bluuebunny/crossref_metadata_2025_split huggingface dataset:
Current Status of Systemic Antibiotic Usage in Destructive Periodontal Disease
Authors: Gordon Jeffrey M. , Walker Clay B. 
Published: March 2012

The recognition that periodontal diseases are primarily caused by specific microorganisms has led researchers to explore the possibility that antibiotics may enhance the effect of mechanical debridement procedures such as scaling and surgery. For some selected periodontal diseases, this has proven to be true. This paper will review systemically‐administered antibiotics and the clinical studies and case reports supporting their use. In periodontal therapy, the tetracyclines are the most commonly‐used antibiotics in the United States. Tetracycline hydrochloride, minocycline, and doxycycline have been shown to inhibit in vitro most putative periodontal pathogens. Several studies support the use of tetracyclines in the treatment of localized juvenile periodontitis. Penicillins such as amoxicillin are effective in vitro against most periodontal pathogens but have limited efficacy due to the presence of beta‐lactamases in gingival fluid. Amoxicillin/ clavulanate potassium (Au) has proven effective in treating adult refractory periodontitis characterized by a Gram‐positive flora. Metronidazole is an effective adjunct in adult periodontitis associated with high numbers of “black‐pigmented Bacteroides” and spirochetes. A combination of metronidazole and amoxicillin produces a synergistic effect against A. actinomycetemcomitans and has been shown to be effective at eliminating this organism. Clindamycin is an effective adjunct in the treatment of adult refractory periodontitis associated with a predominantly Gram‐negative flora.The use of macrolides, quinolones, and combinations of antibiotics is discussed. Clinical studies do not support the use of systemically‐administered antibiotics in routine adult periodontitis. Clinical studies do, however, support the use of antibiotics in the treatment of specific periodontal diseases. J Periodontol 1993; 64:760–771.
Evaluation of Chemical Treatment on Zirconia Surface with Two Primer Agents and an Alkaline Solution on Bond Strength
Authors: Lorenzoni FC , Leme VP , Santos LA , de Oliveira PCG , Martins LM , Bonfante G 
Published: March 2012

SUMMARYObjectivesThis study evaluated the effect of an alkaline solution and two 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-based primer agents on bond strength to zirconia (yttria-stabilized tetragonal zirconium polycrystal [Y-TZP]) through the shear bond strength (SBS) test.Materials and MethodsSixty square-shaped Y-TZP samples were embedded in an acrylic resin mold, polished, and randomly assigned to one of six groups (n=10) according to treatment surface: group CR, no treatment (control); group NaOH, 0.5 M NaOH; group AP, Alloy Primer; group ZP, Z-Primer Plus; group NaOH-AP, 0.5 M NaOH + Alloy Primer; and group NaOH-ZP, 0.5 M NaOH + Z-Primer Plus. The resin cement (Rely X U100) was applied inside a matrix directly onto the Y-TZP surface, and it was light-cured for 40 seconds. The samples were stored in distilled water at 37°C for 24 hours prior to the test, which was performed in a universal machine at a crosshead-speed of 0.5 mm/min. The data were analyzed by one-way analysis of variance and Tukey tests (p&lt;0.05). Light stereomicroscopy and scanning electron microscopy were used to assess the surface topography and failure mode.ResultsThe SBS was significantly affected by the chemical treatment (p&lt;0.0001). The AP group displayed the best results, and the use of NaOH did not improve SBS results relative to either AP or ZP. The samples treated with Alloy Primer displayed mainly mixed failures, whereas those conditioned with Z-Primer Plus or with 0.5 M NaOH presented a balanced distribution of adhesive and mixed failure modes.ConclusionsThe use of a NaOH solution may have modified the reactivity of the Y-TZP surface, whereas the employment of a MDP/6-4-vinylbenzyl-n-propyl amino-1,3,5-triazine-2,4-dithione–based primer enhanced the Y-TZP bond strength.
Weak Versions of Stochastic Adams-Bashforth and Semi-implicit Leapfrog Schemes for SDEs
Authors: Ewald Brian 
Published: March 2012

AbstractWe consider the weak analogues of certain strong stochastic
numerical schemes, namely an Adams-Bashforth scheme and a semi-implicit leapfrog scheme. We show
that the weak version of the Adams-Bashforth scheme converges weakly
with order 2, and the weak version of the semi-implicit leapfrog
scheme converges weakly with order 1. We also note that the weak
schemes are computationally simpler and easier to implement than the
corresponding strong schemes, resulting in savings in both
programming and computational effort.
An Approximation Method Based on Matrix Formulated Algorithm for the Heat Equation with Nonlocal Boundary Conditions
Authors: Shahmorad Sedaghat , Borhanifar Abdollah , Soltanalizadeh Babak 
Published: March 2012

Abstract
In this paper, we utilize a matrix formulation for the heat equation
with nonlocal boundary conditions. We give details of the method and
verify the existence of a solution for the given equation under a
new suitable condition. A simple and efficient algorithm is
presented for the numerical results illustrating the accuracy of the
method.
A Concept of a Passive Radar with Quadrature Microwave Phase Discriminators
Authors: Rutkowski Adam 
Published: March 2012

A Concept of a Passive Radar with Quadrature Microwave Phase Discriminators
Passive radar does not have its own emitter. It uses so-called signals of opportunity emitted by non-cooperative illuminators. During the detection of reflected signals, a direct signal from a non-cooperative emitter is used as the reference signal. Detection of electromagnetic echoes is, in present day radars, performed by finding the maximum of the cross ambiguity function. This function is based on the multiplication of the received signal and the reference signal. Detection of echoes by means of a quadrature microwave phase discriminator QMPD was proposed in the work as an alternative solution for ambiguity function evaluation. This discriminator carries out vectorial summing of the received and the reference signals. The summing operations in QMPD are carried out with the aid of microwave elements and without the use of expensive digital signal processors. Definitions of the phase and phase difference of the so-called simple signals and noise signals were described. A proposal of a passive radar equipped with several independent quadrature microwave phase discriminators was presented. Ideas of algorithms of object detection and of the distance-to-object estimation designed for this radar have been also sketched.
Maturity Assessment of Maintenance Processes at ATC-Service Providers
Authors: Kundler Jörg 
Published: March 2012

Maturity Assessment of Maintenance Processes at ATC-Service Providers
The focus of the research is the analysis and assessment of Air Traffic Control (ATC) maintenance and technical service processes. Deriving from the general ATC process model, which is the part of the Air Transport System, the related ATC Services including a Key Performance Indicator System were developed. A theoretical analysis was performed to develop a special correlation matrix between the Air Transport System to ATC service and ATC technical services, which reflect the top-down approach of process modelling proceeding. A particular research of different international ATC service organization, selected by defined parameter was performed for analysis. The analysis was implemented with different scientific research methods. Basing on this international research, a detailed SWOT analysis and conclusions of each ATC organization itself and additionally a parameter-oriented comparison between the different organizations and their specifics were performed. The results of this research were described in a SWOT analysis, rating assessment of utilization of the theoretical methods and qualified evaluation of implemented KPI System. For final maintenance process evaluation an ATC-Maintenance Process Maturity method based on ISO /IEC Standard 15504 was developed. The results and developments of the research will be the essential prerequisite for the further research of dissertation and development of a harmonized ATC Meta Frame Maintenance Process Model as a part of the Air Transport System on macro model level and deriving to the ATC specific Maintenance Service Model on micro level for the specific ATC organization basing on service and business modelling methods.
Fractal morphology of Beta vulgaris L. cell suspension culture permeabilized with Triton X-100®
Authors: Arenas-Ocampo M. , Alamilla-Beltrán L. , Vanegas-Espinoza P. , Camacho-Díaz B. , Campos-Mendiola R. , Gutiérrez-López G. , Jiménez-Aparicio A. 
Published: March 2012

Fractal morphology of Beta vulgaris L. cell suspension culture permeabilized with Triton X-100®
In this work, morphology of Beta vulgaris L. cells permeabilized with 0.7mM of Triton X-100® was evaluated using digital image processing and concepts of fractal dimension (perimeter- area relations). Important morphometric changes were found when the contact-time with chemical agent was increased. The size of cells decreased, the cells lost the roundness and their shape was more sinuous; this behaviour was a result of a probable shrinkage caused by the excess of exposure with the permeabilization agent. Morphology of B. vulgaris cells after permeabilization, exhibited a fractal nature since the slope of the ratio of the logarithm of the perimeter vs logarithm of the area was higher than unit. Fractal geometry of the cell morphology was affected as a result of the exposure to Triton X-100®. Those changes can be attributed to the loss of turgor and structure of the cell wall.
Influence of phosphate ions on buffer capacity of soil humic acids
Authors: Boguta P. , Sokołowska Z. 
Published: March 2012

Influence of phosphate ions on buffer capacity of soil humic acidsThe object of this study was to determine change of natural buffer capacity of humic acids by strong buffering agents, which were phosphate ions. Studies were carried out on the humic acids extracted from peat soils. Additional information was obtained by determination of water holding capacity, density, ash and pH for peats and optical parameter Q4/6for humic acids. Humic acid suspensions exhibited the highest buffer properties at low pH and reached maximum at pH ~ 4. Phosphates possessed buffer properties in the pH range from 4.5 to 8.0. The maximum of buffering was at pH~6.8 and increased proportionally with an increase in the concentration of phosphate ions. The study indicated that the presence of phosphate ions may strongly change natural buffer capacity of humic acids by shifting buffering maximum toward higher pH values. Significant correlations were found for the degree of the secondary transformation with both the buffer capacity and the titrant volume used during titration.
Effects of temperature and desiccation on ex situ conservation of nongreen fern spores
Authors: Ballesteros Daniel , Estrelles Elena , Walters Christina , Ibars Ana M. 
Published: March 2012

•Premise of the study:Fern spores are unicellular and haploid, making them a potential model system to study factors that regulate lifespan and mechanisms of aging. Aging rates of nongreen spores were measured to compare longevity characteristics among diverse fern species and test for orthodox response to storage temperature and moisture.•Methods:Aging of spores from 10 fern species was quantified by changes in germination and growth parameters. Storage temperature ranged from ambient room to −196°C (liquid nitrogen); spores were dried to ambient relative humidity (RH) or using silica gel.•Key results:Survival of spores varied under ambient storage conditions, with one species dying within a year and two species having greater than 50% survival after 3 years. Few changes in germination or growth were observed in spores stored at either −80°C or −196°C over the same 3‐yr study period. Spores stored at −25°C aged anomalously quickly, especially those dried to ambient RH or subjected to repeated freeze–thaw cycles.•Conclusions:Spore longevity is comparable to orthodox seed longevity under ambient storage conditions, with wide variation among species and shelflife extended by drying or cooling. However, faster aging during freezer storage may indicate a similar syndrome of damage experienced by seeds categorized as “intermediate”. The damage is avoided by storage at −80°C or liquid nitrogen temperatures, making cryoconservation an effective and broadly applicable tool to extend fern spore longevity. The study demonstrates that spore banks are a feasible approach for ex situ conservation of this important plant group.
Phylogeny, divergence times, and historical biogeography of New World Dryopteris (Dryopteridaceae)
Authors: Sessa Emily B. , Zimmer Elizabeth A. , Givnish Thomas J. 
Published: March 2012

• Premise of the study: Dryopteris is a large, cosmopolitan fern genus ideal for addressing questions about diversification, biogeography, hybridization, and polyploidy, which have historically been understudied in ferns. We constructed a highly resolved, well‐supported phylogeny for New World Dryopteris and used it to investigate biogeographic patterns and divergence times.• Methods: We analyzed relationships among 97 species of Dryopteris, including taxa from all major biogeographic regions, with analyses based on 5699 aligned nucleotides from seven plastid loci. Phylogenetic analyses used maximum parsimony, maximum likelihood, and Bayesian inference. We conducted divergence time analyses using BEAST and biogeographic analyses using maximum parsimony, maximum likelihood, Bayesian, and S‐DIVA approaches. We explored the monophyly of subgenera and sections in the most recent generic classification and of geographic groups of taxa using Templeton tests.• Key results: The genus Dryopteris arose ca. 42 million years ago (Ma). Most of the Central and South American species form a well‐supported clade which arose 32 Ma, but the remaining New World species are the result of multiple, independent dispersal and vicariance events involving Asia, Europe, and Africa over the last 15 Myr. We identified six long‐distance dispersal events and three vicariance events in the immediate ancestry of New World species; reconstructions for another four lineages were ambiguous.• Conclusions: New World Dryopteris are not monophyletic; vicariance has dominated the history of the North American species, while long‐distance dispersal prevails in the Central and South American species, a pattern not previously seen in plants.
Conformational preferences of 4‐chloroproline residues
Authors: Park Hae Sook , Byun Byung Jin , Motooka Daisuke , Kawahara Kazuki , Doi Masamitsu , Nakazawa Takashi , Kobayashi Yuji , Kang Young Kee 
Published: March 2012

AbstractConformational preferences of the (2S,4R)‐4‐chloroproline (Clp) and (2S,4S)‐4‐chloroproline (clp) residues are explored at the M06‐2X/cc‐pVTZ//M06‐2X/6‐31+G(d) level of theory in the gas phase and in water, where solvation free energies were calculated using the implicit solvation model, and by an X‐ray diffraction study in the solid state. In the gas phase, the down‐puckered γ‐turn structure with the trans prolyl peptide bond is most preferred for both Ac‐Clp‐NHMe and Ac‐clp‐NHMe, in which the C7 hydrogen bond between two terminal groups seems to play a role, as found for Ac‐Pro‐NHMe. In water, the Clp residue has a strong preference for the up‐puckered PPII structure, whereas the up‐puckered PPII structure prevails a little over the down‐puckered PPII structure for the clp residue, similar to the Pro residue. Hence, our calculated results on the puckering preference of the Clp and clp residues in water are in accord with the observed results deduced from the relative stabilities of the triple helices of the collagen model peptides. The X‐ray structure of Ac‐clp‐NHMe was found to be the most preferred in water but that of Ac‐Clp‐NHMe was located as a local minimum with ΔG = 2.0 kcal/mol. In particular, the X‐ray structure of Ac‐Clp‐NHMe was quite different from that of Ac‐Clp‐OMe but similar to that of Ac‐Pro‐NHMe. The lowest rotational barriers to the prolyl cis–trans isomerization for Ac‐Clp‐NHMe become nearly the same as those for Ac‐Pro‐NHMe in water, whereas the barriers are lower by ∼2 kcal/mol for Ac‐clp‐NHMe. It was found that the cis–trans isomerization may proceed through the clockwise or anticlockwise rotations for Ac‐Clp‐NHMe and the anticlockwise rotation for Ac‐clp‐NHMe and Ac‐Pro‐NHMe in water. © 2012 Wiley Periodicals, Inc. Biopolymers 97: 629–641, 2012.
Development of QSARs for the toxicity of chlorobenzenes to the soil dwelling springtail Folsomia candida
Authors: Giesen Daniel , Jonker Michiel T.O. , van Gestel Cornelis A. M. 
Published: March 2012

Abstract
To meet the goals of Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH) as formulated by the European Commission, fast and resource-effective tools are needed to predict the toxicity of compounds in the environment. We developed quantitative structure-activity relationships (QSARs) for the toxicity of nine chlorinated benzenes to the soil-dwelling collembolan Folsomia candida in natural LUFA2.2 (Landwirtschaftliche Untersuchungs und Forschungsanstalt [LUFA]) standard soil and in Organisation for Economic Co-operation and Development artificial soil. Toxicity endpoints used were the effect concentrations causing 10% (EC10) and 50% (EC50) reduction in the reproduction of the test organism over 28 d, while lethal effects on survival (LC50) were used for comparisons with earlier studies. Chlorobenzene toxicity was based on concentrations in interstitial water as estimated using nominal concentrations in soil and literature soil–water partition coefficients. Additionally, for LUFA2.2 soil the estimated concentrations in interstitial water were experimentally determined by solid-phase microextraction measurements. Measured and estimated concentrations showed the same general trend, but significant differences were observed. With the exception of hexachlorobenzene, estimated EC10 and EC50 values were all negatively correlated with their logKow and QSARs were developed. However, no correlation for the LC50 could be derived and 1,2,4,5-tetrachlorobenzene and hexachlorobenzene had no effect on adult survival at all. The derived QSARs may contribute to the development of better ecotoxicity-based models serving the REACH program. Environ. Toxicol. Chem. 2012; 31: 1136–1142. © 2012 SETAC
Multiple electrosprays generated from a single polycarbonate microstructured fibre
Authors: Gibson Graham T. T. , Wright Ramin D. , Oleschuk Richard D. 
Published: March 2012

ABSTRACTElectrospray ionization (ESI) has been invaluable to the mass spectrometric detection of biomolecules, due largely to the sensitivity afforded by the ionization technique. Lower flow rates, e.g. in the nanoelectrospray regime, result in smaller initial electrosprayed droplets, leading to higher ionization efficiency and greater signal. One approach to improving sensitivity without lowering flow rate is to generate multiple electrosprays (MESs) from the same sample, essentially splitting one larger flow into smaller flows in the nanoESI regime. Presented here is a series of novel MES emitters in the form of polycarbonate fibres. Based on microstructured fibre (MSF) technology whereby a set of homogeneous parallel channels are formed in a heat‐drawn fibre intended to conduct light, a custom design was fabricated in which 3, 6, 9 and 12 holes were arranged in a radial pattern to prevent inhomogeneities in the electric field. The MSFs have dimensions that are compatible with current standards in nanoESI equipment, and the tip is more compatible with standard MS orifices than other larger multielectrospray emitters. By measuring the spray current provided by the various emitters under the same solvent/voltage/total flow rate conditions, a plot was obtained clearly demonstrating the expected dependence on the square root of the number of holes, i.e. the number of independent electrosprays. With this firm proof of principle using this design/format, further effort is justified in developing similar emitters in alternative materials that better prevent surface wetting and allow greater hole density, ultimately leading to greater signal enhancement. Copyright © 2012 John Wiley & Sons, Ltd.
Characteristics of electrical field and ion motion in surface‐electrode ion traps
Authors: Zhou Xiaoyu , Xu Gaoping , Xiong Caiqiao , Chen Rui , Qiao Haoxue , Nie Zongxiu 
Published: March 2012

ABSTRACTIn this article, we calculated the potential function of the surface‐electrode ion trap (SEIT) by using Green's function method, optimized trap size, obtained the coefficients of the multipoles and analyzed ion trajectories in the RF potential. The optimized SEIT not only increases its trapping well depth by a factor of about 15, but also has relatively good linearity of the field (or large quadrupole component). The current design of SEIT can work well either as the ion guide for ion transmission or as the ion trap for ion confinement. Our research can be used to calculate the potential function in the SEIT with different device parameters, understand ion motions in the traps and optimize instrument performance. The method for calculating potential function can be expanded to planar and halo ion traps. Copyright © 2012 John Wiley & Sons, Ltd.
Micromechanical model of weakly‐cemented sediments
Authors: Holtzman R. 
Published: March 2012

SUMMARYExperiments indicate that the bulk stiffness of weakly‐cemented granular materials increases significantly with the applied load, a nonlinearity which is not captured by most micromechanical models. Here, we study the deformation of weakly‐cemented materials through grain‐scale simulations. We show that the frequently‐made assumption of linear‐elastic cement and intergranular contact area which varies according to a Hertzian‐type model cannot explain the observed nonlinearity of the bulk response. We introduce the micromechanical effect of mechanisms such as closure and opening of microcracks, granular cement and material heterogeneity through an effective contact stiffness which depends on the local deformation. We find that an exponential dependence between the effective stiffness and the local deformation, with a high exponent value, provides bulk stiffness which is in good agreement with experimental data. The inability of models with weaker intergranular stiffness‐deformation dependence to reproduce the experimental data demonstrates the highly‐nonlinear nature of the intergranular deformation. Our results highlight the importance of accounting for grain‐scale mechanisms in modeling granular materials, and provide a plausible explanation for the nonlinear behavior of weakly‐cemented sediments. Copyright © 2012 John Wiley & Sons, Ltd.