bluuebunny/crossref_metadata_2025 huggingface dataset:
Muddy Waters: The Political Construction of Deliberative River Basin Governance in Brazil
Authors: ABERS REBECCA NEAERA , KECK MARGARET E.
Published: October 2006

Over the last two decades, numerous international conferences and organizations have espoused managing water as an economic good, involving participatory forums in systems of decentralized management at the river‐basin level. In the 1990s, Brazil adopted such a model. More than a simple transfer of power from the national to the local level or from bureaucratic to deliberative decision‐making, however, this process requires multi‐directional power transfers among a variety of policy arenas and actors and among national, state, municipal and river‐basin institutions, as well as a complex — and ongoing — negotiation over the meanings of both water pricing and participation. Focusing on the politics of reform legislation in the state of São Paulo and nationally, the article examines how political‐institutional features of federalism and executive‐legislative relations constrained the passage of reform legislation, and how pro‐reform actors attempted to surmount such institutional limitations with networking strategies and by fostering incremental changes in practices on the ground.
Context Sampling Descriptive Assessment: A Pilot Study of a Further Approach to Functional Assessment1
Authors: Garbutt Nathalie , Furniss Frederick
Published: October 2006

Background  The ability of descriptive assessments to differentiate functions of problem behaviours might be increased by systematically sampling natural contexts characterized by different establishing operations. This study evaluated the stability of such characteristics, and variability in challenging behaviour, for three school contexts.

Method  A 10‐year‐old girl with severe intellectual disability and her carers were repeatedly observed in three situations hypothesized to vary in levels of demand and attention presented by carers.

Results  Levels of demand and attention were stable within, and varied systematically between, contexts; however, characteristics of one situation were not as expected. Levels of problem behaviour were reliably higher in one context than in the other two.

Conclusions  The demand and attention characteristics of two natural contexts were found to reliably resemble some antecedent conditions typically used in experimental functional analyses. Context sampling may improve the power of descriptive assessments to differentiate functions of problem behaviour.
Disease modifying therapy for AD?1
Authors: Golde Todd E.
Published: October 2006

Alzheimer's disease (AD) is the most common form of dementia in industrialized nations. If more effective therapies are not developed that either prevent AD or block progression of the disease in its very early stages, the economic and societal cost of caring for AD patients will be devastating. Only two types of drugs are currently approved for the treatment of AD: inhibitors of acetyl cholinesterase, which symptomatically enhance cognitive state to some degree but are not disease modifying; and the adamantane derivative, memantine. Memantine preferentially blocks excessive NMDA receptor activity without disrupting normal receptor activity and is thought to be a neuroprotective agent that blocks excitotoxicty. Memantine therefore may have a potentially disease modifying effect in multiple neurodegenerative conditions. An improved understanding of the pathogeneses of AD has now led to the identification of numerous therapeutic targets designed to alter amyloid β protein (Aβ) or tau accumulation. Therapies that alter Aβ and tau through these various targets are likely to have significant disease modifying effects. Many of these targets have been validated in proof of concept studies in preclinical animal models, and some potentially disease modifying therapies targeting Aβ or tau are being tested in the clinic. This review will highlight both the promise of and the obstacles to developing such disease modifying AD therapies.
Alois Alzheimer and Alzheimer's disease: a centennial perspective
Authors: Small David H. , Cappai Roberto
Published: October 2006

The year 2006 is the centenary of the famous presentation of Alois Alzheimer which first described the neuropathology of Alzheimer's disease (AD). Since this presentation, enormous progress has been made in understanding the biology of AD. The central role of the β‐amyloid protein (Aβ) in the pathogenesis of AD and the relationship between plaque and tangle pathology is now much better understood. In this article, we review the current status of the amyloid hypothesis of AD and its role in the development of future therapy.
Metal limitation of cyanobacterial N2fixation and implications for the Precambrian nitrogen cycle
Authors: ZERKLE A. L. , HOUSE C. H. , COX R. P. , CANFIELD D. E.
Published: October 2006

Nitrogen fixation is a critical part of the global nitrogen cycle, replacing biologically available reduced nitrogen lost by denitrification. The redox‐sensitive trace metals Fe and Mo are key components of the primary nitrogenase enzyme used by cyanobacteria (and other prokaryotes) to fix atmospheric N2into bioessential compounds. Progressive oxygenation of the Earth's atmosphere has forced changes in the redox state of the oceans through geologic time, from anoxic Fe‐enriched waters in the Archean to partially sulfidic deep waters by the mid‐Proterozoic. This development of ocean redox chemistry during the Precambrian led to fluctuations in Fe and Mo availability that could have significantly impacted the ability of prokaryotes to fix nitrogen. It has been suggested that metal limitation of nitrogen fixation and nitrate assimilation, along with increased rates of denitrification, could have resulted in globally reduced rates of primary production and nitrogen‐starved oceans through much of the Proterozoic. To test the first part of this hypothesis, we grew N2‐fixing cyanobacteria in cultures with metal concentrations reflecting an anoxic Archean ocean (high Fe, low Mo), a sulfidic Proterozoic ocean (low Fe, moderate Mo), and an oxic Phanerozoic ocean (low Fe, high Mo). We measured low rates of cellular N2fixation under [Fe] and [Mo] estimated for the Archean ocean. With decreased [Fe] and higher [Mo] representing sulfidic Proterozoic conditions, N2fixation, growth, and biomass C:N were similar to those observed with metal concentrations of the fully oxygenated oceans that likely developed in the Phanerozoic. Our results raise the possibility that an initial rise in atmospheric oxygen could actually have enhanced nitrogen fixation rates to near modern marine levels, providing that phosphate was available and rising O2levels did not markedly inhibit nitrogenase activity.
Alteration of iron‐rich lacustrine sediments by dissimilatory iron‐reducing bacteria
Authors: CROWE S. A. , ROBERTS J. A. , WEISENER C. G. , FOWLE D. A.
Published: October 2006

The reduction of Fe during bacterial anaerobic respiration in sediments and soils not only causes the degradation of organic matter but also results in changes in mineralogy and the redistribution of many nutrients and trace metals. Understanding trace metal patterns in sedimentary rocks and predicting the fate of contaminants in the environment requires a detailed understanding of the mechanisms through which they are redistributed during Fe reduction. In this work, lacustrine sediments from Lake Matano in Indonesia were incubated in a minimal media with the dissimilatory iron reducing (DIR) bacterium Shewanella putrefaciens 200R. These sediments were reductively dissolved at rates slower than pure synthetic goethite despite the presence of an ‘easily reducible’ component, as defined by selective extractions. DIR of the lacustrine sediments resulted in the substrate‐dependent production of abundant quantities of extracellular polymeric substances. Trace elements, including Ni, Co, P, Si, and As, were released from the sediments with progressive Fe reduction while Cr was sequestered. Much of the initial trace metal mobility can be attributed to the rapid reduction of a Mn‐rich oxyhydroxide phase. The production of organo‐Fe(III) reveals that DIR bacteria can generate significant metal complexation capacity. This work demonstrates that DIR induces the release of many elements associated with Fe‐Mn oxyhydroxides, despite secondary mineralization.
Liver‐type fatty acid binding protein in serum and broncho‐alveolar lavage in a model of acute respiratory failure because of surfactant depletion – a possible marker for lung damage?
Authors: Lachmann R. A. , Werchan S. , Schachtrup C. , Haitsma J. J. , Spener F. , Lachmann B.
Published: October 2006

Introduction  Liver‐type fatty acid binding proteins (L‐FABP) have been shown to be present in alveolar macrophages and type II pneumocytes of the lung. This study determined levels of L‐FABP in serum and broncho‐alveolar lavage (BAL) during experimental acute respiratory failure (ARF) to evaluate whether this molecule can serve as a marker for lung damage.

Methods  Male Sprague–Dawley rats (n = 24) were ventilated and either lung lavaged or lavaged and treated with surfactant, and compared to ventilated, non‐lavaged controls. Blood samples were drawn every hour for 4 h to measure L‐FABP concentrations in serum. At the end of the experiment a BAL was performed to determine L‐FABP levels in BAL fluid. L‐FABP was measured with a sandwich enzyme‐linked immunosorbent assays.

Results  Serum L‐FABP concentrations rose significantly during the first 2 h of ventilation in all groups compared with baseline values. After 2 h L‐FABP levels were significantly higher in lavaged animals compared with the ventilated controls and to animals treated with surfactant. After 4 h of ventilation, L‐FABP in BAL was significantly higher in lavaged, non‐surfactant treated animals compared with the ventilated controls.

Conclusion  In the early phase of experimental ARF serum L‐FABP levels correlate well with the degree of lung injury.
Isochromatic Demodulation by Fringe Scanning
Authors: Grewal G. S. , Dubey V. N. , Claremont D. J.
Published: October 2006

Abstract:  RGB calibration is the fastest isochromatic demodulation technique, as it does not require unwrapping as in the case of phase‐shifting method. The technique is based on constructing a look up table (LUT) of fringe order against RGB triplet from digital images and decoding the test image from the LUT. Research has shown that the technique, though very fast, is limited to fringe orders up to three with the conventional white light. The colours tend to merge beyond that and make it difficult to obtain a unique value of RGB triplet. Changes in fringe gradient caused by stretching/bunching of fringes in test model further add to errors. Special light sources with narrow‐band spectral response are required with fringe tracking algorithms to demodulate higher fringe orders. The calibration technique is also sensitive to geometric and chromatic variations. This paper presents a cost‐effective alternative solution to conventional RGB technique using a flatbed scanner. The system is capable of demodulating higher fringe order and incorporates information from other colour spaces. It does not require separate light sources and cameras, and is found to be insensitive to geometric and chromatic variations. Curve fitting technique has been proposed to determine accurate fringe orders.
Androgen Treatment and Muscle Strength in Elderly Men: A Meta‐Analysis
Authors: Ottenbacher Kenneth J. , Ottenbacher Margaret E. , Ottenbacher Allison J. , Acha Ana Alfaro , Ostir Glenn V.
Published: October 2006

OBJECTIVES: To review published, randomized trials examining the effect of androgen treatment on muscle strength in older men.

DESIGN: Systematic review using meta‐analysis procedures.

SETTING: Computerized and manual searches.

PARTICIPANTS: MEDLINE, EMBASE, CINAHL, and the Cochrane Register were searched for trials. Key words included testosterone, androgen, sarcopenia, muscle loss, aged, aging, elderly, older, geriatric, randomized controlled trials, and controlled clinical trials. Sixty‐five nonoverlapping studies were found. Meta‐analysis methods were used to evaluate the 11 randomized, double‐blind trials.

INTERVENTION: Testosterone or dihydrotestosterone (DHT) replacement therapy in healthy men aged 65 and older.

MEASUREMENTS: Tests of muscle strength.

RESULTS: The studies included 38 statistical comparisons. The mean g‐index (gi) adjusted for sample size was 0.53 (95% confidence interval (CI)=0.21–0.86). Subanalyses revealed larger effects for measures of lower extremity muscle strength (gi=0.63, 95% CI=0.03–1.28) than for upper extremity muscle strength (gi=0.47, 95% CI=0.12–0.84). A larger mean g‐index was found for injected (gi=0.95, 95% CI=0.33–1.58) than topical (gi=0.26, 95% CI=0.08–0.42) or oral (gi=−0.21, 95% CI=−1.40–1.02) administration of testosterone/DHT. Effect sizes were related to study characteristics such as subject attrition and design‐quality ratings. Sensitivity analyses revealed that the elimination of one study reduced the mean g‐index from 0.53 to 0.23.

CONCLUSION: The results suggest that testosterone/DHT therapy produced a moderate increase in muscle strength in men participating in 11 randomized trials. One study influenced the mean effect size.
From the Inside Out: Environmental Agency Views about Communications with the Public
Authors: Johnson Branden B. , Chess Caron
Published: October 2006

Relatively few studies have examined risk communication with the public from the viewpoint of the staff of institutions attempting such communications. This paper reports results of interviews with managers and staff of the New Jersey Department of Environmental Protection, on their programs' current and ideal communications with the public. Q analysis revealed two orthogonal perspectives on current program communications, the Enthused and the Constrained views. The primary focus of their divergence was on the matter of commitment and support for such communications. The Enthused group felt that they had attitudinal support from program culture and managers; the Constrained group focused on the lack of concrete operational support in terms of time, money, and expertise. These differences between the two groups did not appear to be associated with gender, managerial status, education, communication training, or organizational unit. When ideal program communications were discussed, the focus was on the need for all kinds of commitment and support (i.e., culture, managers, time, money, building expertise through training), as well as on more proactive and responsive communication. Both perspectives agreed that communication with the public is essential to their programs' success, trying new ways to communicate is worthwhile, scientific bases for decisions are not compromised by communication, and communication is not delegated to specialists. While varying ideas were held of the public's capacity and interest in communication, citizens were largely not held responsible for communication problems.
Trust Relations in High‐Reliability Organizations
Authors: Cox Sue , Jones Bethan , Collinson David
Published: October 2006

Workplace trust has been recognized by researchers and practitioners alike to be an important component of an effective safety culture. However, despite this, the concept of trust as it relates to safety has been underresearched, particularly within high‐reliability organizations. This article examines the importance of trust relations and their concomitant impact on safety culture within the specific context of high‐reliability organizations using relevant literatures. The article then explores the implications of high and low trust situations for safety through case studies conducted within the nuclear and offshore industries as exemplars of organizations operating within high‐reliability sectors.
Effects of Altered Temperature and Precipitation on Desert Protozoa Associated with Biological Soil Crusts
Authors: DARBY BRIAN J. , HOUSMAN DAVID C. , ZAKI AMR M. , SHAMOUT YASSEIN , ADL SINA M. , BELNAP JAYNE , NEHER DEBORAH A.
Published: October 2006

ABSTRACT. Biological soil crusts are diverse assemblages of bacteria, cyanobacteria, algae, fungi, lichens, and mosses that cover much of arid land soils. The objective of this study was to quantify protozoa associated with biological soil crusts and test the response of protozoa to increased temperature and precipitation as is predicted by some global climate models. Protozoa were more abundant when associated with cyanobacteria/lichen crusts than with cyanobacteria crusts alone. Amoebae, flagellates, and ciliates originating from the Colorado Plateau desert (cool desert, primarily winter precipitation) declined 50‐, 10‐, and 100‐fold, respectively, when moved in field mesocosms to the Chihuahuan Desert (hot desert, primarily summer rain). However, this was not observed in protozoa collected from the Chihuahuan Desert and moved to the Sonoran desert (hot desert, also summer rain, but warmer than Chihuahuan Desert). Protozoa in culture began to encyst at 37°C. Cysts survived the upper end of daily temperatures (37–55°C), and could be stimulated to excyst if temperatures were reduced to 15°C or lower. Results from this study suggest that cool desert protozoa are influenced negatively by increased summer precipitation during excessive summer temperatures, and that desert protozoa may be adapted to a specific desert's temperature and precipitation regime.
Costs and benefits of host feeding in the parasitoid wasp Trichogramma turkestanica
Authors: Ferracini Chiara , Boivin Guy , Alma Alberto
Published: October 2006

Females of the parasitoid wasp Trichogramma turkestanica Meyer (Hymenoptera: Trichogrammatidae) generally host feed after ovipositing on the first egg of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) they encounter. We measured the impact of host feeding on the fecundity and longevity of females, in absence of host or food, and on the fitness of their progeny. We also determined if the frequency of host feeding is influenced by the humidity level at which T. turkestanica females developed. Host feeding increased egg production by 70% but decreased female longevity. This impact of host feeding on the longevity of females is probably due to the allocation of carbohydrates to egg production at the expense of somatic maintenance. Humidity did not influence the occurrence or duration of host feeding. The size of individuals developing in eggs on which females host fed was smaller, indicating that their fitness was affected.
Granulomatous arteritis in cutaneous lesions of Churg–Strauss syndrome
Authors: Chen Ko‐Ron , Sakamoto Michiie , Ikemoto Kumiko , Abe Riichiro , Shimizu Hiroshi
Published: October 2006

Background:  Although granulomatous arteritis is usually found in extracutaneous Churg–Strauss syndrome (CSS) lesions, the vasculitis in CSS cutaneous lesions typically shows small vessel vasculitis (leukocytoclastic vasculitis) without demonstrating the feature of granulomatous arteritis confirming the proper classification of CSS in the category of granulomatous vasculitis.

Methods:  Four deep excisional biopsies were obtained from three untreated CSS patients who presented with livedo reticularis and subcutaneous nodules. Tissue blocks were recut and submitted for hematoxylin and eosin and elastic tissue staining to evaluate the histological features of the affected vessels. Immunostaining for histiocytes, lymphocytes, and neutrophils were performed on serial sections to confirm the cellular infiltration.

Results:  In all specimens, subcutaneous granulomatous arteritis was observed. The unique histological feature distinct from other vasculitic disorders is characterized by marked infiltration of histiocytes and multinucleated giant cells in and around the disrupted subcutaneous arterial walls mixed with an eosinophilic infiltrate. In two specimens, granulomatous arteritis was found in the subsequent serial sections, not in the initial sections. The initial section may show extravascular granulomatous inflammation without evidence of vasculitis.

Conclusions:  Granulomatous arteritis as identified in the extracutaneous lesions can also be found in subcutaneous CSS lesions presenting with livedo reticularis and/or subcutaneous nodules.
Cross‐species amplification of Lolium microsatellites in Poa ssp
Authors: Kindiger Bryan
Published: October 2006

Cross‐species amplification of 47 Lolium ssp. microsatellite primers were evaluated across eight Poa species or subspecies. Of the 47 evaluated Lolium simple sequence repeat (SSR) primer pairs examined, 18 generated one or more amplification products. Of these, only two resulted in the identification of Poa ssp. microsatellite motifs, of which only one was complementary to the microsatellite motif identified in Lolium. Though few Poa ssp. microsatellite regions were identified, several of the amplification products were polymorphic within and across the Poa ssp. and could be utilized as markers in Poa ssp. intergeneric hybrid studies. Results of the research suggest the use of Lolium microsatellite derived primers to identify complementary SSR regions in Poa is not an effective approach for the development of microsatellite markers in Poa.
Approximation of the Vibration Modes of a Plate and Shells Coupled With a Fluid
Authors: Hernández E.
Published: October 2006

We consider a method to compute the vibration modes of an elastic thin structure (shell or plate) in contact with a compressible fluid. For the structure, the classical Naghdi equations, based on the Reissner–Mindlin hypothesis, are considered and its approximation using the mixed interpolation of tensorial component 4 finite element method. The fluid equations are discretized by using Raviart–Thomas elements, and a non-conforming coupling is used on the fluid-solid interface. Numerical experiments are reported, assessing the efficiency of this coupled scheme.
Numerical Aspects on
the Prediction of Stability Boundaries of Two-Phase Natural Circulation Circuits, Considering
Flashing Evaluation
Authors: Zanocco P. , Delmastro D. , Giménez M.
Published: October 2006

In this work, the stability of a two-phase, natural circulation circuit is analyzed, using a specially developed model. This thermohydraulic model results in a set of coupled, nonlinear, first-order partial differential equations, which are solved by means of the up-wind finite difference method, using combinations of explicit and implicit methods for the numerical integration of the different balance equations. An adaptive nodalization scheme is implemented, minimizing the error of the propagation of small perturbations through the discretized volumes and especially the ones having two-phase flow regime. A linearization method is implemented by means of numerical perturbations. Frequency domain calculations are carried out, allowing a rapid visualization of the stability of the linearized system. Two cases are analyzed: a test case, where the code is compared in a wide range of qualities with an analytical model, and an application case, where the model is used to analyze the stability of an integral reactor cooled by natural circulation. The CAREM prototype is taken as a reference. In both cases, the numerical diffusion and integration errors are analyzed in the stability limit prediction by means of a convergence analysis using different nodalization and numerical integration criteria.
On-Line Prediction of Motor Shaft Misalignment Using Fast Fourier Transform Generated Spectra Data and Support Vector Regression
Authors: Omitaomu Olufemi A. , Jeong Myong K. , Badiru Adedeji B. , Hines J. Wesley
Published: October 2006

Shaft alignment prediction is essential for the development of effective coupling and rotating equipment maintenance systems. In this paper, we present a modified support vector regression (SVR) approach for shaft alignment predictions based on fast Fourier transform generated spectra data. The modified SVR approach uses data-dependent parameters in order to reduce computation time and achieve better predictions. The spectra data used is characterized by a large number of descriptors and very few data points. The strengths of SVR for shaft misalignment prediction include its ability to represent data in high-dimensional space through kernel functions. We reduce the dimension of the data using a multivariate AIC criterion in order to guarantee that the selected spectra are response dependent. We compare the performance of SVR with two of the most popular techniques used in condition monitoring, partial least squares, and principal components regression. Our results show that we can improve the performance of shaft misalignment prediction using SVR and the approach compares very favorably with partial least squares and principal components regression approaches. Also, we present a quantitative measure, shaft misalignment monitoring index, which can be used to facilitate easy identification of the alignment condition and as input to maintenance systems design.
Geometry Method for Localization Analysis in Gradient-Dependent J2 Plasticity
Authors: Etse G. , Vrech S. M.
Published: October 2006

In this work the geometrical method for the assessment of discontinuous bifurcation conditions is extended to encompass gradient-dependent plasticity. To this end, the gradient-dependent localization condition is cast in the form of an elliptical envelope condition in the coordinates of Mohr. The results in this work demonstrate the capability of thermodynamically consistent gradient-dependent elastoplastic model formulations to suppress the localized failure modes of the classical plasticity that take place when the hardening/softening modulus H¯ equals the critical value for localization H¯c, provided the characteristic length l remains positive.
Viscous Wave Interaction Due to Motion of a Surface Wave Over a Sediment Bed
Authors: Jamali Mirmosadegh , Lawrence Gregory A.
Published: October 2006

The results of a flume experiment and a theoretical study of surface wave motion over a fluidized bed are presented. It is shown that a resonant wave interaction between a surface wave and two interfacial waves at the interface of the fresh water and the fluidized bed is a strong mechanism for instability of the interface and the subsequent mixing of the layers. The interfacial waves are subharmonic to the surface wave and form a standing wave at the interface. The interaction is investigated theoretically using a viscous interaction analysis. It is shown that surface wave height and viscous effects are the determining factors in the instability mechanism. The results indicate that the net effect of viscosity on the interaction is to suppress the interfacial waves.
Machine Tool Chatter and Surface Location Error in Milling Processes
Authors: Insperger Tamás , Gradišek Janez , Kalveram Martin , Stépán Gábor , Winert Klaus , Govekar Edvard
Published: October 2006

A two degree of freedom model of the milling process is investigated. The governing equation of motion is decomposed into two parts: an ordinary differential equation describing the periodic chatter-free motion of the tool and a delay-differential equation describing chatter. The stability chart is derived by using the semi-discretization method for the delay-differential equation corresponding to the chatter motion. The periodic chatter-free motion of the tool and the associated surface location error (SLE) are obtained by a conventional solution technique of ordinary differential equations. It is shown that the SLE is large at the spindle speeds where the ratio of the dominant frequency of the tool and the tooth passing frequency is an integer. This phenomenon is explained by the large amplitude of the periodic chatter-free motion of the tool at these resonant spindle speeds. It is shown that large stable depths of cut with a small SLE can still be attained close to the resonant spindle speeds by using the SLE diagrams associated with stability charts. The results are confirmed experimentally on a high-speed milling center.
Laser Interferometry Hologram Registration for Three-Dimensional Precision Measurements
Authors: Huang Zhenhua , Shih Albert J. , Ni Jun
Published: October 2006

A hologram registration method is developed for the laser holographic interferometry measurement of the 3D surface profile of objects which are larger than the field of view (FOV). The theory of laser holographic interferometry, including the phase-shifting and multiwavelength tuning, is described. The hologram registration without using targets is elaborated. The cross-correlation analysis is used to find the translation and overlapped regions, which determine the tilt and shift correction for data registration. The proposed method is validated using two examples with different approaches. The first example, a wheel hub, is smaller than the FOV and demonstrates only 0.1μm discrepancy of the surface flatness between the registered and standard measurements. The second example, an engine combustion deck surface, is larger than the FOV. The registered surface measurements are compared to that of coordinate measurement machine (CMM) with only 2.5% discrepancy of the peak-to-valley flatness. This data registration method enables the sub-μm precision and large depth of field (several centimeters) measurement of large size objects.
Edge Trimming of Aluminum Sheets Using Shear Slitting at a Rake Angle
Authors: Lu Hongbing , Ma Jin , Li Ming
Published: October 2006

Edge burr is inevitably present at a slit edge when an aluminum web is shear slit by a pair of rotary knives (or blades) engaged and rotated in opposite directions. This paper presents a new method of shear slitting for an aluminum sheet to produce very low edge burr height, for use in edge trimming. The method uses the same bottom rotary blade as in the traditional shear slitting, but a revised top blade that forms a rake angle with respect to the bottom blade. The top blade edge is chamfered so that the surface of the top blade edge is parallel to the surface of the bottom blade edge to produce a pair of shearing surfaces to shear slit the aluminum sheet. A sequential set of micrographs of an aluminum slit edge are taken to visualize different stages of the shear slitting process. The observation indicates that this new slitting configuration induces a local tension as a result of blade relative motion so that a combined tension∕shear is applied to the aluminum sheet to facilitate early separation in the aluminum sheets. As a result, a clean edge with very small burr height is produced consistently. Edge trimming of aluminum sheet over a wide range of slitting conditions indicates that the new configuration is insensitive to blade gap and overlap, and can lead to a clean cut with very low edge burr height even when two blades are separated by a gap that is a few times of the sheet thickness.
Preacceleration without radiation: The nonexistence of preradiation phenomenon
Authors: Heras José A.
Published: October 2006

An unexpected prediction of classical electrodynamics is that a charge can accelerate before a force is applied. We would expect that a preaccelerated charge would radiate so that there would be spontaneous preradiation, an acausal phenomenon. We reexamine the subtle relation between the Larmor formula for the power radiated by a point charge and the Abraham-Lorentz equation and find that for well-behaved external forces acting for finite times, the charge does not radiate in time intervals where there is preacceleration. That is, for these forces preradiation does not exist even though the charge is preaccelerated. The radiative energy is emitted only in time intervals when the external force acts on the charge.
Using introductory labs to engage students in experimental design
Authors: Etkina Eugenia , Murthy Sahana , Zou Xueli
Published: October 2006

The Investigative Science Learning Environment (ISLE) engages students in processes mirroring the practice of science. Laboratories play a central role in this learning environment. Students in ISLE laboratories design their own experiments to investigate new phenomena, test hypotheses, and solve realistic problems. We discuss various issues associated with implementing these labs in large enrollment introductory physics courses. We present examples of experiments that students design, include a sample of student work, and discuss issues related to the choice of experiments for design and practical implementation. We also review assessment techniques and show results of students’ acquisition and transfer of some laboratory-related abilities.
The inertia of stress
Authors: Medina Rodrigo
Published: October 2006

We present a simple example in which the importance of the inertial effects of stress is evident. The system is an insulating solid narrow disc whose faces are uniformly charged with charges of equal magnitude and opposite signs. The motion of the system in two different directions is considered. It is shown how the contributions to energy and momentum of the stress that develops inside the solid to balance the electrostatic forces have to be added to the electromagnetic contributions to obtain the results predicted by the relativistic equivalence of mass and energy.
Differing observations on the landing of the rod into the slot
Authors: Iyer Chandru , Prabhu G. M.
Published: October 2006

In the usual rod and slot paradox a rod falls into a slot due to gravity. Many thought experiments have been conducted where the presence of gravity is eliminated with the rod and slot approaching each other along a line joining their centers. In these experiments the line of motion is not parallel to the axis of the rod or the slot. We consider the cases for which the rod falls into the slot and the rod does not fall into the slot, each from the perspective of the co-moving frames of the rod and the slot. We show that if the rod falls into the slot as determined by Galilean kinematics, the same conclusion is valid for relativistic kinematics. Our conclusion emphasizes that the passing (or crashing) of the rod is unaffected by relativistic kinematics. This determination does not depend on the magnitude of the velocity, but only on the proper lengths and the proper angles of the rod and slot with the line of motion.
ThedpsGene of Symbiotic “CandidatusLegionella jeonii” inAmoeba proteusResponds to Hydrogen Peroxide and Phagocytosis
Authors: Park Miey , Yun Seong Tae , Hwang Sue-Yun , Chun Choong-Ill , Ahn Tae In
Published: October 2006

To survive in host cells, intracellular pathogens or symbiotic bacteria require protective mechanisms to overcome the oxidative stress generated by phagocytic activities of the host. By genomic library tagging, we cloned adps(stands forDNA-bindingprotein fromstarved cells) gene of the symbiotic “CandidatusLegionella jeonii” organism (called the X bacterium) (dpsX) that grows inAmoeba proteus. The gene encodes a 17-kDa protein (pI 5.19) with 91% homology to Dps and DNA-binding ferritin-like proteins of other organisms. The cloned gene complemented thedpsmutant ofEscherichia coliand conferred resistance to hydrogen peroxide. DpsXproteins purified fromE. colitransformed with thedpsXgene were in oligomeric form, formed a complex with pBlueskript SKII DNA, and protected the DNA from DNase I digestion and H2O2-mediated damage. The expression of thedpsXgene in “CandidatusLegionella jeonii” was enhanced when the host amoeba was treated with 2 mM H2O2and by phagocytic activities of the host cell. These results suggested that the Dps protein has a function protective of the bacterial DNA and that its gene expression responds to oxidative stress generated by phagocytic activities of the host cell. With regard to the fact that invasion ofLegionellasp. into respiratory phagocytic cells causes pneumonia in mammals, further characterization ofdpsXexpression in theLegionellasp. that multiplies in a protozoan host in the natural environment may provide valuable information toward understanding the protective mechanisms of intracellular pathogens.
sbcB15
and Δ
sbcB
Mutations Activate Two Types of RecF Recombination Pathways in
Escherichia coli
Authors: Zahradka Ksenija , Šimić Sanela , Buljubašić Maja , Petranović Mirjana , Đermić Damir , Zahradka Davor
Published: October 2006

Escherichia coli
cells with mutations in
recBC
genes are defective for the main RecBCD pathway of recombination and have severe reductions in conjugational and transductional recombination, as well as in recombinational repair of double-stranded DNA breaks. This phenotype can be corrected by suppressor mutations in
sbcB
and
sbcC
(
D
) genes, which activate an alternative RecF pathway of recombination. It was previously suggested that
sbcB15
and Δ
sbcB
mutations, both of which inactivate exonuclease I, are equally efficient in suppressing the
recBC
phenotype. In the present work we reexamined the effects of
sbcB15
and Δ
sbcB
mutations on DNA repair after UV and γ irradiation, on conjugational recombination, and on the viability of
recBC
(
sbcC
) cells. We found that the
sbcB15
mutation is a stronger
recBC
suppressor than Δ
sbcB
, suggesting that some unspecified activity of the mutant SbcB15 protein may be favorable for recombination in the RecF pathway. We also showed that the
xonA2
mutation, a member of another class of ExoI mutations, had the same effect on recombination as Δ
sbcB
, suggesting that it is an
sbcB
null mutation. In addition, we demonstrated that recombination in a
recBC sbcB15 sbcC
mutant is less affected by
recF
and
recQ
mutations than recombination in
recBC
Δ
sbcB sbcC
and
recBC xonA2 sbcC
strains is, indicating that SbcB15 alleviates the requirement for the RecFOR complex and RecQ helicase in recombination processes. Our results suggest that two types of
sbcB
-sensitive RecF pathways can be distinguished in
E. coli
, one that is activated by the
sbcB15
mutation and one that is activated by
sbcB
null mutations. Possible roles of SbcB15 in recombination reactions in the RecF pathway are discussed.
Expression of the
trxC
Gene of
Rhodobacter capsulatus
: Response to Cellular Redox Status Is Mediated by the Transcriptional Regulator OxyR
Authors: Zeller Tanja , Li Kuanyu , Klug Gabriele
Published: October 2006

Despite the importance of thioredoxins in cellular functions, little is known about the regulation of
trx
genes. To understand the molecular mechanisms involved in the regulation of the
Rhodobacter capsulatus trxC
gene, the expression of this gene was investigated. We describe OxyR-dependent redox regulation of the
trxC
gene that adjusts the levels of thioredoxins in the cell.
Agr Interference between Clinical
Staphylococcus aureus
Strains in an Insect Model of Virulence
Authors: Fleming Vicki , Feil Ed , Sewell Andrew K. , Day Nicholas , Buckling Angus , Massey Ruth C.
Published: October 2006

Repression of virulence by
Staphylococcus aureus
strains from different Agr groups has been demonstrated in vitro and is proposed as a means of competitive interference. Here, using the insect
Manduca sexta
, we show for the first time that this interference also occurs in vivo within a mixed population.
Genetic and Biochemical Characterization of the
Streptococcus pneumoniae
PcrA Helicase and Its Role in Plasmid Rolling Circle Replication
Authors: Ruiz-Masó J. A. , Anand S. P. , Espinosa M. , Khan S. A. , del Solar G.
Published: October 2006

PcrA is a chromosomally encoded DNA helicase of gram-positive bacteria involved in replication of rolling circle replicating plasmids. Efficient interaction between PcrA and the plasmid-encoded replication initiator (Rep) protein is considered a requirement for the plasmid to replicate in a given host, and thus, the ability of a Rep protein to interact with heterologous PcrA helicases has been invoked as a determinant of plasmid promiscuity. We characterized transcription of the
Streptococcus pneumoniae pcrA
gene in its genetic context and studied the biochemical properties of its product, the PcrA

Spn

helicase. Transcription of the pneumococcal
pcrA
gene was directed by promoter P
a
, consisting of an extended −10 box. Promoter P
a
also accounted for expression of a second essential gene,
radC
, which was transcribed with much lower efficiency than
pcrA
, probably due to the presence of a terminator/attenuator sequence located between the two genes. PcrA

Spn

displayed single-stranded DNA-dependent ATPase activity. PcrA

Spn

showed 5′→3′ and 3′→5′ helicase activities and bound efficiently to partially duplex DNA containing a hairpin structure adjacent to a 6-nucleotide 5′ or 3′ single-stranded tail and one unpaired (flap) nucleotide in the complementary strand. PcrA

Spn

interacted specifically with RepC, the initiator of staphylococcal plasmid pT181. Although the pneumococcal helicase was able to initiate unwinding of the RepC-nicked pT181 DNA, it was much less processive in this activity than the cognate staphylococcal PcrA protein. Accordingly, PcrA

Spn

was inefficient in in vitro replication of pT181, and perhaps as a consequence, this plasmid could not be established in
S. pneumoniae
.
Multiple Interactions between the Transmembrane Division Proteins ofBacillus subtilisand the Role of FtsL Instability in Divisome Assembly
Authors: Daniel Richard A. , Noirot-Gros Marie-Françoise , Noirot Philippe , Errington Jeff
Published: October 2006

About 11 essential proteins assemble into a ring structure at the surface of the cell to bring about cytokinesis in bacteria. Several of these proteins have their major domains located outside the membrane, forming an assembly that we call the outer ring (OR). Previous work on division inBacillus subtilishas shown that four of the OR proteins—FtsL, DivIC, DivIB, and PBP 2B—are interdependent for assembly. This contrasts with the mainly linear pathway for the equivalent proteins inEscherichia coli. Here we show that the interdependent nature of theB. subtilispathway could be due to effects on FtsL and DivIC stability and that DivIB is an important player in regulating this turnover. Two-hybrid approaches suggest that a multiplicity of protein-protein interactions contribute to the assembly of the OR. DivIC is unusual in interacting strongly only with FtsL. We propose a model for the formation of the OR through the mutual association of the membrane proteins directed by the cytosolic inner-ring proteins.
In silico analysis of 16S ribosomal RNA gene sequencing-based methods for identification of medically important anaerobic bacteria
Authors: Woo Patrick C Y , Chung Liliane M W , Teng Jade L L , Tse Herman , Pang Sherby S Y , Lau Veronica Y T , Wong Vanessa W K , Kam Kwok-ling , Lau Susanna K P , Yuen Kwok-Yung
Published: October 2006

This study is the first study that provides useful guidelines to clinical microbiologists and technicians on the usefulness of full 16S rRNA sequencing, 5′-end 527-bp 16S rRNA sequencing and the existing MicroSeq full and 500 16S rDNA bacterial identification system (MicroSeq, Perkin-Elmer Applied Biosystems Division, Foster City, California, USA) databases for the identification of all existing medically important anaerobic bacteria. Full and 527-bp 16S rRNA sequencing are able to identify 52–63% of 130 Gram-positive anaerobic rods, 72–73% of 86 Gram-negative anaerobic rods and 78% of 23 anaerobic cocci. The existing MicroSeq databases are able to identify only 19–25% of 130 Gram-positive anaerobic rods, 38% of 86 Gram-negative anaerobic rods and 39% of 23 anaerobic cocci. These represent only 45–46% of those that should be confidently identified by full and 527-bp 16S rRNA sequencing. To improve the usefulness of MicroSeq, bacterial species that should be confidently identified by full and/or 527-bp 16S rRNA sequencing but not included in the existing MicroSeq databases should be included.
Abnormalities of chromosome 17 in oesophageal cancer
Authors: Moodley Revendran , Reddi Anunathan , Chetty Runjan , Naidoo Richard
Published: October 2006

Background:Oesophageal cancer is the most common malignancy encountered in South African males, especially in the Eastern Cape and surrounding region of South Africa. There are a number of risk factors and predisposing conditions that have been implicated in the aetiology of the disease. The tylosis oesophageal cancer (TOC) gene, localised to a small region on chromosome 17q25, has been shown to be associated with oesophageal squamous cell carcinoma.

Aim:To investigate loss of heterozygosity (LOH) and microsatellite instability (MSI) in the region of theTOClocus.

Methods:In 74 oesophagectomy specimens for squamous cell carcinoma, microsatellite PCR was performed using five fluorescently labelledTOCmarkers. The PCR products were analysed and the data correlated with clinicopathological findings.

Results:LOH ranged from 25% to 60%. LOH for the individual markers was as follows: D17S1839, 25%; D17S1864, 36%; D17S1817, 38%; D17S785, 47.8%; and D17S579, 60%. MSI ranged from 4.1% to 6.8% for the five loci in the 17q region. MSI was 4.1% for the markers D17S579, D17S785 and D17S1817. Marker D17S1864 showed MSI to occur in 4 cases (5.4%) and marker D17S1839 in 5 cases (6.8%).

Conclusion:No significant relationship between genetic and clinical parameters was observed; however, aberrations in poorly differentiated tumours were high for markers D17S579 and D17S1864 (25% and 37%, respectively), indicating that these markers may have an underlying role in the molecular pathogenesis of oesophageal squamous cell carcinoma. In addition, 63% of patients who died showed LOH for the markers D17S579, D17S1864 and D17S1817.
Serum 25-hydroxyvitamin D levels in early and advanced breast cancer: Table 1
Authors: Palmieri C , MacGregor T , Girgis S , Vigushin D
Published: October 2006

Background:Laboratory and epidemiological studies have implicated vitamin D deficiency in the pathogenesis of breast cancer. 1,25-Dihydroxyvitamin D (1,25(OH)2D) promotes differentiation and apoptosis, and potently inhibits proliferation of malignant breast epithelial cells in culture. Serum levels of 1,25(OH)2D are higher in normal women than in patients with primary breast cancer.

Aim:To clarify the role of vitamin D in breast cancer progression by comparing the levels of serum vitamin D in patients with early and in those with advanced breast cancer.

Methods:Circulating levels of 25-hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH) and calcium were measured prospectively in 279 Caucasian women with invasive breast cancer, 204 women with early-stage disease and 75 women with locally advanced or metastatic disease.

Results:Patients with early-stage breast cancer had significantly higher circulating levels of 25(OH)D (p<0.005) and significantly lower PTH (p<0.001) levels than those with advanced disease. Calcium levels did not differ significantly (p = 0.74).

Conclusion:Serum levels of 25(OH)D are significantly higher in patients with early-stage breast cancer than in those with locally advanced or metastatic disease.
PREPARATION AND CHARACTERIZATION OF ORGANIC THIN FILM OF STEARIC ACID/PYRAZOLINE NANOPARTICLES
Authors: KANG YOUNG SOO , OH SUN WHA , SUH JONG HWA
Published: October 2006

The organic thin films of stearic acid/pyrazoline nanoparticles were prepared by transferring Langmuir monolayer of stearic acid/pyrazoline nanoparticle onto the solid substrate. The complex of stearic acid/pyrazoline nanoparticle was studied with pressure–area isotherm at the air/water interface and identified with linearly increasing optical absorbance around 370 nm by increasing the number of deposited layers. The in situ domain structure and molecular orientation of the complex were measured with BAM. The surface morphology of the Langmuir–Blodgett film was observed with AFM. The dispersion of pyrazoline nanoparticle in the film was studied with TEM.
LOW-TEMPERATURE SYNTHESIS OF NOVEL ZINC OXIDE SINGLE-SIDED COMB-LIKE STRUCTURE
Authors: ZHANG YAOHUA , LIU JUAN , LIU TONG , LI XINGGUO
Published: October 2006

Single-sided ZnO nanocombs have been synthesized by thermal evaporation of Zn powders at 440°C through a vapor–solid (VS) process. The stem ribbon of the as-synthesized nanocomb takes a growth direction of [Formula: see text], and its top/bottom surfaces are [Formula: see text]. The nanoteeth grow epitaxially out of the stem ribbon along [0001]. Such a low temperature process may be useful in future device fabrication.