Machine Learning and Infrared Thermography for Fiber Orientation Assessment on Randomly-Oriented Strands Parts

Science.gov (United States)

Maldague, Xavier

2018-01-01

The use of fiber reinforced materials such as randomly-oriented strands has grown in recent years, especially for manufacturing of aerospace composite structures. This growth is mainly due to their advantageous properties: they are lighter and more resistant to corrosion when compared to metals and are more easily shaped than continuous fiber composites. The resistance and stiffness of these materials are directly related to their fiber orientation. Thus, efficient approaches to assess their fiber orientation are in demand. In this paper, a non-destructive evaluation method is applied to assess the fiber orientation on laminates reinforced with randomly-oriented strands. More specifically, a method called pulsed thermal ellipsometry combined with an artificial neural network, a machine learning technique, is used in order to estimate the fiber orientation on the surface of inspected parts. Results showed that the method can be potentially used to inspect large areas with good accuracy and speed. PMID:29351240

Effect of Board Type on Some Properties of Bamboo Strandboard

Directory of Open Access Journals (Sweden)

Ihak Sumardi

2015-03-01

Full Text Available The objective of this study was to evaluate the properties of bamboo strandboard (OSB by comparing different board types and strand-lengths. Bamboo strandboards with nominal dimensions of 37 mm by 37 mm by 12 mm and target density 0.65 g/cm3 were manufactured using moso bamboo (Pyllostachys pubescent Mezel and MDI resin to produce two types of strandlength. Two types of strand length and MDI resin were used to produce three types of strandboard. The bending properties and dimensional stability of the strandboards were evaluated according to the Japanese Industrial Standard (JIS for particleboard. The results of this experiment indicate that the bending properties and internal bond strength were affected by both board type and strand-length. The distribution of resin inside the 80 mm strandboard was less homogenous than in the 50 mm strandboard, which affects the internal bond strength. Thickness swelling of the RAND board was the highest and linear stability was affected substantially by strand alignment. The RAND board and cross-oriented 3LAY board effectively restrained linear expansion in the direction perpendicular to the strand alignment. A cross-oriented core may be the most effective way to reduce dimensional change and bending property values in perpendicular directions.

Life cycle inventory analysis of regenerative thermal oxidation of air emissions from oriented strand board facilities in Minnesota - a perspective of global climate change

Energy Technology Data Exchange (ETDEWEB)

Nicholson, W.J. [Potlatch Corp., San Francisco, CA (United States)

1997-12-31

Life cycle inventory analysis has been applied to the prospective operation of regenerative thermal oxidation (RTO) technology at oriented strand board plants at Bemidji (Line 1) and Cook, Minnesota. The net system destruction of VOC`s and carbon monoxide, and at Cook a small quantity of particulate, has a very high environmental price in terms of energy and water use, global warming potential, sulfur and nitrogen oxide emissions, solids discharged to water, and solid waste deposited in landfills. The benefit of VOC destruction is identified as minor in terms of ground level ozone at best and possibly slightly detrimental. Recognition of environmental tradeoffs associated with proposed system changes is critical to sound decision-making. There are more conventional ways to address carbon monoxide emissions than combustion in RTO`s. In an environment in which global warming is a concern, fuel supplemental combustion for environmental control does not appear warranted. Consideration of non-combustion approaches to address air emission issues at the two operations is recommended. 1 ref., 5 tabs.

Enabling nurses to lead change: the orientation experiences of nurses to boards.

Science.gov (United States)

Walton, AnnMarie; Lake, Donna; Mullinix, Connie; Allen, Deborah; Mooney, Kathi

2015-01-01

Nurses need to be full partners in shaping health care and health care policy. One way to do this is to be present and active on boards at all levels. The purpose of this study is to examine the orientation experiences of nurses to boards and their preparation to influence health care and health care policy. A Web-based survey about the efficacy of board orientation was sent to members of three local boards made up exclusively of nurses. Liabilities and fiduciary duties were least likely to be addressed in board orientation for nurses. Board members requested more training in finance and a more formal/structured orientation process. Standardizing orientation elements for nurses serving on boards would best prepare them to serve on interprofessional hospital boards and work in the health policy arena. The orientation experience on local- and state-level nursing boards is fundamental to nurses beginning board service. Copyright © 2015 Elsevier Inc. All rights reserved.

USE OF EUCALYPTUS WOOD FOR ORIENTED STRAND BOARD (OSB MANUFACTURING

Directory of Open Access Journals (Sweden)

Setsuo Iwakiri

2004-06-01

Full Text Available This research evaluated the potential use of Eucalyptus species for OSB manufacturing. The boards were manufactured at the density of 0,70 g/cm³ and 6% of the phenol-formaldheyde resin contents. The following Eucalyptus species were studied: E. grandis E. dunnii ,E. tereticornis E. saligna ,E. citriodora, and E. maculata. The results of the physical and mechanical property tests showed high potentiality of the uses of Eucalyptus grandis and Eucalyptus saligna for OSB manufacturing, Boards manufactured with Eucalyptus grandis wood presented similar or higher average values for physical and mechanical properties, in comparison to Pinus taeda, which is the main species used for OSB production in Brazil.

Airborne concentrations of methylene diphenyl diisocyanate (MDI) in North American wood mills during the manufacturing of oriented strand board (OSB).

Science.gov (United States)

Karoly, William J; Flatley, John J; Stevenson, Ralph D; Bowers, John D

2004-12-01

Air monitoring data were collected from industrial hygiene surveys over an 8-year period in oriented strand board (OSB) mills. Personal samples were taken to evaluate potential employee exposures to MDI. Area samples were taken to determine the effectiveness of control measures used in the mills to prevent fugitive emissions of wood dust, MDI, and MDI-coated wood dust from the OSB manufacturing process. Personal sampling results (578 samples covering 11 different job categories) ranged from 0.0002-0.524 mg/m3, with a GM = 0.001 and GSD = 3.71. Area sampling results (1657 samples covering 14 stationary locations in the mills) ranged from 0.0002-2.5 mg/m3, with a GM = 0.004 and GSD = 5.52. The statistical range of the data suggests high variability. While exposures to MDI above the established limits (0.051 mg/m3, 8-hour time-weighted average, 0.2 mg/m3, ceiling) can and do occur when engineering controls are not maintained and/or proper work practices and personal protective equipment are not followed/used for certain high exposure potential tasks, the data indicate that over 97% of the personal and 92% of the area sampling results are less than 0.051 mg/m3. Wipe testing was performed to determine the presence of removable, unreacted diisocyanates (NCO functional groups)from various surfaces. Positive results were found in about 13% of the wipe tests on surfaces confined to the blender, forming line, and hopper deck process areas.

Comparison of Energy Dissipation, Stiffness, and Damage of Structural Oriented Strand Board (OSB, Conventional Gypsum, and Viscoelastic Gypsum Shearwalls Subjected to Cyclic Loads

Directory of Open Access Journals (Sweden)

Andrew S. Blasetti

2012-06-01

Full Text Available A key element in the seismic load resisting system of a wood framed structure is the shear wall which is typically sheathed on one side with plywood or oriented strand board (OSB and gypsum on the other. The shear capacity of gypsum sheathed shear walls is typically neglected in high seismic areas due to the susceptibility of conventional drywall screw connections to damage caused by earthquakes. The earthquake resistance of an innovative viscoelastic (VE gypsum shearwall is evaluated and compared to conventional structural and non-structural walls. Ten 8 ft × 8 ft wood framed wall specimens of three configurations [nailed-OSB, screw-gypsum, and VE polymer-gypsum] were subjected to a cyclic test protocol. The energy dissipation, stiffness, and damage characteristics of all shearwalls are reported herein. Testing results indicate the VE-gypsum walls can dissipate more energy than the OSB structural panels and 500% more energy that the conventional gypsum sheathed walls and contains a constant source of energy dissipation not seen in the structural and non-structural walls. The wall stiffness of the OSB wall degrades at a far greater rate that the VE gypsum wall and at continued cycling degrades below the VE wall stiffness. Unlike both of the conventional wall types, the VE wall showed no visible or audible signs of damage when subjected to shear displacements up to 1.

Prostate brachytherapy postimplant dosimetry: Seed orientation and the impact of dosimetric anisotropy in stranded implants

International Nuclear Information System (INIS)

Chng, Nicholas; Spadinger, Ingrid; Rasoda, Rosey; Morris, W. James; Salcudean, Septimiu

2012-01-01

Purpose: In postimplant dosimetry for prostate brachytherapy, dose is commonly calculated using the TG-43 1D formalism, because seed orientations are difficult to determine from CT images, the current standard for the procedure. However, the orientation of stranded seeds soon after implantation is predictable, as these seeds tend to maintain their relative spacing, and orient themselves along the implant trajectory. The aim of this study was to develop a method for determining seed orientations from reconstructed strand trajectories, and to use this information to investigate the dosimetric impact of applying the TG-43 2D formalism to clinical postimplant analysis. Methods: Using in-house software, the preplan to postimplant seed correspondence was determined for a cohort of 30 patients during routine day-0 CT-based postimplant dosimetry. All patients were implanted with stranded-seed trains. Spline curves were fit to each set of seeds composing a strand, with the requirement that the distance along the spline between seeds be equal to the seed spacing within the strand. The orientations of the seeds were estimated by the tangents to the spline at each seed centroid. Dose distributions were then determined using the 1D and 2D TG-43 formalisms. These were compared using the TG-137 recommended dose metrics for the prostate, prostatic urethra, and rectum. Results: Seven hundred and sixty one strands were analyzed in total. Defining the z-axis to be cranial-positive and the x-axis to be left-lateral positive in the CT coordinate system, the average seed had an inclination of 21 deg. ± 10 deg. and an azimuth of -81 deg. ± 57 deg. These values correspond to the average strand rising anteriorly from apex to base, approximately parallel to the midsagittal plane. Clinically minor but statistically significant differences in dose metrics were noted. Compared to the 2D calculation, the 1D calculation underestimated prostate V100 by 1.1% and D90 by 2.3 Gy, while

Effects of particles thickness and veneer reiforced layer in the properties of oriented strand boards OSB

Directory of Open Access Journals (Sweden)

Setsuo Iwakiri

2009-03-01

Full Text Available This work evaluated the effects of particle thickness and veneer reinforced layer on the physical and mechanicalproperties of OSB made of Pinus taeda L. The boards were manufactured with particle thickness of 0.4, 0.7 and 1.0 mm and phenolformaldehyderesin in the proportion of 6% of solid content. To the veneer reinforced layer was used veneer from Pinus taeda with 2.0mm of thickness. The increase in the slenderness (length/thickness ratio of thins particles, results in the higher values of MOE andMOR in the cross direction. The increase in the particles thickness contributed to higher values of the board internal bond. Thedifferent particles thickness did not clearly affected on the physical properties of OSB. The veneer reinforced layer results in the higheraverage values of MOE and MOR in the cross direction. All of the results of MOE and MOR obtained for boards with differentthickness attend tominimum values required per CSA 0437 (CSA, 1993. For the internal bond, the results were satisfactory to boardsmanufactured with particles thickness of 0.7 and 1.0 mm. According to the results the main conclusions were: (i The increase in theparticles thickness contributed to lower values of MOE and MOR, and higher values of the board internal bond; (ii the veneerreinforced layer increased MOE and MOR values in the cross direction.

Microwave wood strand drying: energy consumption, VOC emission and drying quality

Energy Technology Data Exchange (ETDEWEB)

Wang, S.; Du, G.; Zhang, Y. [Tennessee Univ., Knoxville, TN (United States). Dept. of Forestry, Wildlife and Fisheries

2005-07-01

The objective of this research was to develop microwave drying technology for wood strand drying for oriented strand board (OSB) manufacturing. The advantages of microwave drying included a reduction in the drying time of wood strands and a reduction in the release of volatile organic compounds (VOC) through a decrease in the thermal degradation of the wood material. Temperature and moisture content changes under different microwave drying conditions were investigated. The effects of microwave drying on VOC emissions were evaluated and analyzed using gas chromatography and mass spectrometry. Microwave power input and the mass of drying materials in the microwave oven were found to have a dominant effect on drying quality. Results indicated that an increase in microwave power input and a decrease in sample weights resulted in high drying temperatures, short drying times and a high drying rate. The effect of microwave drying on the strand surfaces was also investigated. Different strand geometries and initial moisture content resulted in varying warm-up curves, but did not influence final moisture content. VOC emissions were quantified by comparing alpha-pinene concentrations. The microwave drying resulted in lower VOC emissions compared with conventional drying methods. It was concluded that the microwave drying technique provided faster strand drying and reduced energy consumption by up to 50 per cent. In addition, the surface wettability of wood strands dried with microwaves was better than with an industrial rotary drum drier. 12 refs., 3 tabs., 5 figs.

Physical, mechanical, and fire properties of oriented strandboard with fire retardant treated veneers

Science.gov (United States)

Nadir Ayrilmis; Zeki Candan; Robert White

2007-01-01

This study evaluated physical, mechanical and fire properties of oriented strand boards (OSB) covered with fire retardant treated veneers. The beech (Fagus orientalis Lipsky) veneers were treated with either monoammonium phosphate, diammonium phosphate, lime water or a borax/boric acid (1 : 1 by weight) mixture. Physical and mechanical properties of the specimens were...

CRISPRstrand: predicting repeat orientations to determine the crRNA-encoding strand at CRISPR loci

DEFF Research Database (Denmark)

Alkhnbashi, Omer S.; Costa, Fabrizio; Shah, Shiraz Ali

2014-01-01

Motivation: The discovery of CRISPR-Cas systems almost 20 years ago rapidly changed our perception of the bacterial and archaeal immune systems. CRISPR loci consist of several repetitive DNA sequences called repeats, inter-spaced by stretches of variable length sequences called spacers. This CRISPR...... array is transcribed and processed into multiple mature RNA species (crRNAs). A single crRNA is integrated into an interference complex, together with CRISPR-associated (Cas) proteins, to bind and degrade invading nucleic acids. Although existing bioinformatics tools can recognize CRISPR loci...... by their characteristic repeat-spacer architecture, they generally output CRISPR arrays of ambiguous orientation and thus do not determine the strand from which crRNAs are processed. Knowledge of the correct orientation is crucial for many tasks, including the classification of CRISPR conservation, the detection...

77 FR 21098 - Notice of Meeting of the Environmental Financial Advisory Board (EFAB), and Transit-Oriented...

Science.gov (United States)

2012-04-09

... ENVIRONMENTAL PROTECTION AGENCY [FRL-9656-6] Notice of Meeting of the Environmental Financial... Financial Advisory Board (EFAB) will hold a meeting on May 22-23, 2012 and a Transit-Oriented Development... discussed include: clean air technology; tribal environmental programs; transit-oriented development; energy...

Multi-board concept - a scenario based approach for supporting product quality and life cycle oriented design

DEFF Research Database (Denmark)

Robotham, Antony John; Hertzum, Morten

2000-01-01

This paper will describe the multi-board concept, which is a working approach for supporting life cycle oriented design and product quality. Aspects of this concept include construction of a common working environment where multiple display boards depict scenarios of the product life cycle...... to believe that the multi-board concept promises to be a useful means of communication amongst the design team. We be-lieve that it fosters a thorough understanding of life cycle events, which, in turn, inspires the design of innovative products of the highest quality......., creating a shared quality mindset amongst design-ers, and developing creativity and synthesis in product design. The appropriateness of scenarios for supporting life cycle oriented design will be ar-gued and preliminary results from early experi-mentation will be presented.Initial results lead us...

Fuzzy Concurrent Object Oriented Expert System for Fault Diagnosis in 8085 Microprocessor Based System Board

OpenAIRE

Mr.D. V. Kodavade; Dr. Mrs.S.D.Apte

2014-01-01

With the acceptance of artificial intelligence paradigm, a number of successful artificial intelligence systems were created. Fault diagnosis in microprocessor based boards needs lot of empirical knowledge and expertise and is a true artificial intelligence problem. Research on fault diagnosis in microprocessor based system boards using new fuzzy-object oriented approach is presented in this paper. There are many uncertain situations observed during fault diagnosis. These uncertain situations...

Application of Magnetic and Geotechnical Methods for Archaeological Site Investigations

Science.gov (United States)

2011-07-01

national historic preservation act NRM natural remnant magnetism NS north-south nT nano Tesla ID inside diameter OSB oriented strand board psi...3.4 Soil Box Experiments Compaction tests were conducted by loading soil into a wooden box (1 m3) constructed of oriented strand board ( OSB ) and

Synchrotron x-ray study of the orientational ordering D2-D1 structural phase transition of freely suspended discotic strands in triphenylene hexa-n-dodecanoate

International Nuclear Information System (INIS)

Safinya, C.R.; Liang, K.S.; Varady, W.A.; Clark, N.A.; Andersson, G.

1984-01-01

We demonstrate the feasibility of x-ray scattering studies of freely suspended strands of discotic liquid crystals (of triphenylene hexa-n-dodecanoate). We are able to grow strands, which are stable for days, of diameter >50 μm with a few single crystal domains. Unexpectedly, we find that the quasi two-dimensional structural phase transition from columnar D2 to columnar D1 corresponds to the orientational ordering of columns of molecules with the molecules tilted at finite angles to the column axis in both phases

Verfahren zur Herstellung von OSB-Platten

OpenAIRE

Buchholzer, P.

2003-01-01

DE 10222955 C UPAB: 20030910 NOVELTY - Manufacture of oriented strand board comprises: (a) producing macro-chips from wood which are suitable for the surface layer;(b) impregnating these with a flame-proofing agent; (c) forming them into a surface layer; (d) spreading adhesive-coated chips suitable for a central layer on to the adhesive-coated surface layer; and (e) pressing to form a board. USE - Manufacture of oriented strand board. ADVANTAGE - The boards produced can be used in more applic...

New views on strand asymmetry in insect mitochondrial genomes.

Directory of Open Access Journals (Sweden)

Shu-Jun Wei

Full Text Available Strand asymmetry in nucleotide composition is a remarkable feature of animal mitochondrial genomes. Understanding the mutation processes that shape strand asymmetry is essential for comprehensive knowledge of genome evolution, demographical population history and accurate phylogenetic inference. Previous studies found that the relative contributions of different substitution types to strand asymmetry are associated with replication alone or both replication and transcription. However, the relative contributions of replication and transcription to strand asymmetry remain unclear. Here we conducted a broad survey of strand asymmetry across 120 insect mitochondrial genomes, with special reference to the correlation between the signs of skew values and replication orientation/gene direction. The results show that the sign of GC skew on entire mitochondrial genomes is reversed in all species of three distantly related families of insects, Philopteridae (Phthiraptera, Aleyrodidae (Hemiptera and Braconidae (Hymenoptera; the replication-related elements in the A+T-rich regions of these species are inverted, confirming that reversal of strand asymmetry (GC skew was caused by inversion of replication origin; and finally, the sign of GC skew value is associated with replication orientation but not with gene direction, while that of AT skew value varies with gene direction, replication and codon positions used in analyses. These findings show that deaminations during replication and other mutations contribute more than selection on amino acid sequences to strand compositions of G and C, and that the replication process has a stronger affect on A and T content than does transcription. Our results may contribute to genome-wide studies of replication and transcription mechanisms.

Economic impacts of short-rotation woody crops for energy or oriented strand board: a Minnesota case study

Science.gov (United States)

William F. Lazarus; Douglas G. Tiffany; Ronald S. Zalesny Jr.; Don E. Riemenschneider

2011-01-01

Short-rotation woody crops (SRWC) such as hybrid poplars are becoming increasingly competitive with agriculture on marginal land. The trees can be grown for energy and for traditional uses such as oriented strandboard. Using IMPLAN (Impact Analysis for Planning) software, we modeled the impacts of shifting land use from hay and pasture for cow-calf beef operations to...

Characterization of a parallel-stranded DNA hairpin

International Nuclear Information System (INIS)

Germann, M.W.; Vogel, H.J.; Pon, R.T.; van de Sande, J.H.

1989-01-01

Recently, the authors have shown that synthetic DNA containing homooligomeric A-T base pairs can form a parallel-stranded intramolecular hairpin structure. In the present study, they have employed NMR and optical spectroscopy to investigate the structure of the parallel-stranded (PS) DNA hairpin 3'-d(T) 8 C 4 (A) 8 -3' and the related antiparallel (APS) hair 5'-d(T) 8 C 4 (A) 8 -3'. The parallel orientation of the strands in the PS oligonucleotide is achieved by introducing a 5'-5' phosphodiester linkage in the hairpin loop. Ultraviolet spectroscopic and fluorescence data of drug binding are consistent with the formation of PS and APS structures, respectively, in these two hairpins. Vacuum circular dichroism measurements in combination with theoretical CD calculations indicate that the PS structure forms a right-handed helix. 31 P NMR measurements indicate that the conformation of the phosphodiester backbone of the PS structure is not drastically different from that of the APS control. The presence of slowly exchanging imino protons at 14 ppm and the observation of nuclear Overhauser enhancement between imino protons and the AH-2 protons demonstrate that similar base pairing and base stacking between T and A residues occur in both hairpins. On the basis of NOESY measurements, they find that the orientation of the bases is in the anti region and that the sugar puckering is in the 2'-endo range. The results indicate a B-like conformation for each of the strands in the stem part of the PS hairpin and reverse Watson-Crick base pairing between the T and A residues. These data are consistent with a previously calculated structure for parallel-stranded DNA

75 FR 52969 - National Park System Advisory Board; Meeting

Science.gov (United States)

2010-08-30

... Board will meet September 15-16, 2010, in Washington, DC. The Board will have an orientation session on... will convene from 8:30 a.m. to 1:15 p.m., for an orientation session for Board members, followed by a... will be accommodated on a first-come basis. Anyone may file with the Board a written statement...

Hospital boards and hospital strategic focus: the impact of board involvement in strategic decision making.

Science.gov (United States)

Ford-Eickhoff, Karen; Plowman, Donde Ashmos; McDaniel, Reuben R

2011-01-01

Despite pressures to change the role of hospital boards, hospitals have made few changes in board composition or director selection criteria. Hospital boards have often continued to operate in their traditional roles as either "monitors" or "advisors." More attention to the direct involvement of hospital boards in the strategic decision-making process of the organizations they serve, the timing and circumstances under which board involvement occurs, and the board composition that enhances their abilities to participate fully is needed. We investigated the relationship between broader expertise among hospital board members, board involvement in the stages of strategic decision making, and the hospital's strategic focus. We surveyed top management team members of 72 nonacademic hospitals to explore the participation of critical stakeholder groups such as the board of directors in the strategic decision-making process. We used hierarchical regression analysis to explore our hypotheses that there is a relationship between both the nature and involvement of the board and the hospital's strategic orientation. Hospitals with broader expertise on their boards reported an external focus. For some of their externally-oriented goals, hospitals also reported that their boards were involved earlier in the stages of decision making. In light of the complex and dynamic environment of hospitals today, those charged with developing hospital boards should match the variety in the external issues that the hospital faces with more variety in board makeup. By developing a board with greater breadth of expertise, the hospital responds to its complex environment by absorbing that complexity, enabling a greater potential for sensemaking and learning. Rather than acting only as monitors and advisors, boards impact their hospitals' strategic focus through their participation in the strategic decision-making process.

78 FR 73187 - Black Hills National Forest Advisory Board

Science.gov (United States)

2013-12-05

... DEPARTMENT OF AGRICULTURE Forest Service Black Hills National Forest Advisory Board AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Black Hills National Forest Advisory Board (Board... all members of the Advisory Board; (2) provide orientation to Board Members on Basic Laws governing...

Nondestructive evaluation of oriented strand board exposed to decay fungi.

Science.gov (United States)

Barbara L. Illman; Vina W. Yang; Robert J. Ross; William J. Nelson

2002-01-01

Stress wave nondestructive evaluation (NDE) technologies are being used in our laboratory to evaluate the performance properties of engineered wood. These techniques have proven useful in the inspection of timber structures to locate internal voids and decayed or deteriorated areas in large timbers. But no information exists concerning NDE and important properties of...

Study on Shear Performance of Cold-formed Steel Composite Wall with New Type of stud

Science.gov (United States)

Wang, Chungang; Yue, Sizhe; Liu, Hong; Zhang, Zhuangnan

2018-03-01

The shear resistance of single oriented-strand board wall and single gypsum board wall can be improved in different degrees by increasing strength of steel. The experimental data of literatures were used, and the test specimens had been simulated and validated by ABAQUS finite element analysis. According to the research, it showed that the compressive bearing capacity of the new stud composite wall was much better than the common stud composite wall, so the establishment and research of all models had been based on the new section stud. The analysis results show that when using new type of stud the shear resistance of the single oriented-strand board wall can be improved efficiently by increasing strength of steel, but the shear resistance of the single gypsum wall can be increased little.

Ca2+ improves organization of single-stranded DNA bases in human Rad51 filament, explaining stimulatory effect on gene recombination.

KAUST Repository

Fornander, Louise H

2012-02-22

Human RAD51 protein (HsRad51) catalyses the DNA strand exchange reaction for homologous recombination. To clarify the molecular mechanism of the reaction in vitro being more effective in the presence of Ca(2+) than of Mg(2+), we have investigated the effect of these ions on the structure of HsRad51 filament complexes with single- and double-stranded DNA, the reaction intermediates. Flow linear dichroism spectroscopy shows that the two ionic conditions induce significantly different structures in the HsRad51/single-stranded DNA complex, while the HsRad51/double-stranded DNA complex does not demonstrate this ionic dependence. In the HsRad51/single-stranded DNA filament, the primary intermediate of the strand exchange reaction, ATP/Ca(2+) induces an ordered conformation of DNA, with preferentially perpendicular orientation of nucleobases relative to the filament axis, while the presence of ATP/Mg(2+), ADP/Mg(2+) or ADP/Ca(2+) does not. A high strand exchange activity is observed for the filament formed with ATP/Ca(2+), whereas the other filaments exhibit lower activity. Molecular modelling suggests that the structural variation is caused by the divalent cation interfering with the L2 loop close to the DNA-binding site. It is proposed that the larger Ca(2+) stabilizes the loop conformation and thereby the protein-DNA interaction. A tight binding of DNA, with bases perpendicularly oriented, could facilitate strand exchange.

Modelling and optimization of the sound absorption of wood-wool cement boards

NARCIS (Netherlands)

Botterman, B.; Doudart de la Grée, G.C.H.; Hornikx, M.C.J.; Yu, Q.; Brouwers, H.J.H.

2018-01-01

The present article aims to characterize and improve the sound absorption of wood-wool cement boards (WWCB) with varying strand widths, densities, thicknesses and applied with varying air cavity thicknesses by using impedance models. Different rigid-frame impedance models were analysed to predict

DNA-imprinted polymer nanoparticles with monodispersity and prescribed DNA-strand patterns

Science.gov (United States)

Trinh, Tuan; Liao, Chenyi; Toader, Violeta; Barłóg, Maciej; Bazzi, Hassan S.; Li, Jianing; Sleiman, Hanadi F.

2018-02-01

As colloidal self-assembly increasingly approaches the complexity of natural systems, an ongoing challenge is to generate non-centrosymmetric structures. For example, patchy, Janus or living crystallization particles have significantly advanced the area of polymer assembly. It has remained difficult, however, to devise polymer particles that associate in a directional manner, with controlled valency and recognition motifs. Here, we present a method to transfer DNA patterns from a DNA cage to a polymeric nanoparticle encapsulated inside the cage in three dimensions. The resulting DNA-imprinted particles (DIPs), which are 'moulded' on the inside of the DNA cage, consist of a monodisperse crosslinked polymer core with a predetermined pattern of different DNA strands covalently 'printed' on their exterior, and further assemble with programmability and directionality. The number, orientation and sequence of DNA strands grafted onto the polymeric core can be controlled during the process, and the strands are addressable independently of each other.

Transcription blockage by homopurine DNA sequences: role of sequence composition and single-strand breaks

Science.gov (United States)

Belotserkovskii, Boris P.; Neil, Alexander J.; Saleh, Syed Shayon; Shin, Jane Hae Soo; Mirkin, Sergei M.; Hanawalt, Philip C.

2013-01-01

The ability of DNA to adopt non-canonical structures can affect transcription and has broad implications for genome functioning. We have recently reported that guanine-rich (G-rich) homopurine-homopyrimidine sequences cause significant blockage of transcription in vitro in a strictly orientation-dependent manner: when the G-rich strand serves as the non-template strand [Belotserkovskii et al. (2010) Mechanisms and implications of transcription blockage by guanine-rich DNA sequences., Proc. Natl Acad. Sci. USA, 107, 12816–12821]. We have now systematically studied the effect of the sequence composition and single-stranded breaks on this blockage. Although substitution of guanine by any other base reduced the blockage, cytosine and thymine reduced the blockage more significantly than adenine substitutions, affirming the importance of both G-richness and the homopurine-homopyrimidine character of the sequence for this effect. A single-strand break in the non-template strand adjacent to the G-rich stretch dramatically increased the blockage. Breaks in the non-template strand result in much weaker blockage signals extending downstream from the break even in the absence of the G-rich stretch. Our combined data support the notion that transcription blockage at homopurine-homopyrimidine sequences is caused by R-loop formation. PMID:23275544

Swi5-Sfr1 protein stimulates Rad51-mediated DNA strand exchange reaction through organization of DNA bases in the presynaptic filament.

KAUST Repository

Fornander, Louise H

2013-12-03

The Swi5-Sfr1 heterodimer protein stimulates the Rad51-promoted DNA strand exchange reaction, a crucial step in homologous recombination. To clarify how this accessory protein acts on the strand exchange reaction, we have analyzed how the structure of the primary reaction intermediate, the Rad51/single-stranded DNA (ssDNA) complex filament formed in the presence of ATP, is affected by Swi5-Sfr1. Using flow linear dichroism spectroscopy, we observe that the nucleobases of the ssDNA are more perpendicularly aligned to the filament axis in the presence of Swi5-Sfr1, whereas the bases are more randomly oriented in the absence of Swi5-Sfr1. When using a modified version of the natural protein where the N-terminal part of Sfr1 is deleted, which has no affinity for DNA but maintained ability to stimulate the strand exchange reaction, we still observe the improved perpendicular DNA base orientation. This indicates that Swi5-Sfr1 exerts its activating effect through interaction with the Rad51 filament mainly and not with the DNA. We propose that the role of a coplanar alignment of nucleobases induced by Swi5-Sfr1 in the presynaptic Rad51/ssDNA complex is to facilitate the critical matching with an invading double-stranded DNA, hence stimulating the strand exchange reaction.

Palm boards are not action measures: an alternative to the two-systems theory of geographical slant perception.

Science.gov (United States)

Durgin, Frank H; Hajnal, Alen; Li, Zhi; Tonge, Natasha; Stigliani, Anthony

2010-06-01

Whereas most reports of the perception of outdoor hills demonstrate dramatic overestimation, estimates made by adjusting a palm board are much closer to the true hill orientation. We test the dominant hypothesis that palm board accuracy is related to the need for motor action to be accurately guided and conclude instead that the perceptual experience of palm-board orientation is biased and variable due to poorly calibrated proprioception of wrist flexion. Experiments 1 and 3 show that wrist-flexion palm boards grossly underestimate the orientations of near, reachable surfaces whereas gesturing with a free hand is fairly accurate. Experiment 2 shows that palm board estimates are much lower than free hand estimates for an outdoor hill as well. Experiments 4 shows that wrist flexion is biased and noisy compared to elbow flexion, while Experiment 5 shows that small changes in palm board height produce large changes in palm board estimates. Together, these studies suggest that palm boards are biased and insensitive measures. The existing literature arguing that there are two systems in the perception of geographical slant is re-evaluated, and a new theoretical framework is proposed in which a single exaggerated representation of ground-surface orientation guides both action and perception. Copyright 2010 Elsevier B.V. All rights reserved.

Propagation Techniques for Highland Bamboo (Arundinaria alpina ...

African Journals Online (AJOL)

1Ethiopian Institute of Agricultural Research, Forestry Research Center, ... (10 new shoots per propagule), along its stem length (at the upper, middle and butt ... laminated bamboo lumber (LBL), oriented strand board (OSB), medium density ...

Stranded costs and exit fees

International Nuclear Information System (INIS)

2002-01-01

The New Brunswick Market Design Committee has been directed to examine the issue of stranded costs since it is a major component of restructuring within the electricity sector. When regulated monopolies are faced with competition, they could find that some of their embedded costs cannot be recovered. These costs are referred to as stranded costs. Common sources include large capital investments in uneconomic plants or expensive power purchase contracts or fuel supply contracts. In general, stranded costs do not include gains or losses associated with normal business risks experienced by regulated utilities. This report presents recommendations for mitigation of stranded costs, valuation methodologies and cost-recovery mechanisms. It also presents a summary of experience with stranded costs in other jurisdictions such as California, Rhode Island, Pennsylvania and Ontario. Stranded costs are often recovered through an obligatory charge on all customers, particularly in jurisdictions where retail competition exists. In the New Brunswick market, however, the only customers who can create stranded costs are those eligible to choose their own suppliers. It is argued that since most customers will not have a choice of electricity suppliers, they cannot generate stranded costs and therefore, should not have to pay costs stranded by others. A method to quantify stranded costs is presented, along with a review of transmission-related stranded costs in New Brunswick. Expansion of self-generation in New Brunswick could strand transmission assets. Currently, self-generators only contribute a small amount to fixed charges of the transmission system. However, under new recommended tariffs, the amount could increase. It is likely that the net amount of stranded transmission costs will not be large. 2 refs., 1 fig

78 FR 64471 - Black Hills National Forest Advisory Board

Science.gov (United States)

2013-10-29

... provide an orientation to the Board regarding Forest Funding, including appropriations and trends; (2... following business will be conducted: (1) Orientation to Forest Funding including appropriations and trends... INFORMATION CONTACT. All reasonable accommodation requests are managed on a case by case basis. Dated: October...

Recycling-oriented characterization of plastic frames and printed circuit boards from mobile phones by electronic and chemical imaging

International Nuclear Information System (INIS)

Palmieri, Roberta; Bonifazi, Giuseppe; Serranti, Silvia

2014-01-01

Highlights: • A recycling oriented characterization of end-of-life mobile phones was carried out. • Characterization was developed in a zero-waste-perspective, aiming to recover all the mobile phone materials. • Plastic frames and printed circuit boards were analyzed by electronic and chemical imaging. • Suitable milling/classification strategies were set up to define specialized-pre-concentrated-streams. • The proposed approach can improve the recovery of polymers, base/precious metals, rare earths and critical raw materials. - Abstract: This study characterizes the composition of plastic frames and printed circuit boards from end-of-life mobile phones. This knowledge may help define an optimal processing strategy for using these items as potential raw materials. Correct handling of such a waste is essential for its further “sustainable” recovery, especially to maximize the extraction of base, rare and precious metals, minimizing the environmental impact of the entire process chain. A combination of electronic and chemical imaging techniques was thus examined, applied and critically evaluated in order to optimize the processing, through the identification and the topological assessment of the materials of interest and their quantitative distribution. To reach this goal, end-of-life mobile phone derived wastes have been systematically characterized adopting both “traditional” (e.g. scanning electronic microscopy combined with microanalysis and Raman spectroscopy) and innovative (e.g. hyperspectral imaging in short wave infrared field) techniques, with reference to frames and printed circuit boards. Results showed as the combination of both the approaches (i.e. traditional and classical) could dramatically improve recycling strategies set up, as well as final products recovery

Recycling-oriented characterization of plastic frames and printed circuit boards from mobile phones by electronic and chemical imaging

Energy Technology Data Exchange (ETDEWEB)

Palmieri, Roberta; Bonifazi, Giuseppe; Serranti, Silvia, E-mail: silvia.serranti@uniroma1.it

2014-11-15

Highlights: • A recycling oriented characterization of end-of-life mobile phones was carried out. • Characterization was developed in a zero-waste-perspective, aiming to recover all the mobile phone materials. • Plastic frames and printed circuit boards were analyzed by electronic and chemical imaging. • Suitable milling/classification strategies were set up to define specialized-pre-concentrated-streams. • The proposed approach can improve the recovery of polymers, base/precious metals, rare earths and critical raw materials. - Abstract: This study characterizes the composition of plastic frames and printed circuit boards from end-of-life mobile phones. This knowledge may help define an optimal processing strategy for using these items as potential raw materials. Correct handling of such a waste is essential for its further “sustainable” recovery, especially to maximize the extraction of base, rare and precious metals, minimizing the environmental impact of the entire process chain. A combination of electronic and chemical imaging techniques was thus examined, applied and critically evaluated in order to optimize the processing, through the identification and the topological assessment of the materials of interest and their quantitative distribution. To reach this goal, end-of-life mobile phone derived wastes have been systematically characterized adopting both “traditional” (e.g. scanning electronic microscopy combined with microanalysis and Raman spectroscopy) and innovative (e.g. hyperspectral imaging in short wave infrared field) techniques, with reference to frames and printed circuit boards. Results showed as the combination of both the approaches (i.e. traditional and classical) could dramatically improve recycling strategies set up, as well as final products recovery.

Strand Displacement by DNA Polymerase III Occurs through a τ-ψ-χ Link to Single-stranded DNA-binding Protein Coating the Lagging Strand Template*

OpenAIRE

Yuan, Quan; McHenry, Charles S.

2009-01-01

In addition to the well characterized processive replication reaction catalyzed by the DNA polymerase III holoenzyme on single-stranded DNA templates, the enzyme possesses an intrinsic strand displacement activity on flapped templates. The strand displacement activity is distinguished from the single-stranded DNA-templated reaction by a high dependence upon single-stranded DNA binding protein and an inability of γ-complex to support the reaction in the absence of τ. However, if γ-complex is p...

Strand displacement by DNA polymerase III occurs through a tau-psi-chi link to single-stranded DNA-binding protein coating the lagging strand template.

Science.gov (United States)

Yuan, Quan; McHenry, Charles S

2009-11-13

In addition to the well characterized processive replication reaction catalyzed by the DNA polymerase III holoenzyme on single-stranded DNA templates, the enzyme possesses an intrinsic strand displacement activity on flapped templates. The strand displacement activity is distinguished from the single-stranded DNA-templated reaction by a high dependence upon single-stranded DNA binding protein and an inability of gamma-complex to support the reaction in the absence of tau. However, if gamma-complex is present to load beta(2), a truncated tau protein containing only domains III-V will suffice. This truncated protein is sufficient to bind both the alpha subunit of DNA polymerase (Pol) III and chipsi. This is reminiscent of the minimal requirements for Pol III to replicate short single-stranded DNA-binding protein (SSB)-coated templates where tau is only required to serve as a scaffold to hold Pol III and chi in the same complex (Glover, B., and McHenry, C. (1998) J. Biol. Chem. 273, 23476-23484). We propose a model in which strand displacement by DNA polymerase III holoenzyme depends upon a Pol III-tau-psi-chi-SSB binding network, where SSB is bound to the displaced strand, stabilizing the Pol III-template interaction. The same interaction network is probably important for stabilizing the leading strand polymerase interactions with authentic replication forks. The specificity constant (k(cat)/K(m)) for the strand displacement reaction is approximately 300-fold less favorable than reactions on single-stranded templates and proceeds with a slower rate (150 nucleotides/s) and only moderate processivity (approximately 300 nucleotides). PriA, the initiator of replication restart on collapsed or misassembled replication forks, blocks the strand displacement reaction, even if added to an ongoing reaction.

Production of oriented strand board using four wood species from forest plantations

Directory of Open Access Journals (Sweden)

Setsuo Iwakiri

2014-06-01

Full Text Available This study aimed to evaluate the feasibility of using wood of Acrocarpus fraxinifolius, grevílea robusta, Melia azedarach, Toona ciliata, and mixture of these species for OSB manufacturing. The panels were produced in the laboratory with a nominal density of 0.80 g / cm ³, using phenol-formaldehyde resin in an amount of 6% of solid resin. There were evaluated the properties of water absorption and thickness swelling - 2 and 24 hours, internal bond, modulus of elasticity and modulus of rupture in the parallel and perpendicular direction, according to EN standards. The OSB panels produced with four species and the mixture of these species showed average values of mechanical properties above the minimum standard established by the CSA 437/1993. The results of the physical and mechanical properties obtained indicate the feasibility of the use of wood of Acrocarpus fraxinifolius, grevílea robusta, Melia azedarach and Toona ciliata, and mixture of these species for OSB manufacturing.

Conflict in the Boardroom : A Participant Observation Study of Non-Executive Board Dynamic

NARCIS (Netherlands)

Heemskerk, E.M.; Heemskerk, K.; Wats, M.M.

We develop a conflict-oriented model of board task performance and argue that a common framework, that is, a shared understanding of its role, helps boards to perform well. Conflict is the mediating effect through which this plays out. We posit that a common framework increases board task

Anchoring device enabling relaxation of a multi-strand prestressing cable

International Nuclear Information System (INIS)

1979-01-01

Anchoring device, in a concrete structure, for a multi-strand prestressing cable, enabling the cable to be stressed or relaxed, comprising: (a) an axisymmetrical block, fitted with channels to enable the cable strands to be stressed and anchored through this block, (b) a duct with its opening splayed to a diameter greater than that of the block over a length corresponding to the stretching of the cable when being stressed, (c) a round bearing plate on the concrete around the expanded hole of the duct and (d) at least one intermediate removable bearing piece coming between the edge of the block and the internal edge of the plate. The removable parts are crown sectors of which the opposite bearing faces of each are slanted with respect to the centre line of the block and orientated in the same direction so as to transmit the cable stress at an angle from the block to the edge of the bearing plate [fr

Roof modular system in wood and particle board (OSB to rural construction

Directory of Open Access Journals (Sweden)

Juliano Fiorelli

2012-06-01

Full Text Available Wood is a material of great applicability in construction, with advantageous properties to form various structural systems, such as walls and roof. Most of the roof structural systems follow models that have remained unchanged for a long time. A roof modular system in distinguished materials is proposed: reforested wood (Pine, oriented strand board (OSB and roof tiles made of recycled long-life packaging material in order to be applied in rural construction. In this alternative, besides the benefit of giving destination packages with long-life thermal comfort, it also highlights the use of reforestated wood being the cultivation of such species that provides incentive for agribusiness. The structural performance of this alternative was evaluated through computer modeling and test results of two modular panels. The analysis is based on the results of vertical displacements, deformations and stresses. A positive correlation between theoretical and experimental values was observed, indicating the model's feasibility for use in roof structures. Therefore, the modular system represents a solution to new architecture conceptions to rural construction, for example, storage construction, cattle handling and poultry, with benefits provided by prefabricated building systems.

Conflict in the Boardroom: A Participant Observation Study of Non-Executive Board Dynamic

OpenAIRE

Heemskerk, E.M.; Heemskerk, K.; Wats, M.M.

2017-01-01

We develop a conflict-oriented model of board task performance and argue that a common framework, that is, a shared understanding of its role, helps boards to perform well. Conflict is the mediating effect through which this plays out. We posit that a common framework increases board task performance because it reduces intragroup relationship conflicts, increases task conflicts within the board, and reduces conflicts in the relationship between board and CEO. We explore the model through a co...

Structural features of single-stranded integron cassette attC sites and their role in strand selection.

Directory of Open Access Journals (Sweden)

Marie Bouvier

2009-09-01

Full Text Available We recently showed that cassette integration and deletion in integron platforms were occurring through unconventional site-specific recombination reactions involving only the bottom strand of attC sites. The lack of sequence conservation among attC sites led us to hypothesize that sequence-independent structural recognition determinants must exist within attC sites. The structural data obtained from a synaptic complex of the Vibrio cholerae integrase with the bottom strand of an attC site has shown the importance of extra helical bases (EHB inside the stem-loop structure formed from the bottom strand. Here, we systematically determined the contribution of three structural elements common to all known single-stranded attC site recombination substrates (the EHBs, the unpaired central spacer (UCS, and the variable terminal structure (VTS to strand choice and recombination. Their roles have been evaluated in vivo in the attIxattC reaction context using the suicide conjugation assay we previously developed, but also in an attCxattC reaction using a deletion assay. Conjugation was used to deliver the attC sites in single-stranded form. Our results show that strand choice is primarily directed by the first EHB, but the presence of the two other EHBs also serves to increase this strand selection. We found that the structure of the central spacer is essential to achieve high level recombination of the bottom strand, suggesting a dual role for this structure in active site exclusion and for hindering the reverse reaction after the first strand exchange. Moreover, we have shown that the VTS has apparently no role in strand selectivity.

Five-Strand versus Four-Strand Hamstring Tendon Graft Technique for Anterior Cruciate Ligament Reconstruction: A Biomechanical Comparison.

Science.gov (United States)

Vaillant, Eric R; Parks, Brent G; Camire, Lyn M; Hinton, Richard Y

2017-11-01

The aim of this article is to compare diameter and stiffness, displacement, and strain in a five-strand versus four-strand hamstring graft for anterior cruciate ligament reconstruction. Eight matched pairs of lower extremities underwent four-strand or five-strand hamstring graft reconstruction. Diameter was significantly higher in the five-strand versus the four-strand construct ( p  = 0.002). No significant difference was found between the groups in construct displacement or stiffness. Significantly higher strain was observed in the inner limb versus the outer limb in the four-strand construct ( p  = 0.001) and in the inner limb versus the fifth limb in the 5-strand construct ( p  = 0.004). A fifth limb added to a four-strand hamstring graft significantly increased graft diameter but did not significantly change stiffness or displacement, suggesting that attachment of additional graft material via suture did not provide for full incorporation of the added limb into the graft at time zero. The inner limb in both constructs absorbed significantly greater load than did other limbs. The use of suture to attach additional material to a four-strand hamstring graft may not contribute to improved biomechanical qualities of the graft at time zero. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Modelling Toehold-Mediated RNA Strand Displacement

OpenAIRE

Šulc, Petr; Ouldridge, Thomas E.; Romano, Flavio; Doye, Jonathan P.K.; Louis, Ard A.

2015-01-01

We study the thermodynamics and kinetics of an RNA toehold-mediated strand displacement reaction with a recently developed coarse-grained model of RNA. Strand displacement, during which a single strand displaces a different strand previously bound to a complementary substrate strand, is an essential mechanism in active nucleic acid nanotechnology and has also been hypothesized to occur in vivo. We study the rate of displacement reactions as a function of the length of the toehold and temperat...

Excess single-stranded DNA inhibits meiotic double-strand break repair.

Directory of Open Access Journals (Sweden)

Rebecca Johnson

2007-11-01

Full Text Available During meiosis, self-inflicted DNA double-strand breaks (DSBs are created by the protein Spo11 and repaired by homologous recombination leading to gene conversions and crossovers. Crossover formation is vital for the segregation of homologous chromosomes during the first meiotic division and requires the RecA orthologue, Dmc1. We analyzed repair during meiosis of site-specific DSBs created by another nuclease, VMA1-derived endonuclease (VDE, in cells lacking Dmc1 strand-exchange protein. Turnover and resection of the VDE-DSBs was assessed in two different reporter cassettes that can repair using flanking direct repeat sequences, thereby obviating the need for a Dmc1-dependent DNA strand invasion step. Access of the single-strand binding complex replication protein A, which is normally used in all modes of DSB repair, was checked in chromatin immunoprecipitation experiments, using antibody against Rfa1. Repair of the VDE-DSBs was severely inhibited in dmc1Delta cells, a defect that was associated with a reduction in the long tract resection required to initiate single-strand annealing between the flanking repeat sequences. Mutants that either reduce Spo11-DSB formation or abolish resection at Spo11-DSBs rescued the repair block. We also found that a replication protein A component, Rfa1, does not accumulate to expected levels at unrepaired single-stranded DNA (ssDNA in dmc1Delta cells. The requirement of Dmc1 for VDE-DSB repair using flanking repeats appears to be caused by the accumulation of large quantities of ssDNA that accumulate at Spo11-DSBs when Dmc1 is absent. We propose that these resected DSBs sequester both resection machinery and ssDNA binding proteins, which in wild-type cells would normally be recycled as Spo11-DSBs repair. The implication is that repair proteins are in limited supply, and this could reflect an underlying mechanism for regulating DSB repair in wild-type cells, providing protection from potentially harmful effects

De materiaaleigenschappen van houtachtige materialen

NARCIS (Netherlands)

Kuilen, J.W.G. van de

2000-01-01

Naast gezaagd hout en gelamineerd hout is een uitgebreid palet aan houtachtige (plaat)materialen ontwikkeld, waarvan triplex en Oriented Strand Board tot de meest gebruikte behoren. Een van de eerste typen plaatmateriaal ontwikkeld op basis van hout is triplex. Daarna zijn vele typen platen

The repetitive portion of the Xenopus IgH Mu switch region mediates orientation-dependent class switch recombination.

Science.gov (United States)

Zhang, Zheng Z; Pannunzio, Nicholas R; Lu, Zhengfei; Hsu, Ellen; Yu, Kefei; Lieber, Michael R

2015-10-01

Vertebrates developed immunoglobulin heavy chain (IgH) class switch recombination (CSR) to express different IgH constant regions. Most double-strand breaks for Ig CSR occur within the repetitive portion of the switch regions located upstream of each set of constant domain exons for the Igγ, Igα or Igϵ heavy chain. Unlike mammalian switch regions, Xenopus switch regions do not have a high G-density on the non-template DNA strand. In previous studies, when Xenopus Sμ DNA was moved to the genome of mice, it is able to support substantial CSR when it is used to replace the murine Sγ1 region. Here, we tested both the 2kb repetitive portion and the 4.6 kb full-length portions of the Xenopus Sμ in both their natural (forward) orientation relative to the constant domain exons, as well as the opposite (reverse) orientation. Consistent with previous work, we find that the 4.6 kb full-length Sμ mediates similar levels of CSR in both the forward and reverse orientations. Whereas, the forward orientation of the 2kb portion can restore the majority of the CSR level of the 4.6 kb full-length Sμ, the reverse orientation poorly supports R-looping and no CSR. The forward orientation of the 2kb repetitive portion has more GG dinucleotides on the non-template strand than the reverse orientation. The correlation of R-loop formation with CSR efficiency, as demonstrated in the 2kb repetitive fragment of the Xenopus switch region, confirms a role played by R-looping in CSR that appears to be conserved through evolution. Copyright © 2015 Elsevier Ltd. All rights reserved.

Decontamination Efficacy of Three Commercial Off-the-Shelf Sporicidal Agents on Medium-Sized Panels Contaminated with Surrogates of Bacillus anthracis

Science.gov (United States)

2012-04-01

Pressure-treated (PT) wood lumber All the panels were made with 7/16 in. thick 4 ft2 oriented strand board ( OSB ) as a backing material (Home Depot...No. 2B finish 20 gauge) stainless steel sheets glued to the OSB backing board with construction adhesive to form a single 4 ft2 panel. PT lumber...PT lumber was secured to the OSB with a single VA in. exterior screw (Home Depot [Cat. No. 131-537]) at each end of the board. The brick panels were

Radiobiology of DNA strand breakage

International Nuclear Information System (INIS)

Johansen, I.

1975-01-01

The yield of single-strand breaks in lambda DNA within lysogenic host bacteria was measured after exposure to 4-MeV electrons (50 msec) and rapid transfer (45 msec) to alkaline detergent. In nitrogen anoxia the yield was 1.2 x 10 -12 DNA single-strand breaks per rad per dalton, and under full oxygenation the yield increased to 5 x 10 -12 breaks per rad per dalton. A search for the presence of fast repair mechanisms failed to demonstrate the presence of any mechanism for repair of strand breaks operating within a fraction of a second. Strand breaks produced in the presence of oxygen were repaired in 30--40 sec, while breaks produced under anoxia were rejoined even slower. A functional product from the polAl gene was needed for the rejoining of the broken molecules. Intermediate levels of DNA strand breakage seen at low concentrations of oxygen are dependent on the concentration of cellular sulfhydryl compounds, suggesting that in strand breakage oxygen and hydrogen donors compete for reactions with radiation-induced transients in the DNA. Intercomparisons of data on radiation-induced lethality of cells and single-strand breaks in episomal DNA allow the distinction between two classes of radiation-induced radicals, R 1 and R 2 , with different chemical properties; R 1 reacts readily with oxygen and N-oxyls under formation of potentially lethal products. The reactivity of oxygen in this reaction is 30--40 times higher than that of TMPN. R 2 reacts 16 times more readily than R 1 with oxygen under formation of single-strand breaks in the DNA. R 2 does not react with N-oxyls

Theoretical analysis on ac loss properties of two-strand parallel conductors composed of superconducting multifilamentary strands

CERN Document Server

Iwakuma, M; Funaki, K

2002-01-01

The ac loss properties of two-strand parallel conductors composed of superconducting multifilamentary strands were theoretically investigated. The constituent strands generally need to be insulated and transposed for the sake of uniform current distribution and low ac loss. In case the transposition points deviate from the optimum ones, shielding current is induced according to the interlinkage magnetic flux of the twisted loop enclosed by the insulated strands and the contact resistances at the terminals. It produces an additional ac loss. Supposing a simple situation where a two-strand parallel conductor with one-point transposition is exposed to a uniform ac magnetic field, the basic equations for the magnetic field were proposed and the theoretical expressions of the additional ac losses derived. As a result, the following features were shown. The additional ac loss in the non-saturation case, where the induced shielding current is less than the critical current of a strand, is proportional to the square ...

Application of Spray Foam Insulation Under Plywood and Oriented Strand Board Roof Sheathing

Energy Technology Data Exchange (ETDEWEB)

Grin, A. [Building Science Corporation, Somerville, MA (United States); Smegal, J. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

2013-10-01

Unvented roof strategies with open cell and closed cell spray polyurethane foam insulation sprayed to the underside of roof sheathing have been used since the mid-1990's to provide durable and efficient building enclosures. However, there have been isolated moisture related incidents reported anecdotally that raise potential concerns about the overall hygrothermal performance of these systems. This project involved hygrothermal modeling of a range of rainwater leakage and field evaluations of in-service residential roofs using spray foam insulation. All of the roof assemblies modeled exhibited drying capacity to handle minor rainwater leakage. All field evaluation locations of in-service residential roofs had moisture contents well within the safe range for wood-based sheathing. Explorations of eleven in-service roof systems were completed. The exploration involved taking a sample of spray foam from the underside of the roof sheathing, exposing the sheathing, then taking a moisture content reading. All locations had moisture contents well within the safe range for wood-based sheathing. One full-roof failure was reviewed, as an industry partner was involved with replacing structurally failed roof sheathing. In this case the manufacturer's investigation report concluded that the spray foam was installed on wet OSB based on the observation that the spray foam did not adhere well to the substrate and the pore structure of the closed cell spray foam at the ccSPF/OSB interface was indicative of a wet substrate.

Asymmetric strand segregation: epigenetic costs of genetic fidelity?

Directory of Open Access Journals (Sweden)

Diane P Genereux

2009-06-01

Full Text Available Asymmetric strand segregation has been proposed as a mechanism to minimize effective mutation rates in epithelial tissues. Under asymmetric strand segregation, the double-stranded molecule that contains the oldest DNA strand is preferentially targeted to the somatic stem cell after each round of DNA replication. This oldest DNA strand is expected to have fewer errors than younger strands because some of the errors that arise on daughter strands during their synthesis fail to be repaired. Empirical findings suggest the possibility of asymmetric strand segregation in a subset of mammalian cell lineages, indicating that it may indeed function to increase genetic fidelity. However, the implications of asymmetric strand segregation for the fidelity of epigenetic information remain unexplored. Here, I explore the impact of strand-segregation dynamics on epigenetic fidelity using a mathematical-modelling approach that draws on the known molecular mechanisms of DNA methylation and existing rate estimates from empirical methylation data. I find that, for a wide range of starting methylation densities, asymmetric -- but not symmetric -- strand segregation leads to systematic increases in methylation levels if parent strands are subject to de novo methylation events. I found that epigenetic fidelity can be compromised when enhanced genetic fidelity is achieved through asymmetric strand segregation. Strand segregation dynamics could thus explain the increased DNA methylation densities that are observed in structured cellular populations during aging and in disease.

Seeing the forest before the trees-spatial orientation in freshwater stingrays (Potamotrygon motoro) in a hole-board task.

Science.gov (United States)

Schluessel, V; Herzog, H; Scherpenstein, M

2015-10-01

Freshwater stingrays (Potamotrygon motoro) have been shown to use a variety of spatial learning strategies including directional, landmark and place learning. In the present study, the significance of landmarks and geometric cues was investigated in a hole-board task. The aim was to determine cue preferences and collect additional information on the orientation mechanisms used in elasmobranchs. In four experiments, five juvenile stingrays had to memorize a fixed goal location within either a rectangular or a circular arena in the presence of goal-associated, signaling landmarks, proximal and distal cues. Transfer tests elucidated which cues the rays used or favored to reach the goal position. All rays successfully solved three of four tasks; as expected, different strategies were used in the process. Small alterations in the positioning of signaling landmarks (causing a spatial conflict between the previous feeding location and the new position of the signaling landmark) caused individuals to visit both locations equally often, whereas large alterations caused animals to ignore signaling cues and return to the previous feeding location. In the last and most complex experiment, three of five rays found the feeding location by remembering the positions of both proximate and distal landmarks in addition to memorizing particular swimming paths. Results showed that rays generally placed more importance on the overall environmental or geometric arrangement of the arena than on (individual) landmarks. This seems ecologically feasible, as distinct landmarks (e.g. rocks, pieces of wood, water plants) in the rays' natural environment may be more easily altered, removed or obscured from view than global ones (e.g. a river bend), which tend to be more stable. Overall, these results confirm those of previous studies, in that freshwater stingrays orient visually, learn quickly and can apply various orientation strategies, which are not mutually exclusive. Copyright © 2015

Modelling toehold-mediated RNA strand displacement.

Science.gov (United States)

Šulc, Petr; Ouldridge, Thomas E; Romano, Flavio; Doye, Jonathan P K; Louis, Ard A

2015-03-10

We study the thermodynamics and kinetics of an RNA toehold-mediated strand displacement reaction with a recently developed coarse-grained model of RNA. Strand displacement, during which a single strand displaces a different strand previously bound to a complementary substrate strand, is an essential mechanism in active nucleic acid nanotechnology and has also been hypothesized to occur in vivo. We study the rate of displacement reactions as a function of the length of the toehold and temperature and make two experimentally testable predictions: that the displacement is faster if the toehold is placed at the 5' end of the substrate; and that the displacement slows down with increasing temperature for longer toeholds. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Second-strand cDNA synthesis: classical method

International Nuclear Information System (INIS)

Gubler, U.

1987-01-01

The classical scheme for the synthesis of double-stranded cDNA as it was reported in 1976 is described. Reverse transcription of mRNA with oligo(dT) as the primer generates first strands with a small loop at the 3' end of the cDNA (the end that corresponds to the 5' end of the mRNA). Subsequent removal of the mRNA by alkaline hydrolysis leaves single-stranded cDNA molecules again with a small 3' loop. This loop can be used by either reverse transcriptase or Klenow fragment of DNA polymerase I as a primer for second-strand synthesis. The resulting products are double-stranded cDNA molecules that are covalently closed at the end corresponding to the 5' end of the original mRNA. Subsequent cleavage of the short piece of single-stranded cDNA within the loop with the single-strand-specific S 1 nuclease generate open double-stranded molecules that can be used for molecular cloning in plasmids or in phage. Useful variations of this scheme have been described

The multiple personalities of Watson and Crick strands.

Science.gov (United States)

Cartwright, Reed A; Graur, Dan

2011-02-08

In genetics it is customary to refer to double-stranded DNA as containing a "Watson strand" and a "Crick strand." However, there seems to be no consensus in the literature on the exact meaning of these two terms, and the many usages contradict one another as well as the original definition. Here, we review the history of the terminology and suggest retaining a single sense that is currently the most useful and consistent. The Saccharomyces Genome Database defines the Watson strand as the strand which has its 5'-end at the short-arm telomere and the Crick strand as its complement. The Watson strand is always used as the reference strand in their database. Using this as the basis of our standard, we recommend that Watson and Crick strand terminology only be used in the context of genomics. When possible, the centromere or other genomic feature should be used as a reference point, dividing the chromosome into two arms of unequal lengths. Under our proposal, the Watson strand is standardized as the strand whose 5'-end is on the short arm of the chromosome, and the Crick strand as the one whose 5'-end is on the long arm. Furthermore, the Watson strand should be retained as the reference (plus) strand in a genomic database. This usage not only makes the determination of Watson and Crick unambiguous, but also allows unambiguous selection of reference stands for genomics. This article was reviewed by John M. Logsdon, Igor B. Rogozin (nominated by Andrey Rzhetsky), and William Martin.

The multiple personalities of Watson and Crick strands

Directory of Open Access Journals (Sweden)

Graur Dan

2011-02-01

Full Text Available Abstract Background In genetics it is customary to refer to double-stranded DNA as containing a "Watson strand" and a "Crick strand." However, there seems to be no consensus in the literature on the exact meaning of these two terms, and the many usages contradict one another as well as the original definition. Here, we review the history of the terminology and suggest retaining a single sense that is currently the most useful and consistent. Proposal The Saccharomyces Genome Database defines the Watson strand as the strand which has its 5'-end at the short-arm telomere and the Crick strand as its complement. The Watson strand is always used as the reference strand in their database. Using this as the basis of our standard, we recommend that Watson and Crick strand terminology only be used in the context of genomics. When possible, the centromere or other genomic feature should be used as a reference point, dividing the chromosome into two arms of unequal lengths. Under our proposal, the Watson strand is standardized as the strand whose 5'-end is on the short arm of the chromosome, and the Crick strand as the one whose 5'-end is on the long arm. Furthermore, the Watson strand should be retained as the reference (plus strand in a genomic database. This usage not only makes the determination of Watson and Crick unambiguous, but also allows unambiguous selection of reference stands for genomics. Reviewers This article was reviewed by John M. Logsdon, Igor B. Rogozin (nominated by Andrey Rzhetsky, and William Martin.

Emergency department boarding: a descriptive analysis and measurement of impact on outcomes.

Science.gov (United States)

Salehi, Leila; Phalpher, Prashant; Valani, Rahim; Meaney, Christopher; Amin, Qamar; Ferrari, Kiki; Mercuri, Mathew

2018-04-05

CLINICIAN'S CAPSULE What is known about the topic? Bed boarding is one of the major contributors to emergency department overcrowding. What did this study ask? What are the characteristics of patients with prolonged boarding times, and what are the impacts on patient-oriented outcomes? What did this study find? Patients who were older, sicker, and had isolation and telemetry requirements experienced longer boarding times, and longer inpatient length of stay even after correcting for confounders. Why does this study matter to clinicians? Organization-wide interventions to improve efficiency and flow are required to mitigate the burden of bed boarding.

40 CFR 63.4681 - Am I subject to this subpart?

Science.gov (United States)

2010-07-01

... (c)(1)(i) through (xi) of this section that are part of plywood and composite wood product...) Primers applied to waferboard or oriented strand board (OSB) siding at the site of manufacture of the...) Synthetic patches, wood patches, and wood putty applied to plywood. (ix) Application of concrete forming and...

Moisture Performance of Energy-Efficient and Conventional Wood-Frame Wall Assemblies in a Mixed-Humid Climate

Science.gov (United States)

Samuel Glass; Vladimir Kochkin; S. Drumheller; Lance Barta

2015-01-01

Long-term moisture performance is a critical consideration for design and construction of building envelopes in energy-efficient buildings, yet field measurements of moisture characteristics for highly insulated wood-frame walls in mixed-humid climates are lacking. Temperature, relative humidity, and moisture content of wood framing and oriented strand board (OSB)...

Ship Dynamics in the Surf Zone Model Testing

Science.gov (United States)

2008-07-01

was implemented for ease of transportation and ease of assembly. Each module was 10 feet square consisting of oriented strand board ( OSB ) plywood with...frame, constructed of 2 inch by 4 inch by 10 feet pieces of wood, was measured, cut, laid, and screwed together for each module. Pieces of OSB

Sea Turtle Stranding Network Reports

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Sea Turtle Stranding and Salvage Network (STSSN) was formally established in 1980 to collect information on and document the stranding of marine turtles along...

Comparative study of electromagnetic compatibility methods in printed circuit board design tools

International Nuclear Information System (INIS)

Marinova, Galia

2002-01-01

The paper considers the state-of-the art in electromagnetic compatibility (EMC) oriented printed circuit board (PCB) design. A general methodology of EMC oriented PCB design is synthesized. The main CAD tools available today are estimated and compared for their abilities to treat EMC oriented design. To help non experts a knowledge-base containing more than 50 basic rules for EMC-oriented PCB design is proposed. It can be applied in the PCB design CAD tools that possess rule-builders or it can help interactive design. Trends in this area of EMC-oriented PCB design are deduced. (Author)

Secondary organic aerosols from ozone-initiated reactions with emissions from wood-based materials and a ‘‘green’’ paint

DEFF Research Database (Denmark)

Toftum, Jørn; Freund, Sarah; Salthammer, Tunga

2008-01-01

This study examined the formation and growth of secondary organic aerosols (SOA) generated when ozone was added to a 1 m3 glass chamber that contained either pine shelving, oriented strand board (OSB), beech boards, or beach boards painted with an ‘‘eco’’ paint. The experiments were conducted...... dramatically; the mass concentration reached w15 mgm3 at w20 ppb O3, and w95 mgm3 at w40 ppb O3. The OSB emitted primarily limonene and a-pinene. Although the particle counts increased when O3 was introduced, the increase was not as large as anticipated based on the terpene concentrations. The beech boards...

Heads or tails: do stranded fish (mosquitofish, Gambusia affinis know where they are on a slope and how to return to the water?

Directory of Open Access Journals (Sweden)

Robert J Boumis

Full Text Available Aquatic vertebrates that emerge onto land to spawn, feed, or evade aquatic predators must return to the water to avoid dehydration or asphyxiation. How do such aquatic organisms determine their location on land? Do particular behaviors facilitate a safe return to the aquatic realm? In this study, we asked: will fully-aquatic mosquitofish (Gambusia affinis stranded on a slope modulate locomotor behavior according to body position to facilitate movement back into the water? To address this question, mosquitofish (n = 53 were placed in four positions relative to an artificial slope (30° inclination and their responses to stranding were recorded, categorized, and quantified. We found that mosquitofish may remain immobile for up to three minutes after being stranded and then initiate either a "roll" or a "leap". During a roll, mass is destabilized to trigger a downslope tumble; during a leap, the fish jumps up, above the substrate. When mosquitofish are oriented with the long axis of the body at 90° to the slope, they almost always (97% initiate a roll. A roll is an energetically inexpensive way to move back into the water from a cross-slope body orientation because potential energy is converted back into kinetic energy. When placed with their heads toward the apex of the slope, most mosquitofish (>50% produce a tail-flip jump to leap into ballistic flight. Because a tail-flip generates a caudually-oriented flight trajectory, this locomotor movement will effectively propel a fish downhill when the head is oriented up-slope. However, because the mass of the body is elevated against gravity, leaps require more mechanical work than rolls. We suggest that mosquitofish use the otolith-vestibular system to sense body position and generate a behavior that is "matched" to their orientation on a slope, thereby increasing the probability of a safe return to the water, relative to the energy expended.

Identification of cis-acting elements on positive-strand subgenomic mRNA required for the synthesis of negative-strand counterpart in bovine coronavirus.

Science.gov (United States)

Yeh, Po-Yuan; Wu, Hung-Yi

2014-07-30

It has been demonstrated that, in addition to genomic RNA, sgmRNA is able to serve as a template for the synthesis of the negative-strand [(-)-strand] complement. However, the cis-acting elements on the positive-strand [(+)-strand] sgmRNA required for (-)-strand sgmRNA synthesis have not yet been systematically identified. In this study, we employed real-time quantitative reverse transcription polymerase chain reaction to analyze the cis-acting elements on bovine coronavirus (BCoV) sgmRNA 7 required for the synthesis of its (-)-strand counterpart by deletion mutagenesis. The major findings are as follows. (1) Deletion of the 5'-terminal leader sequence on sgmRNA 7 decreased the synthesis of the (-)-strand sgmRNA complement. (2) Deletions of the 3' untranslated region (UTR) bulged stem-loop showed no effect on (-)-strand sgmRNA synthesis; however, deletion of the 3' UTR pseudoknot decreased the yield of (-)-strand sgmRNA. (3) Nucleotides positioned from -15 to -34 of the sgmRNA 7 3'-terminal region are required for efficient (-)-strand sgmRNA synthesis. (4) Nucleotide species at the 3'-most position (-1) of sgmRNA 7 is correlated to the efficiency of (-)-strand sgmRNA synthesis. These results together suggest, in principle, that the 5'- and 3'-terminal sequences on sgmRNA 7 harbor cis-acting elements are critical for efficient (-)-strand sgmRNA synthesis in BCoV.

Fair Exchange in Strand Spaces

Directory of Open Access Journals (Sweden)

Joshua D. Guttman

2009-10-01

Full Text Available Many cryptographic protocols are intended to coordinate state changes among principals. Exchange protocols coordinate delivery of new values to the participants, e.g. additions to the set of values they possess. An exchange protocol is fair if it ensures that delivery of new values is balanced: If one participant obtains a new possession via the protocol, then all other participants will, too. Fair exchange requires progress assumptions, unlike some other protocol properties. The strand space model is a framework for design and verification of cryptographic protocols. A strand is a local behavior of a single principal in a single session of a protocol. A bundle is a partially ordered global execution built from protocol strands and adversary activities. The strand space model needs two additions for fair exchange protocols. First, we regard the state as a multiset of facts, and we allow strands to cause changes in this state via multiset rewriting. Second, progress assumptions stipulate that some channels are resilient-and guaranteed to deliver messages-and some principals are assumed not to stop at certain critical steps. This method leads to proofs of correctness that cleanly separate protocol properties, such as authentication and confidentiality, from invariants governing state evolution. G. Wang's recent fair exchange protocol illustrates the approach.

Protected DNA strand displacement for enhanced single nucleotide discrimination in double-stranded DNA.

Science.gov (United States)

Khodakov, Dmitriy A; Khodakova, Anastasia S; Huang, David M; Linacre, Adrian; Ellis, Amanda V

2015-03-04

Single nucleotide polymorphisms (SNPs) are a prime source of genetic diversity. Discriminating between different SNPs provides an enormous leap towards the better understanding of the uniqueness of biological systems. Here we report on a new approach for SNP discrimination using toehold-mediated DNA strand displacement. The distinctiveness of the approach is based on the combination of both 3- and 4-way branch migration mechanisms, which allows for reliable discrimination of SNPs within double-stranded DNA generated from real-life human mitochondrial DNA samples. Aside from the potential diagnostic value, the current study represents an additional way to control the strand displacement reaction rate without altering other reaction parameters and provides new insights into the influence of single nucleotide substitutions on 3- and 4-way branch migration efficiency and kinetics.

Identification of Cis-Acting Elements on Positive-Strand Subgenomic mRNA Required for the Synthesis of Negative-Strand Counterpart in Bovine Coronavirus

Directory of Open Access Journals (Sweden)

Po-Yuan Yeh

2014-07-01

Full Text Available It has been demonstrated that, in addition to genomic RNA, sgmRNA is able to serve as a template for the synthesis of the negative-strand [(−-strand] complement. However, the cis-acting elements on the positive-strand [(+-strand] sgmRNA required for (−-strand sgmRNA synthesis have not yet been systematically identified. In this study, we employed real-time quantitative reverse transcription polymerase chain reaction to analyze the cis-acting elements on bovine coronavirus (BCoV sgmRNA 7 required for the synthesis of its (−-strand counterpart by deletion mutagenesis. The major findings are as follows. (1 Deletion of the 5'-terminal leader sequence on sgmRNA 7 decreased the synthesis of the (−-strand sgmRNA complement. (2 Deletions of the 3' untranslated region (UTR bulged stem-loop showed no effect on (−-strand sgmRNA synthesis; however, deletion of the 3' UTR pseudoknot decreased the yield of (−-strand sgmRNA. (3 Nucleotides positioned from −15 to −34 of the sgmRNA 7 3'-terminal region are required for efficient (−-strand sgmRNA synthesis. (4 Nucleotide species at the 3'-most position (−1 of sgmRNA 7 is correlated to the efficiency of (−-strand sgmRNA synthesis. These results together suggest, in principle, that the 5'- and 3'-terminal sequences on sgmRNA 7 harbor cis-acting elements are critical for efficient (−-strand sgmRNA synthesis in BCoV.

The European Nb3Sn advanced strand development programme

International Nuclear Information System (INIS)

Vostner, A.; Salpietro, E.

2005-01-01

Strands relevant for fusion with high critical current densities and moderate hysteresis losses were developed and already produced on industrial scale. Based on these achievements EFDA-CSU Garching has launched a Nb 3 Sn strand development and procurement action inside Europe in order to assess the current status of the Nb 3 Sn strand production capability. All six addressed companies have replied positively to the strand R and D programme which includes the three major Nb 3 Sn production techniques namely the bronze, internal-tin and powder-in-tube (PIT) route. According to the strand requirements for the ITER TF conductor a critical current density of 800 A/mm 2 (at 12 T, 4.2 K and 10 μV/m) and overall strand hysteresis losses below 500 kJ/m 3 have been specified as the minimum guaranteed strand performance. The second major objective of this programme is to motivate the strand manufacturers to develop and design high performance Nb 3 Sn strands optimised for the ITER conductor. For this purpose, a target critical current density of 1100 A/mm 2 has been added to the specification. This paper describes the strategy behind the strand development programme, the actual status of the strand production as well as first preliminary results obtained from the strand suppliers

The association between length of emergency department boarding and mortality.

Science.gov (United States)

Singer, Adam J; Thode, Henry C; Viccellio, Peter; Pines, Jesse M

2011-12-01

Emergency department (ED) boarding has been associated with several negative patient-oriented outcomes, from worse satisfaction to higher inpatient mortality rates. The current study evaluates the association between length of ED boarding and outcomes. The authors expected that prolonged ED boarding of admitted patients would be associated with higher mortality rates and longer hospital lengths of stay (LOS). This was a retrospective cohort study set at a suburban academic ED with an annual ED census of 90,000 visits. Consecutive patients admitted to the hospital from the ED and discharged between October 2005 and September 2008 were included. An electronic medical record (EMR) system was used to extract patient demographics, ED disposition (discharge, admit to floor), ED and hospital LOS, and in-hospital mortality. Boarding was defined as ED LOS 2 hours or more after decision for admission. Descriptive statistics were used to evaluate the association between length of ED boarding and hospital LOS, subsequent transfer to an intensive care unit (ICU), and mortality controlling for comorbidities. There were 41,256 admissions from the ED. Mortality generally increased with increasing boarding time, from 2.5% in patients boarded less than 2 hours to 4.5% in patients boarding 12 hours or more (p boarding time (p boarded for more than 24 hours. The increases were still apparent after adjustment for comorbid conditions and other factors. Hospital mortality and hospital LOS are associated with length of ED boarding. © 2011 by the Society for Academic Emergency Medicine.

School Board Chairmen and School Superintendents: An Analysis of Perceptions Concerning Special Interest Groups and Educational Governance.

Science.gov (United States)

Feuerstein, Abe; Opfer, V. Darleen

1998-01-01

Surveyed all Virginia school board chairmen and superintendents on local governance issues. Discusses both groups' perceptions of board members' orientation to their role as elected representatives, their personal attitude toward the electoral process, their assessment of interest-group involvement in district decision making, their feelings…

Differential Regulation of Strand-Specific Transcripts from Arabidopsis Centromeric Satellite Repeats.

Directory of Open Access Journals (Sweden)

2005-12-01

Full Text Available Centromeres interact with the spindle apparatus to enable chromosome disjunction and typically contain thousands of tandemly arranged satellite repeats interspersed with retrotransposons. While their role has been obscure, centromeric repeats are epigenetically modified and centromere specification has a strong epigenetic component. In the yeast Schizosaccharomyces pombe, long heterochromatic repeats are transcribed and contribute to centromere function via RNA interference (RNAi. In the higher plant Arabidopsis thaliana, as in mammalian cells, centromeric satellite repeats are short (180 base pairs, are found in thousands of tandem copies, and are methylated. We have found transcripts from both strands of canonical, bulk Arabidopsis repeats. At least one subfamily of 180-base pair repeats is transcribed from only one strand and regulated by RNAi and histone modification. A second subfamily of repeats is also silenced, but silencing is lost on both strands in mutants in the CpG DNA methyltransferase MET1, the histone deacetylase HDA6/SIL1, or the chromatin remodeling ATPase DDM1. This regulation is due to transcription from Athila2 retrotransposons, which integrate in both orientations relative to the repeats, and differs between strains of Arabidopsis. Silencing lost in met1 or hda6 is reestablished in backcrosses to wild-type, but silencing lost in RNAi mutants and ddm1 is not. Twenty-four-nucleotide small interfering RNAs from centromeric repeats are retained in met1 and hda6, but not in ddm1, and may have a role in this epigenetic inheritance. Histone H3 lysine-9 dimethylation is associated with both classes of repeats. We propose roles for transcribed repeats in the epigenetic inheritance and evolution of centromeres.

DNA strand breaks, repair, and survival in x-irradiated mammalian cells

International Nuclear Information System (INIS)

Dugle, D.L.; Gillespie, C.J.; Chapman, J.D.

1976-01-01

The yields of unrepairable single- and double-strand breaks in the DNA of x-irradiated Chinese hamster cells were measured by low-speed neutral and alkaline sucrose density gradient sedimentation in order to investigate the relation between these lesions and reproductive death. After maximal single-strand rejoining, at all doses, the number of residual single-strand breaks was twice the number of residual double-strand breaks. Both double-strand and unrepairable single-strand breaks were proportional to the square of absorbed dose, in the range 10-50 krad. No rejoining of double-strand breaks was observed. These observations suggest that, in mammalian cells, most double-strand breaks are not repairable, while all single-strand breaks are repaired except those that are sufficiently close on complementary strands to constitute double-strand breaks. Comparison with cell survival measurements at much lower doses suggests that loss of reproductive capacity corresponds to induction of approximately one double-strand break

Lumber volume and value recovery from small-diameter black cherry, sugar maple, and red oak logs

Science.gov (United States)

Jan Wiedenbeck; Matthew Scholl; Paul Blankenhorn; Chuck. Ray

2017-01-01

While only a very small percentage of hardwood logs sawn by conventional sawmills in the U.S. have small-end diameters less than 10 in, portable and scragg mills often saw smaller logs. With the closure of regionally important oriented strand board and pulpwood operations, small-diameter logs are considered to have no value in some markets. This study was...

Implementation of hospital governing boards: views from the field.

Science.gov (United States)

McNatt, Zahirah; Thompson, Jennifer W; Mengistu, Abraham; Tatek, Dawit; Linnander, Erika; Ageze, Leulseged; Lawson, Ruth; Berhanu, Negalign; Bradley, Elizabeth H

2014-04-17

Decentralization through the establishment of hospital governing boards has been touted as an effective way to improve the quality and efficiency of hospitals in low-income countries. Although several studies have examined the process of decentralization, few have quantitatively assessed the implementation of hospital governing boards and their impact on hospital performance. Therefore, we sought to describe the functioning of governing boards and to determine the association between governing board functioning and hospital performance. We conducted a cross-sectional study with governing board chairpersons to assess board (1) structure, (2) roles and responsibilities and (3) training and orientation practices. Using bivariate analysis and multivariable regression, we examined the association between governing board functioning and hospital performance. Hospital performance indicators: 1) percent of hospital management standards met, measured with the Ethiopian Hospital Reform Implementation Guidelines and 2) patient experience, measured with the Inpatient and Outpatient Assessment of Healthcare surveys. A total of 92 boards responded to the survey (96% response rate). The average percentage of EHRIG standards met was 58.1% (standard deviation (SD) 21.7 percentage points), and the mean overall patient experience score was 7.2 (SD 2.2). Hospitals with greater hospital management standards met had governing boards that paid members, reviewed performance in several domains quarterly or more frequently, developed new revenue sources, determined services to be outsourced, reviewed patient complaints, and had members with knowledge in business and financial management (all P-values outsourced, and reviewed patient complaints (all P-values < 0.05). These cross-sectional data suggest that strengthening governing boards to perform essential responsibilities may result in improved hospital performance.

77 FR 56840 - Meeting of the Environmental Financial Advisory Board-Public Notice

Science.gov (United States)

2012-09-14

... ENVIRONMENTAL PROTECTION AGENCY [FRL-9727-8] Meeting of the Environmental Financial Advisory Board... meeting. SUMMARY: The United States Environmental Protection Agency's (EPA) Environmental Financial... expected on the following topics: Clean air technology; tribal environmental programs; transit-oriented...

Detection of bacteriophage phi 6 minus-strand RNA and novel mRNA isoconformers synthesized in vivo and in vitro, by strand-separating agarose gels

International Nuclear Information System (INIS)

Pagratis, N.; Revel, H.R.

1990-01-01

Two urea-free agarose gel protocols that resolve the six individual strands of bacteriophage phi 6 dsRNA were developed and used to analyze phage RNA synthesis in vivo and in vitro. Citrate gels separate strands of the large and medium chromosomes while Tris-borate-EDTA (TBE) gels resolve the medium and small dsRNA segments. Minus strands migrate faster than plus strands on citrate gels but are retarded on TBE gels. A study of electrophoretic conditions showed that pH affects strand resolution on citrate gels, and that voltage gradient, agarose concentration, and ethidium bromide significantly alter strand migration on TBE gels. Analysis of native phi 6 RNA synthesized in vivo and in vitro showed that the large and medium message RNAs comigrate with the corresponding plus strands of denatured virion dsRNA. The small messenger RNA is exceptional. Native small mRNA was detected as three isoconformers in vivo and in vitro. The isoconformers were converted by heat denaturation to a single RNA species that comigrates with the virion s+ strand. Minus strands labeled in vivo were detected only after heat denaturation. Minus strand synthesis was detected also in heat-denatured samples from in vitro phi 6 nucleocapsid RNA polymerase reactions at pH values suboptimal for transcription

Dynamics of Leading-strand Lesion Skipping by the Replisome

Science.gov (United States)

Yeeles, Joseph T.P.; Marians, Kenneth J.

2013-01-01

SUMMARY The E. coli replisome stalls transiently when it encounters a lesion in the leading-strand template, skipping over the damage by reinitiating replication at a new primer synthesized downstream by the primase. We report here that template unwinding and lagging-strand synthesis continue downstream of the lesion at a reduced rate after replisome stalling, that one replisome is capable of skipping multiple lesions, and that the rate limiting steps of replication restart involve the synthesis and activation of the new primer downstream. We also find little support for the concept that polymerase uncoupling, where extensive lagging-strand synthesis proceeds downstream in the absence of leading-strand synthesis, involves physical separation of the leading-strand polymerase from the replisome. Instead, our data indicate that extensive uncoupled replication likely results from a failure of the leading-strand polymerase still associated with the DNA helicase and the lagging-strand polymerase that are proceeding downstream to reinitiate synthesis. PMID:24268579

Connecting localized DNA strand displacement reactions

Science.gov (United States)

Mullor Ruiz, Ismael; Arbona, Jean-Michel; Lad, Amitkumar; Mendoza, Oscar; Aimé, Jean-Pierre; Elezgaray, Juan

2015-07-01

Logic circuits based on DNA strand displacement reactions have been shown to be versatile enough to compute the square root of four-bit numbers. The implementation of these circuits as a set of bulk reactions faces difficulties which include leaky reactions and intrinsically slow, diffusion-limited reaction rates. In this paper, we consider simple examples of these circuits when they are attached to platforms (DNA origamis). As expected, constraining distances between DNA strands leads to faster reaction rates. However, it also induces side-effects that are not detectable in the solution-phase version of this circuitry. Appropriate design of the system, including protection and asymmetry between input and fuel strands, leads to a reproducible behaviour, at least one order of magnitude faster than the one observed under bulk conditions.Logic circuits based on DNA strand displacement reactions have been shown to be versatile enough to compute the square root of four-bit numbers. The implementation of these circuits as a set of bulk reactions faces difficulties which include leaky reactions and intrinsically slow, diffusion-limited reaction rates. In this paper, we consider simple examples of these circuits when they are attached to platforms (DNA origamis). As expected, constraining distances between DNA strands leads to faster reaction rates. However, it also induces side-effects that are not detectable in the solution-phase version of this circuitry. Appropriate design of the system, including protection and asymmetry between input and fuel strands, leads to a reproducible behaviour, at least one order of magnitude faster than the one observed under bulk conditions. Electronic supplementary information (ESI) available. See DOI: 10.1039/C5NR02434J

Southeast US Historical Marine Mammal Stranding Database

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Data on marine mammal strandings are collected by the Southeast Marine Mammal Stranding Network. Basic data on the location, species identification, animal...

The stranding anomaly as population indicator

DEFF Research Database (Denmark)

Peltier, Helene; Baagøe, Hans J.; Camphuysen, Kees C. J.

2013-01-01

Ecological indicators for monitoring strategies are expected to combine three major characteristics: ecological significance, statistical credibility, and cost-effectiveness. Strategies based on stranding networks rank highly in cost-effectiveness, but their ecological significance and statistica...... surveys, mostly SCANS surveys (1994 and 2005). This new indicator could be applied to cetacean populations across the world and more widely to marine megafauna....... credibility are disputed. Our present goal is to improve the value of stranding data as population indicator as part of monitoring strategies by constructing the spatial and temporal null hypothesis for strandings. The null hypothesis is defined as: small cetacean distribution and mortality are uniform...

Formation of double-strand breaks in DNA of γ-irradiated bacteria depending on the function of fast repair processes of DNA single-strand breaks

International Nuclear Information System (INIS)

Petrov, S.I.; Gaziev, A.I.

1980-01-01

The formation of double-strand breaks in DNA of γ-irradiated ( 60 Co)Ex coli bacteria depending on the function of fast repair processes of DNA single-strand breaks, is investigated. The profiles of sedimentation of DNA Ex coli cells, irradiated at 0-2 deg C in the salt medium and in EDTA-borate buffer, are presented. It is shown that when irradiating cells in EDTA-borate buffer, the output of single- and double strand breaks in DNA is much higher than in the case of their irradiation in the minimum salt medium. The dependence of output of single-strand and double-strand breaks depending on the radiatier doze of E coli cells in the salt medium and EDTA-borate buffer, is studied. The supposition is made on the presence of a regulative interaction between the accumulation of DNA single-breaks and their repair with the formation of double-strand breaks. The functionating of fast and superfast repair processes considerably affects the formation of double-strand breaks in DNA of a bacterium cell. A considerable amount of double-breaks registered immediately after irradiation forms due to a close position of single-strand breaks on the opposite DNA strands

An investigation of the moisture sorption and permeability properties of mill-fabricated oriented strandboard

Science.gov (United States)

Timusk, Paul Christopher

This thesis brings the disciplines of Building Science and Wood Science together in the study of the moisture-related properties of oriented strand board (OSB). Using controlled mill-manufactured panels specifically made for this project, this research reveals how the sorption and permeance properties of OSB are affected by several variables including production parameters and physical panel properties, moisture-history, and relative humidity exposure. Since OSB varies in composition through its thickness, this study isolated and tested various core and surface components. Permeability and sorption properties of individual OSB layers, intact panel sections, and panel sections that had undergone cyclic wetting and drying or relative humidity cycling prior to testing, were evaluated. After laboratory testing and analysis, a set of OSB permeance and sorption values were entered into the material database of a finite-element hygrothermal computer modeling program. Relying on this data, a series of hygrothermal wall simulations were carried out using standard wall sections exposed to various climate conditions found throughout North America. These simulations revealed that the results vary widely depending upon the permeance and sorption values used. Thus the common practice of characterizing a range of OSB products with various moisture histories by using a single permeance or sorption value may not be wise.

The importance of becoming double-stranded: Innate immunity and the kinetic model of HIV-1 central plus strand synthesis

International Nuclear Information System (INIS)

Poeschla, Eric

2013-01-01

Central initiation of plus strand synthesis is a conserved feature of lentiviruses and certain other retroelements. This complication of the standard reverse transcription mechanism produces a transient “central DNA flap” in the viral cDNA, which has been proposed to mediate its subsequent nuclear import. This model has assumed that the important feature is the flapped DNA structure itself rather than the process that produces it. Recently, an alternative kinetic model was proposed. It posits that central plus strand synthesis functions to accelerate conversion to the double-stranded state, thereby helping HIV-1 to evade single-strand DNA-targeting antiviral restrictions such as APOBEC3 proteins, and perhaps to avoid innate immune sensor mechanisms. The model is consistent with evidence that lentiviruses must often synthesize their cDNAs when dNTP concentrations are limiting and with data linking reverse transcription and uncoating. There may be additional kinetic advantages for the artificial genomes of lentiviral gene therapy vectors. - Highlights: • Two main functional models for HIV central plus strand synthesis have been proposed. • In one, a transient central DNA flap in the viral cDNA mediates HIV-1 nuclear import. • In the other, multiple kinetic consequences are emphasized. • One is defense against APOBEC3G, which deaminates single-stranded DNA. • Future questions pertain to antiviral restriction, uncoating and nuclear import

Specific Modulus and Density Profile as Characterization Criteria of Prefabricated Wood Composite Materials

Directory of Open Access Journals (Sweden)

Pavel Král

2015-01-01

Full Text Available Wood based product industry has developed and modified a wide range of products to cater changing demands of construction industry. Development of a product necessitates characterization to ensure compliance to established standards. Traditionally a product was characterized by properties like bending properties, density and swelling factor etc. Whereas, advances in technology has introduced more sophisticated parameters which represent a combination of various classical factors and provide more practical and detailed information. In this study, we procured four different types of commercial products, viz. Gypsum board, cement board, oriented strand board and gypsum fiber board and tried to characterized them using density profile ratio and stiffness ratio. We observed some interesting empirical relations between various parameters as represented in various plots.

Alaska Beluga Strandings

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NMFS is mandated by the Marine Mammal Protection Act (MMPA) to collect reports of marine mammal stranding events. This particular catalogue item is specific to the...

Low-residue euthanasia of stranded mysticetes.

Science.gov (United States)

Harms, Craig A; McLellan, William A; Moore, Michael J; Barco, Susan G; Clarke, Elsburgh O; Thayer, Victoria G; Rowles, Teresa K

2014-01-01

Euthanasia of stranded large whales poses logistic, safety, pharmaceutical, delivery, public relations, and disposal challenges. Reasonable arguments may be made for allowing a stranded whale to expire naturally. However, slow cardiovascular collapse from gravitational effects outside of neutral buoyancy, often combined with severely debilitating conditions, motivate humane efforts to end the animal's suffering. The size of the animal and prevailing environmental conditions often pose safety concerns for stranding personnel, which take priority over other considerations. When considering chemical euthanasia, the size of the animal also necessitates large quantities of euthanasia agents. Drug residues are a concern for relay toxicity to scavengers, particularly for pentobarbital-containing euthanasia solutions. Pentobarbital is also an environmental concern because of its stability and long persistence in aquatic environments. We describe a euthanasia technique for stranded mysticetes using readily available, relatively inexpensive, preanesthetic and anesthetic drugs (midazolam, acepromazine, xylazine) followed by saturated KCl delivered via custom-made needles and a low-cost, basic, pressurized canister. This method provides effective euthanasia while moderating personnel exposure to hazardous situations and minimizing drug residues of concern for relay toxicity.

Stranded Specimen Data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Marine Mammal and Turtle Division collects data about individual cetaceans and sea turtles that come ashore, or strand on the beach. The date and location of...

Current redistribution in cables made of insulated, soldered, or oxidized strands

International Nuclear Information System (INIS)

Turck, B.

1979-07-01

Current redistributions are compared in cables made of insulated strands, soldered, or oxidized strands and insulated strands with periodic joints. After discussing the different current redistributions in the cases of a rapidly changing current and a dc current, several particular situations are investigated: what happens if a strand is broken, or if a local normal zone appears that does not affect all the strands equally, the detection of this normal zone, and the influence of short circuits between strands

OSB as substrate for engineered wood flooring

Science.gov (United States)

Costel Barbuta; Pierre Blanchet; Alain Cloutier; Vikram Yadama; Eini. Lowell

2012-01-01

Oriented strand board (OSB) is a commodity product subject to market fluctuation. Development of a specialty OSB could lead to a better, and more stable, market segment for OSB. It was demonstrated in a previous study (Barbuta et al. in Eur. 1. Wood Prod. 2010), that OSB may be designed to obtain a high bending modulus of elasticity in the parallel direction, close to...

Strand SPA & Konverentsikeskus

Index Scriptorium Estoniae

2008-01-01

Strand SPA & Konverentsikeskus on Pärnu suurim äri- ja konverentsiklientidele suunatud hotell, mis klientide seas on hinnatud just selle kompleksuse tõttu, kuna kõik, mida külaline vajab ja soovib, on olemas ühe katuse all

Development of strand burner for solid propellant burning rate studies

International Nuclear Information System (INIS)

Aziz, A; Mamat, R; Ali, W K Wan

2013-01-01

It is well-known that a strand burner is an apparatus that provides burning rate measurements of a solid propellant at an elevated pressure in order to obtain the burning characteristics of a propellant. This paper describes the facilities developed by author that was used in his studies. The burning rate characteristics of solid propellant have be evaluated over five different chamber pressures ranging from 1 atm to 31 atm using a strand burner. The strand burner has a mounting stand that allows the propellant strand to be mounted vertically. The strand was ignited electrically using hot wire, and the burning time was recorded by electronic timer. Wire technique was used to measure the burning rate. Preliminary results from these techniques are presented. This study shows that the strand burner can be used on propellant strands to obtain accurate low pressure burning rate data

Double-Stranded Peptide Nucleic Acids

DEFF Research Database (Denmark)

2001-01-01

A novel class of compounds, known as peptide nucleic acids, form double-stranded structures with one another and with ssDNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker.......A novel class of compounds, known as peptide nucleic acids, form double-stranded structures with one another and with ssDNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

The (not so) immortal strand hypothesis.

Science.gov (United States)

Tomasetti, Cristian; Bozic, Ivana

2015-03-01

Non-random segregation of DNA strands during stem cell replication has been proposed as a mechanism to minimize accumulated genetic errors in stem cells of rapidly dividing tissues. According to this hypothesis, an "immortal" DNA strand is passed to the stem cell daughter and not the more differentiated cell, keeping the stem cell lineage replication error-free. After it was introduced, experimental evidence both in favor and against the hypothesis has been presented. Using a novel methodology that utilizes cancer sequencing data we are able to estimate the rate of accumulation of mutations in healthy stem cells of the colon, blood and head and neck tissues. We find that in these tissues mutations in stem cells accumulate at rates strikingly similar to those expected without the protection from the immortal strand mechanism. Utilizing an approach that is fundamentally different from previous efforts to confirm or refute the immortal strand hypothesis, we provide evidence against non-random segregation of DNA during stem cell replication. Our results strongly suggest that parental DNA is passed randomly to stem cell daughters and provides new insight into the mechanism of DNA replication in stem cells. Copyright © 2015. Published by Elsevier B.V.

AMIE Camera System on board SMART-1

Science.gov (United States)

Josset, J. L.; Beauvivre, S.; Amie Team

The Advanced Moon micro-Imager Experiment AMIE on board ESA SMART-1 the first European mission to the Moon launched on 27th September 2003 is an imaging system with scientific technical and public outreach oriented objectives The science objectives are to image the Lunar Poles permanent shadow areas ice deposit eternal light crater rims ancient Lunar Non-mare volcanism local spectro-photometry and physical state of the lunar sur-face and to map high latitudes regions south mainly at far side South Pole Aitken basin The technical objectives are to perform a laserlink experiment detec-tion of laser beam emitted by ESA Tenerife ground station flight demonstration of new technologies and on-board autonomy navigation The public outreach and educational objectives are to promote planetary exploration We present the AMIE instrument and perfomances with respect to the first results

Towards human-oriented norms: Considering the effects of noise exposure on board ships

NARCIS (Netherlands)

Kurt, R.E.; Khalid, H.; Turan, O.; Houben, M.; Bos, J.; Helvacioglu, I.H.

2016-01-01

With modern trends of decrease in crew numbers on board ships together with increased operational demands and paperwork, crew fatigue and comfort have become more critical and are being given more importance. It is well known that environmental factors affect crew comfort and performance. The two

Controlling the stoichiometry and strand polarity of a tetramolecular G-quadruplex structure by using a DNA origami frame

Science.gov (United States)

Rajendran, Arivazhagan; Endo, Masayuki; Hidaka, Kumi; Lan Thao Tran, Phong; Mergny, Jean-Louis; Sugiyama, Hiroshi

2013-01-01

Guanine-rich oligonucleotides often show a strong tendency to form supramolecular architecture, the so-called G-quadruplex structure. Because of the biological significance, it is now considered to be one of the most important conformations of DNA. Here, we describe the direct visualization and single-molecule analysis of the formation of a tetramolecular G-quadruplex in KCl solution. The conformational changes were carried out by incorporating two duplex DNAs, with G–G mismatch repeats in the middle, inside a DNA origami frame and monitoring the topology change of the strands. In the absence of KCl, incorporated duplexes had no interaction and laid parallel to each other. Addition of KCl induced the formation of a G-quadruplex structure by stably binding the duplexes to each other in the middle. Such a quadruplex formation allowed the DNA synapsis without disturbing the duplex regions of the participating sequences, and resulted in an X-shaped structure that was monitored by atomic force microscopy. Further, the G-quadruplex formation in KCl solution and its disruption in KCl-free buffer were analyzed in real-time. The orientation of the G-quadruplex is often difficult to control and investigate using traditional biochemical methods. However, our method using DNA origami could successfully control the strand orientations, topology and stoichiometry of the G-quadruplex. PMID:23863846

DNA strand breakage by 125I-decay in oligoDNA

International Nuclear Information System (INIS)

Lobachevsky, P.; Martin, R.F.

1996-01-01

Full text: A double-stranded oligodeoxynucleotide containing 125 I-dC in a defined location, with 5'- or 3'- 32 P-end-labelling of either strand, was used to investigate DNA strand breakage resulting from 125 I decay. Samples of the 32 P-end-labelled and 125 I-dC containing oligoDNA were incubated in 20 mM phosphate buffer (PB), or PB + 2 M dimethylsulphoxide (DMSO) at 4 deg during 18-20 days. The 32 P-end-labelled DNA fragments produced by 125 I decays were separated on denaturing polyacrylamide gels, and the 3P activity in each fragment was determined by scintillation counting after elution from the gel. The fragment size distribution was then converted to a distribution of single stranded break probabilities at each nucleotide position. The results indicate that each 125 I decay event produces at least one break in the 125 I-dC containing strand, and causes breakage of the opposite strand in 75-80% of events. Thus, the double stranded break is produced by 125 I decay with probability ∼0.8. Most of single stranded breaks (around 90%) occurred within 5-6 nucleotides of the 125 I-dC, however DNA breaks were detected up to 18-20 nucleotides from the decay site. The average numbers of single stranded breaks per decay are 3.7 (PB) and 3.3 (PB+DMSO) in 125 I-dC containing strand, and 1.5 (PB) and 1.3 (PB+DMSO) in the opposite strand. Deconvolution of strand break probabilities as a function of separation from the 125 I, in terms of both distance (to target deoxyribosyl carbon atoms, in B-DNA) and nucleotide number, show that the latter is an important parameter for the shorter-range damage. This could indicate a role for attenuation/dissipation of damage through the stacked bases. In summary, the results represent a much more extensive set of data than available from earlier experiments on DNA breakage from l25 I-decay, and may provide new mechanistic insights

Southeast Region Level A Marine Mammal Stranding Data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Data on marine mammal strandings are collected by the Southeast Marine Mammal Stranding Network. Basic data on the location, species identification, animal...

Tissue strands as "bioink" for scale-up organ printing.

Science.gov (United States)

Yu, Yin; Ozbolat, Ibrahim T

2014-01-01

Organ printing, takes tissue spheroids as building blocks together with additive manufacturing technique to engineer tissue or organ replacement parts. Although a wide array of cell aggregation techniques has been investigated, and gained noticeable success, the application of tissue spheroids for scale-up tissue fabrication is still worth investigation. In this paper, we introduce a new micro-fabrication technique to create tissue strands at the scale of 500-700μm as a "bioink" for future robotic tissue printing. Printable alginate micro-conduits are used as semi-permeable capsules for tissue strand fabrication. Mouse insulinoma beta TC3 cell tissue strands were formed upon 4 days post fabrication with reasonable mechanical strength, high cell viability close to 90%, and tissue specific markers expression. Fusion was readily observed between strands when placing them together as early as 24h. Also, tissue strands were deposited with human umbilical vein smooth muscle cells (HUVSMCs) vascular conduits together to fabricated miniature pancreatic tissue analog. Our study provided a novel technique using tissue strands as "bioink" for scale-up bioprinting of tissues or organs.

A methodology to identify stranded generation facilities and estimate stranded costs for Louisiana's electric utility industry

Science.gov (United States)

Cope, Robert Frank, III

1998-12-01

The electric utility industry in the United States is currently experiencing a new and different type of growing pain. It is the pain of having to restructure itself into a competitive business. Many industry experts are trying to explain how the nation as a whole, as well as individual states, will implement restructuring and handle its numerous "transition problems." One significant transition problem for federal and state regulators rests with determining a utility's stranded costs. Stranded generation facilities are assets which would be uneconomic in a competitive environment or costs for assets whose regulated book value is greater than market value. At issue is the methodology which will be used to estimate stranded costs. The two primary methods are known as "Top-Down" and "Bottom-Up." The "Top-Down" approach simply determines the present value of the losses in revenue as the market price for electricity changes over a period of time into the future. The problem with this approach is that it does not take into account technical issues associated with the generation and wheeling of electricity. The "Bottom-Up" approach computes the present value of specific strandable generation facilities and compares the resulting valuations with their historical costs. It is regarded as a detailed and difficult, but more precise, approach to identifying stranded assets and their associated costs. This dissertation develops a "Bottom-Up" quantitative, optimization-based approach to electric power wheeling within the state of Louisiana. It optimally evaluates all production capabilities and coordinates the movement of bulk power through transmission interconnections of competing companies in and around the state. Sensitivity analysis to this approach is performed by varying seasonal consumer demand, electric power imports, and transmission inter-connection cost parameters. Generation facility economic dispatch and transmission interconnection bulk power transfers, specific

Effect of Twist Pitch in the Strands on the Saturation and Losses in the Nb3Sn Strands for the ITER TF CICC

International Nuclear Information System (INIS)

Martovetsky, N.N.

2007-01-01

ITER TF coils will see a significant longitudinal magnetic field in the event of the plasma disruption. This abrupt change of magnetic fields results in the appearance of an additional electrical field in the strands. The mechanism of this electrical field is the induced currents that expel the flux from the strands. This effect was known since the late 1970's [1-3] and most of the details necessary for the analyses given in this report are presented in [4]. Let's assume for simplicity a zero transport current in the strand. When a longitudinal pulsed field is applied, the outer filaments will carry an induced current repelling the change of flux. The current density of this current is 'critical' in the simplification of Bean's critical state model, where superconducting transition is represented as j=j c at any non-zero electrical field and zero where the electrical field has not penetrated. In reality, since the current density is roughly logarithmic with the electrical field, E=E c *exp[(j-j c )/jo], Bean's model is just a simplification, and current density is slightly nonuniform in the outer filament and more so for the interior strands. The inner portion of the filaments will carry a current of the opposite sign. Even in the Bean's model it is not uniform, but the assumption that it is uniform and less than critical simplifies mathematics significantly and does not deviate far from the real current density distribution. In certain circumstances, the average electrical field in the strands will be high enough to exceed the take-off electrical field averaged across the cross section. In this case, the multifilamentary strand will become unstable and will experience transition to the normal state. With zero transport current, it will eventually recover, of course. This phenomenon is analogous to the flux jump. If the strand carries a transport current, the situation becomes more complicated. If it goes unstable and the transport current is higher than the

In vitro Assays for Eukaryotic Leading/Lagging Strand DNA Replication.

Science.gov (United States)

Schauer, Grant; Finkelstein, Jeff; O'Donnell, Mike

2017-09-20

The eukaryotic replisome is a multiprotein complex that duplicates DNA. The replisome is sculpted to couple continuous leading strand synthesis with discontinuous lagging strand synthesis, primarily carried out by DNA polymerases ε and δ, respectively, along with helicases, polymerase α-primase, DNA sliding clamps, clamp loaders and many other proteins. We have previously established the mechanisms by which the polymerases ε and δ are targeted to their 'correct' strands, as well as quality control mechanisms that evict polymerases when they associate with an 'incorrect' strand. Here, we provide a practical guide to differentially assay leading and lagging strand replication in vitro using pure proteins.

Fragmentation in DNA double-strand breaks

International Nuclear Information System (INIS)

Wei Zhiyong; Suzhou Univ., Suzhou; Zhang Lihui; Li Ming; Fan Wo; Xu Yujie

2005-01-01

DNA double strand breaks are important lesions induced by irradiations. Random breakage model or quantification supported by this concept is suitable to analyze DNA double strand break data induced by low LET radiation, but deviation from random breakage model is more evident in high LET radiation data analysis. In this work we develop a new method, statistical fragmentation model, to analyze the fragmentation process of DNA double strand breaks. After charged particles enter the biological cell, they produce ionizations along their tracks, and transfer their energies to the cells and break the cellular DNA strands into fragments. The probable distribution of the fragments is obtained under the condition in which the entropy is maximum. Under the approximation E≅E 0 + E 1 l + E 2 l 2 , the distribution functions are obtained as exp(αl + βl 2 ). There are two components, the one proportional to exp(βl 2 ), mainly contributes to the low mass fragment yields, the other component, proportional to exp(αl), decreases slowly as the mass of the fragments increases. Numerical solution of the constraint equations provides parameters α and β. Experimental data, especially when the energy deposition is higher, support the statistical fragmentation model. (authors)

Integrating PCR Theory and Bioinformatics into a Research-oriented Primer Design Exercise

OpenAIRE

Robertson, Amber L.; Phillips, Allison R.

2008-01-01

Polymerase chain reaction (PCR) is a conceptually difficult technique that embodies many fundamental biological processes. Traditionally, students have struggled to analyze PCR results due to an incomplete understanding of the biological concepts (theory) of DNA replication and strand complementarity. Here we describe the design of a novel research-oriented exercise that prepares students to design DNA primers for PCR. Our exercise design includes broad and specific learning goals and assessm...

Development and user evaluation of a virtual rehabilitation system for wobble board balance training

OpenAIRE

Fitzgerald, Diarmaid; Trakarnratanakul, Nanthana; Dunne, Lucy; Smyth, Barry; Caulfield, Brian

2008-01-01

We have developed a prototype virtual reality based balance training system using a single inertial orientation sensor attached to the upper surface of a wobble board. This input device has been interfaced with an open source computer game known as Neverball. Users can exercise with the system by standing on the wobble board and tilting it to control an on-screen environment. To evaluate the usability our prototype system we undertook a user evaluation study on twelve healthy novice participa...

Four-Strand Core Suture Improves Flexor Tendon Repair Compared to Two-Strand Technique in a Rabbit Model

Directory of Open Access Journals (Sweden)

Alice Wichelhaus

2016-01-01

Full Text Available Introduction. This study was designed to investigate the influence of the amount of suture material on the formation of peritendinous adhesions of intrasynovial flexor tendon repairs. Materials and Methods. In 14 rabbits, the flexor tendons of the third and the fourth digit of the right hind leg were cut and repaired using a 2- or 4-strand core suture technique. The repaired tendons were harvested after three and eight weeks. The range of motion of the affected toes was measured and the tendons were processed histologically. The distance between the transected tendon ends, the changes in the peritendinous space, and cellular and extracellular inflammatory reaction were quantified by different staining. Results. A 4-strand core suture resulted in significantly less gap formation. The 2-strand core suture showed a tendency to less adhesion formation. Doubling of the intratendinous suture material was accompanied by an initial increase in leukocyte infiltration and showed a greater amount of formation of myofibroblasts. From the third to the eighth week after flexor tendon repair, both the cellular and the extracellular inflammation decreased significantly. Conclusion. A 4-strand core suture repair leads to a significantly better tendon healing process with less diastasis between the sutured tendon ends despite initially pronounced inflammatory response.

Control of DNA strand displacement kinetics using toehold exchange.

Science.gov (United States)

Zhang, David Yu; Winfree, Erik

2009-12-02

DNA is increasingly being used as the engineering material of choice for the construction of nanoscale circuits, structures, and motors. Many of these enzyme-free constructions function by DNA strand displacement reactions. The kinetics of strand displacement can be modulated by toeholds, short single-stranded segments of DNA that colocalize reactant DNA molecules. Recently, the toehold exchange process was introduced as a method for designing fast and reversible strand displacement reactions. Here, we characterize the kinetics of DNA toehold exchange and model it as a three-step process. This model is simple and quantitatively predicts the kinetics of 85 different strand displacement reactions from the DNA sequences. Furthermore, we use toehold exchange to construct a simple catalytic reaction. This work improves the understanding of the kinetics of nucleic acid reactions and will be useful in the rational design of dynamic DNA and RNA circuits and nanodevices.

Electro-mechanical behaviors of composite superconducting strand with filament breakage

International Nuclear Information System (INIS)

Wang, Xu; Gao, Yuanwen; Zhou, Youhe

2016-01-01

Highlights: • The electromechanical behaviors of the superconducting (SC) strand are investigated. • A 3D FEM model for bending behaviors and electric properties of strand is developed. • The influence of breakage of filaments on the critical current of SC strand is calculated. • The impact of current transfer length on the electric properties of SC strand is discussed. - Abstract: The bending behaviors of superconducting strand with typical multi-filament twist configuration are investigated based on a three-dimensional finite element method (FEM) model, named as the Multi-filament twist model, of the strand. In this 3D FEM model, the impacts of initial thermal residual stress, filament-breakage and its evaluation are taken into accounts. The mechanical responses of the strand under bending load are studied with the factors taken into consideration one by one. The distribution of the damage of the filaments and its evolution and the movement of the neutral axis caused by it are studied and displayed in detail. Besides, taking the advantages of the Multi-filament twist model, the normalized critical current of the strand under bending load is also calculated based on the invariant temperature and field strain functions. In addition, the non-negligible influences of the pitch length of the filaments on both the mechanical behaviors and the normalized critical current are discussed. The stress-strain characteristics of the strand under tensile load and the normalized critical current of it under axial and bending loads resulting from the Multi-filament twist model show good agreement with the experimental data.

Electro-mechanical behaviors of composite superconducting strand with filament breakage

Energy Technology Data Exchange (ETDEWEB)

Wang, Xu [Key Laboratory of Mechanics on Environment and Disaster in Western China, The Ministry of Education of China, Lanzhou, Gansu 730000 (China); Department of Mechanics and Engineering Science, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China); Gao, Yuanwen, E-mail: ywgao@lzu.edu.cn [Key Laboratory of Mechanics on Environment and Disaster in Western China, The Ministry of Education of China, Lanzhou, Gansu 730000 (China); Department of Mechanics and Engineering Science, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China); Zhou, Youhe [Key Laboratory of Mechanics on Environment and Disaster in Western China, The Ministry of Education of China, Lanzhou, Gansu 730000 (China); Department of Mechanics and Engineering Science, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China)

2016-10-15

Highlights: • The electromechanical behaviors of the superconducting (SC) strand are investigated. • A 3D FEM model for bending behaviors and electric properties of strand is developed. • The influence of breakage of filaments on the critical current of SC strand is calculated. • The impact of current transfer length on the electric properties of SC strand is discussed. - Abstract: The bending behaviors of superconducting strand with typical multi-filament twist configuration are investigated based on a three-dimensional finite element method (FEM) model, named as the Multi-filament twist model, of the strand. In this 3D FEM model, the impacts of initial thermal residual stress, filament-breakage and its evaluation are taken into accounts. The mechanical responses of the strand under bending load are studied with the factors taken into consideration one by one. The distribution of the damage of the filaments and its evolution and the movement of the neutral axis caused by it are studied and displayed in detail. Besides, taking the advantages of the Multi-filament twist model, the normalized critical current of the strand under bending load is also calculated based on the invariant temperature and field strain functions. In addition, the non-negligible influences of the pitch length of the filaments on both the mechanical behaviors and the normalized critical current are discussed. The stress-strain characteristics of the strand under tensile load and the normalized critical current of it under axial and bending loads resulting from the Multi-filament twist model show good agreement with the experimental data.

Double-Strand DNA Break Repair in Mycobacteria.

Science.gov (United States)

Glickman, Michael S

2014-10-01

Discontinuity of both strands of the chromosome is a lethal event in all living organisms because it compromises chromosome replication. As such, a diversity of DNA repair systems has evolved to repair double-strand DNA breaks (DSBs). In part, this diversity of DSB repair systems has evolved to repair breaks that arise in diverse physiologic circumstances or sequence contexts, including cellular states of nonreplication or breaks that arise between repeats. Mycobacteria elaborate a set of three genetically distinct DNA repair pathways: homologous recombination, nonhomologous end joining, and single-strand annealing. As such, mycobacterial DSB repair diverges substantially from the standard model of prokaryotic DSB repair and represents an attractive new model system. In addition, the presence in mycobacteria of a DSB repair system that can repair DSBs in nonreplicating cells (nonhomologous end joining) or when DSBs arise between repeats (single-strand annealing) has clear potential relevance to Mycobacterium tuberculosis pathogenesis, although the exact role of these systems in M. tuberculosis pathogenesis is still being elucidated. In this article we will review the genetics of mycobacterial DSB repair systems, focusing on recent insights.

Sexual orientation and education politics: gay and lesbian representation in American schools.

Science.gov (United States)

Wald, Kenneth D; Rienzo, Barbara A; Button, James W

2002-01-01

In what has sometimes provoked a "culture war" over America's schools, gays and lesbians have sought an expanded voice in the making of education policy. This paper explores the factors that promote gay representation on school boards, how this variable in turn influences gay representation in both administrative and teaching positions, and how all three forms of gay representation relate to school board policies regarding sexual orientation education. Three of the four models drawn from the social movement literature help to explain gay school board representation. In a manner similar to other minority groups, gay representation on school boards directly or indirectly promotes the appointment of gays to administrative and teaching positions and the adoption of policies that address the problems faced by gay and lesbian students in the public schools.

The (not so) Immortal Strand Hypothesis

OpenAIRE

Tomasetti, Cristian; Bozic, Ivana

2015-01-01

Background: Non-random segregation of DNA strands during stem cell replication has been proposed as a mechanism to minimize accumulated genetic errors in stem cells of rapidly dividing tissues. According to this hypothesis, an “immortal” DNA strand is passed to the stem cell daughter and not the more differentiated cell, keeping the stem cell lineage replication error-free. After it was introduced, experimental evidence both in favor and against the hypothesis has been presented. Principal...

A new cable-in-conduit conductor magnet with insulated strands

International Nuclear Information System (INIS)

Yamaguchi, Satarou; Yamamoto, Junya; Motojima, Osamu.

1995-09-01

Many studies have used cable-in-conduit conductor (CICC) coils in trying to develop an AC superconducting magnet because of its enormous potential if AC losses were low and insulation voltage was high. The strands in the most recent CICC magnets are coated with chromium or another metal with high electrical resistance to order to induce current re-distribution among the strands and to avoid a quench caused by a current imbalance. Current re-distribution is highly complex and very difficult to analyze because the conditions of the strand surfaces and the contact areas vary greatly with the operation of the conductor. If, however, the cable currents were well-balanced, insulating the strands would be the best way to reduce AC losses. We propose a new CICC magnet structure featuring a current lead that balances the strand currents via its resistance. Having calculated current balances, we find that strand currents are well within the present parameters for nuclear fusion experiments and superconducting magnet energy storages. (author)

Problems of boarding educational institutions in the discourse of educational sociology

Directory of Open Access Journals (Sweden)

N. M. Gordienko

2016-11-01

A characteristic of the dependency of graduates’ life paths from the personality model, which was fostered in the boarding school, has been given by the author. Such models are marginal, average, career or creative. It has been found that different types of boarding schools guide their graduates differently towards their future social roles. The schools for orphans and children with special needs are oriented towards the model of average personality, that is, a person who is able to survive and realize his/her needs of the middle level, but who is not ready to be in advance of the modern challenges. Boarding lyceums nurture successful and creative people who are up to the modern demands of the society, can act competitively in the labour market and who have high level of life resources for that. The importance of the consideration paid to sociocultural and natural factors in the analysis of the influence of the education process on boarding school graduates’ life path formation has been revealed by the author.

The risk of stranded assets for utilities in Canada

International Nuclear Information System (INIS)

Schroeder, W.

1998-01-01

The problems of dealing with stranded assets in Canada and the United States were discussed. Compared to the United States, the risk associated with stranded assets for utilities in Canada was considered to be relatively low because of the following factors: (1) low variable cost, (2) isolation, (3) lack of transmission interconnection capacity, (4) lack of tight synchronization in North America, (5) the likelihood of an increase in natural gas prices, (6) the absence of jurisdictional disputes such as FERC versus the states, (7) social considerations, (8) the learning curve, (9) politics, (10) weak balance sheets, (11) relatively low electricity prices, (12) the weak Canadian dollar, and (13) the possibility of refinancing at lower interest rates. Ontario Hydro, New Brunswick and Nova Scotia Power are the three Canadian utilities that may have stranded costs. For Ontario Hydro and New Brunswick Power the stranded costs would be related to nuclear generator problems, whereas for Nova Scotia Power, the stranded costs would be related to the thermal generating base, the threat from Sable Island Gas and the changing tax structure of the utility. Some other reasons why stranded assets could be created in Canada would include low variable costs and high fixed costs, over capacity of at least 30 per cent in generation, limited domestic energy growth, competitive threat from gas, reliability and safety of nuclear plants, and technology change. Five factors in terms of which stranded assets can be expressed are: (1) variable cost definition, (2) total cost definition, (3) operating profit definition, (4) wide geographic definition, and (5) free market definition. In calculating stranded assets, the number of years over which the assets are recovered and the discount rate are considered to be key factors. 26 tabs

Fatigue Characteristic of Chopped Strand Mat/Polyester Composite

Directory of Open Access Journals (Sweden)

I Made Astika

2012-11-01

Full Text Available The application of composite as an alternatif material to substitute of metal has better properties than metal such as light, high elasticity, corrosion and fatigue resistance. Some components in its application are subjected to millions of varying stress cycles that initiated to fatigue failure such as crack, delamination and fracture. The strength of composite is influenced by construction, fiber type, orientation and fiber fraction. The objective of this experiment is to investigate the fatigue characteristic on SCM composite. Material composite to be used is glass fiber with chopped strand mat (CSM as fiber and Yukalac 157 BQTN-EX with 1% hardener (Mexpox as matrix. The mold process was built with hand lay-up. Fiber volume fractions in composite are 40, 32 and 24 %. The tests to be done on composite are fatigue and tensile test. The research show that the increasing of fiber fraction in composite affects increasing of fatigue life, endurance limit and tensile strength. Fatigue failure modes of composite are debonding, matrix cracking, delamination and fiber fracture.

A mass stranding of the squid martialia hyadesi Rochebrune and ...

African Journals Online (AJOL)

1997-02-11

Feb 11, 1997 ... All animals were immature, with females in lower stages of maturity than males. No predatory marine mammals were seen in the area during or after the stranding event. An interpretation of the stranding is presented with reference to historical reports of squid strandings worldwide. Evidence suggests some ...

Equilibrious Strand Exchange Promoted by DNA Conformational Switching

Science.gov (United States)

Wu, Zhiguo; Xie, Xiao; Li, Puzhen; Zhao, Jiayi; Huang, Lili; Zhou, Xiang

2013-01-01

Most of DNA strand exchange reactions in vitro are based on toehold strategy which is generally nonequilibrium, and intracellular strand exchange mediated by proteins shows little sequence specificity. Herein, a new strand exchange promoted by equilibrious DNA conformational switching is verified. Duplexes containing c-myc sequence which is potentially converted into G-quadruplex are designed in this strategy. The dynamic equilibrium between duplex and G4-DNA is response to the specific exchange of homologous single-stranded DNA (ssDNA). The SER is enzyme free and sequence specific. No ATP is needed and the displaced ssDNAs are identical to the homologous ssDNAs. The SER products and exchange kenetics are analyzed by PAGE and the RecA mediated SER is performed as the contrast. This SER is a new feature of G4-DNAs and a novel strategy to utilize the dynamic equilibrium of DNA conformations.

Radiation induced strand breaks and time scale for repair of broken strands in superinfecting phage lambda DNA in Escherichia coli lysogenic for lambda

International Nuclear Information System (INIS)

Johansen, I.; Boye, E.; Brustad, T.

1975-01-01

The production of the first radiation induced break in covalent lambda DNA molecules in pol + and pol A 1 lysogenic host cells was measured after exposure to electrons from a linear accelerator and transfer to alkaline detergent within 100 ms from the onset of irradiation. The results revealed the presence of an oxygen effect in DNA strand breakage. In both pol + and pol A 1 host cells the rate of production in nitrogen was 1.2x10 -12 DNA single strand breaks per rad per dalton as compared to 5x10 -12 in oxygen. The yields of strand breaks in lambda DNA in pol + host cells under oxygenated or anoxic conditions are independent of whether the cells are irradiated in buffer at room temperature, in buffer at ice temperature, or in growth medium at 37 0 C. These results indicate that enzymic repair of DNA strand breaks before analysis is insignificant in these experiments. The presence of an oxygen effect in DNA strand breakage under these conditions suggest that an actual difference exists between initial number of breaks produced in nitrogen and in oxygen. The kinetics of rejoining of broken molecules under optimal growth conditions was measured by incubating the irradiated host cells prior to lysis. In pol + host cells 50% of the lambda DNA molecules broken in presence of oxygen are rejoined within 10 to 20 seconds of incubation. A significantly lower recovery is seen in pol + host cells after irradiation in nitrogen. The rejoining of broken lambda DNA strands in pol A 1 host cells is impaired after irradiation in presence of oxygen as well as under anoxia. These results show that DNA polymerase I is needed for the rapid rejoining of radiation induced strand breaks in the DNA, and that oxygen promoted strand breaks are more easily rejoined than are those produced in nitrogen. (author)

Induction of DNA strand breaks in 14C-labelled cells

International Nuclear Information System (INIS)

Sundell-Bergman, S.; Johanson, K.J.

1979-01-01

Chinese hamster cells grown in vitro were labelled with 14 C-thymidine for 18 hours and after 3 hours in non-radioactive medium they were stored at 0 0 C for various periods ( 1 to 12 hours). During this treatment a number of DNA strand breaks were induced by 14 C decay which were not repaired at 0 0 C. The number of DNA strand breaks was determined using the DNA unwinding technique. At 0.5-1 dpm per cell a detectable number of DNA strand breaks were found. Treatment for six hours (1 dpm per cell) reduced the percentage of double-stranded DNA from 80 to 70%, corresponding to about 750 DNA strand breaks per cell. The rejoining of DNA strand breaks was studied after treatment for 12 hours at 0 0 C followed by incubation of the cells for various periods at 37 0 C. Most of the DNA strand breaks induced by 14 C decay at 0 0 C were repaired after incubation at 37 0 C for 15 minutes. Assuming an absorbed dose of 1.8 mGy per 14 C decay to the cell nucleus an RBE value close to 1 was found for internal irradiation from 14 C decay as compared with 60 Co-gamma irradiation. (author)

Getting Frustrated: Modelling Emotion Contagion in Stranded Passengers

NARCIS (Netherlands)

van der Wal, C. Natalie; Couwenberg, Maik; Bosse, T.

2017-01-01

Train passengers can get stranded due to a variety of events, such as a delay, technical malfunctioning or a natural disaster. Stranded passengers can get frustrated, which could escalate in misbehaviours. Examples are verbal and physical violence or dangerous behaviours such as opening emergency

Inter-strand resistance measurements in the termination of the ITER SULTAN samples

International Nuclear Information System (INIS)

Cau, F; Bruzzone, P

2009-01-01

In cabled conductors a perfect uniformity of the current among the strands is hardly reached, due to the non-homogeneity of the contact resistance distribution between the strands and the copper of the electrical terminations. In the case of large current unbalance, the overloaded strands hit the critical surface at high field early, developing a current sharing voltage, which drives the redistribution of the current, mainly in the electrical terminations where the inter-strand resistance is lower than in the high field conductor. If the inter-strand resistance in the termination is low, the voltage levels are sufficiently low to allow an effective redistribution of the current to the less loaded strands. The inter-strand resistance of three different termination layouts of ITER short length samples is measured to make a database available which can be used to qualify the layout of the joints and their capability of redistributing the current among the strands.

RRP Nb3Sn strand studies for LARP

International Nuclear Information System (INIS)

Barzi, Emanuela; Bossert, Rodger; Caspi, Shlomo; Dietderich, Daniel R.; Ferracin, Paolo; Ghosh, Arup; Turrioni, Daniele

2006-01-01

The Nb 3 Sn strand chosen for the next step in the magnet R and D of the U.S. LHC Accelerator Research Program is the 54/61 sub-element Restacked Rod Process by Oxford Instruments, Superconducting Technology. To ensure that the 0.7 mm RRP strands to be used in the upcoming LARP magnets are suitable, extensive studies were performed. Measurements included the critical current, e , using the voltage-current (V-I) method, the stability current, I S , as the minimal quench current obtained with the voltage-field (V-H) method, and RRR. Magnetization was measured at low and high fields to determine the effective filament size and to detect flux jumps. Effects of heat treatment temperature and durations on I e and I S were also studied. Using strand billet qualification and tests of strands extracted from cables, the short sample limits of magnet performance were obtained. The details and the results of this investigation are herein described

RRP Nb3Sn Strand Studies for LARP

International Nuclear Information System (INIS)

Barzi, Emanuela; Bossert, Rodger; Caspi, Shlomo; Dietderich, Daniel R.; Ferracin, Paolo; Ghosh, Arup; Turrioni, Daniele

2007-01-01

The Nb 3 Sn strand chosen for the next step in the magnet R and D of the U.S. LHC Accelerator Research Program is the 54/61 sub-element Restacked Rod Process by Oxford Instruments, Superconducting Technology. To ensure that the 0.7 mm RRP strands to be used in the upcoming LARP magnets are suitable, extensive studies were performed. Measurements included the critical current, I c , using the voltage-current (V-I) method, the stability current, I S , as the minimal quench current obtained with the voltage-field (V-H) method, and RRR. Magnetization was measured at low and high fields to determine the effective filament size and to detect flux jumps. Effects of heat treatment temperature and durations on I c and I S were also studied. Using strand billet qualification and tests of strands extracted from cables, the short sample limits of magnet performance were obtained. The details and the results of this investigation are herein described

Orientation Mapping of Extruded Polymeric Composites by Polarized Micro-Raman Spectroscopy

Directory of Open Access Journals (Sweden)

Xiaoyun Chen

2015-01-01

Full Text Available Molecular orientation has a strong influence on polymeric composite materials’ mechanical properties. In this paper we describe the use of polarized micro-Raman spectroscopy as a powerful tool to map out the molecular orientation of a uniaxially oriented polypropylene- (PP- based composite material. Initial samples exhibited a high degree of surface fibrillation upon cutting. Raman spectroscopy was used to characterize the degree of orientation in the skin and guide the development of the posttreatment process to optimize the skin relaxation while maintaining the high degree of orientation in the rest of the board. The PP oriented polymer composite (OPC was oriented through an extrusion process and its surface was then treated to achieve relaxation. Micro-Raman analysis at the surface region demonstrated the surface orientation relaxation, and the results provide an effective way to correlate the extent of relaxation and process conditions. Larger scale orientation mapping was also carried out over the entire cross-section (12.7 cm × 2.54 cm. The results agree well with prior expectation of the molecular orientation based on the extrusion and subsequent quenching process. The methodologies described here can be readily applied to other polymeric systems.

Flexural behavior of bonded post-tensioned concrete beams under strand corrosion

International Nuclear Information System (INIS)

Zhang, Xuhui; Wang, Lei; Zhang, Jianren; Ma, Yafei; Liu, Yongming

2017-01-01

Highlights: • Flexural behavior of bonded PT beams with strand corrosion is experimental tested. • Cracking, stiffness, ultimate strength, failure & ductility of beams are clarified. • A coefficient is proposed to measure incompatible strain between strand & concrete. - Abstract: An experimental test is performed to investigate the flexural behavior of bonded post-tensioned concrete beams under strand corrosion. Eight beams are designed and subjected to accelerated method to different corrosion levels. The initial stiffness of beams is observed by cyclic loading-unloading test during the corrosion procedure. Corrosion effects on concrete cracking, post-cracking stiffness, ultimate strength, failure mode and ductility are then clarified by the flexural test. And, a coefficient is introduced to quantify the incompatible strain between corroded strand and concrete. Results show that the prestress force loss of strand has almost the linear relation with corrosion loss. Strand corrosion affects slightly the initial stiffness of beam before flexural cracking, but degrades significantly the post-cracking stiffness of beam as the corrosion loss exceeds 27.0%. Slight corrosion of strand has little effects on beams flexural behavior. The severe corrosion, however, decreases the number of crack, changes the failure mode form the concrete crushing to strand rupture, degrades the ductility and the ultimate strength of beams, and leads to the incompatible strain between strand and concrete. In the present test, the incompatible strain decreases about 20% of the flexural strength as the corrosion loss exceeds 27.0%.

Flexural behavior of bonded post-tensioned concrete beams under strand corrosion

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xuhui [College of Civil Engineering and Mechanics, Xiangtan University, 411105 Xiangtan (China); School of Civil Engineering and Architecture, Changsha University of Science & Technology, 410114 Changsha (China); Industry Key Laboratory of Traffic Infrastructure Security Risk Management (CSUST), 410114 Changsha (China); Wang, Lei, E-mail: leiwlei@hotmail.com [School of Civil Engineering and Architecture, Changsha University of Science & Technology, 410114 Changsha (China); Industry Key Laboratory of Traffic Infrastructure Security Risk Management (CSUST), 410114 Changsha (China); Zhang, Jianren; Ma, Yafei [School of Civil Engineering and Architecture, Changsha University of Science & Technology, 410114 Changsha (China); Industry Key Laboratory of Traffic Infrastructure Security Risk Management (CSUST), 410114 Changsha (China); Liu, Yongming [School for Engineering of Matter, Transport and Energy, Arizona State University, 85281 Tempe, AZ (United States)

2017-03-15

Highlights: • Flexural behavior of bonded PT beams with strand corrosion is experimental tested. • Cracking, stiffness, ultimate strength, failure & ductility of beams are clarified. • A coefficient is proposed to measure incompatible strain between strand & concrete. - Abstract: An experimental test is performed to investigate the flexural behavior of bonded post-tensioned concrete beams under strand corrosion. Eight beams are designed and subjected to accelerated method to different corrosion levels. The initial stiffness of beams is observed by cyclic loading-unloading test during the corrosion procedure. Corrosion effects on concrete cracking, post-cracking stiffness, ultimate strength, failure mode and ductility are then clarified by the flexural test. And, a coefficient is introduced to quantify the incompatible strain between corroded strand and concrete. Results show that the prestress force loss of strand has almost the linear relation with corrosion loss. Strand corrosion affects slightly the initial stiffness of beam before flexural cracking, but degrades significantly the post-cracking stiffness of beam as the corrosion loss exceeds 27.0%. Slight corrosion of strand has little effects on beams flexural behavior. The severe corrosion, however, decreases the number of crack, changes the failure mode form the concrete crushing to strand rupture, degrades the ductility and the ultimate strength of beams, and leads to the incompatible strain between strand and concrete. In the present test, the incompatible strain decreases about 20% of the flexural strength as the corrosion loss exceeds 27.0%.

LHC superconducting strand

CERN Multimedia

Patrice Loiez

1999-01-01

This cross-section through a strand of superconducting matieral as used in the LHC shows the 8000 Niobium-Titanium filaments embedded like a honeycomb in copper. When cooled to 1.9 degrees above absolute zero in the LHC accelerator, these filaments will have zero resistance and so will carry a high electric current with no energy loss.

A Novel Computational Method to Reduce Leaky Reaction in DNA Strand Displacement

Directory of Open Access Journals (Sweden)

Xin Li

2015-01-01

Full Text Available DNA strand displacement technique is widely used in DNA programming, DNA biosensors, and gene analysis. In DNA strand displacement, leaky reactions can cause DNA signals decay and detecting DNA signals fails. The mostly used method to avoid leakage is cleaning up after upstream leaky reactions, and it remains a challenge to develop reliable DNA strand displacement technique with low leakage. In this work, we address the challenge by experimentally evaluating the basic factors, including reaction time, ratio of reactants, and ion concentration to the leakage in DNA strand displacement. Specifically, fluorescent probes and a hairpin structure reporting DNA strand are designed to detect the output of DNA strand displacement, and thus can evaluate the leakage of DNA strand displacement reactions with different reaction time, ratios of reactants, and ion concentrations. From the obtained data, mathematical models for evaluating leakage are achieved by curve derivation. As a result, it is obtained that long time incubation, high concentration of fuel strand, and inappropriate amount of ion concentration can weaken leaky reactions. This contributes to a method to set proper reaction conditions to reduce leakage in DNA strand displacement.

A Stress Measurement Method for Steel Strands Based on LC Oscillation

Directory of Open Access Journals (Sweden)

Dongjun Chen

2018-01-01

Full Text Available The prestress loss is one of the main factors affecting the safety of prestressed concrete structure. While the detecting signals like sound and light are difficult to spread in steel strands, there is no effective method for prestress detection of the bonded prestressed steel strands in existing structures yet. In this paper, taking into consideration that the electromagnetic oscillation characteristic can make the signal propagate effectively on the bonded prestressed steel strands, a nondestructive prestress detection method based on the electromagnetic effect to detect oscillation frequency is proposed. In a detection circuit, the steel strands are simulated as an inductance component, in which an induced electromagnetic signal passes through the steel strands to form resonance. And then, a frequency meter is used to detect the oscillation frequency of the resonant circuit. The oscillation frequency is supposed to have relationship with the prestress loading on the steel strands. A section of steel strands with a length of 1.2 m is adopted to test the correlation of stress and oscillation frequency. Both the theoretical and experimental results show that the resonant frequency of the circuit decreases with the increase of the stress of the strand and is linear in a certain range.

Light Steel-Timber Frame with Composite and Plaster Bracing Panels

OpenAIRE

Scotta, Roberto; Trutalli, Davide; Fiorin, Laura; Pozza, Luca; Marchi, Luca; Stefani, Lorenzo  De

2015-01-01

The proposed light-frame structure comprises steel columns for vertical loads and an innovative bracing system to efficiently resist seismic actions. This seismic force resisting system consists of a light timber frame braced with an Oriented Strand Board (OSB) sheet and an external technoprene plaster-infilled slab. Steel brackets are used as foundation and floor connections. Experimental cyclic-loading tests were conduced to study the seismic response of two shear-wall specimens. A numerica...

A model capturing novel strand symmetries in bacterial DNA

International Nuclear Information System (INIS)

Sobottka, Marcelo; Hart, Andrew G.

2011-01-01

Highlights: → We propose a simple stochastic model to construct primitive DNA sequences. → The model provide an explanation for Chargaff's second parity rule in primitive DNA sequences. → The model is also used to predict a novel type of strand symmetry in primitive DNA sequences. → We extend the results for bacterial DNA sequences and compare distributional properties intrinsic to the model to statistical estimates from 1049 bacterial genomes. → We find out statistical evidences that the novel type of strand symmetry holds for bacterial DNA sequences. -- Abstract: Chargaff's second parity rule for short oligonucleotides states that the frequency of any short nucleotide sequence on a strand is approximately equal to the frequency of its reverse complement on the same strand. Recent studies have shown that, with the exception of organellar DNA, this parity rule generally holds for double-stranded DNA genomes and fails to hold for single-stranded genomes. While Chargaff's first parity rule is fully explained by the Watson-Crick pairing in the DNA double helix, a definitive explanation for the second parity rule has not yet been determined. In this work, we propose a model based on a hidden Markov process for approximating the distributional structure of primitive DNA sequences. Then, we use the model to provide another possible theoretical explanation for Chargaff's second parity rule, and to predict novel distributional aspects of bacterial DNA sequences.

Sub-ensemble monitoring of DNA strand displacement using multiparameter single-molecule FRET

OpenAIRE

Baltierra Jasso, Laura; Morten, Michael; Magennis, Steven William

2018-01-01

Non-enzymatic DNA strand displacement is an important mechanism in dynamic DNA nanotechnology. Here we show that the large parameter space that is accessible by single-molecule FRET is ideal for the simultaneous monitoring of multiple reactants and products of DNA strand exchange reactions. We monitored the strand displacement from double-stranded DNA (dsDNA) by single-stranded DNA (ssDNA) at 37 °C; the data were modelled as a second-order reaction approaching equilibrium, with a rate constan...

Stranding Events of Kogia Whales along the Brazilian Coast.

Directory of Open Access Journals (Sweden)

Jailson F Moura

Full Text Available The genus Kogia, which comprises only two extant species, Kogia sima and Kogia breviceps, represents one of the least known groups of cetaceans in the global ocean. In some coastal regions, however, stranding events of these species have been relatively common over the last decades. Stranding provides the opportunity to investigate the biology of these cetaceans and to explore the epidemiological aspects associated with the mortality of the organisms found on the beach. A number of disturbances (including pelagic fisheries, chemical pollution, boat strikes, and noise pollution have been confirmed to pose a particular threat to the Kogia species. However, no study has yet investigated potential relationships between environmental conditions and stranding events. Here we analyse how a collection of environmental, physical, and biological variables, such as wind, sea surface temperature (SST, water depth, and chlorophyll-a, correlate to Kogia stranding events along the Brazilian coast. The results of our statistical analyses suggest that K. sima is more likely found in warm tropical waters, which provide an explanation for the high frequency of stranding in northeastern Brazilian coast. In contrast, K. breviceps appears to have a preference for temperate and productive waters. Wind speed results to be also an important factor for predicting Kogia strandings in Brazilian coast. Additionally, literature information in combination with our own data and analyses of stomach contents confirms that oceanic cephalopods constitute the primary nutritional source of both Kogia species. By using the available information as a qualitative proxy for habitat preference and feeding ecology, our study provides a novel and comprehensive assessment of Kogia stranding data in relation to environmental conditions along the Brazilian coast.

Graphene levitation and orientation control using a magnetic field

Science.gov (United States)

Niu, Chao; Lin, Feng; Wang, Zhiming M.; Bao, Jiming; Hu, Jonathan

2018-01-01

This paper studies graphene levitation and orientation control using a magnetic field. The torques in all three spatial directions induced by diamagnetic forces are used to predict stable conditions for different shapes of millimeter-sized graphite plates. We find that graphite plates, in regular polygon shapes with an even number of sides, will be levitated in a stable manner above four interleaved permanent magnets. In addition, the orientation of micrometer-sized graphene flakes near a permanent magnet is studied in both air and liquid environments. Using these analyses, we are able to simulate optical transmission and reflection on a writing board and thereby reveal potential applications using this technology for display screens. Understanding the control of graphene flake orientation will lead to the discovery of future applications using graphene flakes.

75 FR 36678 - Prestressed Concrete Steel Wire Strand From China; Determinations

Science.gov (United States)

2010-06-28

... prestressed concrete steel wire strand (PC strand), provided for in subheading 7312.10.30 of the Harmonized... Publication 4162 (June 2010), entitled Prestressed Concrete Steel Wire Strand from China: Investigation Nos... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 701-TA-464 and 731-TA-1160 (Final)] Prestressed...

Flap Endonuclease 1 Limits Telomere Fragility on the Leading Strand*

Science.gov (United States)

Teasley, Daniel C.; Parajuli, Shankar; Nguyen, Mai; Moore, Hayley R.; Alspach, Elise; Lock, Ying Jie; Honaker, Yuchi; Saharia, Abhishek; Piwnica-Worms, Helen; Stewart, Sheila A.

2015-01-01

The existence of redundant replication and repair systems that ensure genome stability underscores the importance of faithful DNA replication. Nowhere is this complexity more evident than in challenging DNA templates, including highly repetitive or transcribed sequences. Here, we demonstrate that flap endonuclease 1 (FEN1), a canonical lagging strand DNA replication protein, is required for normal, complete leading strand replication at telomeres. We find that the loss of FEN1 nuclease activity, but not DNA repair activities, results in leading strand-specific telomere fragility. Furthermore, we show that FEN1 depletion-induced telomere fragility is increased by RNA polymerase II inhibition and is rescued by ectopic RNase H1 expression. These data suggest that FEN1 limits leading strand-specific telomere fragility by processing RNA:DNA hybrid/flap intermediates that arise from co-directional collisions occurring between the replisome and RNA polymerase. Our data reveal the first molecular mechanism for leading strand-specific telomere fragility and the first known role for FEN1 in leading strand DNA replication. Because FEN1 mutations have been identified in human cancers, our findings raise the possibility that unresolved RNA:DNA hybrid structures contribute to the genomic instability associated with cancer. PMID:25922071

Board Task Performance

DEFF Research Database (Denmark)

Minichilli, Alessandro; Zattoni, Alessandro; Nielsen, Sabina

2012-01-01

identify three board processes as micro-level determinants of board effectiveness. Specifically, we focus on effort norms, cognitive conflicts and the use of knowledge and skills as determinants of board control and advisory task performance. Further, we consider how two different institutional settings....... The findings show that: (i) Board processes have a larger potential than demographic variables to explain board task performance; (ii) board task performance differs significantly between boards operating in different contexts; and (iii) national context moderates the relationships between board processes...... and board task performance....

Characteristics of Cu stabilized Nb3Al strands with low Cu ratio

Energy Technology Data Exchange (ETDEWEB)

Kikuchi, A.; Yamada, R.; Barzi, E.; Kobayashi, M.; Lamm, M.; Nakagawa, K.; Sasaki, K.; Takeuchi, T.; Turrioni, D.; Zlobin, A.V.; /NIMC, Tsukuba /Fermilab /Hitachi, Tsuchiura Works /KEK, Tsukuba

2008-12-01

Characteristics of recently developed F4-Nb{sub 3}Al strand with low Cu ratio are described. The overall J{sub c} of the Nb{sub 3}Al strand could be easily increased by decreasing of the Cu ratio. Although the quench of a pulse-like voltage generation is usually observed in superconducting unstable conductor, the F4 strand with a low Cu ratio of 0.61 exhibited an ordinary critical transition of gradual voltage generation. The F4 strand does not have magnetic instabilities at 4.2 K because of the tantalum interfilament matrix. The overall J{sub c} of the F4 strand achieved was 80-85% of the RRP strand. In the large mechanical stress above 100 MPa, the overall J{sub c} of the F4 strand might be comparable to that of high J{sub c} RRP-Nb{sub 3}Sn strands. The Rutherford cable with a high packing factor of 86.5% has been fabricated using F4 strands. The small racetrack magnet, SR07, was also fabricated by a 14 m F4 cable. The quench current, I{sub q}, of SR07 were obtained 22.4 kA at 4.5 K and 25.2 kA at 2.2 K. The tantalum matrix Nb{sub 3}Al strands are promising for the application of super-cooled high-field magnets as well as 4.2 K operation magnets.

Strand displacement activated peroxidase activity of hemin for fluorescent DNA sensing.

Science.gov (United States)

Wang, Quanbo; Xu, Nan; Gui, Zhen; Lei, Jianping; Ju, Huangxian; Yan, Feng

2015-10-07

To efficiently regulate the catalytic activity of the peroxidase mimic hemin, this work designs a double-stranded DNA probe containing an intermolecular dimer of hemin, whose peroxidase activity can be activated by a DNA strand displacement reaction. The double-stranded probe is prepared by annealing two strands of hemin labelled DNA oligonucleotides. Using the fluorescent oxidation product of tyramine by H2O2 as a tracing molecule, the low peroxidase activity of the hemin dimer ensures a low fluorescence background. The strand displacement reaction of the target DNA dissociates the hemin dimer and thus significantly increases the catalytic activity of hemin to produce a large amount of dityramine for fluorescence signal readout. Based on the strand displacement regulated peroxidase activity, a simple and sensitive homogeneous fluorescent DNA sensing method is proposed. The detection can conveniently be carried out in a 96-well plate within 20 min with a detection limit of 0.18 nM. This method shows high specificity, which can effectively distinguish single-base mismatched DNA from perfectly matched target DNA. The DNA strand displacement regulated catalytic activity of hemin has promising application in the determination of various DNA analytes.

Torsional regulation of hRPA-induced unwinding of double-stranded DNA

NARCIS (Netherlands)

De Vlaminck, I.; Vidic, I.; Van Loenhout, M.T.J.; Kanaar, R.; Lebbink, J.H.G.; Dekker, C.

2010-01-01

All cellular single-stranded (ss) DNA is rapidly bound and stabilized by single stranded DNA-binding proteins (SSBs). Replication protein A, the main eukaryotic SSB, is able to unwind double-stranded (ds) DNA by binding and stabilizing transiently forming bubbles of ssDNA. Here, we study the

Role of stranded gas in increasing global gas supplies

Science.gov (United States)

Attanasi, E.D.; Freeman, P.A.

2013-01-01

This report synthesizes the findings of three regional studies in order to evaluate, at the global scale, the contribution that stranded gas resources can make to global natural gas supplies. Stranded gas, as defined for this study, is natural gas in discovered conventional gas and oil fields that is currently not commercially producible for either physical or economic reasons. The regional studies evaluated the cost of bringing the large volumes of undeveloped gas in stranded gas fields to selected markets. In particular, stranded gas fields of selected Atlantic Basin countries, north Africa, Russia, and central Asia are screened to determine whether the volumes are sufficient to meet Europe’s increasing demand for gas imports. Stranded gas fields in Russia, central Asia, Southeast Asia, and Australia are also screened to estimate development, production, and transport costs and corresponding gas volumes that could be supplied to Asian markets in China, India, Japan, and South Korea. The data and cost analysis presented here suggest that for the European market and the markets examined in Asia, the development of stranded gas provides a way to meet projected gas import demands for the 2020-to-2040 period. Although this is a reconnaissance-type appraisal, it is based on volumes of gas that are associated with individual identified fields. Individual field data were carefully examined. Some fields were not evaluated because current technology was insufficient or it appeared the gas was likely to be held off the export market. Most of the evaluated stranded gas can be produced and delivered to markets at costs comparable to historical prices. Moreover, the associated volumes of gas are sufficient to provide an interim supply while additional technologies are developed to unlock gas diffused in shale and hydrates or while countries transition to making a greater use of renewable energy sources.

Photochemical Acceleration of DNA Strand Displacement by Using Ultrafast DNA Photo-crosslinking.

Science.gov (United States)

Nakamura, Shigetaka; Hashimoto, Hirokazu; Kobayashi, Satoshi; Fujimoto, Kenzo

2017-10-18

DNA strand displacement is an essential reaction in genetic recombination, biological processes, and DNA nanotechnology. In particular, various DNA nanodevices enable complicated calculations. However, it takes time before the output is obtained, so acceleration of DNA strand displacement is required for a rapid-response DNA nanodevice. Herein, DNA strand displacement by using DNA photo-crosslinking to accelerate this displacement is evaluated. The DNA photo-crosslinking of 3-cyanovinylcarbazole ( CNV K) was accelerated at least 20 times, showing a faster DNA strand displacement. The rate of photo-crosslinking is a key factor and the rate of DNA strand displacement is accelerated through ultrafast photo-crosslinking. The rate of DNA strand displacement was regulated by photoirradiation energy. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Corrosion characteristics of unprotected post-tensioning strands under stress.

Science.gov (United States)

2014-05-01

An investigation was conducted to determine the effect of stress condition : and environmental exposure on corrosion of post-tensioned strands during ungrouted periods. : Exposures for periods of up to 4 weeks of stressed, as-received strand placed i...

Toward Global Comparability of Sexual Orientation Data in Official Statistics: A Conceptual Framework of Sexual Orientation for Health Data Collection in New Zealand's Official Statistics System

Science.gov (United States)

Gray, Alistair; Veale, Jaimie F.; Binson, Diane; Sell, Randell L.

2013-01-01

Objective. Effectively addressing health disparities experienced by sexual minority populations requires high-quality official data on sexual orientation. We developed a conceptual framework of sexual orientation to improve the quality of sexual orientation data in New Zealand's Official Statistics System. Methods. We reviewed conceptual and methodological literature, culminating in a draft framework. To improve the framework, we held focus groups and key-informant interviews with sexual minority stakeholders and producers and consumers of official statistics. An advisory board of experts provided additional guidance. Results. The framework proposes working definitions of the sexual orientation topic and measurement concepts, describes dimensions of the measurement concepts, discusses variables framing the measurement concepts, and outlines conceptual grey areas. Conclusion. The framework proposes standard definitions and concepts for the collection of official sexual orientation data in New Zealand. It presents a model for producers of official statistics in other countries, who wish to improve the quality of health data on their citizens. PMID:23840231

Stranded cost recovery in electricity market reforms in the US

International Nuclear Information System (INIS)

Woo, C.K.; Lloyd, D.; Karimov, R.; Tishler, A.

2003-01-01

An important element of an electricity market reform is stranded cost recovery. This paper explains the cause of stranded costs, describes four recovery mechanisms, evaluates these mechanisms using the criteria of recovery certainty, economic efficiency and equity, reviews the financial performance of 12 utilities in the US in connection to stranded cost recovery, and shows why the mechanism used in California has contributed to the reform failure in that state. (Author)

A fast, dataflow-oriented preprocessor for cluster counting

International Nuclear Information System (INIS)

Imhof, M.

1995-01-01

One of the main problems in the use of cluster counting for particle identification in high energy physics is the huge primary data rate. By means of an online data reduction system, this data rate can be reduced to the amount known from conventional integral charge/time readout. For tests and optimization of online data reduction algorithms, a RISC-based, data-flow-oriented multiprocessor board has been designed. (orig.)

A novel single fluorophore-labeled double-stranded oligonucleotide probe for fluorescence-enhanced nucleic acid detection based on the inherent quenching ability of deoxyguanosine bases and competitive strand-displacement reaction.

Science.gov (United States)

Zhang, Yingwei; Tian, Jingqi; Li, Hailong; Wang, Lei; Sun, Xuping

2012-01-01

We develop a novel single fluorophore-labeled double-stranded oligonucleotide (OND) probe for rapid, nanostructure-free, fluorescence-enhanced nucleic acid detection for the first time. We further demonstrate such probe is able to well discriminate single-base mutation in nucleic acid. The design takes advantage of an inherent quenching ability of guanine bases. The short strand of the probe is designed with an end-labeled fluorophore that is placed adjacent to two guanines as the quencher located on the long opposite strand, resulting in great quenching of dye fluorescence. In the presence of a target complementary to the long strand of the probe, a competitive strand-displacement reaction occurs and the long strand forms a more stable duplex with the target, resulting in the two strands of the probe being separated from each other. As a consequence of this displacement, the fluorophore and the quencher are no longer in close proximity and dye fluorescence increases, signaling the presence of target.

Bioprinting Using Mechanically Robust Core-Shell Cell-Laden Hydrogel Strands.

Science.gov (United States)

Mistry, Pritesh; Aied, Ahmed; Alexander, Morgan; Shakesheff, Kevin; Bennett, Andrew; Yang, Jing

2017-06-01

The strand material in extrusion-based bioprinting determines the microenvironments of the embedded cells and the initial mechanical properties of the constructs. One unmet challenge is the combination of optimal biological and mechanical properties in bioprinted constructs. Here, a novel bioprinting method that utilizes core-shell cell-laden strands with a mechanically robust shell and an extracellular matrix-like core has been developed. Cells encapsulated in the strands demonstrate high cell viability and tissue-like functions during cultivation. This process of bioprinting using core-shell strands with optimal biochemical and biomechanical properties represents a new strategy for fabricating functional human tissues and organs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechanical behaviors of multi-filament twist superconducting strand under tensile and cyclic loading

Science.gov (United States)

Wang, Xu; Li, Yingxu; Gao, Yuanwen

2016-01-01

The superconducting strand, serving as the basic unit cell of the cable-in-conduit-conductors (CICCs), is a typical multi-filament twist composite which is always subjected to a cyclic loading under the operating condition. Meanwhile, the superconducting material Nb3Sn in the strand is sensitive to strain frequently relating to the performance degradation of the superconductivity. Therefore, a comprehensive study on the mechanical behavior of the strand helps understanding the superconducting performance of the strained Nb3Sn strands. To address this issue, taking the LMI (internal tin) strand as an example, a three-dimensional structural finite element model, named as the Multi-filament twist model, of the strand with the real configuration of the LMI strand is built to study the influences of the plasticity of the component materials, the twist of the filament bundle, the initial thermal residual stress and the breakage and its evolution of the filaments on the mechanical behaviors of the strand. The effective properties of superconducting filament bundle with random filament breakage and its evolution versus strain are obtained based on the damage theory of fiber-reinforced composite materials proposed by Curtin and Zhou. From the calculation results of this model, we find that the occurrence of the hysteresis loop in the cyclic loading curve is determined by the reverse yielding of the elastic-plastic materials in the strand. Both the initial thermal residual stress in the strand and the pitch length of the filaments have significant impacts on the axial and hysteretic behaviors of the strand. The damage of the filaments also affects the axial mechanical behavior of the strand remarkably at large axial strain. The critical current of the strand is calculated by the scaling law with the results of the Multi-filament twist model. The predicted results of the Multi-filament twist model show an acceptable agreement with the experiment.

Molecular investigation of evaporation of biodroplets containing single-strand DNA on graphene surface.

Science.gov (United States)

Akbari, Fahimeh; Foroutan, Masumeh

2018-02-14

In this study, the water droplet behaviour of four different types of single-strand DNA with homogeneous base sequence on a graphene substrate during evaporation of the droplet was investigated using molecular dynamics (MD) simulation. The simulation results indicated that the evaporation depended on the DNA sequence. The observed changes can be divided into four parts: (i) vaporization mode, (ii) evaporation flux, (iii) mechanism of single-strand placement on the surface, and (iv) consideration of remaining single strands after evaporation. Our simulation observations indicated different evaporation modes for thymine biodroplets as compared to those for other biodroplets. The evaporation of the thymine biodroplets occurred with an increase in the contact angle, while that of the other biodroplets occur in a constant contact angle mode. Moreover, thymine biodroplets generate the lowest contact line compared to other single strands, and it is always placed far away from the centre of the droplets during evaporation. Investigating variations in the evaporation flux shows that thymine has the highest evaporation flux and guanine has the lowest. Moreover, during initial evaporation, the flux of evaporation increases at the triple point of the biodroplets containing thymine single strands, while it decreases in the other biodroplets. The following observation was obtained from the study of the placement of single strands on the substrate: guanine and thymine interacted slower than other single strands during evaporation with graphene, adenine single strand had a higher folding during evaporation, and guanine single strand showed the lowest end-to-end distance. The investigation of single-strand DNA after evaporation shows that adenine produces the most stable structure at the end of evaporation. In addition, cytosine is the most stretched single-strand DNA due to its lack of internal π-π stacking and hydrogen bonding. Therefore, cytosine single strand is more

Board effectiveness: Investigating payment asymmetry between board members and shareholders

Directory of Open Access Journals (Sweden)

Wuchun Chi

2008-01-01

Full Text Available Board members may well be responsible for dissension between themselves and shareholders since they are simultaneously the setters and receivers of both board remuneration and dividends. They may act out of their own personal interests at the expense of external shareholders. We investigate the impact of ownership structure, board structure and control deviation on payment asymmetry, where excessively high remuneration is paid to board members but considerably lower dividends are distributed to shareholders. We find strong evidence confirming that the smaller the shareholdings of board members and outside blockholders are, the more asymmetric the payments are. With controlling family members on the board and a higher percentage of seats held by independent board members, there is a slight reduction in the likelihood and severity of payment asymmetry. In addition, it is abundantly clear that the larger the board seat-control deviation is, the greater is the likelihood and severity of payment asymmetry. While prior research has primarily focused on board-manager agency issues, the board-shareholder perspective could be even more important in that it is the board that is the most directly delegated agent of shareholders, not the managers

Flap Endonuclease 1 Limits Telomere Fragility on the Leading Strand.

Science.gov (United States)

Teasley, Daniel C; Parajuli, Shankar; Nguyen, Mai; Moore, Hayley R; Alspach, Elise; Lock, Ying Jie; Honaker, Yuchi; Saharia, Abhishek; Piwnica-Worms, Helen; Stewart, Sheila A

2015-06-12

The existence of redundant replication and repair systems that ensure genome stability underscores the importance of faithful DNA replication. Nowhere is this complexity more evident than in challenging DNA templates, including highly repetitive or transcribed sequences. Here, we demonstrate that flap endonuclease 1 (FEN1), a canonical lagging strand DNA replication protein, is required for normal, complete leading strand replication at telomeres. We find that the loss of FEN1 nuclease activity, but not DNA repair activities, results in leading strand-specific telomere fragility. Furthermore, we show that FEN1 depletion-induced telomere fragility is increased by RNA polymerase II inhibition and is rescued by ectopic RNase H1 expression. These data suggest that FEN1 limits leading strand-specific telomere fragility by processing RNA:DNA hybrid/flap intermediates that arise from co-directional collisions occurring between the replisome and RNA polymerase. Our data reveal the first molecular mechanism for leading strand-specific telomere fragility and the first known role for FEN1 in leading strand DNA replication. Because FEN1 mutations have been identified in human cancers, our findings raise the possibility that unresolved RNA:DNA hybrid structures contribute to the genomic instability associated with cancer. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Board of Directors or Supervisory Board

DEFF Research Database (Denmark)

Werlauff, Erik

2009-01-01

The article analyses the legal consequences of the choice now available to Danish public limited companies, which can now opt for a two-tier management structure, in which the management board undertakes both the day-to-day and the overall management, while a supervisory board exercises control...... over the management board, including its appointment and dismissal. The article considers which companies a two-tier structure may be relevant for, and reviews the consequences for the composition, election and functioning of the company organs....

Towards quantitative viromics for both double-stranded and single-stranded DNA viruses

Directory of Open Access Journals (Sweden)

Simon Roux

2016-12-01

Full Text Available Background Viruses strongly influence microbial population dynamics and ecosystem functions. However, our ability to quantitatively evaluate those viral impacts is limited to the few cultivated viruses and double-stranded DNA (dsDNA viral genomes captured in quantitative viral metagenomes (viromes. This leaves the ecology of non-dsDNA viruses nearly unknown, including single-stranded DNA (ssDNA viruses that have been frequently observed in viromes, but not quantified due to amplification biases in sequencing library preparations (Multiple Displacement Amplification, Linker Amplification or Tagmentation. Methods Here we designed mock viral communities including both ssDNA and dsDNA viruses to evaluate the capability of a sequencing library preparation approach including an Adaptase step prior to Linker Amplification for quantitative amplification of both dsDNA and ssDNA templates. We then surveyed aquatic samples to provide first estimates of the abundance of ssDNA viruses. Results Mock community experiments confirmed the biased nature of existing library preparation methods for ssDNA templates (either largely enriched or selected against and showed that the protocol using Adaptase plus Linker Amplification yielded viromes that were ±1.8-fold quantitative for ssDNA and dsDNA viruses. Application of this protocol to community virus DNA from three freshwater and three marine samples revealed that ssDNA viruses as a whole represent only a minor fraction (<5% of DNA virus communities, though individual ssDNA genomes, both eukaryote-infecting Circular Rep-Encoding Single-Stranded DNA (CRESS-DNA viruses and bacteriophages from the Microviridae family, can be among the most abundant viral genomes in a sample. Discussion Together these findings provide empirical data for a new virome library preparation protocol, and a first estimate of ssDNA virus abundance in aquatic systems.

Toward Global Comparability of Sexual Orientation Data in Official Statistics: A Conceptual Framework of Sexual Orientation for Health Data Collection in New Zealand’s Official Statistics System

Directory of Open Access Journals (Sweden)

Frank Pega

2013-01-01

Full Text Available Objective. Effectively addressing health disparities experienced by sexual minority populations requires high-quality official data on sexual orientation. We developed a conceptual framework of sexual orientation to improve the quality of sexual orientation data in New Zealand’s Official Statistics System. Methods. We reviewed conceptual and methodological literature, culminating in a draft framework. To improve the framework, we held focus groups and key-informant interviews with sexual minority stakeholders and producers and consumers of official statistics. An advisory board of experts provided additional guidance. Results. The framework proposes working definitions of the sexual orientation topic and measurement concepts, describes dimensions of the measurement concepts, discusses variables framing the measurement concepts, and outlines conceptual grey areas. Conclusion. The framework proposes standard definitions and concepts for the collection of official sexual orientation data in New Zealand. It presents a model for producers of official statistics in other countries, who wish to improve the quality of health data on their citizens.

Cetacean strandings along the coast of Izmir Bay, Turkey

NARCIS (Netherlands)

Guclusoy, H.; Veryeri, N.; Cirik, S.

2004-01-01

The present paper provides information on the stranding of cetaceans in Izmir Bay, Aegean Sea, between 1992 and 2004. The data were collected opportunistically during sightings and stranding data collection for Monk Seals. A total of 12 cetaceans, namely Bottle-nosed Dolphin, Tursiops truncatus

DNA turnover and strand breaks in Escherichia coli

International Nuclear Information System (INIS)

Hanawalt, P.; Grivell, A.; Nakayama, H.

1975-01-01

The extent of DNA turnover has been measured in a dnaB mutant of Escherichia coli, temperature sensitive for semiconservative DNA replication. At the nonpermissive temperature about 0.02 percent of the deoxynucleotides in DNA are exchanged per generation period. This turnover rate is markedly depressed in the presence of rifampicin. During thymine starvation strand breaks accumulate in the DNA of E. coli strains that are susceptible to thymineless death. Rifampicin suppresses the appearance of these breaks, consistent with our hypothesis that transcription may be accompanied by repairable single-strand breaks in DNA. DNA turnover is enhanced severalfold in strands containing 5-bromodeoxyuridine in place of thymidine, possibly because the analog (or the deoxyuridine, following debromination) is sometimes recognized and excised

Residual Resistivity Ratio (RRR) Measurements of LHC Superconducting NbTi Cable Strands

CERN Document Server

Charifoulline, Z

2006-01-01

The Rutherford-type superconducting NbTi cables of the LHC accelerator are currently manufactured by six industrial companies. As a part of the acceptance tests, the Residual Resistivity Ratio (RRR) of superconducting strands is systematically measured on virgin strands to qualify the strands before cabling and on extracted strands to qualify the cables and to check the final heat treatment (controlled oxidation to control interstrand resistance). More than 12000 samples of virgin and extracted strands have been measured during last five years. Results show good correlation with the measurements done by the companies and reflect well the technological process of cable production (strand annealing, cabling, cable heat treatment). This paper presents a description of the RRR-test station and the measurement procedure, the summary of the results over all suppliers and finally the correlation between RRR-values of the cables and the magnets.

Tensile and dimensional properties of wood strands made from plantation southern pine lumber

Science.gov (United States)

Qinglin Wu; Zhiyong Cai; Jong N. Lee

2005-01-01

Working stresses and performance of strand composite lumber largely depend upon the properties of each individual strand. Southern pine strands from plantation lumber grown in southern Louisiana were investigated in this study in order to understand strand behaviors. The effects of hot-pressing and resin application on tensile modulus, strength, and dimensional...

Does strand configuration and number of purchase points affect the biomechanical behavior of a tendon repair? A biomechanical evaluation using different kessler methods of flexor tendon repair.

Science.gov (United States)

Dogramaci, Yunus; Kalaci, Aydiner; Sevinç, Teoman Toni; Esen, Erdinc; Komurcu, Mahmut; Yanat, Ahmet Nedim

2008-09-01

This study compares the mechanical properties of modified Kessler and double-modified Kessler flexor tendon repair techniques and evaluates simple modifications on both methods. Forty fresh sheep flexor tendons were divided equally into four groups. A transverse sharp cut was done in the middle of each tendon and then repaired with modified Kessler technique, modified Kessler with additional purchase point in the midpoint of each longitudinal strand, double-modified Kessler technique, or a combination of outer Kessler and inner cruciate configuration based on double-modified Kessler technique. The tendons were tested in a tensile testing machine to assess the mechanical performance of the repairs. Outcome measures included gap formation and ultimate forces. The gap strengths of the double-modified Kessler technique (30.85 N, SD 1.90) and double-modified Kessler technique with inner cruciate configuration (33.60 N, SD 4.64) were statistically significantly greater than that of the two-strand modified Kessler (22.56 N, SD 3.44) and modified Kessler with additional purchase configuration (21.75 N, SD 4.03; Tukey honestly significant difference test, P purchase point in modified Kessler repair or changing the inner strand configuration in double-modified Kessler repair. The results of this study show that the number of strands across the repair site together with the number of locking loops clearly affects the strength of the repair; meanwhile, the longitudinal strand orientation and number of purchase points in a single loop did not affect its strength.

Defense Business Board

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Skip to main content (Press Enter). Toggle navigation Defense Business Board Search Search Defense Business Board: Search Search Defense Business Board: Search Defense Business Board Business Excellence in Defense of the Nation Defense Business Board Home Charter Members Meetings Studies Contact Us The Defense

TALEN-Induced Double-Strand Break Repair of CTG Trinucleotide Repeats

Directory of Open Access Journals (Sweden)

Valentine Mosbach

2018-02-01

Full Text Available Trinucleotide repeat expansions involving CTG/CAG triplets are responsible for several neurodegenerative disorders, including myotonic dystrophy and Huntington’s disease. Because expansions trigger the disease, contracting repeat length could be a possible approach to gene therapy for these disorders. Here, we show that a TALEN-induced double-strand break was very efficient at contracting expanded CTG repeats in yeast. We show that RAD51, POL32, and DNL4 are dispensable for double-strand break repair within CTG repeats, the only required genes being RAD50, SAE2, and RAD52. Resection was totally abolished in the absence of RAD50 on both sides of the break, whereas it was reduced in a sae2Δ mutant on the side of the break containing the longest repeat tract, suggesting that secondary structures at double-strand break ends must be removed by the Mre11-Rad50 complex and Sae2. Following the TALEN double-strand break, single-strand annealing occurred between both sides of the repeat tract, leading to repeat contraction.

Programmable autonomous synthesis of single-stranded DNA

Science.gov (United States)

Kishi, Jocelyn Y.; Schaus, Thomas E.; Gopalkrishnan, Nikhil; Xuan, Feng; Yin, Peng

2018-02-01

DNA performs diverse functional roles in biology, nanotechnology and biotechnology, but current methods for autonomously synthesizing arbitrary single-stranded DNA are limited. Here, we introduce the concept of primer exchange reaction (PER) cascades, which grow nascent single-stranded DNA with user-specified sequences following prescribed reaction pathways. PER synthesis happens in a programmable, autonomous, in situ and environmentally responsive fashion, providing a platform for engineering molecular circuits and devices with a wide range of sensing, monitoring, recording, signal-processing and actuation capabilities. We experimentally demonstrate a nanodevice that transduces the detection of a trigger RNA into the production of a DNAzyme that degrades an independent RNA substrate, a signal amplifier that conditionally synthesizes long fluorescent strands only in the presence of a particular RNA signal, molecular computing circuits that evaluate logic (AND, OR, NOT) combinations of RNA inputs, and a temporal molecular event recorder that records in the PER transcript the order in which distinct RNA inputs are sequentially detected.

Towards human-oriented norms : Considering the effects of noise and vibration exposure on board ships

NARCIS (Netherlands)

Kurt, R.E.; Khalid, H.; Turan, O.; Houben, M.M.J.; Bos, J.E.; Helvacioglu, I.H.

2016-01-01

With modern trends of decrease in crew numbers on board ships together with increased operational demands and paperwork, crew fatigue and comfort have become more critical and are being given more importance. It is well known that environmental factors affect crew comfort and performance. The two

Development of a 10 m quasi-isotropic strand assembled from 2G wires

Science.gov (United States)

Kan, Changtao; Wang, Yinshun; Hou, Yanbing; Li, Yan; Zhang, Han; Fu, Yu; Jiang, Zhe

2018-03-01

Quasi-isotropic strands made of second generation (2G) high temperature superconducting (HTS) wires are attractive to applications of high-field magnets at low temperatures and power transmission cables at liquid nitrogen temperature in virtue of their high current carrying capability and well mechanical property. In this contribution, a 10 m length quasi-isotropic strand is manufactured and successfully tested in liquid nitrogen to verify the feasibility of an industrial scale production of the strand by the existing cabling technologies. The strand with copper sheath consists of 72 symmetrically assembled 2G wires. The uniformity of critical properties of long quasi-isotropic strands, including critical current and n-value, is very important for their using. Critical currents as well as n-values of the strand are measured every 1 m respectively and compared with the simulation results. Critical current and n-value of the strand are calculated basing on the self-consistent model solved by the finite element method (FEM). Effects of self-field on the critical current and n-value distributions in wires of the strand are analyzed in detail. The simulation results show good agreement with the experimental data and the 10 m quasi-isotropic strand has good critical properties uniformity.

Corrosion characteristics of post-tensioning strands in ungrouted ducts : summary.

Science.gov (United States)

2011-01-01

To prevent corrosion of post-tensioning strands, FDOT construction specifications currently require post-tensioning ducts to be grouted within seven calendar days of strand installation. This period challenges construction schedules on large projects...

Field Tested Service Oriented Robotic Architecture: Case Study

Science.gov (United States)

Flueckiger, Lorenzo; Utz, Hanz

2012-01-01

This paper presents the lessons learned from six years of experiments with planetary rover prototypes running the Service Oriented Robotic Architecture (SORA) developed by the Intelligent Robotics Group (IRG) at NASA Ames Research Center. SORA relies on proven software methods and technologies applied to the robotic world. Based on a Service Oriented Architecture and robust middleware, SORA extends its reach beyond the on-board robot controller and supports the full suite of software tools used during mission scenarios from ground control to remote robotic sites. SORA has been field tested in numerous scenarios of robotic lunar and planetary exploration. The results of these high fidelity experiments are illustrated through concrete examples that have shown the benefits of using SORA as well as its limitations.

Patients overwhelmingly prefer inpatient boarding to emergency department boarding.

Science.gov (United States)

Viccellio, Peter; Zito, Joseph A; Sayage, Valerie; Chohan, Jasmine; Garra, Gregory; Santora, Carolyn; Singer, Adam J

2013-12-01

Boarding of admitted patients in the emergency department (ED) is a major cause of crowding. One alternative to boarding in the ED, a full-capacity protocol where boarded patients are redeployed to inpatient units, can reduce crowding and improve overall flow. Our aim was to compare patient satisfaction with boarding in the ED vs. inpatient hallways. We performed a structured telephone survey regarding patient experiences and preferences for boarding among admitted ED patients who experienced boarding in the ED hallway and then were subsequently transferred to inpatient hallways. Demographic and clinical characteristics, as well as patient preferences, including items related to patient comfort and safety using a 5-point scale, were recorded and descriptive statistics were used to summarize the data. Of 110 patients contacted, 105 consented to participate. Mean age was 57 ± 16 years and 52% were female. All patients were initially boarded in the ED in a hallway before their transfer to an inpatient hallway bed. The overall preferred location after admission was the inpatient hallway in 85% (95% confidence interval 75-90) of respondents. In comparing ED vs. inpatient hallway boarding, the following percentages of respondents preferred inpatient boarding with regard to the following 8 items: rest, 85%; safety, 83%; confidentiality, 82%; treatment, 78%; comfort, 79%; quiet, 84%; staff availability, 84%; and privacy, 84%. For no item was there a preference for boarding in the ED. Patients overwhelmingly preferred the inpatient hallway rather than the ED hallway when admitted to the hospital. Copyright © 2013 Elsevier Inc. All rights reserved.

A single-strand specific lesion drives MMS-induced hyper-mutability at a double-strand break in yeast.

Science.gov (United States)

Yang, Yong; Gordenin, Dmitry A; Resnick, Michael A

2010-08-05

Localized hyper-mutability (LHM) can be important in evolution, immunity, and genetic diseases. We previously reported that single-strand DNA (ssDNA) can be an important source of damage-induced LHM in yeast. Here, we establish that the generation of LHM by methyl methanesulfonate (MMS) during repair of a chromosomal double-strand break (DSB) can result in over 0.2 mutations/kb, which is approximately 20,000-fold higher than the MMS-induced mutation density without a DSB. The MMS-induced mutations associated with DSB repair were primarily due to substitutions via translesion DNA synthesis at damaged cytosines, even though there are nearly 10 times more MMS-induced lesions at other bases. Based on this mutation bias, the promutagenic lesion dominating LHM is likely 3-methylcytosine, which is single-strand specific. Thus, the dramatic increase in mutagenesis at a DSB is concluded to result primarily from the generation of non-repairable lesions in ssDNA associated with DSB repair along with efficient induction of highly mutagenic ssDNA-specific lesions. These findings with MMS-induced LHM have broad biological implications for unrepaired damage generated in ssDNA and possibly ssRNA. Published by Elsevier B.V.

Consultation with the filipino boarding home: an after-care facility in Hawaii.

Science.gov (United States)

Yutiao, M; Kinzie, J D

1975-01-01

This report describes a unique Hawaiian after-care facility the Filipino operated boarding home, and the approaches useful in consultation with the operators. The majority of the boarding homes for psychiatric patients are operated by recent Filipino immigrants. This fact is explained by their current social position and also by cultural values--such as aiding others and an extended family system--which are present in the Philippines. In consultation with seventeen such boarding home operators, cultural beliefs and values played a great part in their approach to patients. These approaches created special problems and assets in their management of patients from other ethnic groups such as Japanese, Caucasian and Hawaiian. A problem-oriented approach to consultation proved useful initially and set the stage for other forms of intervention. This included allowing the operator to ventilate her feelings about the patient; bridging the communication gap between operators and patients; dissipating the operators' stereotypic perception of patients; and educating the operators about mental illness. Our impressions and indirect evidence indicated that Filipino boarding home operators perform a useful service and, with consultation sensitive to their values, can become even more effective.

Stem cell identity and template DNA strand segregation.

Science.gov (United States)

Tajbakhsh, Shahragim

2008-12-01

The quest for stem cell properties to distinguish their identity from that of committed daughters has led to a re-investigation of the notion that DNA strands are not equivalent, and 'immortal' DNA strands are retained in stem cells whereas newly replicated DNA strands segregate to the differentiating daughter cell during mitosis. Whether this process occurs only in stem cells, and also in all tissues, remains unclear. That individual chromosomes can be also partitioned non-randomly raises the question if this phenomenon is related to the immortal DNA hypothesis, and it underscores the need for high-resolution techniques to observe these events empirically. Although initially postulated as a mechanism to avoid DNA replication errors, alternative views including epigenetic regulation and sister chromatid silencing may provide insights into this process.

Mechanical behavior of Nb{sub 3}Sn strands under transverse electromagnetic loads

Energy Technology Data Exchange (ETDEWEB)

Ru, Yanyun; Yong, Huadong, E-mail: yonghd@lzu.edu.cn; Zhou, Youhe

2016-11-15

Highlights: • The contact forces between the strands under transverse electromagnetic load are considered. • The indentation depth for two-dimensional contact problem is calculated. • The strand damage for different layers is presented. • We discuss the effect of bending wavelength on the Nb{sub 3}Sn strand. - Abstract: The performance of Nb{sub 3}Sn cable-in-conduit-conductor (CICC) shows a significant degradation with increasing electromagnetic load in the International Thermonuclear Experimental Reactor (ITER). As the strand is under the compression caused by adjacent strands, the strand damage may occur for high contact force. In this paper, we present a 3D helix model based on the TEMLOP and FEMCAM to simulate the contact force among the strands under transverse load. The maximum linear strain and indentation depth induced by contact stress are calculated with two-dimensional contact model of cylinder. The numerical results are compared with the experimental values. Finally, the indentation depth is discussed for different layers and cross angles based on two models. With the increasing of layer number, the degradation of performance will occur. The short bending wavelength leads to small indentation depth.

Sub-Ensemble Monitoring of DNA Strand Displacement Using Multiparameter Single-Molecule FRET.

Science.gov (United States)

Baltierra-Jasso, Laura E; Morten, Michael J; Magennis, Steven W

2018-03-05

Non-enzymatic DNA strand displacement is an important mechanism in dynamic DNA nanotechnology. Here, we show that the large parameter space that is accessible by single-molecule FRET is ideal for the simultaneous monitoring of multiple reactants and products of DNA strand exchange reactions. We monitored the strand displacement from double-stranded DNA (dsDNA) by single-stranded DNA (ssDNA) at 37 °C; the data were modelled as a second-order reaction approaching equilibrium, with a rate constant of 10 m -1  s -1 . We also followed the displacement from a DNA three-way junction (3WJ) by ssDNA. The presence of three internal mismatched bases in the middle of the invading strand did not prevent displacement from the 3WJ, but reduced the second-order rate constant by about 50 %. We attribute strand exchange in the dsDNA and 3WJ to a zero-toehold pathway from the blunt-ended duplex arms. The single-molecule approach demonstrated here will be useful for studying complex DNA networks. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

75 FR 35816 - Establishment of the Consumer Operated and Oriented Plan (CO-OP) Advisory Board

Science.gov (United States)

2010-06-23

... Advisory Committee Act (FACA), a charter has been filed with the Committee Management Secretariat in the... Act. Any individual appointed under the board shall meet ethics and conflict of interest standards... their homes or regular places of business, may be allowed travel expenses, including per diem in lieu of...

Performance optimization of internal tin process multifilamentary Nb{sub 3}Sn strands

Energy Technology Data Exchange (ETDEWEB)

Zhang, Ke, E-mail: zhangke@c-wst.com [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Western Superconducting Technologies Co. Ltd, Xi’an, Shaanxi 710018 (China); State Engineering Lab. of Superconducting Material Preparation, Xi’an, Shaanxi 710018 (China); Zhang, Pingxiang [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Western Superconducting Technologies Co. Ltd, Xi’an, Shaanxi 710018 (China); State Engineering Lab. of Superconducting Material Preparation, Xi’an, Shaanxi 710018 (China); Northwest Institute for Non-ferrous Metal Research, Xi’an, Shaanxi 710016 (China); Shi, Yigong; Liu, Jianwei; Gao, Huixian; Li, Jianfeng; Liu, Xianghong; Feng, Yong [Western Superconducting Technologies Co. Ltd, Xi’an, Shaanxi 710018 (China); State Engineering Lab. of Superconducting Material Preparation, Xi’an, Shaanxi 710018 (China)

2016-11-01

Highlights: • J{sub c} increases by adding Sn cores in the interspaces, hysteresis loss increases at the same time. • Enlarger the number of filaments with the same Sn proportion will increase J{sub c} and hysteresis loss. • Cu split adopted in each sub-element leads to a low hysteresis loss. - Abstract: In this study, internal tin process Nb{sub 3}Sn strands for the International Thermo-nuclear Experimental Reactor are developed in Western Superconducting Technologies. Short cable-in-conduit conductors manufactured with these strands have been qualified. Mass production is accomplished, and all the performances of the strands meet the requirement of ITER project. Besides, more researches on the effect of strand design on critical current density and hysteresis loss for Nb{sub 3}Sn strands are carried out. It is found that critical current density can be enhanced by reducing filament diameter and increasing Sn content, and hysteresis loss of the strands can be significantly reduced through Cu split adopted in sub-element.

Metallographic investigation of fracture behavior in ITER-style Nb$_{3}$Sn superconducting strands

CERN Document Server

Jewell, M C; Larbalestier, D C; Nijhuis, A

2009-01-01

In this work we specify the extent to which fracture in two ITER-style Nb$_{3}$Sn composite strands occurs in a collective or individual manner, under mechanical tension and bending from the TARSIS apparatus at the University of Twente. A bronze-route strand from European Advanced Superconductors (EAS), which has very uniform, well-spaced filaments, has a widely distributed (200 μm) fracture field and exhibits a composite of individual and collective cracks. An internal tin strand from Oxford Instruments – Superconducting Technology (OST) demonstrates much more localized, collective fracture behavior. The filaments in this strand are about four times larger (in area) than the filaments in the EAS strand, and also agglomerate significantly during heat treatment upon conversion of the Nb to Nb$_{3}$Sn. These results demonstrate that the architecture of the strand can play a significant role in determining the mechanical toughness of the composite, and that strand design should incorporate mechanical consider...

The Effect of Basepair Mismatch on DNA Strand Displacement.

Science.gov (United States)

Broadwater, D W Bo; Kim, Harold D

2016-04-12

DNA strand displacement is a key reaction in DNA homologous recombination and DNA mismatch repair and is also heavily utilized in DNA-based computation and locomotion. Despite its ubiquity in science and engineering, sequence-dependent effects of displacement kinetics have not been extensively characterized. Here, we measured toehold-mediated strand displacement kinetics using single-molecule fluorescence in the presence of a single basepair mismatch. The apparent displacement rate varied significantly when the mismatch was introduced in the invading DNA strand. The rate generally decreased as the mismatch in the invader was encountered earlier in displacement. Our data indicate that a single base pair mismatch in the invader stalls branch migration and displacement occurs via direct dissociation of the destabilized incumbent strand from the substrate strand. We combined both branch migration and direct dissociation into a model, which we term the concurrent displacement model, and used the first passage time approach to quantitatively explain the salient features of the observed relationship. We also introduce the concept of splitting probabilities to justify that the concurrent model can be simplified into a three-step sequential model in the presence of an invader mismatch. We expect our model to become a powerful tool to design DNA-based reaction schemes with broad functionality. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Toxin MqsR Cleaves Single-Stranded mRNA with Various 5 Ends

Science.gov (United States)

2016-08-24

either protein ORIGINAL RESEARCH Toxin MqsR cleaves single- stranded mRNA with various 5’ ends Nityananda Chowdhury1,*, Brian W. Kwan1,*, Louise C...in which a single 5′- GCU site was predicted to be single- stranded (ssRNA), double- stranded (dsRNA), in the loop of a stem - loop (slRNA), or in a...single- stranded 5′- GCU sites since cleavage was approximately 20- fold higher than cleavage seen with the 5′- GCU site in the stem - loop and

Nurses on health care governing boards: An integrative review.

Science.gov (United States)

Sundean, Lisa J; Polifroni, E Carol; Libal, Kathryn; McGrath, Jacqueline M

Nurses are key change agents in health care; yet, nurses have not been sufficiently engaged on boards to shape decision making. Without an equal voice in the boardroom, nurses cannot fulfill their professional obligation to society. The purpose of this study was to understand the progression in research focus and recommendations over time about nurses on boards (NOB), identify research gaps, and make research/practice recommendations. An integrative review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines (2009) for data evaluation and analysis. Eleven studies (six quantitative, three qualitative, and two quasi-mixed methods) were included in the review. The focus/recommendations of research about NOB have changed from passive observation to action-oriented inquiry that considers nurse expertise and value but lacks a coordinated approach to advance board appointments for nurses. A systematic approach to the research is needed to advance NOB as key agents in health care transformation and social justice. Copyright © 2017 Elsevier Inc. All rights reserved.

A focus on polarity: Investigating the role of orientation cues in mediating student performance on mRNA synthesis tasks in an introductory cell and molecular biology course.

Science.gov (United States)

Olimpo, Jeffrey T; Quijas, Daniel A; Quintana, Anita M

2017-11-01

The central dogma has served as a foundational model for information flow, exchange, and storage in the biological sciences for several decades. Despite its continued importance, however, recent research suggests that novices in the domain possess several misconceptions regarding the aforementioned processes, including those pertaining specifically to the formation of messenger ribonucleic acid (mRNA) transcripts. In the present study, we sought to expand upon these observations through exploration of the influence of orientation cues on students' aptitude at synthesizing mRNAs from provided deoxyribonucleic acid (DNA) template strands. Data indicated that participants (n = 45) were proficient at solving tasks of this nature when the DNA template strand and the mRNA molecule were represented in an antiparallel orientation. In contrast, participants' performance decreased significantly on items in which the mRNA was depicted in a parallel orientation relative to the DNA template strand. Furthermore, participants' Grade Point Average, self-reported confidence in understanding the transcriptional process, and spatial ability were found to mediate their performance on the mRNA synthesis tasks. Collectively, these data reaffirm the need for future research and pedagogical interventions designed to enhance students' comprehension of the central dogma in a manner that makes transparent its relevance to real-world scientific phenomena. © 2017 by The International Union of Biochemistry and Molecular Biology, 45(6):501-508, 2017. © 2017 The International Union of Biochemistry and Molecular Biology.

Board members’ contribution to strategy: The mediating role of board internal processes

Directory of Open Access Journals (Sweden)

Carmen Barroso-Castro

2017-05-01

Full Text Available This study aims to explore what directors do on the board, to what extent the processes occurring in the board allow the sharing and integrating of the existing knowledge, thus facilitating the board members’ contributions to strategy. We adopt the view that the internal board processes increase the impact of the cognitive resources on board performance. Using survey data from 200 large Spanish companies we demonstrate that directors’ level of knowledge of the firm and board job-related diversity positively influence the degree of the board's strategic involvement. Additionally, the internal processes that take place within the board – particularly Cognitive Conflict, the Critical and Independent Approach and the Comprehensive Discussion Process – influence the board's strategic involvement and play a partial mediating role on the aforementioned relationships. However, our results show no evidence for a positive relationship between Board Meeting Dynamics and the board's strategic involvement.

World-Wide Benchmarking of ITER Nb$_{3}$Sn Strand Test Facilities

CERN Document Server

Jewell, MC; Takahashi, Yoshikazu; Shikov, Alexander; Devred, Arnaud; Vostner, Alexander; Liu, Fang; Wu, Yu; Jewell, Matthew C; Boutboul, Thierry; Bessette, Denis; Park, Soo-Hyeon; Isono, Takaaki; Vorobieva, Alexandra; Martovetsky, Nicolai; Seo, Kazutaka

2010-01-01

The world-wide procurement of Nb$_{3}$Sn and NbTi for the ITER superconducting magnet systems will involve eight to ten strand suppliers from six Domestic Agencies (DAs) on three continents. To ensure accurate and consistent measurement of the physical and superconducting properties of the composite strand, a strand test facility benchmarking effort was initiated in August 2008. The objectives of this effort are to assess and improve the superconducting strand test and sample preparation technologies at each DA and supplier, in preparation for the more than ten thousand samples that will be tested during ITER procurement. The present benchmarking includes tests for critical current (I-c), n-index, hysteresis loss (Q(hys)), residual resistivity ratio (RRR), strand diameter, Cu fraction, twist pitch, twist direction, and metal plating thickness (Cr or Ni). Nineteen participants from six parties (China, EU, Japan, South Korea, Russia, and the United States) have participated in the benchmarking. This round, cond...

Self-Field Effects in Magneto-Thermal Instabilities for Nb-Sn Strands

CERN Document Server

Bordini, B; Fehér, S; Rossi, L; Zlobin, A V

2008-01-01

Recent advancements in the critical current density (Jc) of Nb$_{3}$Sn conductors, coupled with a large effective filament size, have drawn attention to the problem of magnetothermal instabilities. At low magnetic fields, the quench current of such high Jc Nb$_{3}$Sn strands is significantly lower than their critical current because of the above-mentioned instabilities. An adiabatic model to calculate the minimum current at which a strand can quench due to magneto-thermal instabilities is developed. The model is based on an 'integral' approach already used elsewhere [1]. The main difference with respect to the previous model is the addition of the self-field effect that allows to describe premature quenches of non-magnetized Nb$_{3}$Sn strands and to better calculate the quench current of strongly magnetized strands. The model is in good agreement with experimental results at 4.2 K obtained at Fermilab using virgin Modified Jelly Roll (MJR) strands with a low Residual Resistivity Ratio (RRR) of the stabilizin...

On the biophysics and kinetics of toehold-mediated DNA strand displacement.

Science.gov (United States)

Srinivas, Niranjan; Ouldridge, Thomas E; Sulc, Petr; Schaeffer, Joseph M; Yurke, Bernard; Louis, Ard A; Doye, Jonathan P K; Winfree, Erik

2013-12-01

Dynamic DNA nanotechnology often uses toehold-mediated strand displacement for controlling reaction kinetics. Although the dependence of strand displacement kinetics on toehold length has been experimentally characterized and phenomenologically modeled, detailed biophysical understanding has remained elusive. Here, we study strand displacement at multiple levels of detail, using an intuitive model of a random walk on a 1D energy landscape, a secondary structure kinetics model with single base-pair steps and a coarse-grained molecular model that incorporates 3D geometric and steric effects. Further, we experimentally investigate the thermodynamics of three-way branch migration. Two factors explain the dependence of strand displacement kinetics on toehold length: (i) the physical process by which a single step of branch migration occurs is significantly slower than the fraying of a single base pair and (ii) initiating branch migration incurs a thermodynamic penalty, not captured by state-of-the-art nearest neighbor models of DNA, due to the additional overhang it engenders at the junction. Our findings are consistent with previously measured or inferred rates for hybridization, fraying and branch migration, and they provide a biophysical explanation of strand displacement kinetics. Our work paves the way for accurate modeling of strand displacement cascades, which would facilitate the simulation and construction of more complex molecular systems.

The role of cytosine methylation on charge transport through a DNA strand

Energy Technology Data Exchange (ETDEWEB)

Qi, Jianqing, E-mail: jqqi@uw.edu; Anantram, M. P., E-mail: anantmp@uw.edu [Department of Electrical Engineering, University of Washington, Seattle, Washington 98195-2500 (United States); Govind, Niranjan, E-mail: niri.govind@pnnl.gov [William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)

2015-09-07

Cytosine methylation has been found to play a crucial role in various biological processes, including a number of human diseases. The detection of this small modification remains challenging. In this work, we computationally explore the possibility of detecting methylated DNA strands through direct electrical conductance measurements. Using density functional theory and the Landauer-Büttiker method, we study the electronic properties and charge transport through an eight base-pair methylated DNA strand and its native counterpart. We first analyze the effect of cytosine methylation on the tight-binding parameters of two DNA strands and then model the transmission of the electrons and conductance through the strands both with and without decoherence. We find that the main difference of the tight-binding parameters between the native DNA and the methylated DNA lies in the on-site energies of (methylated) cytosine bases. The intra- and inter-strand hopping integrals between two nearest neighboring guanine base and (methylated) cytosine base also change with the addition of the methyl groups. Our calculations show that in the phase-coherent limit, the transmission of the methylated strand is close to the native strand when the energy is nearby the highest occupied molecular orbital level and larger than the native strand by 5 times in the bandgap. The trend in transmission also holds in the presence of the decoherence with the same rate. The lower conductance for the methylated strand in the experiment is suggested to be caused by the more stable structure due to the introduction of the methyl groups. We also study the role of the exchange-correlation functional and the effect of contact coupling by choosing coupling strengths ranging from weak to strong coupling limit.

Higher 5-hydroxymethylcytosine identifies immortal DNA strand chromosomes in asymmetrically self-renewing distributed stem cells.

Science.gov (United States)

Huh, Yang Hoon; Cohen, Justin; Sherley, James L

2013-10-15

Immortal strands are the targeted chromosomal DNA strands of nonrandom sister chromatid segregation, a mitotic chromosome segregation pattern unique to asymmetrically self-renewing distributed stem cells (DSCs). By nonrandom segregation, immortal DNA strands become the oldest DNA strands in asymmetrically self-renewing DSCs. Nonrandom segregation of immortal DNA strands may limit DSC mutagenesis, preserve DSC fate, and contribute to DSC aging. The mechanisms responsible for specification and maintenance of immortal DNA strands are unknown. To discover clues to these mechanisms, we investigated the 5-methylcytosine and 5-hydroxymethylcytosine (5hmC) content on chromosomes in mouse hair follicle DSCs during nonrandom segregation. Although 5-methylcytosine content did not differ significantly, the relative content of 5hmC was significantly higher in chromosomes containing immortal DNA strands than in opposed mitotic chromosomes containing younger mortal DNA strands. The difference in relative 5hmC content was caused by the loss of 5hmC from mortal chromosomes. These findings implicate higher 5hmC as a specific molecular determinant of immortal DNA strand chromosomes. Because 5hmC is an intermediate during DNA demethylation, we propose a ten-eleven translocase enzyme mechanism for both the specification and maintenance of nonrandomly segregated immortal DNA strands. The proposed mechanism reveals a means by which DSCs "know" the generational age of immortal DNA strands. The mechanism is supported by molecular expression data and accounts for the selection of newly replicated DNA strands when nonrandom segregation is initiated. These mechanistic insights also provide a possible basis for another characteristic property of immortal DNA strands, their guanine ribonucleotide dependency.

Tolerance of DNA Mismatches in Dmc1 Recombinase-mediated DNA Strand Exchange*

Science.gov (United States)

Borgogno, María V.; Monti, Mariela R.; Zhao, Weixing; Sung, Patrick; Argaraña, Carlos E.; Pezza, Roberto J.

2016-01-01

Recombination between homologous chromosomes is required for the faithful meiotic segregation of chromosomes and leads to the generation of genetic diversity. The conserved meiosis-specific Dmc1 recombinase catalyzes homologous recombination triggered by DNA double strand breaks through the exchange of parental DNA sequences. Although providing an efficient rate of DNA strand exchange between polymorphic alleles, Dmc1 must also guard against recombination between divergent sequences. How DNA mismatches affect Dmc1-mediated DNA strand exchange is not understood. We have used fluorescence resonance energy transfer to study the mechanism of Dmc1-mediated strand exchange between DNA oligonucleotides with different degrees of heterology. The efficiency of strand exchange is highly sensitive to the location, type, and distribution of mismatches. Mismatches near the 3′ end of the initiating DNA strand have a small effect, whereas most mismatches near the 5′ end impede strand exchange dramatically. The Hop2-Mnd1 protein complex stimulates Dmc1-catalyzed strand exchange on homologous DNA or containing a single mismatch. We observed that Dmc1 can reject divergent DNA sequences while bypassing a few mismatches in the DNA sequence. Our findings have important implications in understanding meiotic recombination. First, Dmc1 acts as an initial barrier for heterologous recombination, with the mismatch repair system providing a second level of proofreading, to ensure that ectopic sequences are not recombined. Second, Dmc1 stepping over infrequent mismatches is likely critical for allowing recombination between the polymorphic sequences of homologous chromosomes, thus contributing to gene conversion and genetic diversity. PMID:26709229

Checkpoint Kinase Rad53 Couples Leading- and Lagging-Strand DNA Synthesis under Replication Stress.

Science.gov (United States)

Gan, Haiyun; Yu, Chuanhe; Devbhandari, Sujan; Sharma, Sushma; Han, Junhong; Chabes, Andrei; Remus, Dirk; Zhang, Zhiguo

2017-10-19

The checkpoint kinase Rad53 is activated during replication stress to prevent fork collapse, an essential but poorly understood process. Here we show that Rad53 couples leading- and lagging-strand synthesis under replication stress. In rad53-1 cells stressed by dNTP depletion, the replicative DNA helicase, MCM, and the leading-strand DNA polymerase, Pol ε, move beyond the site of DNA synthesis, likely unwinding template DNA. Remarkably, DNA synthesis progresses further along the lagging strand than the leading strand, resulting in the exposure of long stretches of single-stranded leading-strand template. The asymmetric DNA synthesis in rad53-1 cells is suppressed by elevated levels of dNTPs in vivo, and the activity of Pol ε is compromised more than lagging-strand polymerase Pol δ at low dNTP concentrations in vitro. Therefore, we propose that Rad53 prevents the generation of excessive ssDNA under replication stress by coordinating DNA unwinding with synthesis of both strands. Copyright © 2017 Elsevier Inc. All rights reserved.

Estimation of Prestress Force Distribution in the Multi-Strand System of Prestressed Concrete Structures

Directory of Open Access Journals (Sweden)

Keunhee Cho

2015-06-01

Full Text Available Prestressed concrete (PSC is one of the most reliable, durable and widely used construction materials, which overcomes the weakness of concrete in tension by the introduction of a prestress force. Smart strands enabling measurement of the prestress force have recently been developed to maintain PSC structures throughout their lifetime. However, the smart strand cannot give a representative indication of the whole prestress force when used in multi-strand systems since each strand sustains a different prestress force. In this paper, the actual distribution of the prestress force in a multi-strand system is examined using elastomagnetic (EM sensors to develop a method for tracking representative indicators of the prestress force using smart strands.

Estimation of Prestress Force Distribution in the Multi-Strand System of Prestressed Concrete Structures.

Science.gov (United States)

Cho, Keunhee; Park, Sung Yong; Cho, Jeong-Rae; Kim, Sung Tae; Park, Young-Hwan

2015-06-15

Prestressed concrete (PSC) is one of the most reliable, durable and widely used construction materials, which overcomes the weakness of concrete in tension by the introduction of a prestress force. Smart strands enabling measurement of the prestress force have recently been developed to maintain PSC structures throughout their lifetime. However, the smart strand cannot give a representative indication of the whole prestress force when used in multi-strand systems since each strand sustains a different prestress force. In this paper, the actual distribution of the prestress force in a multi-strand system is examined using elastomagnetic (EM) sensors to develop a method for tracking representative indicators of the prestress force using smart strands.

78 FR 66384 - Membership of the Merit Systems Protection Board's Performance Review Board

Science.gov (United States)

2013-11-05

... MERIT SYSTEMS PROTECTION BOARD Membership of the Merit Systems Protection Board's Performance Review Board AGENCY: Merit Systems Protection Board. ACTION: Notice. SUMMARY: Notice is hereby given of the members of the Merit Systems Protection Board's Performance Review Board. DATES: November 5, 2013...

DNA strand breakage repair in ataxia telangiectasia fibroblast-like cells

Energy Technology Data Exchange (ETDEWEB)

Vincent, Jr, R A; Sheridan, III, R B; Huang, P C [Johns Hopkins Univ., Baltimore, Md. (USA). Dept. of Environmental and Biophysical Sciences

1975-12-01

Human diploid fibroblast-like cells derived from four patients with the genetic disease ataxia telangiectasia and from two non-mutant donors were examined for the repair of x-ray induced strand breaks in DNA. The ataxia telangiectasia cultures showed no significant differences from the non-mutant cultures in the kinetics and extent of strand repair. This suggests that the increased spontaneous and x-ray induced chromatid aberrations observed in ataxia telangiectasia cells are not caused by a defect in the repair of single strand breaks as might be suspected from a general model of aberration production.

Survey of stranded gas and delivered costs to Europe of selected gas resources

Science.gov (United States)

Attanasi, E.D.; Freeman, P.A.

2011-01-01

Two important trends affecting the expected growth of global gas markets are (1) the shift by many industrialized countries from coal-fired electricity generation to the use of natural gas to generate electricity and (2) the industrialization of the heavily populated Asian countries of India and China. This paper surveys discovered gas in stranded conventional gas accumulations and presents estimates of the cost of developing and producing stranded gas in selected countries. Stranded gas is natural gas in discovered or identified fields that is not currently commercially producible for either physical or economic reasons. Published reserves of gas at the global level do not distinguish between volumes of gas in producing fields and volumes in nonproducing fields. Data on stranded gas reported here-that is the volumes, geographical distribution, and size distributions of stranded gas fields at the country and regional level-are based on the examination of individual-field data and represent a significant improvement in information available to industry and government decision makers. Globally, stranded gas is pervasive, but large volumes in large accumulations are concentrated in only a few areas. The cost component of the paper focuses on stranded conventional gas accumulations in Africa and South America that have the potential to augment supplies to Europe. The methods described for the computation of extraction and transport costs are innovative in that they use information on the sizes and geographical distribution of the identified stranded gas fields. The costs are based on industry data specific to the country and geologic basin where the stranded gas is located. Gas supplies to Europe can be increased significantly at competitive costs by the development of stranded gas. Net extraction costs of producing the identified gas depend critically on the natural-gas-liquids (NGLs) content, the prevailing prices of liquids, the size of the gas accumulation, and the

Viral DNA Replication Orientation and hnRNPs Regulate Transcription of the Human Papillomavirus 18 Late Promoter.

Science.gov (United States)

Wang, Xiaohong; Liu, Haibin; Ge, Hui; Ajiro, Masahiko; Sharma, Nishi R; Meyers, Craig; Morozov, Pavel; Tuschl, Thomas; Klar, Amar; Court, Donald; Zheng, Zhi-Ming

2017-05-30

The life cycle of human papillomaviruses (HPVs) is tightly linked to keratinocyte differentiation. Although expression of viral early genes is initiated immediately upon virus infection of undifferentiated basal cells, viral DNA amplification and late gene expression occur only in the mid to upper strata of the keratinocytes undergoing terminal differentiation. In this report, we show that the relative activity of HPV18 TATA-less late promoter P 811 depends on its orientation relative to that of the origin (Ori) of viral DNA replication and is sensitive to the eukaryotic DNA polymerase inhibitor aphidicolin. Additionally, transfected 70-nucleotide (nt)-long single-strand DNA oligonucleotides that are homologous to the region near Ori induce late promoter activity. We also found that promoter activation in raft cultures leads to production of the late promoter-associated, sense-strand transcription initiation RNAs (tiRNAs) and splice-site small RNAs (spliRNAs). Finally, a cis -acting AAGTATGCA core element that functions as a repressor to the promoter was identified. This element interacts with hnRNP D0B and hnRNP A/B factors. Point mutations in the core prevented binding of hnRNPs and increased the promoter activity. Confirming this result, knocking down the expression of both hnRNPs in keratinocytes led to increased promoter activity. Taking the data together, our study revealed the mechanism of how the HPV18 late promoter is regulated by DNA replication and host factors. IMPORTANCE It has been known for decades that the activity of viral late promoters is associated with viral DNA replication among almost all DNA viruses. However, the mechanism of how DNA replication activates the viral late promoter and what components of the replication machinery are involved remain largely unknown. In this study, we characterized the P 811 promoter region of HPV18 and demonstrated that its activation depends on the orientation of DNA replication. Using single-stranded

Knotting probabilities after a local strand passage in unknotted self-avoiding polygons

International Nuclear Information System (INIS)

Szafron, M L; Soteros, C E

2011-01-01

We investigate, both theoretically and numerically, the knotting probabilities after a local strand passage is performed in an unknotted self-avoiding polygon (SAP) on the simple cubic lattice. In the polygons studied, it is assumed that two polygon segments have already been brought close together for the purpose of performing a strand passage. This restricts the polygons considered to those that contain a specific pattern called Θ at a fixed location; an unknotted polygon containing Θ is called a Θ-SAP. It is proved that the number of n-edge Θ-SAPs grows exponentially (with n) at the same rate as the total number of n-edge unknotted SAPs (those with no prespecified strand passage structure). Furthermore, it is proved that the same holds for subsets of n-edge Θ-SAPs that yield a specific after-strand-passage knot-type. Thus, the probability of a given after-strand-passage knot-type does not grow (or decay) exponentially with n. Instead, it is conjectured that these after-strand-passage knot probabilities approach, as n goes to infinity, knot-type dependent amplitude ratios lying strictly between 0 and 1. This conjecture is supported by numerical evidence from Monte Carlo data generated using a composite (aka multiple) Markov chain Monte Carlo BFACF algorithm developed to study Θ-SAPs. A new maximum likelihood method is used to estimate the critical exponents relevant to this conjecture. We also obtain strong numerical evidence that the after-strand-passage knotting probability depends on the local structure around the strand-passage site. If the local structure and the crossing sign at the strand-passage site are considered, then we observe that the more 'compact' the local structure, the less likely the after-strand-passage polygon is to be knotted. This trend for compactness versus knotting probability is consistent with results obtained for other strand-passage models; however, we are the first to note the influence of the crossing-sign information. We

75 FR 62820 - Screening Framework Guidance for Providers of Synthetic Double-Stranded DNA

Science.gov (United States)

2010-10-13

... Providers of Synthetic Double- Stranded DNA AGENCY: Department of Health and Human Services, Office of the.... Government has developed Guidance that provides a framework for screening synthetic double-stranded DNA (dsDNA). This document, the Screening Framework Guidance for Providers of Synthetic Double-Stranded DNA...

Stress-rupture lifetimes of organic fiber-epoxy strands and pressure vessels

International Nuclear Information System (INIS)

Hahn, H.T.; Chiu, I.L.; Gates, T.L.

1979-01-01

Long-term behavior of filament-wound pressure vessels were tested, Kevlar 49 epoxy strands were studied in stress-rupture for more than a year. Because the strands are the smallest structural unit in filament winding, their behavior directly controls the performance of vessels. Five different stress levels were studied: 86, 80, 74, 68, and 50% of the mean ultimate tensile strength (UTS). At each stress level, approximately one-hundred strands were hung in a room maintained at 22 to 24 0 C and below 20% relative humidity. Failure times were automatically recorded by a data acquisition system. Lifetimes were analyzed statistically using a two-parameter Weibull distribution. The maximum-likelihood method was used to estimate the parameters. The shape parameter, which is a measure of scatter and failure-rate change, increased with decreasing stress level. Less scatter and increasing failure rates were observed at lower stresses. There was no sign of an endurance limit down to 68% UTS. At 50% UTS no failure had yet occurred after 9000 h. The strand data were compared with data on lifetimes of pressure vessels wound with the same fiber and epoxy. The strands had slightly longer characteristic lifetimes, except at 86% UTS, and slightly less scatter, except at 68% UTS. The results of this study indicate that strands can provide valuable information about the long-term performance of filament-wound pressure vessels

DNA with Parallel Strand Orientation: A Nanometer Distance Study with Spin Labels in the Watson-Crick and the Reverse Watson-Crick Double Helix.

Science.gov (United States)

Wunnicke, Dorith; Ding, Ping; Yang, Haozhe; Seela, Frank; Steinhoff, Heinz-Jürgen

2015-10-29

Parallel-stranded (ps) DNA characterized by its sugar-phosphate backbones pointing in the same direction represents an alternative pairing system to antiparallel-stranded (aps) DNA with the potential to inhibit transcription and translation. 25-mer oligonucleotides were selected containing only dA·dT base pairs to compare spin-labeled nucleobase distances over a range of 10 or 15 base pairs in ps DNA with those in aps DNA. By means of the copper(I)-catalyzed Huisgen-Meldal-Sharpless alkyne-azide cycloaddition, the spin label 4-azido-2,2,6,6-tetramethylpiperidine-1-oxyl was clicked to 7-ethynyl-7-deaza-2'-deoxyadenosine or 5-ethynyl-2'-deoxyuridine to yield 25-mer oligonucleotides incorporating two spin labels. The interspin distances between spin labeled residues were determined by pulse EPR spectroscopy. The results reveal that in ps DNA these distances are between 5 and 10% longer than in aps DNA when the labeled DNA segment is located near the center of the double helix. The interspin distance in ps DNA becomes shorter compared with aps DNA when one of the spin labels occupies a position near the end of the double helix.

Transformation of Saccharomyces cerevisiae with UV-irradiated single-stranded plasmid.

Science.gov (United States)

Zgaga, Z

1991-08-01

UV-irradiated single-stranded replicative plasmids were used to transform different yeast strains. The low doses of UV used in this study (10-75 J/m2) caused a significant decrease in the transforming efficiency of plasmid DNA in the Rad+ strain, while they had no effect on transformation with double-stranded plasmids of comparable size. Neither the rev3 mutation, nor the rad18 or rad52 mutations influenced the efficiency of transformation with irradiated single-stranded plasmid. However, it was found to be decreased in the double rev3 rad52 mutant. Extracellular irradiation of plasmid that contains both URA3 and LEU2 genes (psLU) gave rise to up to 5% Leu- transformants among selected Ura+ ones in the repair-proficient strain. Induction of Leu- transformants was dose-dependent and only partially depressed in the rev3 mutant. These results suggest that both mutagenic and recombinational repair processes operate on UV-damaged single-stranded DNA in yeast.

Hospital board effectiveness: relationships between board training and hospital financial viability.

Science.gov (United States)

Molinari, C; Morlock, L; Alexander, J; Lyles, C A

1992-01-01

This study examined whether hospital governing boards that invest in board education and training are more informed and effective decision-making bodies. Measures of hospital financial viability (i.e., selected financial ratios and outcomes) are used as indicators of hospital board effectiveness. Board participation in educational programs was significantly associated with improved profitability, liquidity, and occupancy levels, suggesting that investment in the education of directors is likely to enhance hospital viability and thus increase board effectiveness.

Metallographic autopsies of full-scale ITER prototype cable-in-conduit conductors after full cyclic testing in SULTAN: II. Significant reduction of strand movement and strand damage in short twist pitch CICCs

International Nuclear Information System (INIS)

Sanabria, Carlos; Lee, Peter J; Starch, William; Larbalestier, David C; Devred, Arnaud

2015-01-01

Prototype cable-in-conduit-conductors (CICCs) destined for use in the toroidal field and central solenoid coils of the ITER experimental fusion reactor underwent severe cyclic loading in the SULTAN facility. Their autopsies revealed significant and permanent transverse strand migration due to the large Lorentz forces of the SULTAN test. The movement resulted in a 3%–7% void fraction increase on the low pressure (LP) side of the longer twist pitch CICCs. However, short twist pitch conductors exhibited less than 1% void fraction increase in the LP side, as well as a complete absence of the Nb 3 Sn filament fractures observed in the longer twist pitch conductors. We report here a detailed strand-to-cable analysis of short and longer ‘baseline’ twist pitch CICCs. It was found that the use of internal tin (IT) strands in the longer ‘baseline’ twist pitch CICCs can be beneficial possibly because of their superior stiffness—which better resist strand movement—while the use of bronze process strands showed more movement and poorer cyclic test performance. This was not the case for the short twist pitch CICC. Such conductor design seems to work well with both strand types. But it was found that despite the absence of filament fractures, the short twist pitch CICC made from the IT strands studied here developed severe strand distortion during cabling which resulted in diffusion barrier breaks and Sn contamination of the Cu stabilizer during the heat treatment. Conversely, the short twist pitch CICC made from bronze process strands preserved diffusion barrier integrity. (paper)

Late Quaternary slip history of the Mill Creek strand of the San Andreas fault in San Gorgonio Pass, southern California: The role of a subsidiary left-lateral fault in strand switching

Science.gov (United States)

Kendrick, Katherine J.; Matti, Jonathan; Mahan, Shannon

2015-01-01

The fault history of the Mill Creek strand of the San Andreas fault (SAF) in the San Gorgonio Pass region, along with the reconstructed geomorphology surrounding this fault strand, reveals the important role of the left-lateral Pinto Mountain fault in the regional fault strand switching. The Mill Creek strand has 7.1–8.7 km total slip. Following this displacement, the Pinto Mountain fault offset the Mill Creek strand 1–1.25 km, as SAF slip transferred to the San Bernardino, Banning, and Garnet Hill strands. An alluvial complex within the Mission Creek watershed can be linked to palinspastic reconstruction of drainage segments to constrain slip history of the Mill Creek strand. We investigated surface remnants through detailed geologic mapping, morphometric and stratigraphic analysis, geochronology, and pedogenic analysis. The degree of soil development constrains the duration of surface stability when correlated to other regional, independently dated pedons. This correlation indicates that the oldest surfaces are significantly older than 500 ka. Luminescence dates of 106 ka and 95 ka from (respectively) 5 and 4 m beneath a younger fan surface are consistent with age estimates based on soil-profile development. Offset of the Mill Creek strand by the Pinto Mountain fault suggests a short-term slip rate of ∼10–12.5 mm/yr for the Pinto Mountain fault, and a lower long-term slip rate. Uplift of the Yucaipa Ridge block during the period of Mill Creek strand activity is consistent with thermochronologic modeled uplift estimates.

Workshop on effects of chromium coating on Nb3Sn superconductor strand: Proceedings

International Nuclear Information System (INIS)

1994-01-01

This report discusses the following topics: Chromium coating on superconductor strand -- an overview; technology of chromium plating; comparison of wires plated by different platers; search for chromium in copper; strand manufactures' presentations; chromium plating at the Lawrence Livermore National Laboratory; a first look at a chromium plating process development project tailored for T.P.X. and I.T.E.R. strand; and influence of chromium diffusion and related phenomena on the reference ratios of bare and chromium plated Nb 3 Sn strand

Tolerance of DNA Mismatches in Dmc1 Recombinase-mediated DNA Strand Exchange.

Science.gov (United States)

Borgogno, María V; Monti, Mariela R; Zhao, Weixing; Sung, Patrick; Argaraña, Carlos E; Pezza, Roberto J

2016-03-04

Recombination between homologous chromosomes is required for the faithful meiotic segregation of chromosomes and leads to the generation of genetic diversity. The conserved meiosis-specific Dmc1 recombinase catalyzes homologous recombination triggered by DNA double strand breaks through the exchange of parental DNA sequences. Although providing an efficient rate of DNA strand exchange between polymorphic alleles, Dmc1 must also guard against recombination between divergent sequences. How DNA mismatches affect Dmc1-mediated DNA strand exchange is not understood. We have used fluorescence resonance energy transfer to study the mechanism of Dmc1-mediated strand exchange between DNA oligonucleotides with different degrees of heterology. The efficiency of strand exchange is highly sensitive to the location, type, and distribution of mismatches. Mismatches near the 3' end of the initiating DNA strand have a small effect, whereas most mismatches near the 5' end impede strand exchange dramatically. The Hop2-Mnd1 protein complex stimulates Dmc1-catalyzed strand exchange on homologous DNA or containing a single mismatch. We observed that Dmc1 can reject divergent DNA sequences while bypassing a few mismatches in the DNA sequence. Our findings have important implications in understanding meiotic recombination. First, Dmc1 acts as an initial barrier for heterologous recombination, with the mismatch repair system providing a second level of proofreading, to ensure that ectopic sequences are not recombined. Second, Dmc1 stepping over infrequent mismatches is likely critical for allowing recombination between the polymorphic sequences of homologous chromosomes, thus contributing to gene conversion and genetic diversity. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Performance of Nb3Sn RRP strands and cables based on a 108/127 stack design

International Nuclear Information System (INIS)

Barzi, E.; Ambrosio, G.; Andreev, N.; Bossert, R.; Carcagno, R.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.; Pishalnikov, Y.; Sylvester, C.; Tartaglia, M.; Turrioni, D.; Yamada, R.; Zlobin, A.V.; Field, M.; Hong, S.; Parrell, J.; Zhang, Y.

2006-01-01

The high performance Nb 3 Sn strand produced by Oxford Superconducting Technology (OST) with the Restack Rod Process (RRP) is presently considered as a baseline conductor for the Fermilab's accelerator magnet R and D program. To improve the strand stability in the current and field range expected in magnet models, the number of subelements in the strand was increased by a factor of two (from 54 to 108), which resulted in a smaller effective filament size. The performance of the 1.0 and 0.7 mm strands of this design was studied using virgin and deformed strand samples. 27-strand Rutherford cables made of 1 mm strand were also tested using a superconducting transformer, small racetrack and 1-m shell-type dipole coils. This paper presents the RRP strand and cable parameters, and reports the results of strand, cable and coil testing

Orientation of coronal bright points and small-scale magnetic bipoles

International Nuclear Information System (INIS)

MINENKO, E.P.; SHERDANOV, CH.T.; SATTAROV, I.; KARACHIK, N.V.

2014-01-01

Using the observations from Extreme-Ultraviolet Imaging Telescope (EIT) on the SOHO board and longitudinal full-disk magnetograms (vector spectromagnetograph - VSM) from the Synoptic Optical Long-Term Investigations of the Sun (SOLIS), we explore the orientation and relationship between the coronal bright points at 195 A o (hereafter CBPs) and magnetic bipoles (only for the central zone of solar disk). The magnetic bipoles are identified as a pair of streams of positive and negative polarities with a shortest distance between them. This paper presents a study of the structure and orientation (angles) of magnetic bipoles to the solar equator and two types of CBPs: 'dim' CBPs in the quiet regions of the Sun and 'bright' CBPs associated with active regions. For these magnetic bipoles associated with 'bright' CBPs, we find that their orientation angles are distributed randomly along the equator. (authors)

Strand-Specific Analysis of DNA Synthesis and Proteins Association with DNA Replication Forks in Budding Yeast.

Science.gov (United States)

Yu, Chuanhe; Gan, Haiyun; Zhang, Zhiguo

2018-01-01

DNA replication initiates at DNA replication origins after unwinding of double-strand DNA(dsDNA) by replicative helicase to generate single-stranded DNA (ssDNA) templates for the continuous synthesis of leading-strand and the discontinuous synthesis of lagging-strand. Therefore, methods capable of detecting strand-specific information will likely yield insight into the association of proteins at leading and lagging strand of DNA replication forks and the regulation of leading and lagging strand synthesis during DNA replication. The enrichment and Sequencing of Protein-Associated Nascent DNA (eSPAN), which measure the relative amounts of proteins at nascent leading and lagging strands of DNA replication forks, is a step-wise procedure involving the chromatin immunoprecipitation (ChIP) of a protein of interest followed by the enrichment of protein-associated nascent DNA through BrdU immunoprecipitation. The isolated ssDNA is then subjected to strand-specific sequencing. This method can detect whether a protein is enriched at leading or lagging strand of DNA replication forks. In addition to eSPAN, two other strand-specific methods, (ChIP-ssSeq), which detects potential protein-ssDNA binding and BrdU-IP-ssSeq, which can measure synthesis of both leading and lagging strand, were developed along the way. These methods can provide strand-specific and complementary information about the association of the target protein with DNA replication forks as well as synthesis of leading and lagging strands genome wide. Below, we describe the detailed eSPAN, ChIP-ssSeq, and BrdU-IP-ssSeq protocols.

Stranding of two sperm whales (Physeter macrocephalus) in the "North Sea trap" at Henne Strand, Denmark

DEFF Research Database (Denmark)

Hansen, Mette Sif; Alstrup, Aage K. O.; Hansen, Jørgen H.

2016-01-01

In February 2014 two male sperm whales (Physeter macrocephalus) stranded at Henne Strand, Denmark. One whale (MCE 1644) was found dead, while the other (MCE 1645) was still alive, but drowned during the high tide. To increase our knowledge of sperm whales, conduct forage investigations, post......-mortem and diagnostic examinations were carried out. The decay of the carcasses progressed quickly. The whales had large (MCE 1644) or moderate (MCE 1645) numbers of squid beaks (Gonatus fabricii) in the stomachventricles, but no evidence of recentfresh feeding. Both whales had acute dermatitis probably due to trauma...... severe localized or systemic infections. The finding of large volumes of bloody pleural fluid with large quantities of C. septicum suggests that MCE 1644 died of infection. However, reservations must be taken due to the pronounced decay of the carcass. Sperm whales have strong social bonds where...

Coronavirus minus-strand RNA synthesis and effect of cycloheximide on coronavirus RNA synthesis

International Nuclear Information System (INIS)

Sawicki, S.G.; Sawicki, D.L.

1986-01-01

The temporal sequence of coronavirus plus-strand and minus-strand RNA synthesis was determined in 17CL1 cells infected with the A59 strain of mouse hepatitis virus (MHV). MHV-induced fusion was prevented by keeping the pH of the medium below pH 6.8. This had no effect on the MHV replication cycle, but gave 5- to 10-fold-greater titers of infectious virus and delayed the detachment of cells from the monolayer which permitted viral RNA synthesis to be studied conveniently until at least 10 h postinfection. Seven species of poly(A)-containing viral RNAs were synthesized at early and late times infection, in nonequal but constant ratios. MHV minus-strand RNA synthesis was first detected at about 3 h after infection and was found exclusively in the viral replicative intermediates and was not detected in 60S single-stranded form in infected cells. Early in the replication cycle, from 45 to 65% of the [ 3 H]uridine pulse-labeled RF core of purified MHV replicative intermediates was in minus-strand RNA. The rate of minus-strand synthesis peaked at 5 to 6 h postinfection and then declined to about 20% of the maximum rate. The addition of cycloheximide before 3 h postinfection prevented viral RNA synthesis, whereas the addition of cycloheximide after viral RNA synthesis had begun resulted in the inhibition of viral RNA synthesis. The synthesis of both genome and subgenomic mRNAs and of viral minus strands required continued protein synthesis, and minis-strand RNA synthesis was three- to fourfold more sensitive to inhibition of cycloheximide than was plus-strand synthesis

Strand critical current degradation in $Nb_{3}$ Sn Rutherford cables

CERN Document Server

Barzi, E; Higley, H C; Scanlan, R M; Yamada, R; Zlobin, A V

2001-01-01

Fermilab is developing 11 Tesla superconducting accelerator magnets based on Nb/sub 3/Sn superconductor. Multifilamentary Nb/sub 3/Sn strands produced using the modified jelly roll, internal tin, and powder-in-tube technologies were used for the development and test of the prototype cable. To optimize the cable geometry with respect to the critical current, short samples of Rutherford cable with packing factors in the 85 to 95% range were fabricated and studied. In this paper, the results of measurements of critical current, n-value and RRR made on the round virgin strands and on the strands extracted from the cable samples are presented. (5 refs).

Performance of Nb3Sn RRP strands and cables based on a 108/127 stack design

Energy Technology Data Exchange (ETDEWEB)

Barzi, E.; Ambrosio, G.; Andreev, N.; Bossert, R.; Carcagno, R.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.; /Fermilab /Oxford Supercond. Tech., Carteret

2006-08-01

The high performance Nb{sub 3}Sn strand produced by Oxford Superconducting Technology (OST) with the Restack Rod Process (RRP) is presently considered as a baseline conductor for the Fermilab's accelerator magnet R&D program. To improve the strand stability in the current and field range expected in magnet models, the number of subelements in the strand was increased by a factor of two (from 54 to 108), which resulted in a smaller effective filament size. The performance of the 1.0 and 0.7 mm strands of this design was studied using virgin and deformed strand samples. 27-strand Rutherford cables made of 1 mm strand were also tested using a superconducting transformer, small racetrack and 1-m shell-type dipole coils. This paper presents the RRP strand and cable parameters, and reports the results of strand, cable and coil testing.

Engineering Assessment of Big House at Summit Station, Greenland

Science.gov (United States)

2011-04-01

exterior consisted of 127-mm structural insulated panels (SIP), with 12.7- mm stressed oriented strand board ( OSB ) skins (CPS 2009b; Tobiasson unpublished...Penetrations Common\\construction\\Big House Penetrations.txt 2009 November 17th Tuesday Walls are 8 in. thick: 5 in. SIP (1/2 in. OSB + 4 in...yellow open cella + 0.5 in. OSB + metal cladding) + 1.5 in. closed(?) cell foamb + 0.5 in. T-1-11. Roof is 9 in. thick: 5 in. SIP + ~3.5 in. foam + 1

De novo-engineered transcription activator-like effector (TALE) hybrid nuclease with novel DNA binding specificity creates double-strand breaks

KAUST Repository

Mahfouz, Magdy M.

2011-01-24

Site-specific and rare cutting nucleases are valuable tools for genome engineering. The generation of double-strand DNA breaks (DSBs) promotes homologous recombination in eukaryotes and can facilitate gene targeting, additions, deletions, and inactivation. Zinc finger nucleases have been used to generate DSBs and subsequently, for genome editing but with low efficiency and reproducibility. The transcription activator-like family of type III effectors (TALEs) contains a central domain of tandem repeats that could be engineered to bind specific DNA targets. Here, we report the generation of a Hax3-based hybrid TALE nuclease with a user-selected DNA binding specificity. We show that the engineered TALE nuclease can bind to its target sequence in vitro and that the homodimeric TALE nuclease can cleave double-stranded DNA in vitro if the DNA binding sites have the proper spacing and orientation. Transient expression assays in tobacco leaves suggest that the hybrid nuclease creates DSB in its target sequence, which is subsequently repaired by nonhomologous end-joining repair. Taken together, our data show the feasibility of engineering TALE-based hybrid nucleases capable of generating site-specific DSBs and the great potential for site-specific genome modification in plants and eukaryotes in general.

Induction and repair of double- and single-strand DNA breaks in bacteriophage lambda superinfecting Escherichia coli

International Nuclear Information System (INIS)

Boye, E.; Krisch, R.E.

1980-01-01

Induction and repair of double-and single-strand DNA breaks have been measured after decays of 125 I and 3 H incorporated into the DNA and after external irradiation with 4 MeV electrons. For the decay experiments, cells of wild type Escherichia coli K-12 were superinfected with bacteriophage lambda DNA labelled with 5'-( 125 I)iodo-2'-deoxyuridine or with (methyl- 3 H)thymidine and frozen in liquid nitrogen. Aliquots were thawed at intervals and lysed at neutral pH, and the phage DNA was assayed for double- and single-strand breakage by neutral sucrose gradient centrifugation. The gradients used allowed measurements of both kinds of breaks in the same gradient. Decays of 125 I induced 0.39 single-strand breaks per double-strand break. No repair of either break type could be detected. Each 3 H disintegration caused 0.20 single-strand breaks and very few double-strand breaks. The single-strand breaks were rapidly rejoined after the cells were thawed. For irradiation with 4 MeV electrons, cells of wild type E. coli K-12 were superinfected with phage lambda and suspended in growth medium. Irradiation induced 42 single-strand breaks per double-strand break. The rates of break induction were 6.75 x 10 -14 (double-strand breaks) and 2.82 x 10 -12 (single-strand breaks) per rad and per dalton. The single-strand breaks were rapidly repaired upon incubation whereas the double-strand breaks seemed to remain unrepaired. It is concluded that double-strand breaks in superinfecting bacteriophage lambda DNA are repaired to a very small extent, if at all. (Author)

Mammalian DNA single-strand break repair: an X-ra(y)ted affair.

Science.gov (United States)

Caldecott, K W

2001-05-01

The genetic stability of living cells is continuously threatened by the presence of endogenous reactive oxygen species and other genotoxic molecules. Of particular threat are the thousands of DNA single-strand breaks that arise in each cell, each day, both directly from disintegration of damaged sugars and indirectly from the excision repair of damaged bases. If un-repaired, single-strand breaks can be converted into double-strand breaks during DNA replication, potentially resulting in chromosomal rearrangement and genetic deletion. Consequently, cells have adopted multiple pathways to ensure the rapid and efficient removal of single-strand breaks. A general feature of these pathways appears to be the extensive employment of protein-protein interactions to stimulate both the individual component steps and the overall repair reaction. Our current understanding of DNA single-strand break repair is discussed, and testable models for the architectural coordination of this important process are presented. Copyright 2001 John Wiley & Sons, Inc.

The Effect of Basepair Mismatch on DNA Strand Displacement

OpenAIRE

Broadwater, D.?W.?Bo; Kim, Harold?D.

2016-01-01

DNA strand displacement is a key reaction in DNA homologous recombination and DNA mismatch repair and is also heavily utilized in DNA-based computation and locomotion. Despite its ubiquity in science and engineering, sequence-dependent effects of displacement kinetics have not been extensively characterized. Here, we measured toehold-mediated strand displacement kinetics using single-molecule fluorescence in the presence of a single base pair mismatch. The apparent displacement rate varied si...

Repair and gamma radiation-induced single- and double-strand breaks in DNA of Escherichia coli

International Nuclear Information System (INIS)

Petrov, S.I.

1981-01-01

Studies in the kinetics of repair of γ-radiation-induced single- and double-strand breaks in DNA of E. coli cells showed that double-strand DNA breaks are rejoined by the following two ways. The first way is conditioned by repair of single-strand breaks and represents the repair of ''oblique'' double-strand breaks in DNA, whereas the second way is conditioned by functioning of the recombination mechanisms and, to all appearance, represents the repair of ''direct'' double-strand breaks in DNA

Interstrand cross-links arising from strand breaks at true abasic sites in duplex DNA

Science.gov (United States)

Yang, Zhiyu; Price, Nathan E.; Johnson, Kevin M.

2017-01-01

Abstract Interstrand cross-links are exceptionally bioactive DNA lesions. Endogenous generation of interstrand cross-links in genomic DNA may contribute to aging, neurodegeneration, and cancer. Abasic (Ap) sites are common lesions in genomic DNA that readily undergo spontaneous and amine-catalyzed strand cleavage reactions that generate a 2,3-didehydro-2,3-dideoxyribose sugar remnant (3’ddR5p) at the 3’-terminus of the strand break. Interestingly, this strand scission process leaves an electrophilic α,β-unsaturated aldehyde residue embedded within the resulting nicked duplex. Here we present evidence that 3’ddR5p derivatives generated by spermine-catalyzed strand cleavage at Ap sites in duplex DNA can react with adenine residues on the opposing strand to generate a complex lesion consisting of an interstrand cross-link adjacent to a strand break. The cross-link blocks DNA replication by ϕ29 DNA polymerase, a highly processive polymerase enzyme that couples synthesis with strand displacement. This suggests that 3’ddR5p-derived cross-links have the potential to block critical cellular DNA transactions that require strand separation. LC-MS/MS methods developed herein provide powerful tools for studying the occurrence and properties of these cross-links in biochemical and biological systems. PMID:28531327

The dBoard: a Digital Scrum Board for Distributed Software Development

DEFF Research Database (Denmark)

Esbensen, Morten; Tell, Paolo; Cholewa, Jacob Benjamin

2015-01-01

In this paper we present the dBoard - a digital Scrum Board for distributed Agile software development teams. The dBoard is designed as a 'virtual window' between two Scrum team spaces. It connects two locations with live video and audio, which is overlaid with a synchronized and interactive...... digital Scrum board, and it adapts the fidelity of the video/audio to the presence of people in front of it. The dBoard is designed to work (i) as a passive information radiator from which it is easy to get an overview of the status of work, (ii) as a media space providing awareness about the presence...... of remote co-workers, and (iii) as an active meeting support tool. The paper presents a case study of distributed Scrum in a large software company that motivates the design of the dBoard, and details the design and technical implementation of the dBoard. The paper also reports on an initial user study...

Magnetization, Low Field Instability and Quench of RHQT Nb(3)Al Strands

Energy Technology Data Exchange (ETDEWEB)

Yamada, R.; Wake, M.; Kikuchi, A.; Velev, V.; /Fermilab

2009-01-01

Since 2005, we made and tested three RHQT Nb{sub 3}Al strands, one with Nb matrix and two with Ta matrix, which are fully stabilized with Cu electroplating. We observed anomalously large magnetization curves extending beyond 1 to 1.5 Tesla with the F1 Nb matrix strand at 4.2 K, when we measured its magnetization with a balanced coil magnetometer. This problem was eliminated with the Ta matrix strands operating at 4.2 K. But with these strands a similar but smaller anomalous magnetization was observed at 1.9 K. We studied these phenomena with FEM. With the F1 Nb matrix strand, it is explained that at low external field, inter-filamentary coupling currents in the outer layers of sub-elements create a shielding effect. It reduces the inside field, keeps the inside Nb matrix superconductive, and stands against a higher outside field beyond the Hc of Nb. At an even higher external field, the superconductivity of the whole Nb matrix collapses and releases a large amount of energy, which may cause a big quench. Depending on the size of the energy in the strand or the cable, a magnet could quench, causing the low field instability. Some attempt to analyze the anomaly with FEM is presented.

Development of Nb3Sn strands for ITER in Japan

International Nuclear Information System (INIS)

Isono, T.; Nunoya, Y.; Matsui, K.; Nabara, Y.; Koizumi, N.; Takahashi, Y.; Okuno, K.

2007-01-01

Nb 3 Sn strands for ITER Toroidal Field (TF) coils and Central Solenoids (CS) are required to have both high current density (Jc) and low hysteresis loss. The required Jc at 12 T, 4.2 K and no external strain is lager than 700 A/mm 2 for bronze processed strand and lager than 800 A/mm 2 for internal tin processed one at 12 T, 4.2 K and no external strain. Upper limit of hysteresis loss is 1,000 mJ/cm 3 at 4.2 K and a cycle of ±3 T. Outer diameter is 0.82 mm and 0.83 mm for TF coils and CS, respectively. Area ratio of copper to non copper is one and outer surface is Cr plated. Japan will procure 25% of Nb 3 Sn for ITER TF coils and 100% for ITER CS. There are four Nb 3 Sn strand suppliers in Japan; three of them use bronze process and the other uses internal tin process. For bronze processed strand, increase Jc was achieved by using bronze with high tin content of 15 to 16%. To keep productivity while using the harder bronze with high tin content, Nb is used for barrier in place of Ta. The material is expected to have better adhesion to other materials such as bronze and copper. For internal tin process, size of modules, each of which has a tin rod and a lot of Nb filaments embedded in a copper cylinder, is reduced, while total amount of tin increase in order to satisfy both required high Jc and low hysteresis loss. Each supplier fabricated a strand of more than 0.1 ton for TF coils and succeeded to develop a strand satisfying the ITER requirements of Jc and hysteresis loss. (authors)

Influence of DNA conformation on radiation-induced single-strand breaks

International Nuclear Information System (INIS)

Barone, F.; Belli, M.; Mazzei, F.

1994-01-01

We performed experiments on two DNA fragments of about 300 bp having different conformation to test whether radiation-induced single-strand breakage is dependent on DNA conformation. Breakage analysis was carried out by denaturing polyacrylamide gel electrophoresis, which allows determination of the broken site at single nucleotide resolution. We found uniform cutting patterns in B-form regions. On the contrary, X- or γ-irradiation of curved fragments of kinetoplast DNA showed that the distribution of single-strand breaks was not uniform along the fragment, as the cleavage pattern was modulated in phase with the runs of A-T pairs. This modulation likely reflected the reduced accessibility of the sites which on hydroxyl-radical attack give rise to strand breaks. The cleavage pattern was phased with the runs of A-T pairs. Moreover, the overall yield of strand breaks was considerably lower in curved DNA fragments than in those with extended straight regions. The conformation effect found here indicates that the cleavage pattern reflects the fine structural features of DNA. (orig./MG)

Offshore Earthquakes Do Not Influence Marine Mammal Stranding Risk on the Washington and Oregon Coasts

Science.gov (United States)

Grant, Rachel A.; Savirina, Anna

2018-01-01

Simple Summary Marine mammals stranding on coastal beaches is not unusual. However, there appears to be no single cause for this, with several causes being probable, such as starvation, contact with humans (for example boat strike or entanglement with fishing gear), disease, and parasitism. We evaluated marine mammal stranding off the Washington and Oregon coasts and looked at offshore earthquakes as a possible contributing factor. Our analysis showed that offshore earthquakes did not make marine mammals more likely to strand. We also analysed a subset of data from the north of Washington State and found that non-adult animals made up a large proportion of stranded animals, and for dead animals the commonest cause of death was disease, traumatic injury, or starvation. Abstract The causes of marine mammals stranding on coastal beaches are not well understood, but may relate to topography, currents, wind, water temperature, disease, toxic algal blooms, and anthropogenic activity. Offshore earthquakes are a source of intense sound and disturbance and could be a contributing factor to stranding probability. We tested the hypothesis that the probability of marine mammal stranding events on the coasts of Washington and Oregon, USA is increased by the occurrence of offshore earthquakes in the nearby Cascadia subduction zone. The analysis carried out here indicated that earthquakes are at most, a very minor predictor of either single, or large (six or more animals) stranding events, at least for the study period and location. We also tested whether earthquakes inhibit stranding and again, there was no link. Although we did not find a substantial association of earthquakes with strandings in this study, it is likely that there are many factors influencing stranding of marine mammals and a single cause is unlikely to be responsible. Analysis of a subset of data for which detailed descriptions were available showed that most live stranded animals were pups, calves, or

Investigations of radiation-induced strand breaks of poly(U) in aqueous solutions

International Nuclear Information System (INIS)

Lemaire, D.G.E.

1984-01-01

DNA strand breaks induced by γ irradiation were studied in polyuridylic acid (Poly(U)), a single-strand model substance with a single base. Poly(U) in diluted, aqueous solution was irradiated in a Co-γ source, and the 100 eV yields of strand breaks (Cr values) were determined on the basis of the loss of molecular weight. The molecular weight was determined by small-angle laser light scattering. (orig./PW) [de

Electron attachment to DNA single strands: gas phase and aqueous solution.

Science.gov (United States)

Gu, Jiande; Xie, Yaoming; Schaefer, Henry F

2007-01-01

The 2'-deoxyguanosine-3',5'-diphosphate, 2'-deoxyadenosine-3',5'-diphosphate, 2'-deoxycytidine-3',5'-diphosphate and 2'-deoxythymidine-3',5'-diphosphate systems are the smallest units of a DNA single strand. Exploring these comprehensive subunits with reliable density functional methods enables one to approach reasonable predictions of the properties of DNA single strands. With these models, DNA single strands are found to have a strong tendency to capture low-energy electrons. The vertical attachment energies (VEAs) predicted for 3',5'-dTDP (0.17 eV) and 3',5'-dGDP (0.14 eV) indicate that both the thymine-rich and the guanine-rich DNA single strands have the ability to capture electrons. The adiabatic electron affinities (AEAs) of the nucleotides considered here range from 0.22 to 0.52 eV and follow the order 3',5'-dTDP > 3',5'-dCDP > 3',5'-dGDP > 3',5'-dADP. A substantial increase in the AEA is observed compared to that of the corresponding nucleic acid bases and the corresponding nucleosides. Furthermore, aqueous solution simulations dramatically increase the electron attracting properties of the DNA single strands. The present investigation illustrates that in the gas phase, the excess electron is situated both on the nucleobase and on the phosphate moiety for DNA single strands. However, the distribution of the extra negative charge is uneven. The attached electron favors the base moiety for the pyrimidine, while it prefers the 3'-phosphate subunit for the purine DNA single strands. In contrast, the attached electron is tightly bound to the base fragment for the cytidine, thymidine and adenosine nucleotides, while it almost exclusively resides in the vicinity of the 3'-phosphate group for the guanosine nucleotides due to the solvent effects. The comparatively low vertical detachment energies (VDEs) predicted for 3',5'-dADP(-) (0.26 eV) and 3',5'-dGDP(-) (0.32 eV) indicate that electron detachment might compete with reactions having high activation barriers

Utility of ck metrics in predicting size of board-based software games

International Nuclear Information System (INIS)

Sabhat, N.; Azam, F.; Malik, A.A.

2017-01-01

Software size is one of the most important inputs of many software cost and effort estimation models. Early estimation of software plays an important role at the time of project inception. An accurate estimate of software size is, therefore, crucial for planning, managing, and controlling software development projects dealing with the development of software games. However, software size is unavailable during early phase of software development. This research determines the utility of CK (Chidamber and Kemerer) metrics, a well-known suite of object-oriented metrics, in estimating the size of software applications using the information from its UML (Unified Modeling Language) class diagram. This work focuses on a small subset dealing with board-based software games. Almost sixty games written using an object-oriented programming language are downloaded from open source repositories, analyzed and used to calibrate a regression-based size estimation model. Forward stepwise MLR (Multiple Linear Regression) is used for model fitting. The model thus obtained is assessed using a variety of accuracy measures such as MMRE (Mean Magnitude of Relative Error), Prediction of x(PRED(x)), MdMRE (Median of Relative Error) and validated using K-fold cross validation. The accuracy of this model is also compared with an existing model tailored for size estimation of board games. Based on a small subset of desktop games developed in various object-oriented languages, we obtained a model using CK metrics and forward stepwise multiple linear regression with reasonable estimation accuracy as indicated by the value of the coefficient of determination (R2 = 0.756).Comparison results indicate that the existing size estimation model outperforms the model derived using CK metrics in terms of accuracy of prediction. (author)

Controlled Folding, Motional, and Constitutional Dynamic Processes of Polyheterocyclic Molecular Strands.

Science.gov (United States)

Barboiu, Mihail; Stadler, Adrian-Mihail; Lehn, Jean-Marie

2016-03-18

General design principles have been developed for the control of the structural features of polyheterocyclic strands and their effector-modulated shape changes. Induced defined molecular motions permit designed enforcement of helical as well as linear molecular shapes. The ability of such molecular strands to bind metal cations allows the generation of coiling/uncoiling processes between helically folded and extended linear states. Large molecular motions are produced on coordination of metal ions, which may be made reversible by competition with an ancillary complexing agent and fueled by sequential acid/base neutralization energy. The introduction of hydrazone units into the strands confers upon them constitutional dynamics, whereby interconversion between different strand compositions is achieved through component exchange. These features have relevance for nanomechanical devices. We present a morphological and functional analysis of such systems developed in our laboratories. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enzyme-free colorimetric detection systems based on the DNA strand displacement competition reaction

Science.gov (United States)

Zhang, Z.; Birkedal, V.; Gothelf, K. V.

2016-05-01

The strand displacement competition assay is based on the dynamic equilibrium of the competitive hybridization of two oligonucleotides (A and B) to a third oligonucleotide (S). In the presence of an analyte that binds to a specific affinity-moiety conjugated to strand B, the equilibrium shifts, which can be detected by a shift in the fluorescence resonance energy transfer signal between dyes attached to the DNA strands. In the present study we have integrated an ATP aptamer in the strand B and demonstrated the optical detection of ATP. Furthermore we explore a new readout method using a split G-quadruplex DNAzyme for colorimetric readout of the detection of streptavidin by the naked eye. Finally, we integrate the whole G-quadruplex DNAzyme system in a single DNA strand and show that it is applicable to colorimetric detection.

Enzyme-free colorimetric detection systems based on the DNA strand displacement competition reaction

DEFF Research Database (Denmark)

Zhang, Zhao; Birkedal, Victoria; Gothelf, Kurt Vesterager

2016-01-01

The strand displacement competition assay is based on the dynamic equilibrium of the competitive hybridization of two oligonucleotides (A and B) to a third oligonucleotide (S). In the presence of an analyte that binds to a specific affinity-moiety conjugated to strand B, the equilibrium shifts, w...... G-quadruplex DNAzyme for colorimetric readout of the detection of streptavidin by the naked eye. Finally, we integrate the whole G-quadruplex DNAzyme system in a single DNA strand and show that it is applicable to colorimetric detection......., which can be detected by a shift in the fluorescence resonance energy transfer signal between dyes attached to the DNA strands. In the present study we have integrated an ATP aptamer in the strand B and demonstrated the optical detection of ATP. Furthermore we explore a new readout method using a split...

Board game

International Nuclear Information System (INIS)

Brennan, N.S.

1982-01-01

A board game comprises a board, a number of counters and two dice. The board is marked to provide a central area, representing the nucleus of an atom, and six or more annular rings extending concentrically around the central area, the rings being divided into 2,8,18,32,48 and 72 squares. Each ring represents an electron shell, and some of the squares are numbered, the number representing the atomic number of different elements. (author)

Interstrand cross-links arising from strand breaks at true abasic sites in duplex DNA.

Science.gov (United States)

Yang, Zhiyu; Price, Nathan E; Johnson, Kevin M; Wang, Yinsheng; Gates, Kent S

2017-06-20

Interstrand cross-links are exceptionally bioactive DNA lesions. Endogenous generation of interstrand cross-links in genomic DNA may contribute to aging, neurodegeneration, and cancer. Abasic (Ap) sites are common lesions in genomic DNA that readily undergo spontaneous and amine-catalyzed strand cleavage reactions that generate a 2,3-didehydro-2,3-dideoxyribose sugar remnant (3'ddR5p) at the 3'-terminus of the strand break. Interestingly, this strand scission process leaves an electrophilic α,β-unsaturated aldehyde residue embedded within the resulting nicked duplex. Here we present evidence that 3'ddR5p derivatives generated by spermine-catalyzed strand cleavage at Ap sites in duplex DNA can react with adenine residues on the opposing strand to generate a complex lesion consisting of an interstrand cross-link adjacent to a strand break. The cross-link blocks DNA replication by ϕ29 DNA polymerase, a highly processive polymerase enzyme that couples synthesis with strand displacement. This suggests that 3'ddR5p-derived cross-links have the potential to block critical cellular DNA transactions that require strand separation. LC-MS/MS methods developed herein provide powerful tools for studying the occurrence and properties of these cross-links in biochemical and biological systems. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Development of an Adjustable board and a Rotational Board for Scaffold

Science.gov (United States)

Jang, Myunghoun

2017-06-01

Scaffold is widely used in high work-places inside and outside of a building construction site. It is inexpensive and is installed and dismantled easily. Although standards and ledgers of a steel tube and coupler scaffold are installed in a regular distance, the distances of transoms are not equal in some places. Sometimes a working platform or a board is absent in the corner of scaffold. This may cause safety accidents because a foothold is not stable on the transoms. An adjustable safety board and a rotational safety board are suggested in this paper. The adjustable board consists of two footholds. The small one is inserted into the large one. The rotational board covers not only right angle but also acute or obtuse angles. These safety boards for scaffold help to decrease safety accidents in construction sites.

Critical current scaling and the pivot-point in Nb3Sn strands

International Nuclear Information System (INIS)

Tsui, Y; Hampshire, D P

2012-01-01

Detailed measurements are provided of the engineering critical current density (J c ) and the index of transition (n-value) of two different types of advanced ITER Nb 3 Sn superconducting strand for fusion applications. The samples consist of one internal-tin strand (OST) and two bronze-route strands (BEAS I and BEAS II—reacted using different heat treatments). Tests on different sections of these wires show that prior to applying strain, J c is homogeneous to better than 2% along the length of each strand. J c data have been characterized as a function of magnetic field (B ≤ 14.5 T), temperature (4.2 K ≤ T ≤ 12 K) and applied axial strain ( − 1% ≤ ε A ≤ 0.8%). Strain-cycling tests demonstrate that the variable strain J c data are reversible to better than 2% when the applied axial strain is in the range of − 1% ≤ ε A ≤ 0.5%. The wires are damaged when the intrinsic strain (ε I ) is ε I ≥ 0.55% and ε I ≥ 0.23% for the OST and BEAS strands, respectively. The strain dependences of the normalized J c for each type of strand are similar to those of prototype strands of similar design measured in 2005 and 2008 to about 2% which makes them candidate strands for a round-robin interlaboratory comparison. The J c data are described by Durham, ITER and Josephson-junction parameterizations to an accuracy of about 4%. For all of these scaling laws, the percentage difference between the data and the parameterization is larger when J c is small, caused by high B, T or |ε I |. The n-values can be described by a modified power law of the form n=1+rI c s , where r and s are approximately constant and I c is the critical current. It has long been known that pivot-points (or cross-overs) in J c occur at high magnetic field and temperature. Changing the magnetic field or temperature from one side of the pivot-point to the other changes the highest J c sample to the lowest J c sample and vice versa. The pivot-point follows the B–T phase boundary

DNA Strand Breaks in Mitotic Germ Cells of Caenorhabditis elegans Evaluated by Comet Assay

Science.gov (United States)

Park, Sojin; Choi, Seoyun; Ahn, Byungchan

2016-01-01

DNA damage responses are important for the maintenance of genome stability and the survival of organisms. Such responses are activated in the presence of DNA damage and lead to cell cycle arrest, apoptosis, and DNA repair. In Caenorhabditis elegans, double-strand breaks induced by DNA damaging agents have been detected indirectly by antibodies against DSB recognizing proteins. In this study we used a comet assay to detect DNA strand breaks and to measure the elimination of DNA strand breaks in mitotic germline nuclei of C. elegans. We found that C. elegans brc-1 mutants were more sensitive to ionizing radiation and camptothecin than the N2 wild-type strain and repaired DNA strand breaks less efficiently than N2. This study is the first demonstration of direct measurement of DNA strand breaks in mitotic germline nuclei of C. elegans. This newly developed assay can be applied to detect DNA strand breaks in different C. elegans mutants that are sensitive to DNA damaging agents. PMID:26903030

Breaking DNA strands by extreme-ultraviolet laser pulses in vacuum

Czech Academy of Sciences Publication Activity Database

Nováková, Eva; Vyšín, Luděk; Burian, Tomáš; Juha, Libor; Davídková, Marie; Múčka, V.; Čuba, V.; Grisham, M. E.; Heinbuch, S.; Rocca, J.J.

2015-01-01

Roč. 91, č. 4 (2015), "042718-1"-"042718-8" ISSN 1539-3755 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA ČR GA13-28721S Institutional support: RVO:68378271 ; RVO:61389005 Keywords : XUV * DNA damages * single- strand breaks (SSBs) * double- strand breaks (DSBs) Subject RIV: BO - Biophysics Impact factor: 2.288, year: 2014

Filamentary structure and magnetic field orientation in Musca

Science.gov (United States)

Cox, N. L. J.; Arzoumanian, D.; André, Ph.; Rygl, K. L. J.; Prusti, T.; Men'shchikov, A.; Royer, P.; Kóspál, Á.; Palmeirim, P.; Ribas, A.; Könyves, V.; Bernard, J.-Ph.; Schneider, N.; Bontemps, S.; Merin, B.; Vavrek, R.; Alves de Oliveira, C.; Didelon, P.; Pilbratt, G. L.; Waelkens, C.

2016-05-01

Herschel has shown that filamentary structures are ubiquitous in star-forming regions, in particular in nearby molecular clouds associated with Gould's Belt. High dynamic range far-infrared imaging of the Musca cloud with SPIRE and PACS reveals at least two types of filamentary structures: (1) the main ~10-pc scale high column-density linear filament; and (2) low column-density striations in close proximity to the main filament. In addition, we find features with intermediate column densities (hair-like strands) that appear physically connected to the main filament. We present an analysis of this filamentary network traced by Herschel and explore its connection with the local magnetic field. We find that both the faint dust emission striations and the plane-of-the-sky (POS) magnetic field are locally oriented close to perpendicular to the high-density main filament (position angle ~25-35°). The low-density striations and strands are oriented parallel to the POS magnetic field lines, which are derived previously from optical polarization measurements of background stars and more recently from Planck observations of dust polarized emission. The position angles are 97 ± 25°, 105 ± 7°, and 105 ± 5°. From these observations, we propose a scenario in which local interstellar material in this cloud has condensed into a gravitationally-unstable filament (with "supercritical" mass per unit length) that is accreting background matter along field lines through the striations. We also compare the filamentary structure in Musca with what is seen in similar Herschel observations of the Taurus B211/3 filament system and find that there is significantly less substructure in the Musca main filament than in the B211/3 filament. We suggest that the Musca cloud may represent an earlier evolutionary stage in which the main filament has not yet accreted sufficient mass and energy to develop a multiple system of intertwined filamentary components. Herschel is an ESA space

Design and Characterization of DNA Strand-Displacement Circuits in Serum-Supplemented Cell Medium.

Science.gov (United States)

Fern, Joshua; Schulman, Rebecca

2017-09-15

The functional stability and lifetimes of synthetic molecular circuits in biological environments are important for long-term, stable sensors or controllers of cell or tissue behavior. DNA-based molecular circuits, in particular DNA strand-displacement circuits, provide simple and effective biocompatible control mechanisms and sensors, but are vulnerable to digestion by nucleases present in living tissues and serum-supplemented cell culture. The stability of double-stranded and single-stranded DNA circuit components in serum-supplemented cell medium and the corresponding effect of nuclease-mediated degradation on circuit performance were characterized to determine the major routes of degradation and DNA strand-displacement circuit failure. Simple circuit design choices, such as the use of 5' toeholds within the DNA complexes used as reactants in the strand-displacement reactions and the termination of single-stranded components with DNA hairpin domains at the 3' termini, significantly increase the functional lifetime of the circuit components in the presence of nucleases. Simulations of multireaction circuits, guided by the experimentally measured operation of single-reaction circuits, enable predictive realization of multilayer and competitive-reaction circuit behavior. Together, these results provide a basic route to increased DNA circuit stability in cell culture environments.

Long-Term Seasonal and Interannual Patterns of Marine Mammal Strandings in Subtropical Western South Atlantic

Science.gov (United States)

Prado, Jonatas H. F.; Mattos, Paulo H.; Silva, Kleber G.; Secchi, Eduardo R.

2016-01-01

Understanding temporal patterns of marine mammal occurrence is useful for establishing conservation strategies. We used a 38 yr-long dataset spanning 1976 to 2013 to describe temporal patterns and trends in marine mammal strandings along a subtropical stretch of the east coast of South America. This region is influenced by a transitional zone between tropical and temperate waters and is considered an important fishing ground off Brazil. Generalized Additive Models were used to evaluate the temporal stranding patterns of the most frequently stranded species. Forty species were documented in 12,540 stranding events. Franciscana (n = 4,574), South American fur seal, (n = 3,419), South American sea lion (n = 2,049), bottlenose dolphins (n = 293) and subantarctic fur seal (n = 219) were the most frequently stranded marine mammals. The seasonality of strandings of franciscana and bottlenose dolphin coincided with periods of higher fishing effort and strandings of South American and subantarctic fur seals with post-reproductive dispersal. For South American sea lion the seasonality of strandings is associated with both fishing effort and post-reproductive dispersal. Some clear seasonal patterns were associated with occurrence of cold- (e.g. subantarctic fur seal) and warm-water (e.g. rough-toothed dolphin) species in winter and summer, respectively. Inter-annual increases in stranding rate were observed for franciscana and South American fur seal and these are likely related to increased fishing effort and population growth, respectively. For subantarctic fur seal the stranding rate showed a slight decline while for bottlenose dolphin it remained steady. No significant year to year variation in stranding rate was observed for South American sea lion. The slight decrease in frequency of temperate/polar marine mammals and the increased occurrence of subtropical/tropical species since the late 1990s might be associated with environmental changes linked to climate change

Long-Term Seasonal and Interannual Patterns of Marine Mammal Strandings in Subtropical Western South Atlantic.

Directory of Open Access Journals (Sweden)

Jonatas H F Prado

Full Text Available Understanding temporal patterns of marine mammal occurrence is useful for establishing conservation strategies. We used a 38 yr-long dataset spanning 1976 to 2013 to describe temporal patterns and trends in marine mammal strandings along a subtropical stretch of the east coast of South America. This region is influenced by a transitional zone between tropical and temperate waters and is considered an important fishing ground off Brazil. Generalized Additive Models were used to evaluate the temporal stranding patterns of the most frequently stranded species. Forty species were documented in 12,540 stranding events. Franciscana (n = 4,574, South American fur seal, (n = 3,419, South American sea lion (n = 2,049, bottlenose dolphins (n = 293 and subantarctic fur seal (n = 219 were the most frequently stranded marine mammals. The seasonality of strandings of franciscana and bottlenose dolphin coincided with periods of higher fishing effort and strandings of South American and subantarctic fur seals with post-reproductive dispersal. For South American sea lion the seasonality of strandings is associated with both fishing effort and post-reproductive dispersal. Some clear seasonal patterns were associated with occurrence of cold- (e.g. subantarctic fur seal and warm-water (e.g. rough-toothed dolphin species in winter and summer, respectively. Inter-annual increases in stranding rate were observed for franciscana and South American fur seal and these are likely related to increased fishing effort and population growth, respectively. For subantarctic fur seal the stranding rate showed a slight decline while for bottlenose dolphin it remained steady. No significant year to year variation in stranding rate was observed for South American sea lion. The slight decrease in frequency of temperate/polar marine mammals and the increased occurrence of subtropical/tropical species since the late 1990s might be associated with environmental changes linked to

Necropsy report of a fin whale (Balaenoptera physalus) stranded in Denmark in 2010

DEFF Research Database (Denmark)

Alstrup, Aage K. O.; Hedayat, Abdi; Jensen, Trine Hammer

2013-01-01

There is little detailed information on stranded fin whales (Balaenoptera physalus) in the scientific literature (Notarbartolo di Sciara et al., 2003). In Denmark, at least eight fin whales stranded between the years 1603 and 1958 (Kinze, 1995). On 16 June 2010, a live subadult or adult male fin...... whale stranded in the Bay of Vejle (55º 69' N, 9º 58' E), Denmark. Despite several attempts, it was not possible to rescue the fin whale, which was only partially exposed by the water. The fin whale succumbed after 5 d stranded in shallow water. The dead fin whale was transported to a nearby pier...

Statistical Assessment of Cetacean Stranding Events in Cape Cod (Massachusetts, USA) area.

Science.gov (United States)

Zellar, R.; Pulkkinen, A. A.; Moore, K.; Reeb, D.; Karakoylu, E.; Uritskaya, O.

2017-12-01

Cetacean (whales, dolphins and porpoises) mass strandings are a longstanding mystery in the field of marine biology that continue to be recorded in coastal environments around the world. For each of these events, anywhere from a few to several hundred otherwise healthy animals strand in onshore environments, often for no apparent reason. While the causes of these events remain unclear, anthropogenic and naturogenic mechanisms have been suggested. We present results of an inter-disciplinary study that draws expertise from space weather, marine mammal biology and ecology, and marine mammal stranding response. This study assessed 16 years of cetacean stranding events in the Cape Cod (Massachusetts, USA) area concurrently with a large dataset of meteorological, geophysical, biological, oceanographic and space weather data to produce inferences about possible causes for these unexplained events.

Protected DNA strand displacement for enhanced single nucleotide discrimination in double-stranded DNA

OpenAIRE

Khodakov, Dmitriy A.; Khodakova, Anastasia S.; Huang, David M.; Linacre, Adrian; Ellis, Amanda V.

2015-01-01

Single nucleotide polymorphisms (SNPs) are a prime source of genetic diversity. Discriminating between different SNPs provides an enormous leap towards the better understanding of the uniqueness of biological systems. Here we report on a new approach for SNP discrimination using toehold-mediated DNA strand displacement. The distinctiveness of the approach is based on the combination of both 3- and 4-way branch migration mechanisms, which allows for reliable discrimination of SNPs within doubl...

Structural features in the HIV-1 repeat region facilitate strand transfer during reverse transcription

NARCIS (Netherlands)

Berkhout, B.; Vastenhouw, N. L.; Klasens, B. I.; Huthoff, H.

2001-01-01

Two obligatory DNA strand transfers take place during reverse transcription of a retroviral RNA genome. The first strand transfer is facilitated by terminal repeat (R) elements in the viral genome. This strand-transfer reaction depends on base pairing between the cDNA of the 5'R and the 3'R. There

Strand Tension Control in Anchor Span for Suspension Bridge Using Dynamic Balance Theory

Directory of Open Access Journals (Sweden)

Da Wang

Full Text Available Abstract Strand tension control is essential in suspension bridge safety. However, few quantitative studies have examined the bending rigidity and boundary condition behavior of strands in the anchor span of suspension bridges because of their special structure and complex configuration. In this paper, a new calculation method for strand tension is explored by using dynamic balance theory to determine the effect of bending rigidity and boundary conditions. The accuracy and effectiveness of the proposed method are tested and confirmed with verification examples and application on Nanxi Yangtze Suspension Bridge in China. The results indicated that only low-order frequency calculation could be used to calculate the strand tension without considering the effect of bending rigidity to ensure control accuracy. The influence of bending rigidity on the control precision is related to the tension and the length of the strands, which is significantly determined by the specific value between the stress rigidity and the bending rigidity. The uncertain boundary conditions of the anchor span cable, which are fixed between consolidated and hinged, also have a major effect on the control accuracy. To improve the accuracy of strand tension control, the least squares method is proposed during the tension construction control of the anchor span. This approach can significantly improve the accuracy of the tension control of the main cable strand. Some recommendations for future bridge analysis are provided based on the results of this study.

Genetic analysis of RPA single-stranded DNA binding protein in Haloferax volcanii

OpenAIRE

Stroud, A. L.

2012-01-01

Replication protein A (RPA) is a single-stranded DNA-binding protein that is present in all three domains of life. The roles of RPA include stabilising and protecting single- stranded DNA from nuclease degradation during DNA replication and repair. To achieve this, RPA uses an oligosaccharide-binding fold (OB fold) to bind single- stranded DNA. Haloferax volcanii encodes three RPAs – RPA1, RPA2 and RPA3, of which rpa1 and rpa3 are in operons with genes encoding associated proteins (APs). ...

Genetic transformation of Neisseria gonorrhoeae shows a strand preference

OpenAIRE

Duffin, Paul M.; Seifert, H. Steven

2012-01-01

Natural transformation is the main means of horizontal genetic exchange in the obligate human pathogen Neisseria gonorrhoeae. Neisseria spp. have been shown to preferentially take up and transform their own DNA by recognizing a non-palindromic 10 or 12 nucleotide DNA uptake sequence (DUS10 or DUS12). We investigated the ability of the DUS12 to enhance single-stranded DNA (ssDNA) transformation. Given the non-palindromic nature of the DUS12, we tested whether both strands of the DUS equally en...

Using DNA origami nanostructures to determine absolute cross sections for UV photon-induced DNA strand breakage.

Science.gov (United States)

Vogel, Stefanie; Rackwitz, Jenny; Schürman, Robin; Prinz, Julia; Milosavljević, Aleksandar R; Réfrégiers, Matthieu; Giuliani, Alexandre; Bald, Ilko

2015-11-19

We have characterized ultraviolet (UV) photon-induced DNA strand break processes by determination of absolute cross sections for photoabsorption and for sequence-specific DNA single strand breakage induced by photons in an energy range from 6.50 to 8.94 eV. These represent the lowest-energy photons able to induce DNA strand breaks. Oligonucleotide targets are immobilized on a UV transparent substrate in controlled quantities through attachment to DNA origami templates. Photon-induced dissociation of single DNA strands is visualized and quantified using atomic force microscopy. The obtained quantum yields for strand breakage vary between 0.06 and 0.5, indicating highly efficient DNA strand breakage by UV photons, which is clearly dependent on the photon energy. Above the ionization threshold strand breakage becomes clearly the dominant form of DNA radiation damage, which is then also dependent on the nucleotide sequence.

7 CFR 1160.105 - Board.

Science.gov (United States)

2010-01-01

... and Orders; Milk), DEPARTMENT OF AGRICULTURE FLUID MILK PROMOTION PROGRAM Fluid Milk Promotion Order Definitions § 1160.105 Board. Board means the National Processor Advertising and Promotion Board established... Promotion Board or Board). ...

Magnetization Losses of Roebel Cable Samples with 2G YBCO Coated Conductor Strands

CERN Document Server

Yang, Y.; Falorio, I.; Young, E.A.; Kario, A.; Goldacker, W.; Dhallé, M. M. J.; van Nugteren, J.; Kirby, G.; Bottura, L.; Ballarino, A.

2016-01-01

Roebel cable with 2G YBCO strands is one of the promising HTS solutions of fully transposed high current conductors for high field accelerator magnets. Following the considerable research effort on the manufacturing of Roebel cables in recent years, sample conductors are now available in useful lengths with reproducible performances to allow detailed characterizations beyond the standard critical current measurements. The ac loss and strands coupling are of significant interest for the field quality of the accelerator magnets. We report a set of systematic ac loss measurements on two different Roebel cable samples prepared for the EuCARD2 collaboration. The measurements were performed over a wide range of temperature between 5 K and 90 K and the results were analyzed in the context of strands architecture and coupling. The results show that the transposed bundles are partially decoupled and the strands in transposition sections behave as an isolated single tape if the strands are insulated.

Analytical model of the critical current of a bent Nb3Sn strand

International Nuclear Information System (INIS)

Koizumi, Norikiyo; Murakami, Haruyuki; Hemmi, Tsutomu; Nakajima, Hideo

2011-01-01

The critical current performance of a large Nb 3 Sn cable-in-conduit conductor (CICC) was degraded by periodic bending of strands due to a large transverse electromagnetic force. The degradation of each strand due to this bending should be evaluated in calculations of the critical current of a CICC, but a suitable model has not been developed yet. Therefore, the authors have developed a new analytical model which takes into account plastic deformation of copper and bronze and filament breakage. The calculated results were compared with test results for uniformly bent Nb 3 Sn bronze-route strands. The calculated results assuming a high transverse resistance model (HTRM) show good agreement with the test results, a finding which confirms the validity of the model. Because of a much shorter calculation time than for numerical simulation, the developed model seems much more practical for use in calculating the critical current performance of a Nb 3 Sn CICC. In addition, simulation results show that since the neutral axis of a bent strand shifts to the compressive side due to plastic deformation of the copper and bronze, and/or filament breakage, the strand is elongated by bending. This elongation may enhance the strand's critical current performance. Moreover, the calculated results indicate that the dependence of the critical current on the bending strain is affected by the bending history if the strand is excessively bent, especially when filaments are broken. In a real magnet, since a strand in a CICC is normally subject to the maximum electromagnetic force prior to an evaluation of its performance at a lower electromagnetic force, the effect of over-bending should be taken into account in calculations of its critical current performance, especially when filament breakage occurs.

Breaks in plasmid DNA strand induced by laser radiation at a wavelength of 193 nm

International Nuclear Information System (INIS)

Gurzadyan, G.G.; Shul'te Frolinde, D.

1996-01-01

DNA of plasmid pB322 irradiated with laser at a wavelength of 193 nm was treated with an extract containing proteins from E.coli K12 AB1157 (wild-type). The enzymes were found to produce single- and double-strand DNA breaks, which was interpreted as a transformation of a portion of cyclobutane pyrimidine dimers and (6-4) photoproducts into nonrepairable single-strand DNA breaks. The products resulted from ionization of DNA, in particular, single-strand breaks, transform to double-strand breaks. A comparison of these data with the data on survival of plasmid upon transformation of E.coli K12 AB1157 enables one to assess the biological significance of single- and double-strand breaks. The inactivation of the plasmid is mainly determined by the number of directly formed laser-induced single-strand breaks. 26 refs.; 2 figs

Paul Strand y las paradojas de la modernidad americana

Directory of Open Access Journals (Sweden)

Vicente Sánchez Biosca

2010-06-01

Full Text Available As contribuições de Strand para o cinema estão estreitamente relacionadas com seus trabalhos fotográficos da época e mesmo com um olhar que, apesar de suas múltiplas diferenças, possui muitos pontos em comum. Se em Manhatta (1920, Strand (em colaboração com Sheeler oferece uma síntese da natureza e da modernidade, em Redes (1934 o que predomina, em contrapartida, é a experiência da arte muralista mexicana e a influência de Eisenstein (em suas andanças por México são os fatores que determinam seus esforços na construção de uma épica dos operários. Mas sem dúvida, o projeto mais ambicioso de Strand (ao mando da produtora Frontier Films foi Native Land, o filme que atendeu às demandas do American Popular Front e as moldou nas palavras dos fundadores da pátria americana.

IHF-independent assembly of the Tn10 strand transfer transpososome: implications for inhibition of disintegration

OpenAIRE

Stewart, Barry J.; Wardle, Simon J.; Haniford, David B.

2002-01-01

The frequency of DNA transposition in transposition systems that employ a strand transfer step may be significantly affected by the occurrence of a disintegration reaction, a reaction that reverses the strand transfer event. We have asked whether disintegration occurs in the Tn10 transposition system. We show that disintegration substrates (substrates constituting one half of the strand transfer product) are assembled into a transpososome that mimics the strand transfer intermediate. This str...

Chirality induction and protonation-induced molecular motions in helical molecular strands.

Science.gov (United States)

Kolomiets, Elena; Berl, Volker; Lehn, Jean-Marie

2007-01-01

The long oligopyridinedicarboxamide strand 9, containing 15 heterocyclic rings has been synthesized and its helical structure determined by X-ray crystallography. It was shown that the shorter analogue 6 displays induced circular dichroism and amplification of induced chirality upon dissolution in an optically active solvent, diethyl-L-tartrate. A novel class of helical foldamers was prepared, strands 14-16, based on two oligopyridine carboxamide segments linked through a L-tartaric acid derived spacer. These tartro strands display internal chirality induction as well as chirality amplification. NMR spectroscopy (on 8 and 9) and circular dichroism (on 16) studies show that the oligopyridine carboxamide strands undergo reversible unfolding/folding upon protonation. The protonation-induced unfolding has been confirmed by X-ray crystallographic determination of the molecular structure of the extended protonated heptameric form 8(+). The molecular-scale mechano-chemical motions of the protonation-induced structural switching consist of a change of the length of the molecule, from 6 angstroms (6, coiled form) to 29 angstroms (8(+), uncoiled form) for the heptamer and from 12.5 angstroms (9, coiled form, X-ray structure) to 57 angstroms (9(+), uncoiled form, from modeling) for the pentadecamer. Similar unfolding/folding motional processes take place in the L-tartro strands 15 and 16 upon protonation/deprotonation, with loss of helicity-induced circular dichroism on unfolding as shown for the protonated form 16(+).

Evolutionary implications of inversions that have caused intra-strand parity in DNA

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Wei John

2007-06-01

Full Text Available Abstract Background Chargaff's rule of DNA base composition, stating that DNA comprises equal amounts of adenine and thymine (%A = %T and of guanine and cytosine (%C = %G, is well known because it was fundamental to the conception of the Watson-Crick model of DNA structure. His second parity rule stating that the base proportions of double-stranded DNA are also reflected in single-stranded DNA (%A = %T, %C = %G is more obscure, likely because its biological basis and significance are still unresolved. Within each strand, the symmetry of single nucleotide composition extends even further, being demonstrated in the balance of di-, tri-, and multi-nucleotides with their respective complementary oligonucleotides. Results Here, we propose that inversions are sufficient to account for the symmetry within each single-stranded DNA. Human mitochondrial DNA does not demonstrate such intra-strand parity, and we consider how its different functional drivers may relate to our theory. This concept is supported by the recent observation that inversions occur frequently. Conclusion Along with chromosomal duplications, inversions must have been shaping the architecture of genomes since the origin of life.

Time-dependent evolution of strand transfer length in pretensioned prestressed concrete members

Science.gov (United States)

Caro, L. A.; Martí-Vargas, J. R.; Serna, P.

2013-11-01

For design purposes, it is generally considered that prestressing strand transfer length does not change with time. However, some experimental studies on the effect of time on transfer lengths show contradictory results. In this paper, an experimental research to study transfer length changes over time is presented. A test procedure based on the ECADA testing technique to measure prestressing strand force variation over time in pretensioned prestressed concrete specimens has been set up. With this test method, an experimental program that varies concrete strength, specimen cross section, age of release, prestress transfer method, and embedment length has been carried out. Both the initial and long-term transfer lengths of 13-mm prestressing steel strands have been measured. The test results show that transfer length variation exists for some prestressing load conditions, resulting in increased transfer length over time. The applied test method based on prestressing strand force measurements has shown more reliable results than procedures based on measuring free end slips and longitudinal strains of concrete. An additional factor for transfer length models is proposed in order to include the time-dependent evolution of strand transfer length in pretensioned prestressed concrete members.

Utilization of waste tire rubber in manufacture of oriented strandboard.

Science.gov (United States)

Ayrilmis, Nadir; Buyuksari, Umit; Avci, Erkan

2009-09-01

Some physical and mechanical properties of oriented strandboards (OSBs) containing waste tire rubber at various addition levels based on the oven-dry strand weight, using the same method as that used in the manufacture of OSB. Two resin types, phenol-formaldehyde (PF) and polyisocyanate, were used in the experiments. The manufacturing parameters were: a specific gravity of 0.65 and waste tire rubber content (10/90, 20/80 and 30/70 by wt.% of waste tire rubber/wood strand). Average internal bond values of PF-bonded OSB panels with rubber chips were between 17.6% and 48.5% lower than the average of the control samples while polyisocyanate bonded OSBs were 16.5-50.6%. However, water resistance and mechanical properties of OSBs made using polyisocyanate resin were found to comply with general-purpose OSB minimum property requirements of EN 300 Type 1 (1997) values for use in dry conditions at the lowest tire rubber loading level (10%) based on the oven-dry panel weight. The tire rubber improved water resistance of the OSB panel due to its almost hydrophobic property. Based on the findings obtained from this study, we concluded that waste tire rubber could be used for general-purpose OSB manufacturing up to 10% ratio based on the oven-dry panel weight.

Sequential strand displacement beacon for detection of DNA coverage on functionalized gold nanoparticles.

Science.gov (United States)

Paliwoda, Rebecca E; Li, Feng; Reid, Michael S; Lin, Yanwen; Le, X Chris

2014-06-17

Functionalizing nanomaterials for diverse analytical, biomedical, and therapeutic applications requires determination of surface coverage (or density) of DNA on nanomaterials. We describe a sequential strand displacement beacon assay that is able to quantify specific DNA sequences conjugated or coconjugated onto gold nanoparticles (AuNPs). Unlike the conventional fluorescence assay that requires the target DNA to be fluorescently labeled, the sequential strand displacement beacon method is able to quantify multiple unlabeled DNA oligonucleotides using a single (universal) strand displacement beacon. This unique feature is achieved by introducing two short unlabeled DNA probes for each specific DNA sequence and by performing sequential DNA strand displacement reactions. Varying the relative amounts of the specific DNA sequences and spacing DNA sequences during their coconjugation onto AuNPs results in different densities of the specific DNA on AuNP, ranging from 90 to 230 DNA molecules per AuNP. Results obtained from our sequential strand displacement beacon assay are consistent with those obtained from the conventional fluorescence assays. However, labeling of DNA with some fluorescent dyes, e.g., tetramethylrhodamine, alters DNA density on AuNP. The strand displacement strategy overcomes this problem by obviating direct labeling of the target DNA. This method has broad potential to facilitate more efficient design and characterization of novel multifunctional materials for diverse applications.

Comparison Between Nb3Al and Nb3Sn Strands and Cables for High Field Accelerator Magnets

Energy Technology Data Exchange (ETDEWEB)

Yamada, R.; Kikuchi, A.; Barzi, E.; Chlachidze, G.; Rusy, A.; Takeuchi, T.; Tartaglia, M.; Turrioni, D.; Velev, V.; Wake, M.; Zlobin, A.V.; /Fermilab

2010-01-01

The Nb{sub 3}Al small racetrack magnet, SR07, has been successfully built and tested to its short sample limit beyond 10 Tesla without any training. Thus the practical application of Nb{sub 3}Al strands for high field accelerator magnets is established. The characteristics of the representative F4 strand and cable, are compared with the typical Nb{sub 3}Sn strand and cable. It is represented by the OST high current RRP Nb{sub 3}Sn strand with 108/127 configuration. The effects of Rutherford cabling to both type strands are explained and the inherent problem of the Nb{sub 3}Sn strand is discussed. Also the test results of two representative small racetrack magnets are compared from the stand point of Ic values, and training. The maximum current density of the Nb{sub 3}Al strands is still smaller than that of the Nb{sub 3}Sn strands, but if we take into account of the stress-strain characteristics, Nb{sub 3}Al strands become somewhat favorable in some applications.

The impact of the board's strategy-setting role on board-management relations and hospital performance.

Science.gov (United States)

Büchner, Vera Antonia; Schreyögg, Jonas; Schultz, Carsten

2014-01-01

The appropriate governance of hospitals largely depends on effective cooperation between governing boards and hospital management. Governing boards play an important role in strategy-setting as part of their support for hospital management. However, in certain situations, this active strategic role may also generate discord within this relationship. The objective of this study is to investigate the impact of the roles, attributes, and processes of governing boards on hospital performance. We examine the impact of the governing board's strategy-setting role on board-management collaboration quality and on financial performance while also analyzing the interaction effects of board diversity and board activity level. The data are derived from a survey that was sent simultaneously to German hospitals and their associated governing board, combined with objective performance information from annual financial statements and quality reports. We use a structural equation modeling approach to test the model. The results indicate that different board characteristics have a significant impact on hospital performance (R = .37). The strategy-setting role and board-management collaboration quality have a positive effect on hospital performance, whereas the impact of strategy-setting on collaboration quality is negative. We find that the positive effect of strategy-setting on performance increases with decreasing board diversity. When board members have more homogeneous backgrounds and exhibit higher board activity levels, the negative effect of the strategy-setting on collaboration quality also increases. Active strategy-setting by a governing board may generally improve hospital performance. Diverse members of governing boards should be involved in strategy-setting for hospitals. However, high board-management collaboration quality may be compromised if managerial autonomy is too highly restricted. Consequently, hospitals should support board-management collaboration about

Missing Strands? Dealing with Hair Loss

Science.gov (United States)

... 2017 Print this issue Missing Strands? Dealing with Hair Loss En español Send us your comments Hair loss is often associated with men and aging, but ... or their treatments, and many other things cause hair loss. The most common type of hair loss is ...

The stranding anomaly as population indicator: the case of harbour porpoise Phocoena phocoena in North-Western Europe.

Directory of Open Access Journals (Sweden)

Helene Peltier

Full Text Available Ecological indicators for monitoring strategies are expected to combine three major characteristics: ecological significance, statistical credibility, and cost-effectiveness. Strategies based on stranding networks rank highly in cost-effectiveness, but their ecological significance and statistical credibility are disputed. Our present goal is to improve the value of stranding data as population indicator as part of monitoring strategies by constructing the spatial and temporal null hypothesis for strandings. The null hypothesis is defined as: small cetacean distribution and mortality are uniform in space and constant in time. We used a drift model to map stranding probabilities and predict stranding patterns of cetacean carcasses under H0 across the North Sea, the Channel and the Bay of Biscay, for the period 1990-2009. As the most common cetacean occurring in this area, we chose the harbour porpoise Phocoena phocoena for our modelling. The difference between these strandings expected under H0 and observed strandings is defined as the stranding anomaly. It constituted the stranding data series corrected for drift conditions. Seasonal decomposition of stranding anomaly suggested that drift conditions did not explain observed seasonal variations of porpoise strandings. Long-term stranding anomalies increased first in the southern North Sea, the Channel and Bay of Biscay coasts, and finally the eastern North Sea. The hypothesis of changes in porpoise distribution was consistent with local visual surveys, mostly SCANS surveys (1994 and 2005. This new indicator could be applied to cetacean populations across the world and more widely to marine megafauna.

Findings of the Work Improvement on Board (WIB) programme by the Fishery Agency in Japan.

Science.gov (United States)

Hisamune, Shuji; Kogi, Kazutaka

2015-01-01

Concerns are growing about the safety and health of seamen exposed to high risks while working on vessels. Their accident rate in 2013 was 9.9 per 1000 workers, 5 times higher than that in industry. In order to mitigate the risks of seamen, we developed the Work Improvement on Board (WIB) programme by applying participatory action-oriented training (PAOT) methods that have proven effective for reducing work-related risks in small enterprises, construction sites, and agriculture. We analysed which features of the WIB programme would be most effective for facilitating the planning and implementation of practical improvements on vessels. We examined action -oriented tools used, including a WIB action checklist and good examples, and practical improvements proposed by the participants in 1-day or half-day WIB workshops. To study the effectiveness of the WIB programme, we analysed 1121 replies of a questionnaire distributed to 1459 participants of the programme. We compared the types of improvements achieved and the improvement costs in the WIB programme with those in other PAOT programmes. The impact of the WIB programme on promoting primary prevention by seamen and fishermen was discussed. The action checklist listing practical improvements on board and good example photos apparently facilitated the planning and implementation of improvements feasible on board. The participating crews could propose readily applicable improvements of their vessels within short time. In the case of workshops held in 10 harbours between August and October 2014, participants coming from 110 vessels presented 228 improvement proposals which were mostly feasible at low cost. Among the 1121 questionnaire replies from participants of the WIB programme, over 75% evaluated the programme as necessary, practical and easy-to-understand. These positive results led to the adoption of the WIB programme for training fishermen and seamen on commercial vessels by the Fishery Agency and the Ministry of

Influence of oxidized purine processing on strand directionality of mismatch repair.

Science.gov (United States)

Repmann, Simone; Olivera-Harris, Maite; Jiricny, Josef

2015-04-17

Replicative DNA polymerases are high fidelity enzymes that misincorporate nucleotides into nascent DNA with a frequency lower than [1/10(5)], and this precision is improved to about [1/10(7)] by their proofreading activity. Because this fidelity is insufficient to replicate most genomes without error, nature evolved postreplicative mismatch repair (MMR), which improves the fidelity of DNA replication by up to 3 orders of magnitude through correcting biosynthetic errors that escaped proofreading. MMR must be able to recognize non-Watson-Crick base pairs and excise the misincorporated nucleotides from the nascent DNA strand, which carries by definition the erroneous genetic information. In eukaryotes, MMR is believed to be directed to the nascent strand by preexisting discontinuities such as gaps between Okazaki fragments in the lagging strand or breaks in the leading strand generated by the mismatch-activated endonuclease of the MutL homologs PMS1 in yeast and PMS2 in vertebrates. We recently demonstrated that the eukaryotic MMR machinery can make use also of strand breaks arising during excision of uracils or ribonucleotides from DNA. We now show that intermediates of MutY homolog-dependent excision of adenines mispaired with 8-oxoguanine (G(O)) also act as MMR initiation sites in extracts of human cells or Xenopus laevis eggs. Unexpectedly, G(O)/C pairs were not processed in these extracts and failed to affect MMR directionality, but extracts supplemented with exogenous 8-oxoguanine DNA glycosylase (OGG1) did so. Because OGG1-mediated excision of G(O) might misdirect MMR to the template strand, our findings suggest that OGG1 activity might be inhibited during MMR. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Propriedades de chapas tipo OSB, fabricadas com partículas acetiladas de madeiras de Eucalyptus grandis, Eucalyptus urophylla, Eucalyptus cloeziana e Pinus elliottii Properties of OSB manufactured with wood strands of Eucalyptus grandis, Eucalyptus urophylla, Eucalyptus cloeziana and Pinus elliottii

Directory of Open Access Journals (Sweden)

Carla Priscilla Távora Cabral

2006-08-01

� compressão longitudinal foi afetada pela região de origem da madeira. Os painéis fabricados com madeira de Eucalyptus urophylla, oriunda do Município de Três Marias, tiveram médias inferiores aos das chapas feitas com a mesma espécie, porém oriundas do Município do Rio Doce.The objectives of this work was to evaluate the properties of OSB (Oriented Strand Board. Wood was collected from Eucalyptus grandis, Eucalyptus urophylla and Eucalyptus cloeziana on the municipalities of Ponte Alta and Três Marias, in the state of Minas Gerais. Wood densities were respectively: Ponte Alta (0.55, 0.61 and 0.70g/cm³ and Três Marias (0.56, 0.58 e 0.69g/cm³. Strands of Pinus elliottii, derived from the city of Viçosa, with density of 0.45g/cm³, were added to strands of eucalyptus when necessary to keep board densities close to 0.70g/cm³. Flakes were fabricated in a laboratory disk flaker measuring approximately 20.00 x 0.46 x 90.00 mm. Phenol-formaldehyde adhesive was applied at 8% solid rate, in relation to particle dry mass. Part of the treatment was carried out with flakes from acetylated eucalyptus. The boards were pressed at 170°C and 32 kgf/cm² pressure. Boards properties were determined according to the ABNT NBR 14810-3 (2002 and ASTM-D 1037 (1991 norms. The results were compared using the ANSI/A - 208.1 (1993 and CSA 0437-93 (1993 norms. OSB manufactured with any amount of acetylated flakes was more stable and absorbed less water. However the resistance to perpendicular traction of OSB with 100% of acetylated flakes was inferior to the stipulated by the CSA O437-0/93 (1993 norm. It was also found that acetylation had a negative effect on screw withdrawal resistance, module of rupture (parallel and perpendicular and longitudinal compression resistance (perpendicular of Eucalyptus grandis OSB having 100% of their flakes acetylated. Boards that presented numerically the highest means were manufactured with non-acetylated flakes of Eucalyptus grandis (Janka hardness

Study in regularities in the formation of double stranded DNA breaks in irradiated rat thymocytes

International Nuclear Information System (INIS)

Ivannik, B.P.; ProskuryakoV, S.Ya.; Ryabchenko, N.I.

1979-01-01

Using low-gradient viscosimetry of neutral detergent nuclear lysates a study was made of postradiation changes in the molecular weight of double-stranded DNA of thymocytes. It was established that 375 eV are needed for one double-stranded break to appear, and a dose of 1 rad is required for 0.275 double-stranded break to occur at the site of DNA with m.w. 10 12 dalton. The repair of double-stranded breaks is only observed when rats are exposed to a dose of 500 R. It is assumed that the absence of repair of double-stranded DNA breaks and the presence of secondary postradiation degradation of DNA are responsible for thymocyte death

Velocity and processivity of helicase unwinding of double-stranded nucleic acids

International Nuclear Information System (INIS)

Betterton, M D; Juelicher, F

2005-01-01

Helicases are molecular motors which unwind double-stranded nucleic acids (dsNA) in cells. Many helicases move with directional bias on single-stranded (ss) nucleic acids, and couple their directional translocation to strand separation. A model of the coupling between translocation and unwinding uses an interaction potential to represent passive and active helicase mechanisms. A passive helicase must wait for thermal fluctuations to open dsNA base pairs before it can advance and inhibit NA closing. An active helicase directly destabilizes dsNA base pairs, accelerating the opening rate. Here we extend this model to include helicase unbinding from the nucleic-acid strand. The helicase processivity depends on the form of the interaction potential. A passive helicase has a mean attachment time which does not change between ss translocation and ds unwinding, while an active helicase in general shows a decrease in attachment time during unwinding relative to ss translocation. In addition, we describe how helicase unwinding velocity and processivity vary if the base-pair binding free energy is changed

MEASUREMENT OF LARGE-SCALE SOLAR POWER PLANT BY USING IMAGES ACQUIRED BY NON-METRIC DIGITAL CAMERA ON BOARD UAV

Directory of Open Access Journals (Sweden)

R. Matsuoka

2012-07-01

Full Text Available This paper reports an experiment conducted in order to investigate the feasibility of the deformation measurement of a large-scale solar power plant on reclaimed land by using images acquired by a non-metric digital camera on board a micro unmanned aerial vehicle (UAV. It is required that a root mean squares of errors (RMSE in height measurement should be less than 26 mm that is 1/3 of the critical limit of deformation of 78 mm off the plane of a solar panel. Images utilized in the experiment have been obtained by an Olympus PEN E-P2 digital camera on board a Microdrones md4-1000 quadrocopter. The planned forward and side overlap ratios of vertical image acquisition have been 60 % and 60 % respectively. The planned flying height of the UAV has been 20 m above the ground level and the ground resolution of an image is approximately 5.0 mm by 5.0 mm. 8 control points around the experiment area are utilized for orientation. Measurement results are evaluated by the space coordinates of 220 check points which are corner points of 55 solar panels selected from 1768 solar panels in the experiment area. Two teams engage in the experiment. One carries out orientation and measurement by using 171 images following the procedure of conventional aerial photogrammetry, and the other executes those by using 126 images in the manner of close range photogrammetry. The former fails to satisfy the required accuracy, while the RMSE in height measurement by the latter is 8.7 mm that satisfies the required accuracy. From the experiment results, we conclude that the deformation measurement of a large-scale solar power plant on reclaimed land by using images acquired by a nonmetric digital camera on board a micro UAV would be feasible if points utilized in orientation and measurement have a sufficient number of bundles in good geometry and self-calibration in orientation is carried out.

Motives and Power of School Board Members: Implications for School Board-Superintendent Relationships

Science.gov (United States)

Mountford, Meredith

2004-01-01

The qualitative study presented in this article explores motivations for school board membership and conceptions of power held by school board members. The findings of the study suggest a relationship exists between the way board members define power and the type of motivation board members have for service. The implications of these findings for…

Enzymatic induction of DNA double-strand breaks in γ-irradiated Escherichia coli K-12

International Nuclear Information System (INIS)

Bonura, T.; Smith, K.C.; Kaplan, H.S.

1975-01-01

The polA1 mutation increases the sensitivity of E. coli K-12 to killing by γ-irradiation in air by a factor of 2.9 and increases the yield of DNA double-strand breaks by a factor of 2.5. These additional DNA double-strand breaks appear to be due to the action of nucleases in the polA1 strain rather than to the rejoining of radiation-induced double-strand breaks in the pol + strain. This conclusion is based upon the observation that γ-irradiation at 3 0 did not affect the yield of DNA double-strand breaks in the pol + strain, but decreased the yield in the polA1 strain by a factor of 2.2. Irradiation of the polA1 strain at 3 0 followed by incubation at 3 0 for 20 min before plating resulted in approximately a 1.5-fold increase in the D 0 . The yield of DNA double-strand breaks was reduced by a factor of 1.5. The pol + strain, however, did not show the protective effect of the low temperature incubation upon either survival or DNA double-strand breakage. We suggest that the increased yield of DNA double-strand breaks in the polA 1 strain may be the result of the unsuccessful excision repair of ionizing radiation-induced dna base damage

Three methods to determine the yields of DNA double-strand breaks

International Nuclear Information System (INIS)

Erzgraeber, G.; Lapidus, I.L.

1985-01-01

A possibility of determining the yield of DNA double-strand breaks in cells of the Chinese hamster (V79-4) by finding the amount of DNA released as a result of breaks and by determining the relative sedimentation velocity of DNA-membrane complexes affected by ionizing radiations with different physical characteristics is discussed. Results of the analysis are compared with the data obtained by a traditional method of sedimentation in the neutral sucrose density gradient. Comparative characterization of the methods is discussed. The yields of DNA double-strand breaks determined by the suggested independent methods are in good agreement, which opens possibilities of studying induction and repair of double-strand breaks by means of simpler and more reliable methods

77 FR 2541 - Board Meeting

Science.gov (United States)

2012-01-18

... FARM CREDIT SYSTEM INSURANCE CORPORATION Board Meeting AGENCY: Farm Credit System Insurance Corporation Board; Regular Meeting. SUMMARY: Notice is hereby given of the regular meeting of the Farm Credit System Insurance Corporation Board (Board). DATE AND TIME: The meeting of the Board will be held at the...

RNA STRAND: The RNA Secondary Structure and Statistical Analysis Database

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Andronescu Mirela

2008-08-01

Full Text Available Abstract Background The ability to access, search and analyse secondary structures of a large set of known RNA molecules is very important for deriving improved RNA energy models, for evaluating computational predictions of RNA secondary structures and for a better understanding of RNA folding. Currently there is no database that can easily provide these capabilities for almost all RNA molecules with known secondary structures. Results In this paper we describe RNA STRAND – the RNA secondary STRucture and statistical ANalysis Database, a curated database containing known secondary structures of any type and organism. Our new database provides a wide collection of known RNA secondary structures drawn from public databases, searchable and downloadable in a common format. Comprehensive statistical information on the secondary structures in our database is provided using the RNA Secondary Structure Analyser, a new tool we have developed to analyse RNA secondary structures. The information thus obtained is valuable for understanding to which extent and with which probability certain structural motifs can appear. We outline several ways in which the data provided in RNA STRAND can facilitate research on RNA structure, including the improvement of RNA energy models and evaluation of secondary structure prediction programs. In order to keep up-to-date with new RNA secondary structure experiments, we offer the necessary tools to add solved RNA secondary structures to our database and invite researchers to contribute to RNA STRAND. Conclusion RNA STRAND is a carefully assembled database of trusted RNA secondary structures, with easy on-line tools for searching, analyzing and downloading user selected entries, and is publicly available at http://www.rnasoft.ca/strand.

Comparison of DNA strand-break simulated with different DNA models

International Nuclear Information System (INIS)

Xie, Wenzhang; Li, Junli; Qiu, Rui; Yan, Congchong; Zeng, Zhi; Li, Chunyan

2013-01-01

Full text of the publication follows. In Monte Carlo simulation of DNA damage, the geometric model of DNA is of great importance. To study the influence of DNA model on the simulation of DNA damage, three DNA models were created in this paper. They were a volume model and two atomic models with different parameters. Direct DNA strand-break induced by low-energy electrons were simulated respectively with the three models. The results show that most of the energy depositions in the DNA segments do not lead to strand-breaks. The simple single strand-break (SSB) tends to be the predominant damage type, and the contribution of complex double strand-break (DSB) to the total DSB cannot be neglected. Among the yields of all the three DNA target models applied here, the yields of the volume model are the highest, the yields of the atomic model with double van der Waals radii (r) take the second place, whereas the yields of the atomic model with single r come last. On average, the ratios of SSB yields are approximately equivalent to the corresponding ratios of the models' volume. However, there seems to be no clear relationship between the DSB yields and the models' volume. (authors)

Real-time monitoring of enzyme-free strand displacement cascades by colorimetric assays

Science.gov (United States)

Duan, Ruixue; Wang, Boya; Hong, Fan; Zhang, Tianchi; Jia, Yongmei; Huang, Jiayu; Hakeem, Abdul; Liu, Nannan; Lou, Xiaoding; Xia, Fan

2015-03-01

The enzyme-free toehold-mediated strand displacement reaction has shown potential for building programmable DNA circuits, biosensors, molecular machines and chemical reaction networks. Here we report a simple colorimetric method using gold nanoparticles as signal generators for the real-time detection of the product of the strand displacement cascade. During the process the assembled gold nanoparticles can be separated, resulting in a color change of the solution. This assay can also be applied in complex mixtures, fetal bovine serum, and to detect single-base mismatches. These results suggest that this method could be of general utility to monitor more complex enzyme-free strand displacement reaction-based programmable systems or for further low-cost diagnostic applications.The enzyme-free toehold-mediated strand displacement reaction has shown potential for building programmable DNA circuits, biosensors, molecular machines and chemical reaction networks. Here we report a simple colorimetric method using gold nanoparticles as signal generators for the real-time detection of the product of the strand displacement cascade. During the process the assembled gold nanoparticles can be separated, resulting in a color change of the solution. This assay can also be applied in complex mixtures, fetal bovine serum, and to detect single-base mismatches. These results suggest that this method could be of general utility to monitor more complex enzyme-free strand displacement reaction-based programmable systems or for further low-cost diagnostic applications. Electronic supplementary information (ESI) available: Experimental procedures and analytical data are provided. See DOI: 10.1039/c5nr00697j

Multiple pathways of DNA double-strand break processing in a mutant Indian muntjac cell line

International Nuclear Information System (INIS)

Bouffler, S.D.; Jha, B.; Johnson, R.T.

1990-01-01

DNA break processing is compared in the Indian muntjac cell lines, SVM and DM. The initial frequencies and resealing of X-ray generated single- and double-strand breaks are similar in the two cell lines. Inhibiting the repair of UV damage leads to greater double-strand breakage in SVM than in DM, and some of these breaks are not repaired; however, repair-associated single-strand breakage and resealing are normal. Dimethylsulfate also induces excess double-strand breakage in SVM, and these breaks are irreparable. Restricted plasmids are reconstituted correctly in SVM at approximately 30% of the frequency observed in DM. Thus SVM has a reduced capacity to repair certain types of double-strand break. This defect is not due to a DNA ligase deficiency. We conclude that DNA double-strand breaks are repaired by a variety of pathways within mammalian cells and that the structure of the break or its mode of formation determines its subsequent fate

Does Board Diversity Really Matter?

DEFF Research Database (Denmark)

Rose, Caspar; Munch-Madsen, Peter; Funch, Maja

2013-01-01

We study the impact of female board representation as well as citizenship on corporate performance based on a sample of the largest listed firms in the Nordic countries as well as Germany. We also seek to determine the variation of board structures using factor analysis. We find no support for any...... performance impact relating to female board representation. However, we find an impact of board citizenship on performance showing that board members with a background from common law have a significant positive influence on corporate performance measured as ROA, ROE and ROCE. Consistent with other studies we...... also document that large boards impact corporate performance negatively. Moreover we also show that data set on boards can be explained by four underlying factors. This article adds insight to board determinants of corporate performance as well as the classification of board variation. Specifically...

Benchmarking of the advanced hygrothermal model-hygIRC with mid scale experiments

Energy Technology Data Exchange (ETDEWEB)

Maref, W.; Lacasse, M.; Kumaran, K.; Swinton, M.C. [National Research Council of Canada, Ottawa, ON (Canada). Inst. for Research in Construction

2002-07-01

An experimental study has been conducted to benchmark an advanced hygrothermal model entitled hygIRC which can be used to estimate the drying response of oriented strand board (OSB) used in timber-frame construction. Three specimens of OSB boards were immersed in water for 5 days and then allowed to stabilise in a sealed tank. A comparison of results from the computer model simulations to those obtained from experimental tests and laboratory measurements showed good agreement in terms of the shape of the drying curve and time taken to reach equilibrium moisture content. In general, it was determined that the drying process is controlled by the vapour permeability of the membrane. The higher the vapour permeability, the faster the rate of drying in a given condition. 11 refs., 1 tab., 9 figs.

Dynamics of DNA replication loops reveal temporal control of lagging-strand synthesis

NARCIS (Netherlands)

Hamdan, Samir M.; Loparo, Joseph J.; Takahashi, Masateru; Richardson, Charles C.; Oijen, Antoine M. van

2009-01-01

In all organisms, the protein machinery responsible for the replication of DNA, the replisome, is faced with a directionality problem. The antiparallel nature of duplex DNA permits the leading-strand polymerase to advance in a continuous fashion, but forces the lagging-strand polymerase to

Human Cell Assays for Synthesis-Dependent Strand Annealing and Crossing over During Double-Strand Break Repair.

Science.gov (United States)

Zapotoczny, Grzegorz; Sekelsky, Jeff

2017-04-03

DNA double-strand breaks (DSBs) are one of the most deleterious types of lesions to the genome. Synthesis-dependent strand annealing (SDSA) is thought to be a major pathway of DSB repair, but direct tests of this model have only been conducted in budding yeast and Drosophila To better understand this pathway, we developed an SDSA assay for use in human cells. Our results support the hypothesis that SDSA is an important DSB repair mechanism in human cells. We used siRNA knockdown to assess the roles of a number of helicases suggested to promote SDSA. None of the helicase knockdowns reduced SDSA, but knocking down BLM or RTEL1 increased SDSA. Molecular analysis of repair products suggests that these helicases may prevent long-tract repair synthesis. Since the major alternative to SDSA (repair involving a double-Holliday junction intermediate) can lead to crossovers, we also developed a fluorescent assay that detects crossovers generated during DSB repair. Together, these assays will be useful in investigating features and mechanisms of SDSA and crossover pathways in human cells. Copyright © 2017 Zapotoczny and Sekelsky.

Human Cell Assays for Synthesis-Dependent Strand Annealing and Crossing over During Double-Strand Break Repair

Directory of Open Access Journals (Sweden)

Grzegorz Zapotoczny

2017-04-01

Full Text Available DNA double-strand breaks (DSBs are one of the most deleterious types of lesions to the genome. Synthesis-dependent strand annealing (SDSA is thought to be a major pathway of DSB repair, but direct tests of this model have only been conducted in budding yeast and Drosophila. To better understand this pathway, we developed an SDSA assay for use in human cells. Our results support the hypothesis that SDSA is an important DSB repair mechanism in human cells. We used siRNA knockdown to assess the roles of a number of helicases suggested to promote SDSA. None of the helicase knockdowns reduced SDSA, but knocking down BLM or RTEL1 increased SDSA. Molecular analysis of repair products suggests that these helicases may prevent long-tract repair synthesis. Since the major alternative to SDSA (repair involving a double-Holliday junction intermediate can lead to crossovers, we also developed a fluorescent assay that detects crossovers generated during DSB repair. Together, these assays will be useful in investigating features and mechanisms of SDSA and crossover pathways in human cells.

Evolutionary dynamics of adult stem cells: comparison of random and immortal-strand segregation mechanisms.

Science.gov (United States)

Tannenbaum, Emmanuel; Sherley, James L; Shakhnovich, Eugene I

2005-04-01

This paper develops a point-mutation model describing the evolutionary dynamics of a population of adult stem cells. Such a model may prove useful for quantitative studies of tissue aging and the emergence of cancer. We consider two modes of chromosome segregation: (1) random segregation, where the daughter chromosomes of a given parent chromosome segregate randomly into the stem cell and its differentiating sister cell and (2) "immortal DNA strand" co-segregation, for which the stem cell retains the daughter chromosomes with the oldest parent strands. Immortal strand co-segregation is a mechanism, originally proposed by [Cairns Nature (London) 255, 197 (1975)], by which stem cells preserve the integrity of their genomes. For random segregation, we develop an ordered strand pair formulation of the dynamics, analogous to the ordered strand pair formalism developed for quasispecies dynamics involving semiconservative replication with imperfect lesion repair (in this context, lesion repair is taken to mean repair of postreplication base-pair mismatches). Interestingly, a similar formulation is possible with immortal strand co-segregation, despite the fact that this segregation mechanism is age dependent. From our model we are able to mathematically show that, when lesion repair is imperfect, then immortal strand co-segregation leads to better preservation of the stem cell lineage than random chromosome segregation. Furthermore, our model allows us to estimate the optimal lesion repair efficiency for preserving an adult stem cell population for a given period of time. For human stem cells, we obtain that mispaired bases still present after replication and cell division should be left untouched, to avoid potentially fixing a mutation in both DNA strands.

The improvement of the edge screw connection in OSB and conventional particleboard

Directory of Open Access Journals (Sweden)

Popović Mlađan

2006-01-01

Full Text Available This work presents the method for improvement of direct screw connection performance in conventional particleboard (PB and oriented strand board (OSB. It is conceived on adhesive insertion into the pilot hole prior to embedment of the screw. The tests were carried out on the PB and OSB, both presenting interior boards and with the same nominal thickness of 18 mm. Particleboard screws of the 5 mm in diameter were inserted in the edge of the board. Pilot hole diameters were 2,5 mm and 3,0 mm and the depth of embedment was 30 mm for all tests. The chosen PVAc adhesive (type 3 with the addition of wood flour as consolidator in the range from 3-10% was inserted into pilot-hole. Tests were also obtained after consequent reassembly of the screw connection in order to examine the ratio of loss in withdrawal forces in such case. It was found that the insertion of PVAc adhesive into the pilot hole and the addition of wood flour have the positive effects on the screw withdrawal force in the tested boards.

d-Cysteine Ligands Control Metal Geometries within De Novo Designed Three-Stranded Coiled Coils

DEFF Research Database (Denmark)

Ruckthong, Leela; Peacock, Anna F.A.; Pascoe, Cherilyn E.

2017-01-01

Although metal ion binding to naturally occurring l-amino acid proteins is well documented, understanding the impact of the opposite chirality (d-)amino acids on the structure and stereochemistry of metals is in its infancy. We examine the effect of a d-configuration cysteine within a designed l......-amino acid three-stranded coiled coil in order to enforce a precise coordination number on a metal center. The d chirality does not alter the native fold, but the side-chain re-orientation modifies the sterics of the metal binding pocket. l-Cys side chains within the coiled-coil structure have previously...... by comparison of the structure of ZnIICl(CSL16DC)3 2- to the published structure of ZnII(H2O)(GRAND-CSL12AL16LC)3 -. Moreover, spectroscopic analysis indicates that the CdII geometry observed by using l-Cys ligands (a mixture of three- and four-coordinate CdII) is altered to a single four-coordinate species...

NEXAFS characterization of DNA components and molecular-orientation of surface-bound DNA oligomers

International Nuclear Information System (INIS)

Samuel, Newton T.; Lee, C.-Y.; Gamble, Lara J.; Fischer, Daniel A.; Castner, David G.

2006-01-01

Single stranded DNA oligomers (ssDNA) immobilized onto solid surfaces forms the basis for several biotechnological applications such as DNA microarrays, affinity separations, and biosensors. Surface structure of Surface-bound oligomers is expected to significantly influence their biological activity and interactions with the environment. In this study near-edge X-ray absorption fine structure spectroscopy (NEXAFS) is used to characterize the components of DNA (nucleobases, nucleotides and nucleosides) and the orientation information of surface-bound ssDNA. The K-edges of carbon, nitrogen and oxygen have spectra with features that are characteristic of the different chemical species present in the nucleobases of DNA. The effect of addition of the DNA sugar and phosphate components on the NEXAFS K-edge spectra was also investigated. The polarization-dependent nitrogen K-edge NEXAFS data show significant changes for different orientations of surface bound ssDNA. These results establish NEXAFS as a powerful technique for chemical and structural characterization of surface-bound DNA oligomers

Diffusion of Corporate Governance Beliefs: Board independence and the emergence of a shareholder value orientation in the Netherlands

NARCIS (Netherlands)

P.J. Bezemer (Pieter-Jan)

2010-01-01

textabstractThe globalization and liberalization of national economies have contributed to an increasing diffusion of Anglo-American corporate governance practices worldwide. In this dissertation, we examine the spread of two types of corporate governance beliefs: the emerging focus on board

14 CFR 250.5 - Amount of denied boarding compensation for passengers denied boarding involuntarily.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Amount of denied boarding compensation for passengers denied boarding involuntarily. 250.5 Section 250.5 Aeronautics and Space OFFICE OF THE SECRETARY... boarding compensation for passengers denied boarding involuntarily. (a) Subject to the exceptions provided...

The percentage of bacterial genes on leading versus lagging strands is influenced by multiple balancing forces

Science.gov (United States)

Mao, Xizeng; Zhang, Han; Yin, Yanbin; Xu, Ying

2012-01-01

The majority of bacterial genes are located on the leading strand, and the percentage of such genes has a large variation across different bacteria. Although some explanations have been proposed, these are at most partial explanations as they cover only small percentages of the genes and do not even consider the ones biased toward the lagging strand. We have carried out a computational study on 725 bacterial genomes, aiming to elucidate other factors that may have influenced the strand location of genes in a bacterium. Our analyses suggest that (i) genes of some functional categories such as ribosome have higher preferences to be on the leading strands; (ii) genes of some functional categories such as transcription factor have higher preferences on the lagging strands; (iii) there is a balancing force that tends to keep genes from all moving to the leading and more efficient strand and (iv) the percentage of leading-strand genes in an bacterium can be accurately explained based on the numbers of genes in the functional categories outlined in (i) and (ii), genome size and gene density, indicating that these numbers implicitly contain the information about the percentage of genes on the leading versus lagging strand in a genome. PMID:22735706

Learning and Study Strategies Inventory subtests and factors as predictors of National Board of Chiropractic Examiners Part 1 examination performance.

Science.gov (United States)

Schutz, Christine M; Dalton, Leanne; Tepe, Rodger E

2013-01-01

This study was designed to extend research on the relationship between chiropractic students' learning and study strategies and national board examination performance. Sixty-nine first trimester chiropractic students self-administered the Learning and Study Strategies Inventory (LASSI). Linear trends tests (for continuous variables) and Mantel-Haenszel trend tests (for categorical variables) were utilized to determine if the 10 LASSI subtests and 3 factors predicted low, medium and high levels of National Board of Chiropractic Examiners (NBCE) Part 1 scores. Multiple regression was performed to predict overall mean NBCE examination scores using the 3 LASSI factors as predictor variables. Four LASSI subtests (Anxiety, Concentration, Selecting Main Ideas, Test Strategies) and one factor (Goal Orientation) were significantly associated with NBCE examination levels. One factor (Goal Orientation) was a significant predictor of overall mean NBCE examination performance. Learning and study strategies are predictive of NBCE Part 1 examination performance in chiropractic students. The current study found LASSI subtests Anxiety, Concentration, Selecting Main Ideas, and Test Strategies, and the Goal-Orientation factor to be significant predictors of NBCE scores. The LASSI may be useful to educators in preparing students for academic success. Further research is warranted to explore the effects of learning and study strategies training on GPA and NBCE performance.

Postreplicational formation and repair of DNA double-strand breaks in UV-irradiated Escherichia coli uvrB cells

International Nuclear Information System (INIS)

Wang, Tzuchien V.; Smith, K.C.

1986-01-01

The number of DNA double-strand breaks formed in UV-irradiated uvrB recF recB cells correlates with the number of unrepaired DNA daughter-strand gaps, and is dependent on DNA synthesis after UV-irradiation. These results are consistent with the model that the DNA double-strand breaks that are produced in UV-irradiated excision-deficient cells occur as the result of breaks in the parental DNA opposite unrepaired DNA daughter-strand gaps. By employing a temperature-sensitive recA200 mutation, we have devised an improved assay for studying the formation and repair of these DNA double-strand breaks. Possible mechanisms for the postreplication repair of DNA double-strand breaks are discussed. (Auth.)

Refinement of boards' role required.

Science.gov (United States)

Umbdenstock, R J

1987-01-01

The governing board's role in health care is not changing, but new competitive forces necessitate a refinement of the board's approach to fulfilling its role. In a free-standing, community, not-for-profit hospital, the board functions as though it were the "owner." Although it does not truly own the facility in the legal sense, the board does have legal, fiduciary, and financial responsibilities conferred on it by the state. In a religious-sponsored facility, the board fulfills these same obligations on behalf of the sponsoring institute, subject to the institute's reserved powers. In multi-institutional systems, the hospital board's power and authority depend on the role granted it by the system. Boards in all types of facilities are currently faced with the following challenges: Fulfilling their basic responsibilities, such as legal requirements, financial duties, and obligations for the quality of care. Encouraging management and the board itself to "think strategically" in attacking new competitive market forces while protecting the organization's traditional mission and values. Assessing recommended strategies in light of consequences if constituencies think the organization is abandoning its commitments. Boards can take several steps to match their mode of operation with the challenges of the new environment. Boards must rededicate themselves to the hospital's mission. Trustees must expand their understanding of health care trends and issues and their effect on the organization. Boards must evaluate and help strengthen management's performance, rather than acting as a "watchdog" in an adversarial position. Boards must think strategically, rather than focusing solely on operational details. Boards must evaluate the methods they use for conducting business.

Decamp Clock Board Firmware

Energy Technology Data Exchange (ETDEWEB)

Vicente, J. de; Castilla, J.; Martinez, G.

2007-09-27

Decamp (Dark Energy Survey Camera) is a new instrument designed to explore the universe aiming to reveal the nature of Dark Energy. The camera consists of 72 CCDs and 520 Mpixels. The readout electronics of DECam is based on the Monsoon system. Monsoon is a new image acquisition system developed by the NOAO (National Optical Astronomical Observatory) for the new generation of astronomical cameras. The Monsoon system uses three types of boards inserted in a Eurocard format based crate: master control board, acquisition board and clock board. The direct use of the Monsoon system for DECam readout electronics requires nine crates mainly due to the high number of clock boards needed. Unfortunately, the available space for DECam electronics is constrained to four crates at maximum. The major drawback to achieve such desired compaction degree resides in the clock board signal density. This document describes the changes performed at CIEMAT on the programmable logic of the Monsoon clock board aiming to meet such restricted space constraints. (Author) 5 refs.

Decamp Clock Board Firmware

International Nuclear Information System (INIS)

Vicente, J. de; Castilla, J.; Martinez, G.

2007-01-01

Decamp (Dark Energy Survey Camera) is a new instrument designed to explore the universe aiming to reveal the nature of Dark Energy. The camera consists of 72 CCDs and 520 Mpixels. The readout electronics of DECam is based on the Monsoon system. Monsoon is a new image acquisition system developed by the NOAO (National Optical Astronomical Observatory) for the new generation of astronomical cameras. The Monsoon system uses three types of boards inserted in a Eurocard format based crate: master control board, acquisition board and clock board. The direct use of the Monsoon system for DECam readout electronics requires nine crates mainly due to the high number of clock boards needed. Unfortunately, the available space for DECam electronics is constrained to four crates at maximum. The major drawback to achieve such desired compaction degree resides in the clock board signal density. This document describes the changes performed at CIEMAT on the programmable logic of the Monsoon clock board aiming to meet such restricted space constraints. (Author) 5 refs

Probing electronic coupling between adenine bases in RNA strands from synchrotron radiation circular dichroism experiments

DEFF Research Database (Denmark)

Nielsen, Lisbeth Munksgård; Hoffmann, Søren Vrønning; Nielsen, Steen Brøndsted

2012-01-01

Circular dichroism spectra (176–330 nm) of RNA adenine oligomers, (rA)n (n = 1–10, 12, 15, and 20), reveal electronic coupling between two bases in short strands. The number of interacting bases in long strands is more and larger than that reported previously for the corresponding DNA strands....

Transmission pricing and stranded costs in the electric power industry

International Nuclear Information System (INIS)

Baumol, W.J.; Sidak, J.G.

1995-09-01

Stranded costs are those costs that electric utilities are currently permitted to recover through their rates but whose recovery may be impeded or prevented by the advent of competition in the industry. Estimates of these costs run from the tens to the hundreds of billions of dollars. Should regulators permit utilities to recover stranded costs while they take steps to promote competition in the electric power industry. William Baumol and J. Gregory Sidak argue that answer to that question should be yes.The authors show that a transmission price, the price for sending electricity over the transmission grid, can be determined in a manner that is compatible with economic efficiency and clearly neutral in its effects upon all competitors in electricity generation. A correctly constructed regime of transmission pricing may in fact achieve the efficiency and equity goals that justify the recovery of stranded costs

Informal Science learning in PIBID: identifying and interpreting the strands

Directory of Open Access Journals (Sweden)

Thomas Barbosa Fejolo

2013-10-01

Full Text Available This paper presents a research on informal Science learning in the context of the Institutional Scholarship Program Initiation to Teaching (PIBID. We take as reference the strands of informal Science learning (FAC, representing six dimensions of learning, they are: 1 Development of interest in Science; 2 Understanding of scientific knowledge; 3 Engaging in scientific reasoning; 4 Reflection on Science; 5 Engagement in scientific practice; 6 Identification with Science. For the lifting data, it was used the filming record of the interactions and dialogues of undergraduate students while performing activities of Optical Spectroscopy in the laboratory. Based on the procedures of content analysis and interpretations through communication, we investigate which of the six strands were present during the action of the students in activities. As a result we have drawn a learning profile for each student by distributing communications in different strands of informal Science learning.

7 CFR 1755.370 - RUS specification for seven wire galvanized steel strand.

Science.gov (United States)

2010-01-01

... 7 Agriculture 11 2010-01-01 2010-01-01 false RUS specification for seven wire galvanized steel..., ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.370 RUS specification for seven wire galvanized... Steel Wire Strand, issued May 1978. All seven wire galvanized steel strand purchased after April 1, 1990...

Enhanced Strain Measurement Range of an FBG Sensor Embedded in Seven-Wire Steel Strands.

Science.gov (United States)

Kim, Jae-Min; Kim, Chul-Min; Choi, Song-Yi; Lee, Bang Yeon

2017-07-18

FBG sensors offer many advantages, such as a lack of sensitivity to electromagnetic waves, small size, high durability, and high sensitivity. However, their maximum strain measurement range is lower than the yield strain range (about 1.0%) of steel strands when embedded in steel strands. This study proposes a new FBG sensing technique in which an FBG sensor is recoated with polyimide and protected by a polyimide tube in an effort to enhance the maximum strain measurement range of FBG sensors embedded in strands. The validation test results showed that the proposed FBG sensing technique has a maximum strain measurement range of 1.73% on average, which is 1.73 times higher than the yield strain of the strands. It was confirmed that recoating the FBG sensor with polyimide and protecting the FBG sensor using a polyimide tube could effectively enhance the maximum strain measurement range of FBG sensors embedded in strands.

Reconstitution of a eukaryotic replisome reveals suppression mechanisms that define leading/lagging strand operation

Science.gov (United States)

Georgescu, Roxana E; Schauer, Grant D; Yao, Nina Y; Langston, Lance D; Yurieva, Olga; Zhang, Dan; Finkelstein, Jeff; O'Donnell, Mike E

2015-01-01

We have reconstituted a eukaryotic leading/lagging strand replisome comprising 31 distinct polypeptides. This study identifies a process unprecedented in bacterial replisomes. While bacteria and phage simply recruit polymerases to the fork, we find that suppression mechanisms are used to position the distinct eukaryotic polymerases on their respective strands. Hence, Pol ε is active with CMG on the leading strand, but it is unable to function on the lagging strand, even when Pol δ is not present. Conversely, Pol δ-PCNA is the only enzyme capable of extending Okazaki fragments in the presence of Pols ε and α. We have shown earlier that Pol δ-PCNA is suppressed on the leading strand with CMG (Georgescu et al., 2014). We propose that CMG, the 11-subunit helicase, is responsible for one or both of these suppression mechanisms that spatially control polymerase occupancy at the fork. DOI: http://dx.doi.org/10.7554/eLife.04988.001 PMID:25871847

77 FR 2958 - Prestressed Concrete Steel Wire Strand From Thailand: Correction to Notice of Opportunity To...

Science.gov (United States)

2012-01-20

... DEPARTMENT OF COMMERCE International Trade Administration [A-549-820] Prestressed Concrete Steel Wire Strand From Thailand: Correction to Notice of Opportunity To Request Administrative Review AGENCY... prestressed concrete steel wire strand (``PC Strand'') from Thailand. See Antidumping or Countervailing Duty...

Rigidity of the polypeptide backbone in the triple-stranded collagen molecule.

Science.gov (United States)

Nemethy, G

1981-02-01

Conformational energy computations were carried out on collagen-like triple-stranded conformations of several polytripeptides with the structure CH3CO(GXY)3NHCH3, where X and Y can be Pro, Ala, or Gly. The computed minimum-energy conformations for various sequences are compared with that computed earlier for poly(Gly-Pro-Pro). Usually, substitution of Ala or Gly residues for Pro does not cause any strain or distortion of the conformation of the triple-stranded complex. Thus, the structure is a very stable and essentially rigid one. Unfavorable interactions were found only in the case of CH3CO(Gly-Ala-Pro)NHCH3. These interactions are a consequence of differences between the residue geometry of Ala and Pro. They result in small changes of some backbone dihedral angles and in an increase of intra- and interchain energies. The presence of a single Gly-Ala-Pro tripeptide within a sequence of Gly-Pro-Pro tripeptides is not sufficient, however, to cause even a small distoration of the triple strand. No deviation of the peptide groups from planarity is required to stabilize the triple-stranded structure.

Magnetization anomaly of Nb3Al strands and instability of Nb3Al Rutherford cables

International Nuclear Information System (INIS)

Yamada, Ryuji; Kikuchi, Akihiro; Wake, Masayoshi

2006-01-01

Using a Cu stabilized Nb 3 Al strand with Nb matrix, a 30 meter long Nb 3 Al Rutherford cable was made by a collaboration of Fermilab and NIMS. Recently the strand and cable were tested. In both cases instability was observed at around 1.5 Tesla. The magnetization of this Nb 3 Al strand was measured first using a balanced coil magnetometer at 4.2 K. Strands showed an anomalously large magnetization behavior around at 1.6 T, which is much higher than the usual B c2 ∼ 0.5 Tesla (4.2 K) of Nb matrix. This result is compared with the magnetization data of short strand samples using a SQUID magnetometer, in which a flux-jump signal was observed at 0.5 Tesla, but not at higher field. As a possible explanation for this magnetization anomaly, the interfilament coupling through the thin Nb films in the strands is suggested. The instability problem observed in low field tests of the Nb 3 Al Rutherford cables is attributed to this effect

Two-dimensional numerical simulation of flow around three-stranded rope

Science.gov (United States)

Wang, Xinxin; Wan, Rong; Huang, Liuyi; Zhao, Fenfang; Sun, Peng

2016-08-01

Three-stranded rope is widely used in fishing gear and mooring system. Results of numerical simulation are presented for flow around a three-stranded rope in uniform flow. The simulation was carried out to study the hydrodynamic characteristics of pressure and velocity fields of steady incompressible laminar and turbulent wakes behind a three-stranded rope. A three-cylinder configuration and single circular cylinder configuration are used to model the three-stranded rope in the two-dimensional simulation. The governing equations, Navier-Stokes equations, are solved by using two-dimensional finite volume method. The turbulence flow is simulated using Standard κ-ɛ model and Shear-Stress Transport κ-ω (SST) model. The drag of the three-cylinder model and single cylinder model is calculated for different Reynolds numbers by using control volume analysis method. The pressure coefficient is also calculated for the turbulent model and laminar model based on the control surface method. From the comparison of the drag coefficient and the pressure of the single cylinder and three-cylinder models, it is found that the drag coefficients of the three-cylinder model are generally 1.3-1.5 times those of the single circular cylinder for different Reynolds numbers. Comparing the numerical results with water tank test data, the results of the three-cylinder model are closer to the experiment results than the single cylinder model results.

Enzymatic quantification of strand breaks of DNA induced by vacuum-UV radiation

International Nuclear Information System (INIS)

Ito, Takashi

1986-01-01

Hind3 digested plasmid DNA dried on an aluminum plate was irradiated by vacuum-UV at 160 and 195 nm using a synchrotron irradiation system. A change induced in the DNA, presumably a single strand break, was quantified by the aid of the strand break-derived stimulation of poly(ADP-ribose) synthetase activity. The end group of strand breaks so induced was recognized by the enzyme as effectively as that by DNase 1 treatment, suggesting a nicking as the major lesion inflicted on the DNA. The fluence (UV) dependent stimulation of poly(ADP-ribose) synthetase activity was much higher upon 160 nm irradiation than upon 195 nm irradiation. (Auth.)

Prediction of guide strand of microRNAs from its sequence and secondary structure

Directory of Open Access Journals (Sweden)

Ahmed Firoz

2009-04-01

Full Text Available Abstract Background MicroRNAs (miRNAs are produced by the sequential processing of a long hairpin RNA transcript by Drosha and Dicer, an RNase III enzymes, and form transitory small RNA duplexes. One strand of the duplex, which incorporates into RNA-induced silencing complex (RISC and silences the gene expression is called guide strand, or miRNA; while the other strand of duplex is degraded and called the passenger strand, or miRNA*. Predicting the guide strand of miRNA is important for better understanding the RNA interference pathways. Results This paper describes support vector machine (SVM models developed for predicting the guide strands of miRNAs. All models were trained and tested on a dataset consisting of 329 miRNA and 329 miRNA* pairs using five fold cross validation technique. Firstly, models were developed using mono-, di-, and tri-nucleotide composition of miRNA strands and achieved the highest accuracies of 0.588, 0.638 and 0.596 respectively. Secondly, models were developed using split nucleotide composition and achieved maximum accuracies of 0.553, 0.641 and 0.602 for mono-, di-, and tri-nucleotide respectively. Thirdly, models were developed using binary pattern and achieved the highest accuracy of 0.708. Furthermore, when integrating the secondary structure features with binary pattern, an accuracy of 0.719 was seen. Finally, hybrid models were developed by combining various features and achieved maximum accuracy of 0.799 with sensitivity 0.781 and specificity 0.818. Moreover, the performance of this model was tested on an independent dataset that achieved an accuracy of 0.80. In addition, we also compared the performance of our method with various siRNA-designing methods on miRNA and siRNA datasets. Conclusion In this study, first time a method has been developed to predict guide miRNA strands, of miRNA duplex. This study demonstrates that guide and passenger strand of miRNA precursors can be distinguished using their

Conformal geometry and invariants of 3-strand Brownian braids

International Nuclear Information System (INIS)

Nechaev, Sergei; Voituriez, Raphael

2005-01-01

We propose a simple geometrical construction of topological invariants of 3-strand Brownian braids viewed as world lines of 3 particles performing independent Brownian motions in the complex plane z. Our construction is based on the properties of conformal maps of doubly-punctured plane z to the universal covering surface. The special attention is paid to the case of indistinguishable particles. Our method of conformal maps allows us to investigate the statistical properties of the topological complexity of a bunch of 3-strand Brownian braids and to compute the expectation value of the irreducible braid length in the non-Abelian case

Possible causes of a harbour porpoise mass stranding in Danish waters in 2005.

Directory of Open Access Journals (Sweden)

Andrew J Wright

Full Text Available An unprecedented 85 harbour porpoises stranded freshly dead along approximately 100 km of Danish coastline from 7-15 April, 2005. This total is considerably above the mean weekly stranding rate for the whole of Denmark, both for any time of year, 1.23 animals/week (ranging from 0 to 20 during 2003-2008, excluding April 2005, and specifically in April, 0.65 animals/week (0 to 4, same period. Bycatch was established as the cause of death for most of the individuals through typical indications of fisheries interactions, including net markings in the skin and around the flippers, and loss of tail flukes. Local fishermen confirmed unusually large porpoise bycatch in nets set for lumpfish (Cyclopterus lumpus and the strandings were attributed to an early lumpfish season. However, lumpfish catches for 2005 were not unusual in terms of season onset, peak or total catch, when compared to 2003-2008. Consequently, human activity was combined with environmental factors and the variation in Danish fisheries landings (determined through a principal component analysis in a two-part statistical model to assess the correlation of these factors with both the presence of fresh strandings and the numbers of strandings on the Danish west coast. The final statistical model (which was forward selected using Akaike information criterion; AIC indicated that naval presence is correlated with higher rates of porpoise strandings, particularly in combination with certain fisheries, although it is not correlated with the actual presence of strandings. Military vessels from various countries were confirmed in the area from the 7th April, en route to the largest naval exercise in Danish waters to date (Loyal Mariner 2005, 11-28 April. Although sonar usage cannot be confirmed, it is likely that ships were testing various equipment prior to the main exercise. Thus naval activity cannot be ruled out as a possible contributing factor.

Untangling the Strands of the Fourteenth Amendment.

Science.gov (United States)

Lupu, Ira C.

1979-01-01

Explores trends in the Court's interpretation of the libertarian and egalitarian dimensions of the Fourteenth Amendment and offers a theory of the two strands. Available from Michigan Law Review, Hutchins Hall, Ann Arbor, MI 48109; single issues $3.50. (Author/IRT)

What makes great boards great.

Science.gov (United States)

Sonnenfeld, Jeffrey A

2002-09-01

In the wake of meltdowns at WorldCom, Tyco, and Enron, enormous attention has been focused on the companies' boards. It seems inconceivable that business disasters of such magnitude could happen without gross or even criminal negligence on the part of board members. And yet a close examination of those boards reveals no broad pattern of incompetence or corruption. In fact, they followed most of the accepted standards for board operations: Members showed up for meetings; they had money invested in the company; audit committees, compensation committees, and codes of ethics were in place; the boards weren't too small or too big, nor were they dominated by insiders. In other words, they passed the tests that would normally be applied to determine whether a board of directors was likely to do a good job. And that's precisely what's so scary, according to corporate governance expert Jeffrey Sonnenfeld, who suggests that it's time for some new thinking about how corporate boards operate and are evaluated. He proposes thinking not only about how to structure the board's work but also about how to manage it as a social system. Good boards are, very simply, high-functioning work groups. They're distinguished by a climate of respect, trust, and candor among board members and between the board and management. Information is shared openly and on time; emergent political factions are quickly eliminated. Members feel free to challenge one another's assumptions and conclusions, and management encourages lively discussion of strategic issues. Directors feel a responsibility to contribute meaningfully to the board's performance. In addition, good boards assess their own performance, both collectively and individually.

Methods for the preparation of large quantities of complex single-stranded oligonucleotide libraries.

Science.gov (United States)

Murgha, Yusuf E; Rouillard, Jean-Marie; Gulari, Erdogan

2014-01-01

Custom-defined oligonucleotide collections have a broad range of applications in fields of synthetic biology, targeted sequencing, and cytogenetics. Also, they are used to encode information for technologies like RNA interference, protein engineering and DNA-encoded libraries. High-throughput parallel DNA synthesis technologies developed for the manufacture of DNA microarrays can produce libraries of large numbers of different oligonucleotides, but in very limited amounts. Here, we compare three approaches to prepare large quantities of single-stranded oligonucleotide libraries derived from microarray synthesized collections. The first approach, alkaline melting of double-stranded PCR amplified libraries with a biotinylated strand captured on streptavidin coated magnetic beads results in little or no non-biotinylated ssDNA. The second method wherein the phosphorylated strand of PCR amplified libraries is nucleolyticaly hydrolyzed is recommended when small amounts of libraries are needed. The third method combining in vitro transcription of PCR amplified libraries to reverse transcription of the RNA product into single-stranded cDNA is our recommended method to produce large amounts of oligonucleotide libraries. Finally, we propose a method to remove any primer binding sequences introduced during library amplification.

Estimation of Prestress Force Distribution in Multi-Strand System of Prestressed Concrete Structures Using Field Data Measured by Electromagnetic Sensor.

Science.gov (United States)

Cho, Keunhee; Cho, Jeong-Rae; Kim, Sung Tae; Park, Sung Yong; Kim, Young-Jin; Park, Young-Hwan

2016-08-18

The recently developed smart strand can be used to measure the prestress force in the prestressed concrete (PSC) structure from the construction stage to the in-service stage. The higher cost of the smart strand compared to the conventional strand renders it unaffordable to replace all the strands by smart strands, and results in the application of only a limited number of smart strands in the PSC structure. However, the prestress forces developed in the strands of the multi-strand system frequently adopted in PSC structures differ from each other, which means that the prestress force in the multi-strand system cannot be obtained by simple proportional scaling using the measurement of the smart strand. Therefore, this study examines the prestress force distribution in the multi-strand system to find the correlation between the prestress force measured by the smart strand and the prestress force distribution in the multi-strand system. To that goal, the prestress force distribution was measured using electromagnetic sensors for various factors of the multi-strand system adopted on site in the fabrication of actual PSC girders. The results verified the possibility to assume normal distribution for the prestress force distribution per anchor head, and a method computing the mean and standard deviation defining the normal distribution is proposed. This paper presents a meaningful finding by proposing an estimation method of the prestress force based upon field-measured data of the prestress force distribution in the multi-strand system of actual PSC structures.

Ontario electricity industry restructuring : preliminary asset valuation and calculation of stranded debt

International Nuclear Information System (INIS)

1998-01-01

The rationale for restructuring Ontario's electricity industry was restated. Financial elements of the Government's White Paper on the electrical industry included the following: (1) establishing a level playing field on taxes and regulation, (2) restructuring Ontario Hydro into new companies with clear business mandates, and (3) taking action to put the new companies on solid financial ground. To achieve these objectives requires valuation of the new companies as a key part in the restructuring process. This Ministry of Finance document contains preliminary estimates of the total debt and liabilities of Ontario Hydro ($ 39.1 billion), the value of the new generation and service companies ($ 15.8 billion), and the stranded debt ($ 23.3 billion, less the value of dedicated revenue streams of $ 15.4 billion, equal to the residual stranded debt of $ 7.9 billion). The method by which the stranded debt was calculated is also described. It is stressed that the overriding principles governing the financial restructuring plan are to achieve restructuring without increasing electricity rates, to retain maximum value in the electricity sector until stranded debt is retired, and to recover stranded debt from the electricity sector and not from taxpayers. Ministry advisors indicate that these preliminary valuations would allow the new companies to operate as commercial companies in a competitive market and receive investment grade credit ratings. 44 figs

Double Strand Break Repair, one mechanism can hide another: Alternative non-homologous end joining

International Nuclear Information System (INIS)

Rass, E.; Grabarz, A.; Bertrand, P.; Lopez, B.S.

2012-01-01

DNA double strand breaks are major cytotoxic lesions encountered by the cells. They can be induced by ionizing radiation or endogenous stress and can lead to genetic instability. Two mechanisms compete for the repair of DNA double strand breaks: homologous recombination and non-homologous end joining (NHEJ). Homologous recombination requires DNA sequences homology and is initiated by single strand resection. Recently, advances have been made concerning the major steps and proteins involved in resection. NHEJ, in contrast, does not require sequence homology. The existence of a DNA double strand break repair mechanism, independent of KU and ligase IV, the key proteins of the canonical non homologous end joining pathway, has been revealed lately and named alternative non homologous end joining. The hallmarks of this highly mutagenic pathway are deletions at repair junctions and frequent use of distal micro-homologies. This mechanism is also initiated by a single strand resection of the break. The aim of this review is firstly to present recent data on single strand resection, and secondly the alternative NHEJ pathway, including a discussion on the fidelity of NHEJ. Based on current knowledge, canonical NHEJ does not appear as an intrinsically mutagenic mechanism, but in contrast, as a conservative one. The structure of broken DNA ends actually dictates the quality repair of the alternative NHEJ and seems the actual responsible for the mutagenesis attributed beforehand to the canonical NHEJ. The existence of this novel DNA double strand breaks repair mechanism needs to be taken into account in the development of radiosensitizing strategies in order to optimise the efficiency of radiotherapy. (authors)

The Perceptions of Georgia School Board Members' Need for Training on School Board Governance

Science.gov (United States)

Nutt, Pamela Studdard

2010-01-01

This study explored the perceptions of training needs of school board members in Georgia. The study examined perceptions of school board chairs, board members with 1 to 5 years experience, members with 6 to 10 years experience, members with 11 to 15 years experience and board members with 16 plus years experience in the areas of school board…

77 FR 55837 - Board Meeting

Science.gov (United States)

2012-09-11

... FARM CREDIT SYSTEM INSURANCE CORPORATION Board Meeting AGENCY: Farm Credit System Insurance Corporation. ACTION: Regular meeting. SUMMARY: Notice is hereby given of the regular meeting of the Farm Credit System Insurance Corporation Board (Board). Date and Time: The meeting of the Board will be held...

75 FR 9196 - Letter From Secretary of Energy Accepting Defense Nuclear Facilities Safety Board (Board...

Science.gov (United States)

2010-03-01

... DEPARTMENT OF ENERGY Letter From Secretary of Energy Accepting Defense Nuclear Facilities Safety Board (Board) Recommendation 2009-2 AGENCY: Department of Energy. ACTION: Notice. SUMMARY: The...: The Department of Energy (DOE) acknowledges receipt of Defense Nuclear Facilities Safety Board (Board...

Board affiliation and pay gap

Directory of Open Access Journals (Sweden)

Shenglan Chen

2014-06-01

Full Text Available This paper examines the effects of board affiliation on the corporate pay gap. Using a sample of Chinese listed firms from 2005 to 2011, we find that boards with a greater presence of directors appointed by block shareholders have lower pay gaps. Furthermore, the governance effects of board affiliation with and without pay are distinguished. The empirical results show that board affiliation without pay is negatively related to the pay gap, while board affiliation with pay is positively related to the pay gap. Overall, the results shed light on how block shareholders affect their companies’ pay gaps through board affiliation.

49 CFR 1011.2 - The Board.

Science.gov (United States)

2010-10-01

... TRANSPORTATION GENERAL RULES AND REGULATIONS BOARD ORGANIZATION; DELEGATIONS OF AUTHORITY § 1011.2 The Board. (a... submitted for decision except those assigned to an individual Board Member or employee or an employee board...) The Board may bring before it any matter assigned to an individual Board Member or employee or...

The general atomic strand winding machine

International Nuclear Information System (INIS)

Matt, P.

1976-01-01

In conjunction with the integrated development of their high temperature gas cooled reactors (HTGR), General Atomic of San Diego, USA, also developed a strand winding system for the horizontal prestressing of pressure vessels. The machine lay-out, its capabilities and the test program carried out in the laboratory and on a full scale pressure vessel model are described. (author)

The (not so immortal strand hypothesis

Directory of Open Access Journals (Sweden)

Cristian Tomasetti

2015-03-01

Significance: Utilizing an approach that is fundamentally different from previous efforts to confirm or refute the immortal strand hypothesis, we provide evidence against non-random segregation of DNA during stem cell replication. Our results strongly suggest that parental DNA is passed randomly to stem cell daughters and provides new insight into the mechanism of DNA replication in stem cells.

Janet L. Yellen resigned as a member of the Board of Governors, effective February 17, 1997

OpenAIRE

anonymous

1997-01-01

It has been a privilege, an honor, and an education to serve as a member of the Federal Reserve Board since August, 1994. I have found it enormously rewarding to help craft a monetary policy oriented toward job creation and price stability, new supervisory and regulatory approaches to insure the safe and sound operation of our financial system, and programs in the areas of community and economic development. ..

78 FR 4847 - Board Meeting

Science.gov (United States)

2013-01-23

... FARM CREDIT SYSTEM INSURANCE CORPORATION Board Meeting AGENCY: Farm Credit System Insurance Corporation. SUMMARY: Notice is hereby given of the regular meeting of the Farm Credit System Insurance Corporation Board (Board). DATE AND TIME: The meeting of the Board will be held at the offices of the Farm...

Mouse RAD54 affects DNA double-strand break repair and sister chromatid exchange

NARCIS (Netherlands)

H.B. Beverloo (Berna); R.D. Johnson (Roger); M. Jasin (Maria); R. Kanaar (Roland); J.H.J. Hoeijmakers (Jan); M.L.G. Dronkert (Mies)

2000-01-01

textabstractCells can achieve error-free repair of DNA double-strand breaks (DSBs) by homologous recombination through gene conversion with or without crossover. In contrast, an alternative homology-dependent DSB repair pathway, single-strand annealing (SSA), results in deletions. In this study, we

DNA template strand sequencing of single-cells maps genomic rearrangements at high resolution

NARCIS (Netherlands)

Falconer, Ester; Hills, Mark; Naumann, Ulrike; Poon, Steven S. S.; Chavez, Elizabeth A.; Sanders, Ashley D.; Zhao, Yongjun; Hirst, Martin; Lansdorp, Peter M.

DNA rearrangements such as sister chromatid exchanges (SCEs) are sensitive indicators of genomic stress and instability, but they are typically masked by single-cell sequencing techniques. We developed Strand-seq to independently sequence parental DNA template strands from single cells, making it

NbTi Strands Verification for ITER PF CICC Process Qualification of CNDA

Science.gov (United States)

Liu, F.; Liu, H.; Liu, S.; Liu, B.; Lei, L.; Wu, Y.

2014-05-01

China is in charge of most of Poloidal Field (PF) conductors production for the International Thermonuclear Experimental Reactor (ITER). The execution for PF conductors shall be in three main phases. According to ITER Procurement Arrangement (PA), the Domestic Agency (DA) shall be required to verify the room and low temperature acceptance tests carried out by the strand suppliers. As the reference laboratory of Chinese DA (CNDA), the superconducting strands test laboratory of Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) was undertaking the task of strands verification for ITER conductors. The verification test includes: diameter, Nickel plating thickness, copper-to-non-copper volume ratio, twist pitch direction and length, standard critical current (IC) and resistive transition index (n), residual resistance ration (RRR), and hysteresis loss. 48 NbTi strands with 7 billets were supplied for the PF Cable-In-Conduit Conductor (CICC) process qualification. In total, 54 samples were measured. The verification level for PF CICC process qualification was 100%. The test method, facility and results of each item are described in detail in this publication.

Interstrand cross-links arising from strand breaks at true abasic sites in duplex DNA

OpenAIRE

Yang, Zhiyu; Price, Nathan E.; Johnson, Kevin M.; Wang, Yinsheng; Gates, Kent S.

2017-01-01

Abstract Interstrand cross-links are exceptionally bioactive DNA lesions. Endogenous generation of interstrand cross-links in genomic DNA may contribute to aging, neurodegeneration, and cancer. Abasic (Ap) sites are common lesions in genomic DNA that readily undergo spontaneous and amine-catalyzed strand cleavage reactions that generate a 2,3-didehydro-2,3-dideoxyribose sugar remnant (3?ddR5p) at the 3?-terminus of the strand break. Interestingly, this strand scission process leaves an electr...

Pilot Boarding Areas

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Pilot boarding areas are locations at sea where pilots familiar with local waters board incoming vessels to navigate their passage to a destination port. Pilotage is...

THE INSTABILITY AND NON-EXISTENCE OF MULTI-STRANDED LOOPS WHEN DRIVEN BY TRANSVERSE WAVES

Energy Technology Data Exchange (ETDEWEB)

Magyar, N.; Van Doorsselaere, T., E-mail: norbert.magyar@wis.kuleuven.be [Centre for Mathematical Plasma Astrophysics (CmPA), KU Leuven, Celestijnenlaan 200B bus 2400, 3001 Leuven (Belgium)

2016-06-01

In recent years, omni-present transverse waves have been observed in all layers of the solar atmosphere. Coronal loops are often modeled as a collection of individual strands in order to explain their thermal behavior and appearance. We perform three-dimensional (3D) ideal magnetohydrodynamics simulations to study the effect of a continuous small amplitude transverse footpoint driving on the internal structure of a coronal loop composed of strands. The output is also converted into synthetic images, corresponding to the AIA 171 and 193 Å passbands, using FoMo. We show that the multi-stranded loop ceases to exist in the traditional sense of the word, because the plasma is efficiently mixed perpendicularly to the magnetic field, with the Kelvin–Helmholtz instability acting as the main mechanism. The final product of our simulation is a mixed loop with density structures on a large range of scales, resembling a power-law. Thus, multi-stranded loops are unstable to driving by transverse waves, and this raises strong doubts on the usability and applicability of coronal loop models consisting of independent strands.

Board Certification in Counseling Psychology

Science.gov (United States)

Crowley, Susan L.; Lichtenberg, James W.; Pollard, Jeffrey W.

2012-01-01

Although specialty board certification by the American Board of Professional Psychology (ABPP) has been a valued standard for decades, the vast majority of counseling psychologists do not pursue board certification in the specialty. The present article provides a brief history of board certification in general and some historical information about…

Women on Boards and Corporate Social Responsibility

Directory of Open Access Journals (Sweden)

Eunjung Hyun

2016-03-01

Full Text Available A growing body of research suggests that having more women in the boardroom leads to better corporate social responsibility (CSR performance. However, much of this work views the CSR-enhancing effect of women directors as largely driven by their moral orientations and rarely considers other underlying mechanisms. Moreover, less explored are the firm-specific conditions under which such CSR-promoting roles of female directors might be performed more (or less effectively. In this paper, we seek to bridge this gap in the literature by (1 proposing an additional account for the positive influence of female independent directors on the firm’s CSR and (2 illuminating the organizational context in which female directorship is likely to translate into good CSR performance. We argue that women independent directors might take CSR issues more seriously than their male counterparts not only because of their stronger moral orientations, but also because they have reputational reasons to do so. Further, we suggest that female directors’ concerns about CSR-relevant matters are more (less likely to gain support from other members of the organization when their company is doing more (less business in the product markets where reputation for CSR is more (less vital for success. Using a sample of Standard & Poor’s (S&P 1500 index firms (2000–2009 and the data on their board composition and CSR ratings, we find strong support for our argument. We find that the number (or proportion of women independent directors is positively associated with a firm’s CSR ratings and that the strength of this relationship depends on the level of the firm’s consumer market orientation.

Detection of DNA strand breaks in mammalian cells using the radioresistant bacterium PprA protein

International Nuclear Information System (INIS)

Satoh, Katsuya; Wada, Seiichi; Narumi, Issay; Kikuchi, Masahiro; Funayama, Tomoo; Kobayashi, Yasuhiko

2003-01-01

We have previously found that the PprA protein from Deinococcus radiodurans possesses ability to recognize DNA carrying strand breaks. In the present study, we attempted to visualize radiation-induced DNA strand breaks with PprA protein using immunofluorescence technique to elucidate the DNA damage response mechanism in mammalian cultured cells. As a result, colocalization of Cy2 and DAPI fluorescent signals was observed. This observation suggests that DNA strand breaks in the nucleus of CHO-K1 cells were effectively detected using the PprA protein. The amount of DNA strand breaks (integrated density of Cy2 fluorescent signals) was increased with the increase in the radiation dose. (author)

Industry participation workshop: Chromium electroplating of superconductor strand. Proceedings

International Nuclear Information System (INIS)

1994-01-01

The primary objective of the workshop was to inform US plating vendors about the opportunity to participate in the effort on Cr plating of large quantities of superconducting wires required for the ITER and the TPX projects and DOE's interest in developing several reliable and high quality suppliers of Chromium plating services for the superconducting strand industry. The objective was also to inform plating vendors about the Cr plating technology developed in LLNL and invite interested plating vendors to get the technology. Finally the workshop was intended to inform the plating vendors about the plan to get verification of capability of two to four vendors for Cr plating of superconducting strands

Nucleic Acid Analogue Induced Transcription of Double Stranded DNA

DEFF Research Database (Denmark)

1998-01-01

RNA is transcribed from a double stranded DNA template by forming a complex by hybridizing to the template at a desired transcription initiation site one or more oligonucleic acid analogues of the PNA type capable of forming a transcription initiation site with the DNA and exposing the complex...... to the action of a DNA dependant RNA polymerase in the presence of nucleoside triphosphates. Equal length transcripts may be obtained by placing a block to transcription downstream from the initiation site or by cutting the template at such a selected location. The initiation site is formed by displacement...... of one strand of the DNA locally by the PNA hybridization....

Effects of hyperthermia on repair of radiation-induced DNA strand breaks

International Nuclear Information System (INIS)

Mills, M.D.; Meyn, R.E.

1981-01-01

Previous reports have suggested a relationship between the heat-induced changes in nucleoprotein and the hyperthermic enhancement of radiation sensitivity. In an effort to further understand these relationships, we measured the level of initial DNA strand break damage and the DNA strand break rejoining kinetics in Chinese hamster ovary cells following combined hyperthermia and ionizing radiation treatments. The amount of protein associated with DNA measured as the ratio of [ 3 H)leucine to [ 14 C]thymidine was also compared in chromatin isolated from both heated and unheated cells. The results of these experiments show that the initial level of radiation-induced DNA strand breaks is significantly enhanced by a prior hyperthermia treatment of 43 0 C for 30 min. Treatments at higher temperatures and longer treatments at the same temperature magnified this effect. Hyperthermia was also shown to cause a substantial inhibition of the DNA strand break rejoining after irradiation. Both the initial level of DNA damage and the rejoining kinetics recovered to normal levels with incubation at 37 0 C between the hyperthermia and radiation treatments. Recovery of these parameters coincided with the return of the amount of protein associated with DNA to normal values, further suggesting a relationship between the changes in nucleoprotein and the hyperthermic enhancement of radiation sensivivity

Plasmid-derived DNA Strand Displacement Gates for Implementing Chemical Reaction Networks.

Science.gov (United States)

Chen, Yuan-Jyue; Rao, Sundipta D; Seelig, Georg

2015-11-25

DNA nanotechnology requires large amounts of highly pure DNA as an engineering material. Plasmid DNA could meet this need since it is replicated with high fidelity, is readily amplified through bacterial culture and can be stored indefinitely in the form of bacterial glycerol stocks. However, the double-stranded nature of plasmid DNA has so far hindered its efficient use for construction of DNA nanostructures or devices that typically contain single-stranded or branched domains. In recent work, it was found that nicked double stranded DNA (ndsDNA) strand displacement gates could be sourced from plasmid DNA. The following is a protocol that details how these ndsDNA gates can be efficiently encoded in plasmids and can be derived from the plasmids through a small number of enzymatic processing steps. Also given is a protocol for testing ndsDNA gates using fluorescence kinetics measurements. NdsDNA gates can be used to implement arbitrary chemical reaction networks (CRNs) and thus provide a pathway towards the use of the CRN formalism as a prescriptive molecular programming language. To demonstrate this technology, a multi-step reaction cascade with catalytic kinetics is constructed. Further it is shown that plasmid-derived components perform better than identical components assembled from synthetic DNA.

MEIOB targets single-strand DNA and is necessary for meiotic recombination.

Directory of Open Access Journals (Sweden)

Benoit Souquet

Full Text Available Meiotic recombination is a mandatory process for sexual reproduction. We identified a protein specifically implicated in meiotic homologous recombination that we named: meiosis specific with OB domain (MEIOB. This protein is conserved among metazoan species and contains single-strand DNA binding sites similar to those of RPA1. Our studies in vitro revealed that both recombinant and endogenous MEIOB can be retained on single-strand DNA. Those in vivo demonstrated the specific expression of Meiob in early meiotic germ cells and the co-localization of MEIOB protein with RPA on chromosome axes. MEIOB localization in Dmc1 (-/- spermatocytes indicated that it accumulates on resected DNA. Homologous Meiob deletion in mice caused infertility in both sexes, due to a meiotic arrest at a zygotene/pachytene-like stage. DNA double strand break repair and homologous chromosome synapsis were impaired in Meiob (-/- meiocytes. Interestingly MEIOB appeared to be dispensable for the initial loading of recombinases but was required to maintain a proper number of RAD51 and DMC1 foci beyond the zygotene stage. In light of these findings, we propose that RPA and this new single-strand DNA binding protein MEIOB, are essential to ensure the proper stabilization of recombinases which is required for successful homology search and meiotic recombination.

Protection for low current superconducting coils wound with insulated strand cable

International Nuclear Information System (INIS)

Satti, J.

1980-09-01

The insulated strand cable concept for winding of low current superconducting coil leads to an ideal quench protection by induction coupling. A superconducting secondary loop was made within a cable of a 6.2 Henry dipole coil. When quenching occurred, current was induced in the secondary strand above the critical value. The normal strand quenched the whole cable due to good thermal contact. The secondary loop works as a heater turned on as the wire becomes normal throughout the coil. With a well spread quench, the energy dissipation density is decreased thus preventing local burnout. The mechanism is possible because of close coupling that is present in the insulated cable as in bifilar winding. For the coil tested a 12 strand cable was used, thus a favorable 11 to 1 turn ratio was obtained for the primary to secondary. The superconductor in the secondary had a lower resistance until the critical current was achieved. A theoretical explanation is described for a simplified circuit. Test on the dipole coil with four individual shells showed that the one shell protected with the induced coupling heater always had a more rapid reduction of current. The induced coupling heater tested and explained in this paper works automatically and does not rely on mechanical or electrical devices

Replication of vertebrate mitochondrial DNA entails transient ribonucleotide incorporation throughout the lagging strand.

Science.gov (United States)

Yasukawa, Takehiro; Reyes, Aurelio; Cluett, Tricia J; Yang, Ming-Yao; Bowmaker, Mark; Jacobs, Howard T; Holt, Ian J

2006-11-15

Using two-dimensional agarose gel electrophoresis, we show that mitochondrial DNA (mtDNA) replication of birds and mammals frequently entails ribonucleotide incorporation throughout the lagging strand (RITOLS). Based on a combination of two-dimensional agarose gel electrophoretic analysis and mapping of 5' ends of DNA, initiation of RITOLS replication occurs in the major non-coding region of vertebrate mtDNA and is effectively unidirectional. In some cases, conversion of nascent RNA strands to DNA starts at defined loci, the most prominent of which maps, in mammalian mtDNA, in the vicinity of the site known as the light-strand origin.

Xeroderma pigmentosum complementation group C cells remove pyrimidine dimers selectively from the transcribed strand of active genes

International Nuclear Information System (INIS)

Venema, J.; van Hoffen, A.; Karcagi, V.; Natarajan, A.T.; van Zeeland, A.A.; Mullenders, L.H.

1991-01-01

The authors have measured the removal of UV-induced pyrimidine dimers from DNA fragments of the adenosine deaminase (ADA) and dihydrofolate reductase (DHFR) genes in primary normal human and xeroderma pigmentosum complementation group C (XP-C) cells. Using strand-specific probes, we show that in normal cells, preferential repair of the 5' part of the ADA gene is due to the rapid and efficient repair of the transcribed strand. Within 8 h after irradiation with UV at 10 J m-2, 70% of the pyrimidine dimers in this strand are removed. The nontranscribed strand is repaired at a much slower rate, with 30% dimers removed after 8 h. Repair of the transcribed strand in XP-C cells occurs at a rate indistinguishable from that in normal cells, but the nontranscribed strand is not repaired significantly in these cells. Similar results were obtained for the DHFR gene. In the 3' part of the ADA gene, however, both normal and XP-C cells perform fast and efficient repair of either strand, which is likely to be caused by the presence of transcription units on both strands. The factor defective in XP-C cells is apparently involved in the processing of DNA damage in inactive parts of the genome, including nontranscribed strands of active genes. These findings have important implications for the understanding of the mechanism of UV-induced excision repair and mutagenesis in mammalian cells

Development and test of Nb(3)Sn cos-theta dipoles based on PIT strands

International Nuclear Information System (INIS)

Zlobin, A.V.; Ambrosio, G.; Andreev, N.; Barzi, E.; Bossert, R.; Carcagno, R.; Chichili, D.R.; Elementi, L.; Feher, S.; Kashikhin, V.V.; Lamm, M.J.; Novitski, I.; Pischalnikov, Yu.; Sylvester, C.; Tartaglia, M.; Yamada, R.

2004-01-01

Fermilab is involved in the development of new generation high-field accelerator magnets using state-of-the-art Nb 3 Sn strands produced using different technologies. Two 1-m long models--mirror configuration and dipole magnet--were fabricated recently at Fermilab based on powder-in-tube (PIT) Nb 3 Sn strands with small effective filament size. This paper describes the parameters of superconducting strands and cable, the details of magnet design and fabrication procedure, and reports the results of PIT coil testing

Board-to-Board Free-Space Optical Interconnections Passing through Boards for a Bookshelf-Assembled Terabit-Per-Second-Class ATM Switch.

Science.gov (United States)

Hirabayashi, K; Yamamoto, T; Matsuo, S; Hino, S

1998-05-10

We propose free-space optical interconnections for a bookshelf-assembled terabit-per-second-class ATM switch. Thousands of arrayed optical beams, each having a rate of a few gigabits per second, propagate vertically to printed circuit boards, passing through some boards, and are connected to arbitrary transmitters and receivers on boards by polarization controllers and prism arrays. We describe a preliminary experiment using a 1-mm-pitch 2 x 2 beam-collimator array that uses vertical-cavity surface-emitting laser diodes. These optical interconnections can be made quite stable in terms of mechanical shock and temperature fluctuation by the attachment of reinforcing frames to the boards and use of an autoalignment system.

In Defense of Boards

NARCIS (Netherlands)

B. Visser (Bauke); S. Dominguez Martinez (Silvia); O.H. Swank (Otto)

2007-01-01

textabstractIt is often assumed that bad corporate performance means a bad CEO. The task of a board of directors is then simple: dismiss the executive. If it fails to do so, the board is said to be indolent. We take a kinder approach to observed board behaviour and point to the problems even

Use of Cellular Decapping Activators by Positive-Strand RNA Viruses

Directory of Open Access Journals (Sweden)

Jennifer Jungfleisch

2016-12-01

Full Text Available Positive-strand RNA viruses have evolved multiple strategies to not only circumvent the hostile decay machinery but to trick it into being a priceless collaborator supporting viral RNA translation and replication. In this review, we describe the versatile interaction of positive-strand RNA viruses and the 5′-3′ mRNA decay machinery with a focus on the viral subversion of decapping activators. This highly conserved viral trickery is exemplified with the plant Brome mosaic virus, the animal Flock house virus and the human hepatitis C virus.

COLLABORATION BOARD (CB55)

CERN Multimedia

B. Cousins

Open Access Publication Policy ATLAS had recently issued a short statement in support of open access publishing. The mood of the discussions in the December CMS Collaboration Board had appeared to be in favour and so it was being proposed that CMS issue the same statement as that made by ATLAS (the statement is attached to the agenda of this meeting). The Collaboration Board agreed. Election of the Chair of the Collaboration Board Following the agreement to shorten the terms of both the Spokesperson and the Collaboration Board Chair, and to introduce a longer overlap period between the election and the start of the term, the election for the next Collaboration Board Chair was due in December 2007. If the old standard schedule specified in the Constitution were adapted to this date, then the Board should be informed at the present meeting that the election was being prepared. However, it was felt that the experience of the previous year's election of the Spokesperson had shown that it would be desirable to...

Lesion Orientation of O4-Alkylthymidine Influences Replication by Human DNA Polymerase η.

Science.gov (United States)

O'Flaherty, D K; Patra, A; Su, Y; Guengerich, F P; Egli, M; Wilds, C J

2016-08-01

DNA lesions that elude repair may undergo translesion synthesis catalyzed by Y-family DNA polymerases. O 4 -Alkylthymidines, persistent adducts that can result from carcinogenic agents, may be encountered by DNA polymerases. The influence of lesion orientation around the C4- O 4 bond on processing by human DNA polymerase η (hPol η ) was studied for oligonucleotides containing O 4 -methylthymidine, O 4 -ethylthymidine, and analogs restricting the O 4 -methylene group in an anti -orientation. Primer extension assays revealed that the O 4 -alkyl orientation influences hPol η bypass. Crystal structures of hPol η •DNA•dNTP ternary complexes with O 4 -methyl- or O 4 -ethylthymidine in the template strand showed the nucleobase of the former lodged near the ceiling of the active site, with the syn - O 4 -methyl group engaged in extensive hydrophobic interactions. This unique arrangement for O 4 -methylthymidine with hPol η , inaccessible for the other analogs due to steric/conformational restriction, is consistent with differences observed for nucleotide incorporation and supports the concept that lesion conformation influences extension across DNA damage. Together, these results provide mechanistic insights on the mutagenicity of O 4 MedT and O 4 EtdT when acted upon by hPol η .

On the linearity of the dose-effect relationship of DNA double strand breaks

International Nuclear Information System (INIS)

Chadwick, K.H.; Leenhouts, H.P.

1994-01-01

Most radiation biologists believe that DNA double-strand breaks are induced linearly with radiation dose for all types of radiation. Since 1985, with the advent of elution and gel electrophoresis techniques which permit the measurement of DNA double-strand breaks induced in mammalian cells at doses having radiobiological relevance, the true nature of the dose-effect relationship has been brought into some doubt. Many investigators measured curvilinear dose-effect relationships and a few found good correlations between the induction of the DNA double-strand breaks and cell survival. We approach the problem pragmatically by assuming that the induction of DNA double-strand breaks by 125 I Auger electron emitters incorporated into the DNA of the cells is a linear function of the number of 125 I decays, and by comparing the dose-effect relationship for sparsely ionizing radiation against this standard. The conclusion drawn that the curvilinear dose-effect relationships and the correlations with survival are real. (Author)

MDA5 Detects the Double-Stranded RNA Replicative Form in Picornavirus-Infected Cells

Directory of Open Access Journals (Sweden)

Qian Feng

2012-11-01

Full Text Available RIG-I and MDA5 are cytosolic RNA sensors that play a critical role in innate antiviral responses. Major advances have been made in identifying RIG-I ligands, but our knowledge of the ligands for MDA5 remains restricted to data from transfection experiments mostly using poly(I:C, a synthetic dsRNA mimic. Here, we dissected the IFN-α/β-stimulatory activity of different viral RNA species produced during picornavirus infection, both by RNA transfection and in infected cells in which specific steps of viral RNA replication were inhibited. Our results show that the incoming genomic plus-strand RNA does not activate MDA5, but minus-strand RNA synthesis and production of the 7.5 kbp replicative form trigger a strong IFN-α/β response. IFN-α/β production does not rely on plus-strand RNA synthesis and thus generation of the partially double-stranded replicative intermediate. This study reports MDA5 activation by a natural RNA ligand under physiological conditions.

WeaselBoard :

Energy Technology Data Exchange (ETDEWEB)

Mulder, John C.; Schwartz, Moses Daniel; Berg, Michael J.; Van Houten, Jonathan Roger; Urrea, Jorge Mario; King, Michael Aaron; Clements, Abraham Anthony; Jacob, Joshua A.

2013-10-01

Critical infrastructures, such as electrical power plants and oil refineries, rely on programmable logic controllers (PLCs) to control essential processes. State of the art security cannot detect attacks on PLCs at the hardware or firmware level. This renders critical infrastructure control systems vulnerable to costly and dangerous attacks. WeaselBoard is a PLC backplane analysis system that connects directly to the PLC backplane to capture backplane communications between modules. WeaselBoard forwards inter-module traffic to an external analysis system that detects changes to process control settings, sensor values, module configuration information, firmware updates, and process control program (logic) updates. WeaselBoard provides zero-day exploit detection for PLCs by detecting changes in the PLC and the process. This approach to PLC monitoring is protected under U.S. Patent Application 13/947,887.

Hole hopping rates in single strand oligonucleotides

Energy Technology Data Exchange (ETDEWEB)

Borrelli, Raffaele [Dipartimento di Scienze Agrarie, Forestali e Alimentari, Università di Torino, Largo Paolo Braccini 2, I-10095 Grugliasco, TO (Italy); Capobianco, Amedeo [Dipartimento di Chimica e Biologia, Università di Salerno, Via Giovanni Paolo II, I-84084 Fisciano, SA (Italy); Peluso, Andrea, E-mail: apeluso@unisa.it [Dipartimento di Chimica e Biologia, Università di Salerno, Via Giovanni Paolo II, I-84084 Fisciano, SA (Italy)

2014-08-31

Highlights: • DNA hole transfer rates have been computed. • Delocalized adenine domains significantly affect hole transfer rates in DNA. • Franck–Condon weighted density of state from DFT normal modes. • DNA application in molecular electronics. - Abstract: The rates of hole transfer between guanine and adenine in single strand DNA have been evaluated by using Fermi’s golden rule and Kubo’s generating function approach for the Franck–Condon weighted density of states. The whole sets of the normal modes and vibrational frequencies of the two nucleobases, obtained at DFT/B3LYP level of calculation, have been considered in computations. The results show that in single strand the pyramidalization/planarization mode of the amino groups of both nucleobases plays the major role. At room temperature, the Franck–Condon density of states extends over a wide range of hole site energy difference, 0–1 eV, giving some hints about the design of oligonucleotides of potential technological interest.

Development of a three-dimensional high-order strand-grids approach

Science.gov (United States)

Tong, Oisin

Development of a novel high-order flux correction method on strand grids is presented. The method uses a combination of flux correction in the unstructured plane and summation-by-parts operators in the strand direction to achieve high-fidelity solutions. Low-order truncation errors are cancelled with accurate flux and solution gradients in the flux correction method, thereby achieving a formal order of accuracy of 3, although higher orders are often obtained, especially for highly viscous flows. In this work, the scheme is extended to high-Reynolds number computations in both two and three dimensions. Turbulence closure is achieved with a robust version of the Spalart-Allmaras turbulence model that accommodates negative values of the turbulence working variable, and the Menter SST turbulence model, which blends the k-epsilon and k-o turbulence models for better accuracy. A major advantage of this high-order formulation is the ability to implement traditional finite volume-like limiters to cleanly capture shocked and discontinuous flows. In this work, this approach is explored via a symmetric limited positive (SLIP) limiter. Extensive verification and validation is conducted in two and three dimensions to determine the accuracy and fidelity of the scheme for a number of different cases. Verification studies show that the scheme achieves better than third order accuracy for low and high-Reynolds number flows. Cost studies show that in three-dimensions, the third-order flux correction scheme requires only 30% more walltime than a traditional second-order scheme on strand grids to achieve the same level of convergence. In order to overcome meshing issues at sharp corners and other small-scale features, a unique approach to traditional geometry, coined "asymptotic geometry," is explored. Asymptotic geometry is achieved by filtering out small-scale features in a level set domain through min/max flow. This approach is combined with a curvature based strand shortening

MO-AB-BRA-04: Radiation Measurements with a DNA Double-Strand-Break Dosimeter

Energy Technology Data Exchange (ETDEWEB)

Obeidat, M; Cline, K; Stathakis, S; Papanikolaou, N; Rasmussen, K; Gutierrez, A; Ha, CS; Lee, SE; Shim, EY; Kirby, N [University of Texas HSC SA, San Antonio, TX (United States)

2016-06-15

Purpose: Many types of dosimeters are used to measure radiation, but none of them directly measures the biological effect of this dose. The purpose here is to create a dosimeter that can measure the probability of double-strand breaks (DSB) for DNA, which is directly related to the biological effect of radiation. Methods: The dosimeter has DNA strands, which are labeled on one end with biotin and on the other with fluorescein. The biotin attaches these strands to magnetic beads. We suspended the DNA dosimeter in phosphate-buffered saline (PBS) as it matches the internal environment of the body. We placed small volumes (50µL) of the DNA dosimeter into tubes and irradiated these samples in a water-equivalent plastic phantom with several doses (three samples per dose). After irradiating the samples, a magnet was placed against the tubes. The fluorescein attached to broken DNA strands was extracted (called the supernatant) and placed into a different tube. The fluorescein on the unbroken strands remained attached to the beads in the tube and was re-suspended with 50µL of PBS. A fluorescence reader was used to measure the fluorescence for both the re-suspended beads and supernatant. To prove that we are measuring DSB, we tested dosimeter response with two different lengths of attached DNA strands (1 and 4 kilo-base pair). Results: The probability of DSB at the dose levels of 5, 10, 25, and 50 Gy were 0.05, 0.08, 0.12, and 0.19, respectively, while the coefficients of variation were 0.14, 0.07, 0.02, and 0.01, respectively. The 4 kilo-base-pair dosimeter produced 5.3 times the response of the 1 kilo-base-pair dosimeter. Conclusion: The DNA dosimeter yields a measurable response to dose that scales with the DNA strand length. The goal now is to refine the dosimeter fabrication to reproducibly create a low coefficient of variation for the lower doses. This work was supported in part by Yarmouk University (Irbid, Jordan) and CPRIT (RP140105)

MO-AB-BRA-04: Radiation Measurements with a DNA Double-Strand-Break Dosimeter

International Nuclear Information System (INIS)

Obeidat, M; Cline, K; Stathakis, S; Papanikolaou, N; Rasmussen, K; Gutierrez, A; Ha, CS; Lee, SE; Shim, EY; Kirby, N

2016-01-01

Purpose: Many types of dosimeters are used to measure radiation, but none of them directly measures the biological effect of this dose. The purpose here is to create a dosimeter that can measure the probability of double-strand breaks (DSB) for DNA, which is directly related to the biological effect of radiation. Methods: The dosimeter has DNA strands, which are labeled on one end with biotin and on the other with fluorescein. The biotin attaches these strands to magnetic beads. We suspended the DNA dosimeter in phosphate-buffered saline (PBS) as it matches the internal environment of the body. We placed small volumes (50µL) of the DNA dosimeter into tubes and irradiated these samples in a water-equivalent plastic phantom with several doses (three samples per dose). After irradiating the samples, a magnet was placed against the tubes. The fluorescein attached to broken DNA strands was extracted (called the supernatant) and placed into a different tube. The fluorescein on the unbroken strands remained attached to the beads in the tube and was re-suspended with 50µL of PBS. A fluorescence reader was used to measure the fluorescence for both the re-suspended beads and supernatant. To prove that we are measuring DSB, we tested dosimeter response with two different lengths of attached DNA strands (1 and 4 kilo-base pair). Results: The probability of DSB at the dose levels of 5, 10, 25, and 50 Gy were 0.05, 0.08, 0.12, and 0.19, respectively, while the coefficients of variation were 0.14, 0.07, 0.02, and 0.01, respectively. The 4 kilo-base-pair dosimeter produced 5.3 times the response of the 1 kilo-base-pair dosimeter. Conclusion: The DNA dosimeter yields a measurable response to dose that scales with the DNA strand length. The goal now is to refine the dosimeter fabrication to reproducibly create a low coefficient of variation for the lower doses. This work was supported in part by Yarmouk University (Irbid, Jordan) and CPRIT (RP140105)

Review of thirty-two years of toothed whale strandings in Santa Catarina, southern Brazil (Cetacea: Odontoceti

Directory of Open Access Journals (Sweden)

Thaís dos S. Vianna

Full Text Available ABSTRACT Marine mammal strandings provide valuable insights into local biodiversity. Strandings can be caused by both natural and anthropogenic factors. In the state of Santa Catarina, Southern Brazil, organized marine mammal collections started in the 1980s through opportunistic and non-systematic collection efforts, representing a record of over 30 years of marine biodiversity. This study aimed to perform a preliminary review of 32 years of stranding records within this region. The secondary aim was to elucidate the stranding dynamics of the three most commonly recorded species. A total of 460 records were obtained, representing 17 species of odontocetes. The species registered most frequently were the franciscana, Pontoporia blainvillei (Gervais & d' Orbigny, 1844 (n = 173, bottlenose dolphin, Tursiops truncatus (Montagu, 1821 (n = 100, and Guiana dolphin Sotalia guianensis (Van Bénéden, 1864 (n = 97. Most of the stranding records were observed in the second half of the year during the austral winter and spring. The apparent causes of death could not be determined for most of the specimens due to carcass decomposition. For the specimens in which the apparent cause of death could be determined, 27% of the strandings were compatible with anthropogenic interactions. While the focus of this study was a preliminary assessment of stranding data obtained through opportunistic collection, it is evident that future systematic monitoring efforts and stable networks of collaborators will generate more reliable coastal biodiversity inventories and will allow the knowledge of population dynamics of marine mammal species. In particular, for threatened and vulnerable species, or species with poor natural history data, strandings are a fundamental tool for the understanding of marine biodiversity. Ideally, future more refined analyses of stranding data should be used to inform conservation and management policies and to elucidate the biology and ecology of

49 CFR 1011.5 - Employee boards.

Science.gov (United States)

2010-10-01

... 49 Transportation 8 2010-10-01 2010-10-01 false Employee boards. 1011.5 Section 1011.5... OF TRANSPORTATION GENERAL RULES AND REGULATIONS BOARD ORGANIZATION; DELEGATIONS OF AUTHORITY § 1011.5 Employee boards. This section covers matters assigned to the Accounting Board, a board of employees of the...

Board Size and Board Independence: A Quantitative Study on Banking Industry in Pakistan

Directory of Open Access Journals (Sweden)

Kashif Rashid

2014-12-01

Full Text Available This paper aims to investigate the relationship of board independence and board size with productivity and efficiency of the listed banks on the Karachi Stock Exchange, Pakistan. There is a lack of consensus regarding impact of corporate governance practices in correspondence to number of board members and board independence in banking sector. The derived results of the study show that there is a positive relationship between board independence and bank profitability and efficiency. Independent directors play a crucial role in providing genuine advice during executive decision making process which is an important source for improving overall corporate governance. Moreover, results regarding the role of control variables suggest a positive relationship of the total assets and deposits of the firm with the firm’s performance supporting stewardship theory in the market.

Self-field instabilities in high-$J_{c}$ Nb$_{3}$Sn strands the effect of copper RRR

CERN Document Server

Bordini, B

2009-01-01

High critical current density (Jc) Nb$_{3}$Sn conductor is the best candidate for next generation high field (> 10 T) accelerator magnets. Although very promising, state of the art high-Jc Nb$_{3}$Sn strands suffer of magneto-thermal instabilities that can severely limit the strand performance. Recently it has been shown that at 1.9 K the self field instability is the dominating mechanism that limits the performance of strands with a low (<10) Residual Resistivity Ratio (RRR) of the stabilizing copper. At CERN several state of the art high–Jc Nb$_{3}$Sn wires have been tested at 4.2 K and 1.9 K to study the effects on strand self-field instability of: RRR and strand impregnation with stycast. To study the effect of the RRR value on magneto-thermal instabilities, a new 2-D finite element model was also developed at CERN. This model simulates the whole development of the flux jump in the strand cross section also taking into account the heat and current diffusion in the stabilizing copper. In this paper th...

Normal formation and repair of γ-radiation-induced single and double strand DNA breaks in Down syndrome fibroblasts

International Nuclear Information System (INIS)

Steiner, M.E.; Woods, W.G.

1982-01-01

Fibroblasts from patients with Down syndrome (Trisomy 21) were examined for repair capability of γ-radiation-induced single strand and double strand DNA breaks. Formation and repair of DNA breaks were determined by DNA alkaline and non-denaturing elution techniques. Down syndrome fibroblasts were found to repair single strand and double strand breaks as well as fibroblasts from normal controls. (orig.)

Development and test of Nb(3)Sn cos-theta dipoles based on PIT strands

Energy Technology Data Exchange (ETDEWEB)

Zlobin, A.V.; Ambrosio, G.; Andreev, N.; Barzi, E.; Bossert, R.; Carcagno, R.; Chichili, D.R.; Elementi, L.; Feher, S.; Kashikhin, V.V.; Lamm, M.J.; Novitski, I.; Pischalnikov, Yu.; Sylvester, C.; Tartaglia, M.; Yamada, R.; /Fermilab

2004-11-01

Fermilab is involved in the development of new generation high-field accelerator magnets using state-of-the-art Nb{sub 3}Sn strands produced using different technologies. Two 1-m long models--mirror configuration and dipole magnet--were fabricated recently at Fermilab based on powder-in-tube (PIT) Nb{sub 3}Sn strands with small effective filament size. This paper describes the parameters of superconducting strands and cable, the details of magnet design and fabrication procedure, and reports the results of PIT coil testing.

Single-stranded DNA cleavage by divergent CRISPR-Cas9 enzymes

Science.gov (United States)

Ma, Enbo; Harrington, Lucas B.; O’Connell, Mitchell R.; Zhou, Kaihong; Doudna, Jennifer A.

2015-01-01

Summary Double-stranded DNA (dsDNA) cleavage by Cas9 is a hallmark of type II CRISPR-Cas immune systems. Cas9–guide RNA complexes recognize 20-base-pair sequences in DNA and generate a site-specific double-strand break, a robust activity harnessed for genome editing. DNA recognition by all studied Cas9 enzymes requires a protospacer adjacent motif (PAM) next to the target site. We show that Cas9 enzymes from evolutionarily divergent bacteria can recognize and cleave single-stranded DNA (ssDNA) by an RNA-guided, PAM-independent recognition mechanism. Comparative analysis shows that in contrast to the type II-A S. pyogenes Cas9 that is widely used for genome engineering, the smaller type II-C Cas9 proteins have limited dsDNA binding and unwinding activity and promiscuous guide-RNA specificity. These results indicate that inefficiency of type II-C Cas9 enzymes for genome editing results from a limited ability to cleave dsDNA, and suggest that ssDNA cleavage was an ancestral function of the Cas9 enzyme family. PMID:26545076

Heavy metals in tissues of stranded short-finned pilot whales

International Nuclear Information System (INIS)

Stoneburner, D.L.

1978-01-01

Selected tissues from four short-finned pilot whales that stranded at Cumberland Island National Seashore were analyzed for total cadmium, mercury and selenium by neutron activation. Cadmium reached a maximum mean wet weight concentration of 31.4 ppm in the kidney tissues. Maximum mean wet weight concentrations of mercury, 230.9 ppm, and selenium, 44.2 ppm, were found in the liver tissues. The lowest concentration of each metal was found in the blubber. Postmortem examination showed that the whales had no food in their stomachs. The whales must have been utilizing metabolic reserves, contaminated with residual concentrations of heavy metals, prior to beaching. This utilization of reserves probably resulted in the high concentrations of cadmium, mercury and selenium found in the liver and kidney tissues. Since the heavy metal concentrations were three to four times greater in the stranded whales, as compared to apparently healthy whales of the same species, it is suggested that heavy metal toxicosis may have been a factor contributing to this particular stranding. (Auth.)

Preserving the Legitimacy of Board Certification.

Science.gov (United States)

Hanemann, Michael S; Wall, Holly C; Dean, John A

2017-06-01

The aims of this discussion were to inform the medical community about the American Board of Cosmetic Surgery's ongoing attempts in Louisiana to achieve equivalency to American Board of Medical Specialties (ABMS) member boards so that its diplomates may use the term "board certified" in advertising and to ensure public safety by upholding the standards for medical board certification. In 2011, Louisiana passed a truth in medical advertising law, which was intended to protect the public by prohibiting the use of the term "board certified" by improperly credentialed physicians. An American Board of Cosmetic Surgery diplomate petitioned the Louisiana State Board of Medical Examiners to approve a rule that would establish a pathway to equivalency for non-ABMS member boards, whose diplomates have not completed training approved by the Accreditation Council for Graduate Medical Education (ACGME) in the specialty they are certifying. Physicians and physician organizations representing multiple specialties (facial plastic and reconstructive surgery, otolaryngology [head and neck surgery], orthopedic spine surgery, pediatric neurosurgery, dermatology, and plastic surgery) urged the Louisiana State Board of Medical Examiners to clarify its advertising policy, limiting the use of the term "board certified" to physicians who have completed ACGME-approved training in the specialty or subspecialty named in the certificate. The public equates the term "board certified" with the highest level of expertise in a medical specialty. When a certifying board does not require completion of ACGME or American Osteopathic Association (AOA)-accredited training in the specialty it certifies, the result is an unacceptable degree of variability in the education and training standards applied to its diplomates. Independent, third-party oversight of certifying boards and training programs is necessary to ensure quality standards are upheld. Any system that assesses a non-ABMS member or non

X-ray induced DNA double strand break production and repair in mammalian cells as measured by neutral filter elution

Energy Technology Data Exchange (ETDEWEB)

Bradley, M O; Kohn, K W [National Institutes of Health, Bethesda, MD (USA)

1979-10-01

A neutral filter elution method was used for detecting DNA double strand breaks in mouse L1210 cells after X-ray. The assay detected the number of double strand breaks induced by as little as 1000 rad of X-ray. The rate of DNA elution through the filters under neutral conditions increased with X-ray dose. Certain conditions for deproteinization, pH, and filter type were shown to increase the assay's sensitivity. Hydrogen peroxide and Bleomycin also induced apparent DNA double strand breaks, although the ratios of double to single strand breaks varied from those produced by X-ray. The introduction of double strand cuts by HpA I restriction endonuclease in DNA lysed on filters resulted in a rapid rate of elution under neutral conditions, implying that the method can detect double strand breaks if they exist in the DNA. The eluted DNA banded with a double stranded DNA marker in cesium chloride. This evidence suggested that the assay detected DNA double strand breaks. L1210 cells were shown to rejoin most of the DNA double strand breaks induced by 5-10 krad of X-ray with a half-time of about 40 minutes. (author).

Recent Progress in Application of Internal Oxidation Technique in Nb3Sn Strands

Energy Technology Data Exchange (ETDEWEB)

Xu, Xingchen [Fermilab; Peng, Xuan [Hyper Tech Research Inc.; Sumption, Michael [Ohio State U.; Collings, E. W. [Ohio State U.

2016-10-13

The internal oxidation technique can generate ZrO2 nano particles in Nb3Sn strands, which markedly refine the Nb3Sn grain size and boost the high-field critical current density (Jc). This article summarizes recent efforts on implementing this technique in practical Nb3Sn wires and adding Ti as a dopant. It is demonstrated that this technique can be readily incorporated into the present Nb3Sn conductor manufacturing technology. Powder-in-tube (PIT) strands with fine subelements (~25 µm) based on this technique were successfully fabricated, and proper heat treatments for oxygen transfer were explored. Future work for producing strands ready for applications is proposed.

CMG helicase and DNA polymerase ε form a functional 15-subunit holoenzyme for eukaryotic leading-strand DNA replication.

Science.gov (United States)

Langston, Lance D; Zhang, Dan; Yurieva, Olga; Georgescu, Roxana E; Finkelstein, Jeff; Yao, Nina Y; Indiani, Chiara; O'Donnell, Mike E

2014-10-28

DNA replication in eukaryotes is asymmetric, with separate DNA polymerases (Pol) dedicated to bulk synthesis of the leading and lagging strands. Pol α/primase initiates primers on both strands that are extended by Pol ε on the leading strand and by Pol δ on the lagging strand. The CMG (Cdc45-MCM-GINS) helicase surrounds the leading strand and is proposed to recruit Pol ε for leading-strand synthesis, but to date a direct interaction between CMG and Pol ε has not been demonstrated. While purifying CMG helicase overexpressed in yeast, we detected a functional complex between CMG and native Pol ε. Using pure CMG and Pol ε, we reconstituted a stable 15-subunit CMG-Pol ε complex and showed that it is a functional polymerase-helicase on a model replication fork in vitro. On its own, the Pol2 catalytic subunit of Pol ε is inefficient in CMG-dependent replication, but addition of the Dpb2 protein subunit of Pol ε, known to bind the Psf1 protein subunit of CMG, allows stable synthesis with CMG. Dpb2 does not affect Pol δ function with CMG, and thus we propose that the connection between Dpb2 and CMG helps to stabilize Pol ε on the leading strand as part of a 15-subunit leading-strand holoenzyme we refer to as CMGE. Direct binding between Pol ε and CMG provides an explanation for specific targeting of Pol ε to the leading strand and provides clear mechanistic evidence for how strand asymmetry is maintained in eukaryotes.

Role of teh Rad52 Amino-terminal DNA Binding Activity in DNA Strand Capture in Homologous Recombination

DEFF Research Database (Denmark)

Shi, Idina; Hallwyl, Swee Chuang Lim; Seong, Changhyun

2009-01-01

Saccharomyces cerevisiae Rad52 protein promotes homologous recombination by nucleating the Rad51 recombinase onto replication protein A-coated single-stranded DNA strands and also by directly annealing such strands. We show that the purified rad52-R70A mutant protein, with a compromised amino-ter...

SAKAMATA : A tool to avoid whale strandings

NARCIS (Netherlands)

Benders, F.P.A.; Beerens, S.P.; Verboom, W.C.

2004-01-01

World-wide a concern exists about the influence of man-made noise on marine life, and particularly of high power sonar. Most concern lies with marine mammals that use acoustics for hunting, communication and/or navigation. This concern is fed by recent strandings of whales that could be related to

SAKAMATA : A tool to avoid whale strandings

NARCIS (Netherlands)

Benders, F.P.A.; Beerens, S.P.; Verboom, W.C.

2002-01-01

World-wide a concern exists about the influence of man-made noise on marine life, and particularly of high power sonar. Most concern lies with marine mammals that use acoustics for hunting, communication and/or navigation. This concern is fed by recent strandings of whales that could be related to

76 FR 52997 - Public Company Accounting Oversight Board; Order Approving Proposed Board Funding Final Rules for...

Science.gov (United States)

2011-08-24

... Accounting Oversight Board; Order Approving Proposed Board Funding Final Rules for Allocation of the Board's... August 18, 2011. I. Introduction On June 21, 2011, the Public Company Accounting Oversight Board (the... public accounting firm, in amounts that are sufficient to cover the costs of processing and reviewing...

Coordinated leading and lagging strand DNA synthesis by using the herpes simplex virus 1 replication complex and minicircle DNA templates.

Science.gov (United States)

Stengel, Gudrun; Kuchta, Robert D

2011-01-01

The origin-specific replication of the herpes simplex virus 1 genome requires seven proteins: the helicase-primase (UL5-UL8-UL52), the DNA polymerase (UL30-UL42), the single-strand DNA binding protein (ICP8), and the origin-binding protein (UL9). We reconstituted these proteins, excluding UL9, on synthetic minicircular DNA templates and monitored leading and lagging strand DNA synthesis using the strand-specific incorporation of dTMP and dAMP. Critical features of the assays that led to efficient leading and lagging stand synthesis included high helicase-primase concentrations and a lagging strand template whose sequence resembled that of the viral DNA. Depending on the nature of the minicircle template, the replication complex synthesized leading and lagging strand products at molar ratios varying between 1:1 and 3:1. Lagging strand products (∼0.2 to 0.6 kb) were significantly shorter than leading strand products (∼2 to 10 kb), and conditions that stimulated primer synthesis led to shorter lagging strand products. ICP8 was not essential; however, its presence stimulated DNA synthesis and increased the length of both leading and lagging strand products. Curiously, human DNA polymerase α (p70-p180 or p49-p58-p70-p180), which improves the utilization of RNA primers synthesized by herpesvirus primase on linear DNA templates, had no effect on the replication of the minicircles. The lack of stimulation by polymerase α suggests the existence of a macromolecular assembly that enhances the utilization of RNA primers and may functionally couple leading and lagging strand synthesis. Evidence for functional coupling is further provided by our observations that (i) leading and lagging strand synthesis produce equal amounts of DNA, (ii) leading strand synthesis proceeds faster under conditions that disable primer synthesis on the lagging strand, and (iii) conditions that accelerate helicase-catalyzed DNA unwinding stimulate decoupled leading strand synthesis but not

Human RECQ5 helicase promotes repair of DNA double-strand breaks by synthesis-dependent strand annealing

Czech Academy of Sciences Publication Activity Database

Paliwal, S.; Kanagaraj, R.; Sturzenegger, A.; Burdová, Kamila; Janščák, Pavel

2014-01-01

Roč. 42, č. 4 (2014), s. 2380-2390 ISSN 0305-1048 R&D Projects: GA ČR GA204/09/0565; GA ČR GAP305/10/0281 Grant - others:Swiss National Science Foundation(CH) 31003A-129747; Swiss National Science Foundation(CH) 31003A_146206 Institutional support: RVO:68378050 Keywords : Human RECQ5 helicase * DNA double-strand breaks * mitotic homologous recombination Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 9.112, year: 2014

Comparison of the electrophoretic method with the sedimentation method for the analysis of DNA strand breaks

International Nuclear Information System (INIS)

Yamamoto, Osamu; Ogawa, Masaaki; Hoshi, Masaharu

1982-01-01

Application of electrophoresis to the analysis of DNA strand breaks was studied comparing with the sedimentation analysis. A BRL gel electrophoresis system (Type V16) was used for this study. Calf thymus DNA (1 mg/ml) irradiated with 60 Co gamma-rays in SSC solution was applied to both the electrophoretic analysis and the sedimentation analysis. Lamda phage DNA and its fragments were employed as the standard size molecules. In a range from 1 k base pairs to 6 k base pairs in length for double stranded DNA or from 2 k bases to 12 k bases for single stranded DNA, the calculated average molecular weight from the electrophoresis coincided with that from the sedimentation. Number of single strand breaks and double strand breaks were 1.34 x 10 11 breaks/mg/rad (G = 0.215) and 0.48 x 10 5 breaks/mg/rad 2 , respectively. (author)

Status of European manufacture of Toroidal Field conductor and strand for JT-60SA project

Energy Technology Data Exchange (ETDEWEB)

Zani, Louis, E-mail: louis.zani@jt60sa.org [Fusion for Energy, D-85748 Garching (Germany); CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Barabaschi, Pietro; Di Pietro, Enrico [Fusion for Energy, D-85748 Garching (Germany)

2013-10-15

In the framework of the JT-60SA project, part of the Broader Approach (BA) agreement, EURATOM provides to Japan, the Toroidal Field (TF) magnet system, consisting of 18 superconducting coils. The procurement of the conductor for the TF coils is managed by Fusion for Energy, acting as EU representative in the BA agreement. The TF conductor procurement is split into two contracts, one dedicated to the production of Niobium Titanium (NbTi) and Cu strand and the other to TF conductor production through strand cabling and cable jacketing operations. The TF conductor is a rectangular-shaped cable-in-conduit conductor formed by 486 (0.81 mm diameter) strands (2/3 NbTi–1/3 Cu) wrapped in a stainless steel foil and embedded into a stainless steel jacket. The 18 TF coils require (including spares) 115 ‘Unit Lengths’ (UL) of such conductor, each 240 m long for a total of about 28 km. Correspondingly about 10,000 km for NbTi and 5000 km for Cu strand are produced. The Japanese company Furukawa Electric Co. (FEC) is in charge of TF strand manufacture while the Italian company Italian Consortium for Applied Superconductivity (ICAS) is in charge of cabling and jacketing of TF conductor ULs. In the paper, we provide information on the production stages presently achieved in TF strand and conductor contracts.

Advanced materials, strands, and conductors for particle accelerators. Technical report for the year 1994

International Nuclear Information System (INIS)

1994-01-01

The authors research for the Division of High Energy Physics (HEP) began with studies of both the superconducting and matrix components of multifilamentary composites, viz (1) attempts to increase the flux-pinning strength in NbTi, and (2) a method of suppressing proximity effect coupling in fine-filament strands. The latter was fully successful, and stands ready to be invoked as soon as the need arises to: (a) very closely space the filaments in the interests of quality, or (b) re-introduce fine-filament composites for strand-magnetization reduction or AC-loss minimization. But there were also many spin-offs during the life of the program, as indicated in the complete list of publications (copy available on request). For instance, the various other effects and properties that were studied and published over the period of this association with HEP include: (i) reduction in T c due to proximity effect between thin αphase precipitates and the NbTi matrix, (ii) critical field enhancement with reduction of filament diameter in fine-filament composites, (iii) studies and systematics of AC loss in composite strands, (iv) compensation of strand magnetization by means of Ni plating or filament substitution, (v) hysteretic loss due to surface pinning in multifilamentary NbTi, (vi) flux creep in SSC-type strands, (vii) temperature and field dependence of eddy current decay, (vii) influence of Mn doping on the properties of NbTi, (viii) transverse and longitudinal resistivities (including a size-effect contribution) in strands with various filament/matrix configurations

NPS Transit System Passenger Boardings Study: Converting Ticket Sales to Passenger Boardings.

Science.gov (United States)

2016-01-01

This report examines the reporting of passenger boardings (unlinked passenger trips) by NPS transit systems that use a ticket sales conversion methodology. By studying and validating the park units' passenger boarding methodology from converting tick...

Slow conduction in mixed cultured strands of primary ventricular cells and stem cell-derived cardiomyocytes

Directory of Open Access Journals (Sweden)

Jan Pavel Kucera

2015-09-01

Full Text Available Modern concepts for the treatment of myocardial diseases focus on novel cell therapeutic strategies involving stem cell-derived cardiomyocytes (SCMs. However, functional integration of SCMs requires similar electrophysiological properties as primary cardiomyocytes (PCMs and the ability to establish intercellular connections with host myocytes in order to contribute to the electrical and mechanical activity of the heart. The aim of this project was to investigate the properties of cardiac conduction in a co-culture approach using SCMs and PCMs in cultured cell strands. Murine embryonic SCMs were pooled with fetal ventricular cells and seeded in predefined proportions on microelectrode arrays to form patterned strands of mixed cells. Conduction velocity (CV was measured during steady state pacing. SCM excitability was estimated from action potentials measured in single cells using the patch clamp technique. Experiments were complemented with computer simulations of conduction using a detailed model of cellular architecture in mixed cell strands.CV was significantly lower in strands composed purely of SCMs (5.5±1.5 cm/s, n=11 as compared to PCMs (34.9±2.9 cm/s, n=21 at similar refractoriness (100% SCMs: 122±25 ms, n=9; 100% PCMs: 139±67 ms, n=14. In mixed strands combining both cell types, CV was higher than in pure SCMs strands, but always lower than in 100% PCM strands. Computer simulations demonstrated that both intercellular coupling and electrical excitability limit CV.These data provide evidence that in cultures of murine ventricular cardiomyocytes, SCMs cannot restore CV to control levels resulting in slow conduction, which may lead to reentry circuits and arrhythmias.

STRUCTURAL AND FUNCTIONAL-ANALYSIS OF THE SINGLE-STRAND ORIGIN OF REPLICATION FROM THE LACTOCOCCAL PLASMID PWVO1

NARCIS (Netherlands)

SEEGERS, JFML; ZHAO, AC; MEIJER, WJJ; KHAN, SA; VENEMA, G; BRON, S

1995-01-01

The single-strand origin (SSO) of the rolling-circle (RC), broad-host-range lactococcal plasmid pWVO1 was functionally characterized. The activity of this SSO in the conversion of single-stranded DNA to double-stranded DNA was tested both in vivo and in vitro. In addition, the effect of this SSO on

Regions of incompatibility in single-stranded DNA bacteriophages phi X174 and G4

NARCIS (Netherlands)

van der Avoort, H. G.; van der Ende, A.; van Arkel, G. A.; Weisbeek, P. J.

1984-01-01

The intracellular presence of a recombinant plasmid containing the intercistronic region between the genes H and A of bacteriophage phi X174 strongly inhibits the conversion of infecting single-stranded phi X DNA to parental replicative-form DNA. Also, transfection with single-stranded or

Colocalization of multiple DNA double-strand breaks at a single Rad52 repair centre

DEFF Research Database (Denmark)

Lisby, M.; Mortensen, Uffe Hasbro; Rothstein, R.

2003-01-01

DNA double-strand break repair (DSBR) is an essential process for preserving genomic integrity in all organisms. To investigate this process at the cellular level, we engineered a system of fluorescently marked DNA double-strand breaks (DSBs) in the yeast Saccharomyces cerevisiae to visualize in ...

78 FR 54867 - Proposed Information Collection; Comment Request; Marine Mammal Health and Stranding Response...

Science.gov (United States)

2013-09-06

... Collection; Comment Request; Marine Mammal Health and Stranding Response Program, Level A Stranding and... governments; not-for-profit institutions; business or other for-profit organizations. Estimated Number of... collection; they also will become a matter of public record. Dated: August 30, 2013. Gwellnar Banks...

Implementation of a method to visualize noise-induced hearing loss in mass stranded cetaceans

Science.gov (United States)

Morell, Maria; Brownlow, Andrew; McGovern, Barry; Raverty, Stephen A.; Shadwick, Robert E.; André, Michel

2017-02-01

Assessment of the impact of noise over-exposure in stranded cetaceans is challenging, as the lesions that lead to hearing loss occur at the cellular level and inner ear cells are very sensitive to autolysis. Distinguishing ante-mortem pathology from post-mortem change has been a major constraint in diagnosing potential impact. Here, we outline a methodology applicable to the detection of noise-induced hearing loss in stranded cetaceans. Inner ears from two mass strandings of long-finned pilot whales in Scotland were processed for scanning electron microscopy observation. In one case, a juvenile animal, whose ears were fixed within 4 hours of death, revealed that many sensory cells at the apex of the cochlear spiral were missing. In this case, the absence of outer hair cells would be compatible with overexposure to underwater noise, affecting the region which transduces the lowest frequencies of the pilot whales hearing spectrum. Perfusion of cochlea with fixative greatly improved preservation and enabled diagnostic imaging of the organ of Corti, even 30 hours after death. This finding supports adopting a routine protocol to detect the pathological legacy of noise overexposure in mass stranded cetaceans as a key to understanding the complex processes and implications that lie behind such stranding events.

Board of Director Configurations in Mutual Funds Sponsors: A Board-Level Analysis of Director Performance and Ownership

National Research Council Canada - National Science Library

Fraser, Steven

2003-01-01

... (or a cluster of funds); referred to as a Multiple Board Configuration (MBC). In a sample of the largest open-end mutual fund sponsors, I find MBC boards have significantly higher board-level objective-adjusted excess returns than SBC boards...

DOE's Environmental Management Site-Specific Advisory Board: The Roles, Work, and Assessment of the Constituent Local Boards - 13587

International Nuclear Information System (INIS)

Alexander, Catherine; Freeman, Jenny; Cantrell, Yvette

2013-01-01

The charter for the Department of Energy's Environmental Management (EM) Site-Specific Advisory Board (SSAB) was approved under the Federal Advisory Committee Act (FACA) in 1994. With a unique mandate to provide public input on issues associated with the cleanup of nuclear legacy sites in the U.S., the EM SSAB comprises eight local boards, which are based at major EM sites. While each board is unique to the community in which it is located and reflects the diversity of the local population, the boards are governed by FACA, related regulations, and DOE policies that are intended to standardize agency advisory board operations. The EM SSAB local boards are made up of a diverse group of citizens who want to understand the mission and goals of the EM program and to help EM achieve those goals for the benefit of their communities. Some are quite passionate about their mission; others need to be coaxed into active participation. Maintaining productive relationships and a supportive environment for effective board operations is the challenge of board management for DOE EM and the board members themselves. DOE draws on research findings and best practices literature from academics and practitioners in the field of public involvement in its board management practices. The EM SSAB is also evaluated annually under the law to ensure that the investment of taxpayer dollars in the board is warranted in light of the contributions of the board. Further evaluation takes place at the agency and site levels in order to identify what aspects of board functioning the agency and board members find important to its success and to address areas where improvement is needed. Board contributions, compliance factors, and measurable outcomes related to board products and process areas are key to agency commitment to ongoing support of the boards and to participant satisfaction and thus continued member involvement. In addition to evaluation of these factors in improving board effectiveness

A Co-Opted DEAD-Box RNA helicase enhances tombusvirus plus-strand synthesis.

Directory of Open Access Journals (Sweden)

Nikolay Kovalev

2012-02-01

Full Text Available Replication of plus-strand RNA viruses depends on recruited host factors that aid several critical steps during replication. In this paper, we show that an essential translation factor, Ded1p DEAD-box RNA helicase of yeast, directly affects replication of Tomato bushy stunt virus (TBSV. To separate the role of Ded1p in viral protein translation from its putative replication function, we utilized a cell-free TBSV replication assay and recombinant Ded1p. The in vitro data show that Ded1p plays a role in enhancing plus-strand synthesis by the viral replicase. We also find that Ded1p is a component of the tombusvirus replicase complex and Ded1p binds to the 3'-end of the viral minus-stranded RNA. The data obtained with wt and ATPase deficient Ded1p mutants support the model that Ded1p unwinds local structures at the 3'-end of the TBSV (-RNA, rendering the RNA compatible for initiation of (+-strand synthesis. Interestingly, we find that Ded1p and glyceraldehyde-3-phosphate dehydrogenase (GAPDH, which is another host factor for TBSV, play non-overlapping functions to enhance (+-strand synthesis. Altogether, the two host factors enhance TBSV replication synergistically by interacting with the viral (-RNA and the replication proteins. In addition, we have developed an in vitro assay for Flock house virus (FHV, a small RNA virus of insects, that also demonstrated positive effect on FHV replicase activity by the added Ded1p helicase. Thus, two small RNA viruses, which do not code for their own helicases, seems to recruit a host RNA helicase to aid their replication in infected cells.

Conformational analysis and design of cross-strand disulfides in antiparallel β-sheets.

Science.gov (United States)

Indu, S; Kochat, V; Thakurela, S; Ramakrishnan, C; Varadarajan, Raghavan

2011-01-01

Cross-strand disulfides bridge two cysteines in a registered pair of antiparallel β-strands. A nonredundant data set comprising 5025 polypeptides containing 2311 disulfides was used to study cross-strand disulfides. Seventy-six cross-strand disulfides were found of which 75 and 1 occurred at non-hydrogen-bonded (NHB) and hydrogen-bonded (HB) registered pairs, respectively. Conformational analysis and modeling studies demonstrated that disulfide formation at HB pairs necessarily requires an extremely rare and positive χ¹ value for at least one of the cysteine residues. Disulfides at HB positions also have more unfavorable steric repulsion with the main chain. Thirteen pairs of disulfides were introduced in NHB and HB pairs in four model proteins: leucine binding protein (LBP), leucine, isoleucine, valine binding protein (LIVBP), maltose binding protein (MBP), and Top7. All mutants LIVBP T247C V331C showed disulfide formation either on purification, or on treatment with oxidants. Protein stability in both oxidized and reduced states of all mutants was measured. Relative to wild type, LBP and MBP mutants were destabilized with respect to chemical denaturation, although the sole exposed NHB LBP mutant showed an increase of 3.1°C in T(m). All Top7 mutants were characterized for stability through guanidinium thiocyanate chemical denaturation. Both exposed and two of the three buried NHB mutants were appreciably stabilized. All four HB Top7 mutants were destabilized (ΔΔG⁰ = -3.3 to -6.7 kcal/mol). The data demonstrate that introduction of cross-strand disulfides at exposed NHB pairs is a robust method of improving protein stability. All four exposed Top7 disulfide mutants showed mild redox activity. © 2010 Wiley-Liss, Inc.

Influence of RNA Strand Rigidity on Polyion Complex Formation with Block Catiomers.

Science.gov (United States)

Hayashi, Kotaro; Chaya, Hiroyuki; Fukushima, Shigeto; Watanabe, Sumiyo; Takemoto, Hiroyasu; Osada, Kensuke; Nishiyama, Nobuhiro; Miyata, Kanjiro; Kataoka, Kazunori

2016-03-01

Polyion complexes (b-PICs) are prepared by mixing single- or double-stranded oligo RNA (aniomer) with poly(ethylene glycol)-b-poly(L-lysine) (PEG-PLL) (block catiomer) to clarify the effect of aniomer chain rigidity on association behaviors at varying concentrations. Here, a 21-mer single-stranded RNA (ssRNA) (persistence length: 1.0 nm) and a 21-mer double-stranded RNA (small interfering RNA, siRNA) (persistence length: 62 nm) are compared. Both oligo RNAs form a minimal charge-neutralized ionomer pair with a single PEG-PLL chain, termed unit b-PIC (uPIC), at low concentrations (<≈ 0.01 mg mL(-1)). Above the critical association concentration (≈ 0.01 mg mL(-1)), ssRNA b-PICs form secondary associates, PIC micelles, with sizes up to 30-70 nm, while no such multimolecular assembly is observed for siRNA b-PICs. The entropy gain associated with the formation of a segregated PIC phase in the multimolecular PIC micelles may not be large enough for rigid siRNA strands to compensate with appreciably high steric repulsion derived from PEG chains. Chain rigidity appears to be a critical parameter in polyion complex association. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

SMART Boards Rock

Science.gov (United States)

Giles, Rebecca M.; Shaw, Edward L.

2011-01-01

SMART Board is a technology that combines the functionality of a whiteboard, computer, and projector into a single system. The interactive nature of the SMART Board offers many practical uses for providing an introduction to or review of material, while the large work area invites collaboration through social interaction and communication. As a…

Departmental Appeals Board Decisions

Data.gov (United States)

U.S. Department of Health & Human Services — Decisions issued by the Chair and Board Members of the Departmental Appeals Board concerning determinations in discretionary, project grant programs, including...

Method for detecting DNA strand breaks in mammalian cells using the Deinococcus radiodurans PprA protein

International Nuclear Information System (INIS)

Satoh, Katsuya; Wada, Seiichi; Kikuchi, Masahiro; Funayama, Tomoo; Narumi, Issay; Kobayashi, Yasuhiko

2006-01-01

In a previous study, we identified the novel protein PprA that plays a critical role in the radiation resistance of Deinococcus radiodurans. In this study, we focussed on the ability of PprA protein to recognize and bind to double-stranded DNA carrying strand breaks, and attempted to visualize radiation-induced DNA strand breaks in mammalian cultured cells by employing PprA protein using an immunofluorescence technique. Increased PprA protein binding to CHO-K1 nuclei immediately following irradiation suggests the protein is binding to DNA strand breaks. By altering the cell permeabilization conditions, PprA protein binding to CHO-K1 mitochondria, which is probably resulted from DNA strand break immediately following irradiation, was also detected. The method developed and detailed in this study will be useful in evaluating DNA damage responses in cultured cells, and could also be applicable to genotoxic tests in the environmental and pharmaceutical fields

Genome-wide mapping of DNA strand breaks.

Directory of Open Access Journals (Sweden)

Frédéric Leduc

Full Text Available Determination of cellular DNA damage has so far been limited to global assessment of genome integrity whereas nucleotide-level mapping has been restricted to specific loci by the use of specific primers. Therefore, only limited DNA sequences can be studied and novel regions of genomic instability can hardly be discovered. Using a well-characterized yeast model, we describe a straightforward strategy to map genome-wide DNA strand breaks without compromising nucleotide-level resolution. This technique, termed "damaged DNA immunoprecipitation" (dDIP, uses immunoprecipitation and the terminal deoxynucleotidyl transferase-mediated dUTP-biotin end-labeling (TUNEL to capture DNA at break sites. When used in combination with microarray or next-generation sequencing technologies, dDIP will allow researchers to map genome-wide DNA strand breaks as well as other types of DNA damage and to establish a clear profiling of altered genes and/or intergenic sequences in various experimental conditions. This mapping technique could find several applications for instance in the study of aging, genotoxic drug screening, cancer, meiosis, radiation and oxidative DNA damage.

Formation of plasmid DNA strand breaks induced by low-energy ion beam: indication of nuclear stopping effects

International Nuclear Information System (INIS)

Chen Yu; Jiang Bingyao; Chen Youshan; Ding Xingzhao; Liu Xianghuai; Chen Ceshi; Guo Xinyou; Yin Guanglin

1998-01-01

Plasmid pGEM 3zf(+) was irradiated by nitrogen ion beam with energies between 20 and 100 keV and the fluence kept as 1 x 10 12 ions/cm 2 . The irradiated plasmid was assayed by neutral electrophoresis and quantified by densitometry. The yields of DNA with single-strand and double-strand breaks first increased then decreased with increasing ion energy. There was a maximal yield value in the range of 20-100 keV. The relationship between DNA double-strand breaks (DSB) cross-section and linear energy transfer (LET) also showed a peak-shaped distribution. To understand the physical process during DNA strand breaks, a Monte Carlo calculation code known as TRIM (Transport of Ions in Matter) was used to simulate energy losses due to nuclear stopping and to electronic stopping. It can be assumed that nuclear stopping plays a more important role in DNA strand breaks than electronic stopping in this energy range. The physical mechanisms of DNA strand breaks induced by a low-energy ion beam are also discussed. (orig.)

77 FR 1956 - National Science Board; Notice of Opportunity for Public Comment on the National Science Board...

Science.gov (United States)

2012-01-12

... NATIONAL SCIENCE FOUNDATION National Science Board; Notice of Opportunity for Public Comment on the National Science Board Data Policies Report AGENCY: National Science Board (NSB), NSF. ACTION: Request for public comments. SUMMARY: The National Science Board seeks comments from the public on the...

Correlation of superconductor strand, cable, and dipole critical currents in CBA magnets

International Nuclear Information System (INIS)

Tannenbaum, M.J.; Garber, M.; Sampson, W.B.

1982-01-01

A calibration between vendor critical current data for 0.0268'' diameter superconductor strand supplied to Fermilab, and the BNL 10 -12 Ωcm critical current specification is presented. Vendor critical current data for over 400 Fermilab type billets are shown, both as supplied by the vendor and converted to BNL units. Predictions of cable critical current are made using the sum of the critical currents of the 23 strands, where all strands from the same half billet are assigned the same critical current. The measured critical current shows excellent correlation to the predicted value and is approximately 14 +- 2 percent below it. Colliding Beam Accelerator (CBA) full length dipoles reach the conductor critical current limit, essentially without training. Magnet performance is predictable from the measured critical current of a short sample of cable to within 2%

Board diversity in family firms

OpenAIRE

Menozzi, Anna; Fraquelli, Giovanni; Novara, Jolanda de

2015-01-01

The paper deals with diversity as a key factor to improve the board of directors’ decision process in family firms. The empirical literature about board diversity points at the positive impact of diversity on board functioning and firm performance. The paper uses a statistical diversity index to capture the heterogeneity of board of directors and put it in relation with firm performance, as measured by firm profitability. The empirical analysis is based on a newly collected panel of 327 famil...

Genomic mapping of single-stranded DNA in hydroxyurea-challenged yeasts identifies origins of replication.

Science.gov (United States)

Feng, Wenyi; Collingwood, David; Boeck, Max E; Fox, Lindsay A; Alvino, Gina M; Fangman, Walton L; Raghuraman, Mosur K; Brewer, Bonita J

2006-02-01

During DNA replication one or both strands transiently become single stranded: first at the sites where initiation of DNA synthesis occurs (known as origins of replication) and subsequently on the lagging strands of replication forks as discontinuous Okazaki fragments are generated. We report a genome-wide analysis of single-stranded DNA (ssDNA) formation in the presence of hydroxyurea during DNA replication in wild-type and checkpoint-deficient rad53 Saccharomyces cerevisiae cells. In wild-type cells, ssDNA was first observed at a subset of replication origins and later 'migrated' bi-directionally, suggesting that ssDNA formation is associated with continuously moving replication forks. In rad53 cells, ssDNA was observed at virtually every known origin, but remained there over time, suggesting that replication forks stall. Telomeric regions seemed to be particularly sensitive to the loss of Rad53 checkpoint function. Replication origins in Schizosaccharomyces pombe were also mapped using our method.

Dynamic protein assembly by programmable DNA strand displacement

Science.gov (United States)

Chen, Rebecca P.; Blackstock, Daniel; Sun, Qing; Chen, Wilfred

2018-03-01

Inspired by the remarkable ability of natural protein switches to sense and respond to a wide range of environmental queues, here we report a strategy to engineer synthetic protein switches by using DNA strand displacement to dynamically organize proteins with highly diverse and complex logic gate architectures. We show that DNA strand displacement can be used to dynamically control the spatial proximity and the corresponding fluorescence resonance energy transfer between two fluorescent proteins. Performing Boolean logic operations enabled the explicit control of protein proximity using multi-input, reversible and amplification architectures. We further demonstrate the power of this technology beyond sensing by achieving dynamic control of an enzyme cascade. Finally, we establish the utility of the approach as a synthetic computing platform that drives the dynamic reconstitution of a split enzyme for targeted prodrug activation based on the sensing of cancer-specific miRNAs.

Biophysical characterization of the association of histones with single-stranded DNA.

Science.gov (United States)

Wang, Ying; van Merwyk, Luis; Tönsing, Katja; Walhorn, Volker; Anselmetti, Dario; Fernàndez-Busquets, Xavier

2017-11-01

Despite the profound current knowledge of the architecture and dynamics of nucleosomes, little is known about the structures generated by the interaction of histones with single-stranded DNA (ssDNA), which is widely present during replication and transcription. Non-denaturing gel electrophoresis, transmission electron microscopy, atomic force microscopy, magnetic tweezers. Histones have a high affinity for ssDNA in 0.15M NaCl ionic strength, with an apparent binding constant similar to that calculated for their association with double-stranded DNA (dsDNA). The length of DNA (number of nucleotides in ssDNA or base pairs in dsDNA) associated with a fixed core histone mass is the same for both ssDNA and dsDNA. Although histone-ssDNA complexes show a high tendency to aggregate, nucleosome-like structures are formed at physiological salt concentrations. Core histones are able to protect ssDNA from digestion by micrococcal nuclease, and a shortening of ssDNA occurs upon its interaction with histones. The purified (+) strand of a cloned DNA fragment of nucleosomal origin has a higher affinity for histones than the purified complementary (-) strand. At physiological ionic strength histones have high affinity for ssDNA, possibly associating with it into nucleosome-like structures. In the cell nucleus histones may spontaneously interact with ssDNA to facilitate their participation in the replication and transcription of chromatin. Copyright © 2017 Elsevier B.V. All rights reserved.

Assembling of G-strands into novel tetra-molecular parallel G4-DNA nanostructures using avidin-biotin recognition.

Science.gov (United States)

Borovok, Natalia; Iram, Natalie; Zikich, Dragoslav; Ghabboun, Jamal; Livshits, Gideon I; Porath, Danny; Kotlyar, Alexander B

2008-09-01

We describe a method for the preparation of novel long (hundreds of nanometers), uniform, inter-molecular G4-DNA molecules composed of four parallel G-strands. The only long continuous G4-DNA reported so far are intra-molecular structures made of a single G-strand. To enable a tetra-molecular assembly of the G-strands we developed a novel approach based on avidin-biotin biological recognition. The steps of the G4-DNA production include: (i) Enzymatic synthesis of long poly(dG)-poly(dC) molecules with biotinylated poly(dG)-strand; (ii) Formation of a complex between avidin-tetramer and four biotinylated poly(dG)-poly(dC) molecules; (iii) Separation of the poly(dC) strands from the poly(dG)-strands, which are connected to the avidin; (iv) Assembly of the four G-strands attached to the avidin into tetra-molecular G4-DNA. The average contour length of the formed structures, as measured by AFM, is equal to that of the initial poly(dG)-poly(dC) molecules, suggesting a tetra-molecular mechanism of the G-strands assembly. The height of tetra-molecular G4-nanostructures is larger than that of mono-molecular G4-DNA molecules having similar contour length. The CD spectra of the tetra- and mono-molecular G4-DNA are markedly different, suggesting different structural organization of these two types of molecules. The tetra-molecular G4-DNA nanostructures showed clear electrical polarizability. This suggests that they may be useful for molecular electronics.

Buddy Board

DEFF Research Database (Denmark)

Enggaard, Helle; Moselund, Lene

2015-01-01

Projekt ’BuddyBoard’ er kommet i stand via et samarbejde mellem Frederikshavn kommune, Bunker43 og Lab. X. Afdeling en ’Havly’ på Sæby Ældrecenter fungerer som living lab, hvilket betyder, at det udgør et levende laboratorium for udvikling og afprøvning af teknologi (Schultz, 2013). Projektet er....... Bunker43 har udviklet en teknologi (BuddyBoard) til hurtig formidling af billeder fra pårørende og personale til beboere på institutioner. Pårørende og personale uploader billeder via en APP eller en hjemmeside og har mulighed for at tilføje en kort forklarende tekst til hvert billede. Beboeren ser...... billederne via en tablet. Systemet bygger på et simpelt og brugervenligt design, så ældre med kognitive og/eller fysiske funktionsnedsættelser kan anvende teknologien. BuddyBoard fungerer via internettet, og billederne gemmes på en sikret server hos udbyderen, som er Bunker43. Intentionerne med BuddyBoard er...

CRISPR/Cas9 cleavages in budding yeast reveal templated insertions and strand-specific insertion/deletion profiles.

Science.gov (United States)

Lemos, Brenda R; Kaplan, Adam C; Bae, Ji Eun; Ferrazzoli, Alexander E; Kuo, James; Anand, Ranjith P; Waterman, David P; Haber, James E

2018-02-27

Harnessing CRISPR-Cas9 technology provides an unprecedented ability to modify genomic loci via DNA double-strand break (DSB) induction and repair. We analyzed nonhomologous end-joining (NHEJ) repair induced by Cas9 in budding yeast and found that the orientation of binding of Cas9 and its guide RNA (gRNA) profoundly influences the pattern of insertion/deletions (indels) at the site of cleavage. A common indel created by Cas9 is a 1-bp (+1) insertion that appears to result from Cas9 creating a 1-nt 5' overhang that is filled in by a DNA polymerase and ligated. The origin of +1 insertions was investigated by using two gRNAs with PAM sequences located on opposite DNA strands but designed to cleave the same sequence. These templated +1 insertions are dependent on the X-family DNA polymerase, Pol4. Deleting Pol4 also eliminated +2 and +3 insertions, which are biased toward homonucleotide insertions. Using inverted PAM sequences, we also found significant differences in overall NHEJ efficiency and repair profiles, suggesting that the binding of the Cas9:gRNA complex influences subsequent NHEJ processing. As with events induced by the site-specific HO endonuclease, CRISPR-Cas9-mediated NHEJ repair depends on the Ku heterodimer and DNA ligase 4. Cas9 events are highly dependent on the Mre11-Rad50-Xrs2 complex, independent of Mre11's nuclease activity. Inspection of the outcomes of a large number of Cas9 cleavage events in mammalian cells reveals a similar templated origin of +1 insertions in human cells, but also a significant frequency of similarly templated +2 insertions.

Effects of DNA double-strand and single-strand breaks on intrachromosomal recombination events in cell-cycle-arrested yeast cells

International Nuclear Information System (INIS)

Galli, A.; Schiestl, R.H.

1998-01-01

Intrachromosomal recombination between repeated elements can result in deletion (DEL recombination) events. We investigated the inducibility of such intrachromosomal recombination events at different stages of the cell cycle and the nature of the primary DNA lesions capable of initiating these events. Two genetic systems were constructed in Saccharomyces cerevisiae that select for DEL recombination events between duplicated alleles of CDC28 and TUB2. We determined effects of double-strand breaks (DSBs) and single-strand breaks (SSBs) between the duplicated alleles on DEL recombination when induced in dividing cells or cells arrested in G1 or G2. Site-specific DSBs and SSBs were produced by overexpression of the I-Sce I endonuclease and the gene II protein (gIIp), respectively. I-Sce I-induced DSBs caused an increase in DEL recombination frequencies in both dividing and cell-cycle-arrested cells, indicating that G1- and G2-arrested cells are capable of completing DSB repair. In contrast, gIIp-induced SSBs caused an increase in DEL recombination frequency only in dividing cells. To further examine these phenomena we used both γ-irradiation, inducing DSBs as its most relevant lesion, and UV, inducing other forms of DNA damage. UV irradiation did not increase DEL recombination frequencies in G1 or G2, whereas γ-rays increased DEL recombination frequencies in both phases. Both forms of radiation, however, induced DEL recombination in dividing cells. The results suggest that DSBsbut not SSBs induce DEL recombination, probably via the single-strand annealing pathway. Further, DSBs in dividing cells may result from the replication of a UV or SSB-damaged template. Alternatively, UV induced events may occur by replication slippage after DNA polymerase pausing in front of the damage. (author)

Solving probability reasoning based on DNA strand displacement and probability modules.

Science.gov (United States)

Zhang, Qiang; Wang, Xiaobiao; Wang, Xiaojun; Zhou, Changjun

2017-12-01

In computation biology, DNA strand displacement technology is used to simulate the computation process and has shown strong computing ability. Most researchers use it to solve logic problems, but it is only rarely used in probabilistic reasoning. To process probabilistic reasoning, a conditional probability derivation model and total probability model based on DNA strand displacement were established in this paper. The models were assessed through the game "read your mind." It has been shown to enable the application of probabilistic reasoning in genetic diagnosis. Copyright © 2017 Elsevier Ltd. All rights reserved.

22 CFR 902.3 - Board staff.

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 2 2010-04-01 2010-04-01 true Board staff. 902.3 Section 902.3 Foreign Relations FOREIGN SERVICE GRIEVANCE BOARD ORGANIZATION § 902.3 Board staff. The chairperson shall select the Board's executive secretary and other staff provided for in the Act. The executive secretary and staff...

76 FR 40950 - Public Company Accounting Oversight Board; Notice of Filing of Proposed Board Funding Final Rules...

Science.gov (United States)

2011-07-12

... available, the issuer's net asset value. (i)(v) Issuer Accounting Support Fee The term ``issuer accounting... Accounting Oversight Board; Notice of Filing of Proposed Board Funding Final Rules for Allocation of the Board's Accounting Support Fee Among Issuers, Brokers, and Dealers, and Other Amendments to the Board's...

Development of Drop/Shock Test in Microelectronics and Impact Dynamic Analysis for Uniform Board Response

Science.gov (United States)

Kallolimath, Sharan Chandrashekar

For the past several years, many researchers are constantly developing and improving board level drop test procedures and specifications to quantify the solder joint reliability performance of consumer electronics products. Predictive finite element analysis (FEA) by utilizing simulation software has become widely acceptable verification method which can reduce time and cost of the real-time test process. However, due to testing and metrological limitations it is difficult not only to simulate exact drop condition and capture critical measurement data but also tedious to calibrate the system to improve test methods. Moreover, some of the important ever changing factors such as board flexural rigidity, damping, drop height, and drop orientation results in non-uniform stress/strain distribution throughout the test board. In addition, one of the most challenging tasks is to quantify uniform stress and strain distribution throughout the test board and identify critical failure factors. The major contributions of this work are in the four aspects of the drop test in electronics as following. First of all, an analytical FEA model was developed to study the board natural frequencies and responses of the system with the consideration of dynamic stiffness, damping behavior of the material and effect of impact loading condition. An approach to find the key parameters that affect stress and strain distributions under predominate mode responses was proposed and verified with theoretical solutions. Input-G method was adopted to study board response behavior and cut boundary interpolation methods was used to analyze local model solder joint stresses with the development of global/local FEA model in ANSYS software. Second, no ring phenomenon during the drop test was identified theoretically when the test board was modeled as both discrete system and continuous system. Numerical analysis was then conducted by FEA method for detailed geometry of attached chips with solder

Negative-strand RNA viruses: The plant-infecting counterparts

NARCIS (Netherlands)

Kormelink, R.J.M.; Garcia, M.L.; Goodin, M.; Sasaya, T.; Haenni, A.L.

2011-01-01

While a large number of negative-strand (-)RNA viruses infect animals and humans, a relative small number have plants as their primary host. Some of these have been classified within families together with animal/human infecting viruses due to similarities in particle morphology and genome

DNA double-strand breaks & poptosis in the testis

NARCIS (Netherlands)

Hamer, Geert

2003-01-01

During spermatogenesis, DNA damage is a naturally occurring event. At a certain stage, during the first meiotic prophase, DNA breaks are endogenously induced and even required for meiotic recombination. We studied these DNA breaks but also used ionizing radiation (IR) to induce DNA double-strand

Design and Analysis of Compact DNA Strand Displacement Circuits for Analog Computation Using Autocatalytic Amplifiers.

Science.gov (United States)

Song, Tianqi; Garg, Sudhanshu; Mokhtar, Reem; Bui, Hieu; Reif, John

2018-01-19

A main goal in DNA computing is to build DNA circuits to compute designated functions using a minimal number of DNA strands. Here, we propose a novel architecture to build compact DNA strand displacement circuits to compute a broad scope of functions in an analog fashion. A circuit by this architecture is composed of three autocatalytic amplifiers, and the amplifiers interact to perform computation. We show DNA circuits to compute functions sqrt(x), ln(x) and exp(x) for x in tunable ranges with simulation results. A key innovation in our architecture, inspired by Napier's use of logarithm transforms to compute square roots on a slide rule, is to make use of autocatalytic amplifiers to do logarithmic and exponential transforms in concentration and time. In particular, we convert from the input that is encoded by the initial concentration of the input DNA strand, to time, and then back again to the output encoded by the concentration of the output DNA strand at equilibrium. This combined use of strand-concentration and time encoding of computational values may have impact on other forms of molecular computation.

Stimulation of NADH-dependent microsomal DNA strand cleavage by rifamycin SV.

Science.gov (United States)

Kukiełka, E; Cederbaum, A I

1995-04-15

Rifamycin SV is an antibiotic anti-bacterial agent used in the treatment of tuberculosis. This drug can autoxidize, especially in the presence of metals, and generate reactive oxygen species. A previous study indicated that rifamycin SV can increase NADH-dependent microsomal production of reactive oxygen species. The current study evaluated the ability of rifamycin SV to interact with iron and increase microsomal production of hydroxyl radical, as detected by conversion of supercoiled plasmid DNA into the relaxed open circular state. The plasmid used was pBluescript II KS(-), and the forms of DNA were separated by agarose-gel electrophoresis. Incubation of rat liver microsomes with plasmid plus NADH plus ferric-ATP caused DNA strand cleavage. The addition of rifamycin SV produced a time- and concentration-dependent increase in DNA-strand cleavage. No stimulation by rifamycin SV occurred in the absence of microsomes, NADH or ferric-ATP. Stimulation occurred with other ferric complexes besides ferric-ATP, e.g. ferric-histidine, ferric-citrate, ferric-EDTA, and ferric-(NH4)2SO4. Rifamycin SV did not significantly increase the high rates of DNA strand cleavage found with NADPH as the microsomal reductant. The stimulation of NADH-dependent microsomal DNA strand cleavage was completely blocked by catalase, superoxide dismutase, GSH and a variety of hydroxyl-radical-scavenging agents, but not by anti-oxidants that prevent microsomal lipid peroxidation. Redox cycling agents, such as menadione and paraquat, in contrast with rifamycin SV, stimulated the NADPH-dependent reaction; menadione and rifamycin SV were superior to paraquat in stimulating the NADH-dependent reaction. These results indicate that rifamycin SV can, in the presence of an iron catalyst, increase microsomal production of reactive oxygen species which can cause DNA-strand cleavage. In contrast with other redox cycling agents, the stimulation by rifamycin SV is more pronounced with NADH than with NADPH as the

Bringing out the Best Board Behavior

Science.gov (United States)

Caruso, Nicholas

2004-01-01

The author's advice for for a school board superintendent is to assume incompetence instead of malevolence. Board members who behave inappropriately are a minority, and those with malicious intent are extremely rare. Most misbehaving board members act out of frustration. They may not understand the appropriate role of a board member.…

What makes boards effective? An examination of the relationships between board inputs, structures, processes and effectiveness in non-profit organizations

OpenAIRE

Cornforth, Chris

2001-01-01

Based on a survey of charity boards in England and Wales this paper examines what influence board inputs, structures and processes have on board effectiveness. The findings provide mixed support for the normative literature on board effectiveness. Using stepwise logistic regression the research suggests that board inputs and three process variables are important in explaining board effectiveness, namely: board members have the time, skills and experience to do the job; clear board roles and r...

Quantitation of the repair of gamma-radiation-induced double-strand DNA breaks in human fibroblasts

International Nuclear Information System (INIS)

Woods, W.G.

1981-01-01

The quantitation and repair of double-strand DNA breaks in human fibroblasts has been determined using a method involving the nondenaturing elution of DNA from a filter. DNA from cells from two human fibroblast lines exposed to γ-radiation from 0 to 10000 rad showed increasing retention on a filter with decreasing radiation dose, and the data suggest a linear relationship between double-strand breaks induced and radiation dose. The ability of normal human fibroblasts to repair double-strand breaks with various doses of radiation was demonstrated, with a tsub(1/2) of 10 min for repair of 5000 rad exposure and 39 min for repair of 10000 rad damage. The kinetics of the DNA rejoining were not linear and suggest that, as in the repair of single-strand breaks, both an initial fast and a later slow mechanism may be involved. (Auth.)

Isolation and characterization of Solenopsis invicta virus 3, a new positive-strand RNA virus infecting the red imported fire ant, Solenopsis invicta

International Nuclear Information System (INIS)

Valles, Steven M.; Hashimoto, Yoshifumi

2009-01-01

We report the discovery of a new virus from the red imported fire ant, Solenopsis invicta. Solenopsis invicta virus 3 (SINV-3) represents the third virus discovered from this ant species using the metagenomics approach. The single (positive)-strand RNA, monopartite, bicistronic genome of SINV-3 was sequenced in entirety (GenBank accession number (FJ528584)), comprised of 10,386 nucleotides, and polyadenylated at the 3' terminus. This genome size was confirmed by Northern analysis. The genome revealed 2 large open reading frames (ORFs) in the sense orientation with an untranslated region (UTR) at each end and between the two ORFs. The 5' proximal ORF (ORF 1) encoded a predicted protein of 299.1 kDa (2580 amino acids). The 3' proximal ORF (ORF 2) encoded a predicted protein of 73.2 kDa (651 amino acids). RNA-dependent RNA polymerase (RdRp), helicase, and protease domains were recognized in ORF 1. SDS-PAGE separation of purified SINV-3 particles yielded 2 bands (ostensibly capsid proteins) with a combined molecular mass of 77.3 kDa which was similar to the mass predicted by ORF 2 (73.2 kDa). Phylogenetic analysis of the conserved amino acid sequences containing domains I to VIII of the RdRp from dicistroviruses, iflaviruses, plant small RNA viruses, picornaviruses, and 4 unassigned positive-strand RNA viruses revealed a trichotomous phenogram with SINV-3 and Kelp fly virus comprising a unique cluster. Electron microscopic examination of negatively stained samples of SINV-3 revealed isometric particles with apparent projections and a diameter of 27.3 ± 1.3 nm. SINV-3 was successfully transmitted to uninfected workers by feeding. The minus (replicative) strand of SINV-3 was detected in worker ants indicating replication of the virus. The possibility of using SINV-3 as a microbial control agent for fire ants is discussed.

Single-strand breaks in supercoiled DNA induced by vacuum-UV radiation in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Takakura, Kaoru; Ishikawa, Mitsuo; Hieda, Kotaro; Kobayashi, Katsumi; Ito, Atsushi; Ito, Takashi

1986-09-01

The induction of single-strand breaks in the DNA of plasmid pBR 322 by vacuum-UV radiation above 145 nm in aqueous solutions was studied in relation to the production of OH-radicals in water. The similarity and dissimilarity were examined on the wavelength dependence between the two effects. The maximum of single strand breaks at 150 nm could be explained by the action of OH-radicals derived from direct water photolysis: the maximum at 180 nm remains unexplained. There was no indication that the direct absorption of photon by the DNA molecule plays an important role in the production of single-strand breaks.

Single-strand breaks in supercoiled DNA induced by vacuum-UV radiation in aqueous solution

International Nuclear Information System (INIS)

Takakura, Kaoru; Ishikawa, Mitsuo; Hieda, Kotaro; Kobayashi, Katsumi; Ito, Atsushi; Ito, Takashi

1986-01-01

The induction of single-strand breaks in the DNA of plasmid pBR 322 by vacuum-UV radiation above 145 nm in aqueous solutions was studied in relation to the production of OH-radicals in water. The similarity and dissimilarity were examined on the wavelength dependence between the two effects. The maximum of single strand breaks at 150 nm could be explained by the action of OH-radicals derived from direct water photolysis: the maximum at 180 nm remains unexplained. There was no indication that the direct absorption of photon by the DNA molecule plays an important role in the production of single-strand breaks. (author)

Thioflavin T binds dimeric parallel-stranded GA-containing non-G-quadruplex DNAs: a general approach to lighting up double-stranded scaffolds.

Science.gov (United States)

Liu, Shuangna; Peng, Pai; Wang, Huihui; Shi, Lili; Li, Tao

2017-12-01

A molecular rotor thioflavin T (ThT) is usually used as a fluorescent ligand specific for G-quadruplexes. Here, we demonstrate that ThT can tightly bind non-G-quadruplex DNAs with several GA motifs and dimerize them in a parallel double-stranded mode, accompanied by over 100-fold enhancement in the fluorescence emission of ThT. The introduction of reverse Watson-Crick T-A base pairs into these dimeric parallel-stranded DNA systems remarkably favors the binding of ThT into the pocket between G•G and A•A base pairs, where ThT is encapsulated thereby restricting its two rotary aromatic rings in the excited state. A similar mechanism is also demonstrated in antiparallel DNA duplexes where several motifs of two consecutive G•G wobble base pairs are incorporated and serve as the active pockets for ThT binding. The insight into the interactions of ThT with non-G-quadruplex DNAs allows us to introduce a new concept for constructing DNA-based sensors and devices. As proof-of-concept experiments, we design a DNA triplex containing GA motifs in its Hoogsteen hydrogen-bonded two parallel strands as a pH-driven nanoswitch and two GA-containing parallel duplexes as novel metal sensing platforms where C-C and T-T mismatches are included. This work may find further applications in biological systems (e.g. disease gene detection) where parallel duplex or triplex stretches are involved. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

75 FR 32747 - Prestressed Concrete Steel Wire Strand from Mexico: Rescission of Antidumping Duty Administrative...

Science.gov (United States)

2010-06-09

... DEPARTMENT OF COMMERCE INTERNATIONAL TRADE ADMINISTRATION [A-201-831] Prestressed Concrete Steel Wire Strand from Mexico: Rescission of Antidumping Duty Administrative Review AGENCY: Import... request an administrative review of the antidumping duty order on prestressed concrete steel wire strand...

Governing Board of the Pension Fund

CERN Multimedia

2006-01-01

The Governing Board of the Pension Fund held its 142nd meeting on 14 March 2006. As an introduction to the meeting, the Administrator underlined that, at 12.4%, the performance achieved by the Fund on its assets had been excellent and had taken the Fund's assets at the end of the year to 4,209 MCHF, which was well above the 4 billion Swiss franc mark. The Chairman of the Governing Board, Professor Ferrini, reported on the Board's closed session on 7 March to examine the nominations received for the election of the Vice-Chairmen of the Governing Board of the Pension Fund. The Governing Board had unanimously agreed to recommend the CERN Council to appoint Mr A. J. Naudi and Dr J.-P. Matheys. At its session on 16 March 2006, the Council had followed the recommendation of the Governing Board by re-appointing J.-P. Matheys and A. J. Naudi Vice-Chairmen of the Board until the end of their respective terms of office as members of the Governing Board. Regarding the comparison with other European pension funds launc...

Characterizing the strand-specific distribution of non-CpG methylation in human pluripotent cells.

Science.gov (United States)

Guo, Weilong; Chung, Wen-Yu; Qian, Minping; Pellegrini, Matteo; Zhang, Michael Q

2014-03-01

DNA methylation is an important defense and regulatory mechanism. In mammals, most DNA methylation occurs at CpG sites, and asymmetric non-CpG methylation has only been detected at appreciable levels in a few cell types. We are the first to systematically study the strand-specific distribution of non-CpG methylation. With the divide-and-compare strategy, we show that CHG and CHH methylation are not intrinsically different in human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). We also find that non-CpG methylation is skewed between the two strands in introns, especially at intron boundaries and in highly expressed genes. Controlling for the proximal sequences of non-CpG sites, we show that the skew of non-CpG methylation in introns is mainly guided by sequence skew. By studying subgroups of transposable elements, we also found that non-CpG methylation is distributed in a strand-specific manner in both short interspersed nuclear elements (SINE) and long interspersed nuclear elements (LINE), but not in long terminal repeats (LTR). Finally, we show that on the antisense strand of Alus, a non-CpG site just downstream of the A-box is highly methylated. Together, the divide-and-compare strategy leads us to identify regions with strand-specific distributions of non-CpG methylation in humans.

Genetics of x-ray induced double strand break repair in saccharomyces cerevisiae

International Nuclear Information System (INIS)

Budd, M.E.

1982-07-01

The possible fates of x-ray-induced double-strand breaks in Saccharomyces cerevisiae were examined. One possible pathway which breaks can follow, the repair pathway, was studied by assaying strains with mutations in the RAD51, RAD54, and RAD57 loci for double-strand break repair. In order of increasing radiation sensitivity one finds: rad57-1(23 0 )> rad51-1(30 0 )> rad54-3(36 0 ). At 36 0 , rad54-3 cells cannot repair double-strand breaks, while 23 0 , they can. Strains with the rad57-1 mutation can rejoin broken chromosomes at both temperatures. However, the low survival at 36 0 shows that the assay is not distinguishing large DNA fragments which allow cell survival from those which cause cell death. A rad51-1 strain could also rejoin broken chromosomes, and was thus capable of incomplete repair. The data can be explained with the hypothesis that rad54-3 cells are blocked in an early step of repair, while rad51-1 and rad57-1 strains are blocked in a later step of repair. The fate of double-strand breaks when they are left unrepaired was investigated with the rad54-3 mutation. If breaks are prevented from entering the RAD54 repair pathway they become uncommitted lesions. These lesions are repaired slower than the original breaks. One possible fate for an uncommitted lesion is conversion into a fixed lesion, which is likely to be an unrepairable or misrepaired double-strand break. The presence of protein synthesis after irradiation increases the probability that a break will enter the repair pathway. Evidence shows that increased probability of repair results from enhanced synthesis of repair proteins shortly after radiation

Variation of mutational burden in healthy human tissues suggests non-random strand segregation and allows measuring somatic mutation rates.

Science.gov (United States)

Werner, Benjamin; Sottoriva, Andrea

2018-06-01

The immortal strand hypothesis poses that stem cells could produce differentiated progeny while conserving the original template strand, thus avoiding accumulating somatic mutations. However, quantitating the extent of non-random DNA strand segregation in human stem cells remains difficult in vivo. Here we show that the change of the mean and variance of the mutational burden with age in healthy human tissues allows estimating strand segregation probabilities and somatic mutation rates. We analysed deep sequencing data from healthy human colon, small intestine, liver, skin and brain. We found highly effective non-random DNA strand segregation in all adult tissues (mean strand segregation probability: 0.98, standard error bounds (0.97,0.99)). In contrast, non-random strand segregation efficiency is reduced to 0.87 (0.78,0.88) in neural tissue during early development, suggesting stem cell pool expansions due to symmetric self-renewal. Healthy somatic mutation rates differed across tissue types, ranging from 3.5 × 10-9/bp/division in small intestine to 1.6 × 10-7/bp/division in skin.

Variation of mutational burden in healthy human tissues suggests non-random strand segregation and allows measuring somatic mutation rates.

Directory of Open Access Journals (Sweden)

Benjamin Werner

2018-06-01

Full Text Available The immortal strand hypothesis poses that stem cells could produce differentiated progeny while conserving the original template strand, thus avoiding accumulating somatic mutations. However, quantitating the extent of non-random DNA strand segregation in human stem cells remains difficult in vivo. Here we show that the change of the mean and variance of the mutational burden with age in healthy human tissues allows estimating strand segregation probabilities and somatic mutation rates. We analysed deep sequencing data from healthy human colon, small intestine, liver, skin and brain. We found highly effective non-random DNA strand segregation in all adult tissues (mean strand segregation probability: 0.98, standard error bounds (0.97,0.99. In contrast, non-random strand segregation efficiency is reduced to 0.87 (0.78,0.88 in neural tissue during early development, suggesting stem cell pool expansions due to symmetric self-renewal. Healthy somatic mutation rates differed across tissue types, ranging from 3.5 × 10-9/bp/division in small intestine to 1.6 × 10-7/bp/division in skin.

German versus Nordic Board Models

DEFF Research Database (Denmark)

Ringe, Georg

2016-01-01

Board structure is an important component of the individual governance of firms, and the appropriateness of the various models is one of the most debated issues in corporate governance today. A comparison of the Nordic and German approaches to the structure of corporate boards reveals stark...... conceptual differences, as emphasized by the 2014 Lekvall Report on the Nordic Corporate Governance Model. This article provides a conceptual comparison between the two approaches to board structure and confirms the fundamental divergence between both models. However, relying on a number of recent legal...... changes and developments in business practice, the article argues that board practices in the two systems effectively blur the structural distinction, and that board organization is converging in practice. It thereby contributes to the broader debates on functionality and comparative corporate law...

Fecal bacterial communities of wild-captured and stranded green turtles (Chelonia mydas) on the Great Barrier Reef.

Science.gov (United States)

Ahasan, Md Shamim; Waltzek, Thomas B; Huerlimann, Roger; Ariel, Ellen

2017-12-01

Green turtles (Chelonia mydas) are endangered marine herbivores that break down food particles, primarily sea grasses, through microbial fermentation. However, the microbial community and its role in health and disease is still largely unexplored. In this study, we investigated and compared the fecal bacterial communities of eight wild-captured green turtles to four stranded turtles in the central Great Barrier Reef regions that include Bowen and Townsville. We used high-throughput sequencing analysis targeting the hypervariable V1-V3 regions of the bacterial 16S rRNA gene. At the phylum level, Firmicutes predominated among wild-captured green turtles, followed by Bacteroidetes and Proteobacteria. In contrast, Proteobacteria (Gammaproteobacteria) was the most significantly dominant phylum among all stranded turtles, followed by Bacteroidetes and Firmicutes. In addition, Fusobacteria was also significantly abundant in stranded turtles. No significant differences were found between the wild-captured turtles in Bowen and Townsville. At the family level, the core bacterial community consisted of 25 families that were identified in both the wild-captured and stranded green turtles, while two unique sets of 14 families each were only found in stranded or wild-captured turtles. The predominance of Bacteroides in all groups indicates the importance of these bacteria in turtle gut health. In terms of bacterial diversity and richness, wild-captured green turtles showed a higher bacterial diversity and richness compared with stranded turtles. The marked differences in the bacterial communities between wild-captured and stranded turtles suggest the possible dysbiosis in stranded turtles in addition to potential causal agents. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Test Station for Magnetization Measurements on Large Quantities of Superconducting Strands

CERN Document Server

Le Naour, S; Billan, J; Genest, J

2001-01-01

In the superconducting main magnets of the Large Hadron Collider (LHC), persistent currents in the superconductor determine the field quality at injection field. For this reason it is necessary to check the magnetization of the cable strands during their production. During four years, this requires measurements of the width of the strand magnetization hysteresis loop at 0.5 T, 1.9 K, at a rate of up to eight samples per day. This paper describes the design, construction and the first results of a magnetization test station built for this purpose. The samples are cooled in a cryostat, with a 2-m long elliptic tail. This tail is inserted in a normal conducting dipole magnet with a field between ± 1.5 T. Racetrack pick-up coils, integrated in the cryostat, detect the voltage due to flux change, which is then integrated numerically. The sample holder can contain eight strand samples, each 20 cm long. The test station operates in two modes: either the sample is fixed while the external field is changed, or the sa...

Defective processing of methylated single-stranded DNA by E. coli alkB mutants

Science.gov (United States)

Dinglay, Suneet; Trewick, Sarah C.; Lindahl, Tomas; Sedgwick, Barbara

2000-01-01

Escherichia coli alkB mutants are very sensitive to DNA methylating agents. Despite these mutants being the subject of many studies, no DNA repair or other function has been assigned to the AlkB protein or to its human homolog. Here, we report that reactivation of methylmethanesulfonate (MMS)-treated single-stranded DNA phages, M13, f1, and G4, was decreased dramatically in alkB mutants. No such decrease occurred when using methylated λ phage or M13 duplex DNA. These data show that alkB mutants have a marked defect in processing methylation damage in single-stranded DNA. Recombinant AlkB protein bound more efficiently to single- than double-stranded DNA. The single-strand damage processed by AlkB was primarily cytotoxic and not mutagenic and was induced by SN2 methylating agents, MMS, DMS, and MeI but not by SN1 agent N-methyl-N-nitrosourea or by γ irradiation. Strains lacking other DNA repair activities, alkA tag, xth nfo, uvrA, mutS, and umuC, were not defective in reactivation of methylated M13 phage and did not enhance the defect of an alkB mutant. A recA mutation caused a small but additive defect. Thus, AlkB functions in a novel pathway independent of these activities. We propose that AlkB acts on alkylated single-stranded DNA in replication forks or at transcribed regions. Consistent with this theory, stationary phase alkB cells were less MMS sensitive than rapidly growing cells. PMID:10950872

JOINT ADVISORY APPEALS BOARD

CERN Multimedia

Human Resources Division

2002-01-01

The Joint Advisory Appeals Board was convened to examine the appeal lodged by Mr Luc Vos with regard to advancement. As the appellant has not objected, the report of the Board and the final decision of the Director-General are brought to the notice of the personnel in accordance with Article R VI 1.20 of the Staff Regulations. The relevant documents will therefore be posted on the notice boards of the Administration Building (N° 60) from 14 to 28 June 2002. Human Resources Division Tel. 74128

JOINT ADVISORY APPEALS BOARD

CERN Multimedia

Human Resources Division

2001-01-01

The Joint Advisory Appeals Board was convened to examine the appeal lodged by Mr Olivier Francis Martin with regard to indefinite contract. As the appellant has not objected, the report of the Board and the final decision of the Director-General are brought to the notice of the personnel in accordance with Article R VI 1.20 of the Staff Regulations. The relevant documents will therefore be posted on the notice boards of the Administration Building (N° 60) from 8 to 25 June 2001.

Joint Advisory Appeals Board

CERN Multimedia

2003-01-01

The Joint Advisory Appeals Board was convened to examine the appeal lodged by Mr Aloïs Girardoz with regard to classification and advancement. As the appellant has not objected, the Board's report and the Director-General's decision will be brought to the notice of the personnel in accordance with Article R VI 1.20 of the Staff Regulations. The relevant documents will therefore be posted on the notice boards of the Administration Building (N° 60) from 15 to 29 August 2003. Human Resources Division Tel. 74128

Reconstitution of DNA strand exchange mediated by Rhp51 recombinase and two mediators.

Directory of Open Access Journals (Sweden)

Yumiko Kurokawa

2008-04-01

Full Text Available In the fission yeast Schizosaccharomyces pombe, genetic evidence suggests that two mediators, Rad22 (the S. pombe Rad52 homolog and the Swi5-Sfr1 complex, participate in a common pathway of Rhp51 (the S. pombe Rad51 homolog-mediated homologous recombination (HR and HR repair. Here, we have demonstrated an in vitro reconstitution of the central step of DNA strand exchange during HR. Our system consists entirely of homogeneously purified proteins, including Rhp51, the two mediators, and replication protein A (RPA, which reflects genetic requirements in vivo. Using this system, we present the first robust biochemical evidence that concerted action of the two mediators directs the loading of Rhp51 onto single-stranded DNA (ssDNA precoated with RPA. Dissection of the reaction reveals that Rad22 overcomes the inhibitory effect of RPA on Rhp51-Swi5-Sfr1-mediated strand exchange. In addition, Rad22 negates the requirement for a strict order of protein addition to the in vitro system. However, despite the presence of Rad22, Swi5-Sfr1 is still essential for strand exchange. Importantly, Rhp51, but neither Rad22 nor the Swi5-Sfr1 mediator, is the factor that displaces RPA from ssDNA. Swi5-Sfr1 stabilizes Rhp51-ssDNA filaments in an ATP-dependent manner, and this stabilization is correlated with activation of Rhp51 for the strand exchange reaction. Rad22 alone cannot activate the Rhp51 presynaptic filament. AMP-PNP, a nonhydrolyzable ATP analog, induces a similar stabilization of Rhp51, but this stabilization is independent of Swi5-Sfr1. However, hydrolysis of ATP is required for processive strand transfer, which results in the formation of a long heteroduplex. Our in vitro reconstitution system has revealed that the two mediators have indispensable, but distinct, roles for mediating Rhp51 loading onto RPA-precoated ssDNA.

Normal rejoining of DNA strand breaks in ataxia telangiectasia fibroblast lines after low x-ray exposure

International Nuclear Information System (INIS)

Hariharan, P.V.; Eleczko, S.; Smith, B.P.; Paterson, M.C.