study of the part taken by organic substances in ores that contain uranium in a disseminated form, without mineralization, being considered the reaction between uranium and humus. 'Humic acids' are extracted from the peat by ammonia. By the fact of their ability to cationic exchange, these are forming humates with metal cations; monovalent humates, normally soluble in water, can become insoluble after treatment of humic acids with methanal. The polyvalent humates are insoluble in water, especially humates of U (IV) and uranyl U (VI). Action of Li, Na, K, Mg, Ca uranyl carbonates solutions on the humic acids results in the formation of humates containing uranyl and the other cation. 100 g of humic acids give a fixation of no more than 38 g of uranium as uranyl. In contact with uraniferous weakly concentrated solutions, they fix 4 to 8 g according to pH, with a yield in the extraction greater than 95 per cent. The action of a sodium humate solution on a humate of uranyl give a solution containing a soluble sodium and uranyl humate. The solution is precipitated at various degrees by the polyvalent cations and insoluble humic substances. In all cases, the fixation of uranium with such prepared humic acids corresponds to a chemisorption of uranyl cations. (author) [fr

  18. Motorized injector-assisted intrascleral intraocular lens fixation.

    Hung, Jia-Horung; Wang, Shih-Hao; Teng, Yu-Ti; Hsu, Sheng-Min

    2017-03-01

    For eyes with deficient capsular support, intraocular lens (IOL) implantation has long been a technical challenge. Recently, intrascleral fixation of the haptics of a three-piece posterior chamber IOL has become a popular option. In this procedure, externalization of the leading haptic during IOL injection is a stressful step. We present a modified technique to improve the ease and safety of this step. Our modified technique involves IOL injection with a motorized injector with several important modifications described here. With these modifications, a surgeon can easily maintain the correct orientation of the IOL in a well-controlled manner during IOL injection. The records of 13 patients who underwent this technique were retrospectively evaluated. Corrected-distance visual acuity improved significantly after surgery (pIOL decentration, or vitreous hemorrhage was noted during the follow-up period. In conclusion, the motorized injector-assisted intrascleral IOL fixation technique is a safe and effective alternative to the conventional procedure. This technique makes the process of leading haptic externalization easier and more controllable. Copyright © 2017. Published by Elsevier Taiwan.

  19. Bioptics in sutureless intrascleral multifocal posterior chamber intraocular lens fixation.

    Pavlidis, Mitrofanis; de Ortueta, Diego; Scharioth, Gabor B

    2011-05-01

    To present a technique for sutureless fixation of a three-piece, multifocal, posterior chamber intraocular lens (IOL) in the ciliary sulcus. A 24-year-old woman presented with bilateral subluxation of the crystalline lens. Two straight sclerotomies were prepared with a 24-gauge cannula 2.0 mm from the limbus 180° apart from each other. The cannula was used to create a 2.0- to 3.0-mm tunnel parallel to the limbus starting from the sclerotomies. The leading haptic of the multifocal IOL was grasped at its tip with end-gripping, 25-gauge forceps and pulled through the sclerotomy. The forceps was used to introduce the IOL haptic into the scleral tunnel parallel to the limbus. Multifocal posterior chamber IOLs were stable and well centered. No postoperative complications occurred in the 16-month follow-up period. Preoperative astigmatism was corrected after IOL implantation with corneal wavefront-guided laser epithelial keratomileusis. Sutureless fixation of multifocal posterior chamber IOL haptics in a scleral tunnel parallel to the limbus can be successful, resulting in long-term centration and three-dimensional axial stability for optimal refractive results. If necessary, postoperative wavefront-guided refractive correction can be performed to optimize final refraction. Copyright 2011, SLACK Incorporated.

  20. Motorized injector-assisted intrascleral intraocular lens fixation

    Jia-Horung Hung

    2017-03-01

    Full Text Available For eyes with deficient capsular support, intraocular lens (IOL implantation has long been a technical challenge. Recently, intrascleral fixation of the haptics of a three-piece posterior chamber IOL has become a popular option. In this procedure, externalization of the leading haptic during IOL injection is a stressful step. We present a modified technique to improve the ease and safety of this step. Our modified technique involves IOL injection with a motorized injector with several important modifications described here. With these modifications, a surgeon can easily maintain the correct orientation of the IOL in a well-controlled manner during IOL injection. The records of 13 patients who underwent this technique were retrospectively evaluated. Corrected-distance visual acuity improved significantly after surgery (p<0.05. No postoperative retinal detachment, endophthalmitis, IOL decentration, or vitreous hemorrhage was noted during the follow-up period. In conclusion, the motorized injector-assisted intrascleral IOL fixation technique is a safe and effective alternative to the conventional procedure. This technique makes the process of leading haptic externalization easier and more controllable.