bluuebunny/crossref_metadata_2025 huggingface dataset:
Reservoir to river passage of age‐0+ year fishes, indication of a dispersion pathway for a non‐native species
Authors: Janáč M. , Jurajda P. , Kružíková L. , Roche K. , Prášek V.
Published: February 2013

This study demonstrates passage of age‐0+ year individuals of pikeperch Sander lucioperca, common bream Abramis brama and non‐native tubenose goby Proterorhinus semilunaris from the Nové Mlýny Reservoir into the River Dyje (Danube River basin, Czech Republic) through the turbine of a hydropower facility. Most fishes had standard length (LS) in the range 12–33 mm. Seasonal patterns corresponded with spawning activity, i.e. an early single spawning event for S. lucioperca, multiple spawning events for A. brama and continuous spawning with a later start and prolonged duration for P. semilunaris. Sander lucioperca, P. semilunaris and larger A. brama (>22 mm) drifted almost exclusively during the dark; smaller A. brama displayed no preference for light or dark. Proterorhinus semilunaris displayed significantly lower mortality than other species when passing through the turbine (3% compared to 18%). The passage of high numbers of P. semilunaris from the reservoir (estimated at 473 000 individuals per year), and their subsequent mass downstream drift, may have contributed to rapid population establishment along the River Dyje and the quick downstream expansion.
Effect of Supercritical CO2 Modified with Water Cosolvent on the Sterilization of Fungal Spore‐Contaminated Barley Seeds and the Germination of Barley Seeds
Authors: Park Hyong Seok , Choi Hee Jung , Kim Kyoung Heon
Published: February 2013

We have investigated the effects of supercritical carbon dioxide (SC‐CO2) modified with water as a cosolvent on the inactivation of Penicillium oxalicum spores inoculated on barley grains and also on the germination yield of the SC‐CO2‐treated barley grains. After SC‐CO2 treatment at different conditions of temperature, cosolvent (water) content and treatment times, the number of colony‐forming units (cfus) of fungal spores and the germination of SC‐CO2‐treated barley grains were analyzed. Among the SC‐CO2 treatment parameters, the cosolvent content was the most significant factor affecting the inactivation yields of P. oxalicum spores. When the pressure of SC‐CO2 was fixed at 10 MPa, the optimal conditions obtained by ridge analysis of response surface methodology were cosolvent content of 231 μL, temperature of 44C and treatment duration of 12 min, which resulted in a 6.8 log10 reduction of cfu. However, the germination yield of barley grains decreased significantly by treating with SC‐CO2 modified with water. For example, the addition of only 300 μL water in the SC‐CO2 treatment reduced the germination yield from 65.4% to 1.4% at the same SC‐CO2 treatment conditions (40C, 10 MPa, and 20 min).

Practical Applications

This study demonstrated the lethal effect of modified supercritical carbon dioxide (SC‐CO2) against plant pathogenic fungal spores in barley grains. Water cosolvent showed significant synergism in inactivating fungal spores with SC‐CO2. Treatment using SC‐CO2 modified with water cosolvent could be applied in the sterilization step for preservation of barley grains as an alternate for chemical or thermal processes.
Retinoids and glucocorticoids target common genes in hippocampal HT22 cells
Authors: Brossaud Julie , Roumes Hélène , Moisan Marie‐Pierre , Pallet Véronique , Redonnet Anabelle , Corcuff Jean‐Benoît
Published: February 2013

Vitamin A metabolite retinoic acid (RA) plays a major role in the aging adult brain plasticity. Conversely, chronic excess of glucocorticoids (GC) elicits some deleterious effects in the hippocampus. We questioned here the involvement of RA and GC in the expression of target proteins in hippocampal neurons. We investigated proteins involved either in the signaling pathways [RA receptor β (RARβ) and glucocorticoid receptor (GR)] or in neuron differentiation and plasticity [tissue transglutaminase 2 (tTG) and brain‐derived neurotrophic factor (BDNF)] in a hippocampal cell line, HT22. We applied RA and/or dexamethasone (Dex) as activators of the pathways and investigated mRNA and protein expression of their receptors and of tTG and BDNF as well as tTG activity and BDNF secretion. Our results confirm the involvement of RA‐ and GC‐dependent pathways and their interaction in our neuronal cell model. First, both pathways regulate the transcription and expression of own and reciprocal receptors: RA and Dex increased RARβ and decreased GR expressions. Second, Dex reduces the expression of tTG when associated with RA despite stimulating its expression when used alone. Importantly, when they are combined, RA counteracts the deleterious effect of glucocorticoids on BDNF regulation and thus may improve neuronal plasticity under stress conditions. In conclusion, GC and RA both interact through regulations of the two receptors, RARβ and GR. Furthermore, they both act, synergistically or oppositely, on other target proteins critical for neuronal plasticity, tTG and BDNF.
The remediation challenge: theoretical and methodological insights from a systematic review
Authors: Cleland Jennifer , Leggett Heather , Sandars John , Costa Manuel J , Patel Rakesh , Moffat Mandy
Published: February 2013

Objectives  Remediation is usually offered to medical students and doctors in training who underperform on written or clinical examinations. However, there is uncertainty and conflicting evidence about the effectiveness of remediation. The aim of this systematic review was to synthesise the available evidence to clarify how and why remediation interventions may have worked in order to progress knowledge on this topic.

Methods  The MEDLINE, EMBASE, CINAHL (Cumulative Index to Nursing and Allied Health Literature), ERIC (Educational Resources Information Centre), Web of Science and Scopus databases were searched for papers published from 1984 to April 2012, using the search terms ‘remedial teaching’, ‘education’, ‘medical’, ‘undergraduate’/or ‘clinical clerkship’/or ‘internship and residency’, ‘at risk’ and ‘struggling’. Only studies that included an intervention, then provided retest data, and reported at least one outcome measure of satisfaction, knowledge, skills or effects on patients were eligible for inclusion. Studies of practising doctors were excluded. Data were abstracted independently in duplicate for all items. Coding differences were resolved through discussion.

Results  Thirty‐one of 2113 studies met the review criteria. Most studies were published after 2000 (n = 24, of which 12 were published from 2009 onwards), targeted medical students (n = 22) and were designed to improve performance on an immediately subsequent examination (n = 22). Control or comparison groups, conceptual frameworks, adequate sample sizes and long‐term follow‐up measures were rare. In studies that included long‐term follow‐up, improvements were not sustained. Intervention designs tended to be highly complex, but their design or reporting did not enable the identification of the active components of the remedial process.

Conclusions  Most remediation interventions in medical education focus on improving performance to pass a re‐sit of an examination or assessment and provide no insight into what types of extra support work, or how much extra teaching is critical, in terms of developing learning. More recent studies are generally of better quality. Rigorous approaches to developing and evaluating remediation interventions are required.
Clarifying students’ feedback‐seeking behaviour in clinical clerkships
Authors: Bok Harold G J , Teunissen Pim W , Spruijt Annemarie , Fokkema Joanne P I , van Beukelen Peter , Jaarsma Debbie A D C , van der Vleuten Cees P M
Published: February 2013

Context  Why and how do students seek feedback on their performance in the clinical workplace and which factors influence this? These questions have remained largely unanswered in research into workplace learning during clinical clerkships. Research on feedback has focused mainly on feedback providers. Whether and how feedback recipients actively seek feedback are under‐examined issues. Research in organisational psychology has proposed a mechanism whereby feedback seeking is influenced by motives and goal orientation mediated by the perceived costs and benefits of feedback. Building on a recently published model of resident doctors’ feedback‐seeking behaviour, we conducted a qualitative study to explore students’ feedback‐seeking behaviours in the clinical workplace.

Methods  Between April and June 2011, we conducted semi‐structured face‐to‐face interviews with veterinary medicine students in Years 5 and 6 about their feedback‐seeking behaviour during clinical clerkships. In the interviews, 14 students were asked about their goals and motives for seeking feedback, the characteristics of their feedback‐seeking behaviour and factors influencing that behaviour. Using template analysis, we coded the interview transcripts and iteratively reduced and displayed the data until agreement on the final template was reached.

Results  The students described personal and interpersonal factors to explain their reasons for seeking feedback. The factors related to intentions and the characteristics of the feedback provider, and the relationship between the feedback seeker and provider. Motives relating to image and ego, particularly when students thought that feedback might have a positive effect on image and ego, influenced feedback‐seeking behaviour and could induce specific behaviours related to students’ orientation towards particular sources of feedback, their orientation towards particular topics for and timing of feedback, and the frequency and method of feedback‐seeking behaviour.

Conclusions  This study shows that during clinical clerkships, students actively seek feedback according to personal and interpersonal factors. Perceived costs and benefits influenced this active feedback‐seeking behaviour. These results may contribute towards the optimising and developing of meaningful educational opportunities during clerkships.
Clypeasteroid echinoid tests as benthic islands for gastrochaenid bivalve colonization: evidence from the Middle Miocene of Tarragona, north‐east Spain
Authors: BELAÚSTEGUI ZAIN , DE GIBERT JORDI M. , NEBELSICK JAMES H. , DOMÈNECH ROSA , MARTINELL JORDI
Published: February 2013

Abstract:  Middle Miocene tests of Clypeaster from L’Arrabassada (Tarragona, north‐east Spain) show evidence of intense endoskeletozoan colonization, preserved as borings and associated carbonate secretions that allow gastrochaenid bivalves to be identified as the colonizers. Two modes of occurrence have been recognized for these bivalve dwelling cavities; ‘intrastereom clavate borings’ which are restricted to the echinoid stereom, and ‘semi‐endoskeletal dwellings’, which penetrate across the test wall and extend as carbonate crypts into the sediment fill of the internal test cavity. Their size, density and position rule out a syn‐vivo relationship with the echinoids and demonstrate that colonization was post mortem. Because of the endurance of clypeasteroid skeleton and the pronounced bell‐shaped morphology of Clypeaster, the tests of these echinoids provided the most suitable substrates for hard‐bottom colonizers on an otherwise sandy seafloor. The scenario described from Tarragona can be extended to other Neogene and Quaternary strata elsewhere; there is ample evidence for the long‐term utilization of tests of Clypeaster by gastrochaenid bivalves in shoreface palaeoenvironments.
On the presence of the Late Permian dicynodont Endothiodon in Brazil
Authors: Boos Alessandra D. S. , Schultz Cesar L. , Vega Cristina S. , Aumond Juarês J.
Published: February 2013

The first dicynodont reported for the Permian of South America is described in detail here. The specimen consists of a partial skull and associated lower jaws, collected from the Serra do Cadeado locality, Rio do Rasto Formation, Brazil. The specimen was assigned to the genus Endothiodon Owen in a preliminarily description published in the 1970s. This identification implied a direct correlation with some of the well‐established biozones of the Beaufort Group, South Africa, where this taxon is known to occur. Although badly weathered, the Brazilian material preserves several features that allow us to confirm its assignment to Endothiodon, such as the pineal foramen situated on a boss, the bulbous swellings of the dentaries, a boss situated on the ventral margin of the jugal, the extensive number of dentary teeth and the upturned pointed beak of the lower jaw. However, this set of characters is not enough to establish a specific taxonomic assignment for the specimen, although it seems to be more closely related to E. bathystoma, E. uniseries and E. whaitsi than to E. mahalanobisi. The biostratigraphical correlations proposed for the tetrapod faunas of the Rio do Rasto Formation highlight the similarities between these associations and others from the Mid and Late Permian of South Africa and Eastern Europe. However, until now, these correlations are tentative because only a few faunal elements have been recovered from Brazil, and most of them lack stratigraphic data on the levels from where they were collected. Due to the presence of Endothiodon, at least part of the Rio do Rasto Formation can be correlated with deposits in India, Malawi, Mozambique, South Africa, Tanzania, Zambia and Zimbabwe.
Experimental Investigation of Effect of a Surfactant to Increase Cooling of Hot Steel Plates by a Water Jet
Authors: Mohapatra Soumya S. , Ravikumar Satya V. , Verma Ankur , Pal Surjya K. , Chakraborty Sudipto
Published: February 2013

The requirement for high tensile strength steel has placed greater emphasis on the cooling methods used in the cooling of a hot steel plate. The purpose of this research is to study the effect of surfactant concentration in water jet cooling, and its applicability in the study of ultrafast cooling (UFC) of a hot steel plate. The initial temperature of the plate, before the cooling starts, is kept at 900 °C which is usually observed as the “finish rolling temperature (FRT)” in the hot strip mill of a steel plant. The current heat transfer analysis shows that surfactant added water jet produces higher heat flux than the pure water jet due to the higher forced convection cooling area. Dissolved surfactant increases the transition boiling heat flux, nucleate boiling heat flux and critical heat flux. At a concentration of 600 ppm, the maximum surface heat flux has been observed and further increase in surfactant concentration decreases the surface heat flux. The surface heat flux and the cooling rate show an increasing trend with the increasing water flow rate at a constant surfactant concentration. The achieved cooling rate in case of surfactant added water is almost twice that of jet with pure water, resulting in ultrafast cooling. By assuming the impinging surface consists of three different constant heat flux regions, the surface heat flux and the surface temperatures have been calculated by using intemp software.
Film Cooling of Cylindrical Hole With a Downstream Short Crescent-Shaped Block
Authors: An Baitao , Liu Jianjun , Zhang Chao , Zhou Sijing
Published: February 2013

This paper presents a method to improve the film-cooling effectiveness of cylindrical holes. A short crescent-shaped block is placed at the downstream of a cylindrical cooling hole. The block shape is defined by a number of geometric parameters including block height, length and width, etc. The single row hole on a flat plate with inclination angle of 30 deg, pitch ratio of 3, and length-diameter ratio of 6.25 was chosen as the baseline test case. Film-cooling effectiveness for the cylindrical hole with or without the downstream short crescent-shaped block was measured by using the pressure sensitive paint (PSP) technique. The density ratio of coolant (argon) to mainstream air is 1.38. The blowing ratios vary from 0.5 to 1.25. The results showed that the lateral averaged cooling effectiveness is increased remarkably when the downstream block is present. The downstream short block allows the main body of the coolant jet to pass over the block top and to form a new down-wash vortex pair, which increases the coolant spread in the lateral direction. The effects of each geometrical parameter of the block on the film-cooling effectiveness were studied in detail.
Soret Effect on the Natural Convection From a Vertical Plate in a Thermally Stratified Porous Medium Saturated With Non-Newtonian Liquid
Authors: Narayana M. , Khidir A. A. , Sibanda P. , Murthy P. V. S. N.
Published: February 2013

The paper highlights the application of a recent seminumerical successive linearization method (SLM) in solving highly coupled, nonlinear boundary value problem. The method is presented in detail by solving the problem of free convection flow due to a vertical plate embedded in a non-Darcy thermally stratified porous medium saturated with a non-Newtonian power-law liquid. Thermal-diffusion (Soret) and variable viscosity effects are taken into consideration. The Ostwald–de Waele power-law model is used to characterize the non-Newtonian behavior of the fluid. The governing partial differential equations are transformed into a system of ordinary differential equations and solved by SLM. The accuracy of the SLM has been tested by comparing the results with those obtained using the shooting technique. The effect of various physical parameters such as power-law index, Soret number, variable viscosity parameter, and thermal stratification parameter on the dynamics of the fluid is analyzed through computed results. Heat and mass transfer coefficients are also shown graphically for different values of the parameters.
Effects of Vapor Velocity and Pressure on Marangoni Condensation of Steam-Ethanol Mixtures on a Horizontal Tube
Authors: Ali Hassan , Sheng Wang Hua , Briggs Adrian , Rose John W.
Published: February 2013

Careful heat-transfer measurements have been conducted for condensation of steam-ethanol mixtures flowing vertically downward over a horizontal, water-cooled tube at pressures ranging from around atmospheric down to 14 kPa. Care was taken to avoid error due to the presence of air in the vapor. The surface temperature was accurately measured by embedded thermocouples. The maximum vapor velocity obtainable was limited by the maximum electrical power input to the boiler. At atmospheric pressure this was 7.5 m/s while at the lowest pressure a velocity of 15.0 m/s could be achieved. Concentrations of ethanol by mass in the boiler when cold prior to start up were 0.025%, 0.05%, 0.1%, 0.5%, and 1.0%. Tests were conducted for a range of coolant flow rates. Enhancement of the heat-transfer coefficient over pure steam values was found by a factor up to around 5, showing that the decrease in thermal resistance of the condensate due to Marangoni condensation outweighed diffusion resistance in the vapor. The best performing compositions (in the liquid when cold) depended on vapor velocity but were in the range 0.025–0.1% ethanol in all cases. For the atmospheric pressure tests the heat-transfer coefficient for optimum composition, and at a vapor-to-surface temperature difference of around 15 K, increased from around 55 kW/m2 K to around 110 kW/m2 K as the vapor velocity increased from around 0.8 to 7.5 m/s. For a pressure of 14 kPa the heat-transfer coefficient for optimum composition, and at a vapor-to-surface temperature difference of around 9 K, increased from around 70 kW/m2 K to around 90 kW/m2 K as the vapor velocity increased from around 5.0 to 15.0 m/s. Photographs showing the appearance of Marangoni condensation on the tube surface under different conditions are included in the paper.
Performance of Biopsy Needle With Therapeutic Injection System to Prevent Bleeding Complications
Authors: Wong Philip , Johnson Kent J. , Warner Roscoe L. , Merz Scott I. , Kruger Grant H. , Weitzel William F.
Published: February 2013

Renal disease is epidemic in the United States with approximately 8 × 106 people having chronic kidney disease. Renal biopsies are widely used to provide essential diagnostic information to physicians. However, the risk of bleeding complications possibly leading to life-threatening situations results in the contra-indication of biopsy in certain patient populations. Safer renal biopsies will allow more accurate diagnosis and better management of this epidemic health problem. We report the preclinical testing of a novel biopsy device called the therapeutic injection system (TIS). The device introduces a third stage to the standard two-stage side-cut percutaneous biopsy process. The third stage is designed to reduce bleeding complications by injecting a hemostatic plug at the time of biopsy. Laboratory evaluation and preliminary in vivo animal testing using an anticoagulated porcine model of the TIS and Bard Monopty® (Bard Medical, Covington, GA) control device were performed. The hemostatic material Gelfoam® (Pfizer, Brussels, Belgium) was selected as the active material comprising the hemostatic plugs. The performance of two composite plugs, one composed of polyvinyl alcohol (PVA) combined in 2:1 and 12:1 ratios with the hemostatic material, and one plug composed of 100% hemostatic material were tested. Stroke sequence and hemostatic plug deployment were verified by sequential firing of the TIS biopsy needle into clear gelatin and ex vivo bovine kidney specimens. In vivo trials with porcine specimens revealed a significant reduction in blood loss (8.1 ± 3.9 ml, control versus 1.9 ± 1.6 ml, 12:1 PVA/hemostatic, TIS, α = 0.01, n = 6). The 100% hemostatic plug showed a substantial and immediate reduction in blood loss (9.2 ml, control versus 0.0 ml, TIS, n = 1). The prototype device was shown to work repeatedly and reliably in laboratory trials. Initial results show promise in this approach to control post biopsy bleeding. This solution maintains the simplicity and directness of the percutaneous approach, while not significantly changing the standard percutaneous biopsy procedure.
A New Reactor Concept for Efficient Solar-Thermochemical Fuel Production
Authors: Ermanoski Ivan , Siegel Nathan P. , Stechel Ellen B.
Published: February 2013

We describe and analyze the efficiency of a new solar-thermochemical reactor concept, which employs a moving packed bed of reactive particles produce of H2 or CO from solar energy and H2O or CO2. The packed bed reactor incorporates several features essential to achieving high efficiency: spatial separation of pressures, temperature, and reaction products in the reactor; solid–solid sensible heat recovery between reaction steps; continuous on-sun operation; and direct solar illumination of the working material. Our efficiency analysis includes material thermodynamics and a detailed accounting of energy losses, and demonstrates that vacuum pumping, made possible by the innovative pressure separation approach in our reactor, has a decisive efficiency advantage over inert gas sweeping. We show that in a fully developed system, using CeO2 as a reactive material, the conversion efficiency of solar energy into H2 and CO at the design point can exceed 30%. The reactor operational flexibility makes it suitable for a wide range of operating conditions, allowing for high efficiency on an annual average basis. The mixture of H2 and CO, known as synthesis gas, is not only usable as a fuel but is also a universal starting point for the production of synthetic fuels compatible with the existing energy infrastructure. This would make it possible to replace petroleum derivatives used in transportation in the U.S., by using less than 0.7% of the U.S. land area, a roughly two orders of magnitude improvement over mature biofuel approaches. In addition, the packed bed reactor design is flexible and can be adapted to new, better performing reactive materials.
3D stepped electrodes on a flexible substrate with permanently bonded poly(dimethylsiloxane) channels for moving microfluid
Authors: Guo Xin , Xie Kongying , Campbell Robert J. , Lai Yongjun
Published: February 2013

Interdigitated microelectrode arrays have been exploited to move electrolyte via ac electro-osmosis. The performance of three dimensional (3D) stepped electrodes has been shown to exceed that of planar electrodes. However, to date all prototypes described have been based on solid silicon or glass substrates, limiting the usage of such devices. This report, to our best knowledge, is the first to describe a 3D stepped microelectrode array on a flexible Kapton® substrate. The Kapton surface was modified to make it capable of bonding with poly(dimethylsiloxane) microchannels. The metal electrode was patterned by wet etching, a simpler process than previous approaches. Results of bonding, bending, and fluidic testing are reported. The frequency response obtained using deionized water showed maximum velocities of approximately 370 and 180 μm/s at 5Vpp for testing with a flat and bent substrate, respectively.
On the sensitivity of common gamma‐index evaluation methods to MLC misalignments in Rapidarc quality assurance
Authors: Heilemann G. , Poppe B. , Laub W.
Published: February 2013

Purpose:

In this study the effects of small systematic MLC misalignments and gravitational errors on the quality of Rapidarc treatment plan delivery are investigated with respect to verification measurements with two detector arrays and the evaluation of clinical significance of the error‐induced deviations.

Methods:

Five prostate and six head and neck plans were modified by means of three error types: (1) both MLC banks are opened, respectively, in opposing directions, resulting in larger fields; (2) both MLC banks are closed, resulting in smaller fields; and (3) both MLC banks are shifted for lateral gantry angles, respectively, in the same direction to simulate the effects of gravity on the leaves. Measurements were evaluated with respect to a gamma‐index of 3%/3 mm and 2%/2 mm. Dose in the modified plans was recalculated and the resulting dose volume histograms for target and critical structures were compared to those of the unaltered plans.

Results:

The smallest introduced leaf position deviations which fail the >90% criterion for a gamma‐index of 2%/2 mm are: (1) 1 mm; (2) 0.5 mm for prostate and 1.0 mm for head and neck cases; and (3) 3 mm corresponding to the error types, respectively. These errors would lead to significant changes in mean PTV dose and would not be detected with the more commonly used 3%/3 mm gamma‐index criterion.

Conclusions:

A stricter gamma‐index (2%/2 mm) is necessary in order to detect positional errors of the MLC. Nevertheless, the quality assurance procedure of Rapidarc treatment plans must include a thorough examination of where dose discrepancies occur, and professional judgment is needed when interpreting the gamma‐index analysis, since even a >90% passing rate using the 2%/2 mm gamma‐index criterion does not guarantee the absence of clinically significance dose deviation.
Tumor response parameters for head and neck cancer derived from tumor‐volume variation during radiation therapy
Authors: Chvetsov Alexei V.
Published: February 2013

Purpose:

The main goal of this paper is to reconstruct a distribution of cell survival fractions from tumor‐volume variation for a heterogeneous group of head and neck cancer patients and compare this distribution to the data from predictive assays.

Methods:

To characterize the tumor‐volume variation during radiation therapy treatment, the authors use a two‐level tumor‐volume model of cell population that separates the entire tumor cell population into two subpopulations of viable cells and lethally damaged cells. This parameterized radiobiological model is integrated with a least squares objective function and a simulated annealing optimization algorithm to describe time‐dependent tumor‐volume variation rates in individual patients. Several constraints have been used in the optimization problem because tumor‐volume variation during radiotherapy is described by a sum of exponentials; therefore, the problem of accurately fitting a model to measured data is ill‐posed. The model was applied to measured tumor‐volume variation curves from a clinical study on tumor‐volume variation during radiotherapy for 14 head and neck cancer patients in which an integrated CT/linear particle accelerator (LINAC) system was used for tumor‐volume measurements.

Results:

The two‐level cell population tumor‐volume modeling is capable of describing tumor‐volume variation throughout the entire treatment for 11 of the 14 patients. For three patients, the tumor‐volume variation was described only during the initial part of treatment, a fact that may be related to the neglected hypoxia in the two‐level approximation. The predicted probability density distribution for the survival fractions agrees with the data obtained usingin vitro studies with predictive assays. The mean value 0.35 of survival fraction obtained in this study is larger than the value 0.32 from in vitro studies, which could be expected because of greater repair in vivo. The mean half‐life obtained in this study for the head‐and‐neck squamous cell carcinoma (SCC) is equal to 3.8 mean potential doubling times, which agrees with 4.0 mean potential doubling times obtained previously for lung SCC.

Conclusions:

The distribution of cell survival fractions obtained in this study support the hypothesis that the tumor‐volume variation during radiotherapy treatment for head and neck cancer can be described by the two‐level cell population tumor‐volume model. This model can be used forin vivo evaluation of patient‐specific radiobiological parameters that are needed for tumor‐control probability evaluation.
Integration of cardiac and respiratory motion into MRI roadmaps fused with x‐ray
Authors: Faranesh Anthony Z. , Kellman Peter , Ratnayaka Kanishka , Lederman Robert J.
Published: February 2013

Purpose:

Volumetric roadmaps overlaid on live x‐ray fluoroscopy may be used to enhance image guidance during interventional procedures. These roadmaps are often static and do not reflect cardiac or respiratory motion. In this work, the authors present a method for integrating cardiac and respiratory motion into magnetic resonance imaging (MRI)‐derived roadmaps to fuse with live x‐ray fluoroscopy images, and this method was tested in large animals.

Methods:

Real‐time MR images were used to capture cardiac and respiratory motion. Nonrigid registration was used to calculate motion fields to deform a reference end‐expiration, end‐diastolic image to different cardiac and respiratory phases. These motion fields were fit to separate affine motion models for the aorta and proximal right coronary artery. Under x‐ray fluoroscopy, an image‐based navigator and ECG signal were used as inputs to deform the roadmap for live overlay. Thein vivo accuracy of motion correction was measured in four swine as the ventilator tidal volume was varied.

Results:

Motion correction reduced the root‐mean‐square error between the roadmaps and manually drawn centerlines, even under high tidal volume conditions. For the aorta, the error was reduced from 2.4 ± 1.5 mm to 2.2 ± 1.5 mm (p < 0.05). For the proximal right coronary artery, the error was reduced from 8.8 ± 16.2 mm to 4.3 ± 5.2 mm (p < 0.001). Using real‐time MRI and an affine motion model it is feasible to incorporate physiological cardiac and respiratory motion into MRI‐derived roadmaps to provide enhanced image guidance for interventional procedures.

Conclusions:

A method has been presented for creating dynamic 3D roadmaps that incorporate cardiac and respiratory motion. These roadmaps can be overlaid on live X‐ray fluoroscopy to enhance image guidance for cardiac interventions.
Bringing the Digital Camera to the Physics Lab
Authors: Rossi M. , Gratton L. M. , Oss S.
Published: February 2013

We discuss how compressed images created by modern digital cameras can lead to even severe problems in the quantitative analysis of experiments based on such images. Difficulties result from the nonlinear treatment of lighting intensity values stored in compressed files. To overcome such troubles, one has to adopt noncompressed, native formats, as we examine in this work.
Teaching Astronomy Using Tracker
Authors: Belloni Mario , Christian Wolfgang , Brown Douglas
Published: February 2013

A recent paper in this journal1 presented a set of innovative uses of video analysis for introductory physics using Tracker. In addition, numerous other papers have described how video analysis can be a meaningful part of introductory courses.2–4 Yet despite this, there are few resources for using video analysis in introductory astronomy classes. In this paper we describe the use of Tracker in introductory astronomy to analyze a “video” consisting of a series of still images of star fields and sunspots. Because astronomy focuses on concepts unfamiliar to most students, the visualization that video analysis provides can be especially valuable.
Moving Clocks Do Not Always Appear to Slow Down: Don't Neglect the Doppler Effect
Authors: Wang Frank
Published: February 2013

In popular accounts of the time dilation effect in Einstein's special relativity, one often encounters the statement that moving clocks run slow. For instance, in the acclaimed PBS program “NOVA,”1 Professor Brian Greene says, “[I]f I walk toward that guy… he'll perceive my watch ticking slower.” Also in his earlier piece for The New York Times,2 he writes that “if from your perspective someone is moving, you will see time elapsing slower for him than it does for you. Everything he does … will appear in slow motion.” We need to be care- ful with this kind of description, because sometimes authors neglect to consider the finite time of signal exchange between the two individuals when they observe each other. This article points out that when two individuals approach each other, everything will actually appear in fast motion—a manifestation of the relativistic Doppler effect.3
An Arduino-Controlled Photogate
Authors: Galeriu Calin
Published: February 2013

It is hard to imagine teaching physics without doing experimental measurements of position as a function of time. These measurements, needed for the determination of velocity and acceleration, are most easily performed with the help of photogates.1,2 Unfortunately, commercial photogates are rather expensive. Many require the purchase of an additional matching timer or other electronic device. Sometimes special software is also needed. The total bill can easily become prohibitive. For this reason physics teachers have shown considerable interest for cheaper, in-house designed and manufactured photogates.3–6 The photogate systems described in the literature have their limitations. Some rely on a digital stopwatch and therefore cannot measure time with a precision higher than 0.01 seconds. Some use photoresistors that have a slower response than phototransistors. Some are based on the computer microphone port and therefore cannot handle more than two photogates (two audio channels) at the same time. Extracting the time information from an audio file can also be a challenge for some students. We describe here a photogate system that matches the performance of a commercial one but at a fraction of the cost. The key to this success is the use of an Arduino microcontroller for data collection. The Arduino platform, initially developed for electronics and robotics educational projects, has recently been incorporated in physics labs.7 The Arduino microcontroller, because of its low cost and because it provides a broad exposure to electronics and computer programming, is an ideal tool for integrated STEM projects.
The Orion Constellation as an Installation: An Innovative Three-Dimensional Teaching and Learning Environment
Authors: Brown Daniel
Published: February 2013

Visualizing the three-dimensional distribution of stars within a constellation is highly challenging for both students and educators, but when carried out in an interactive collaborative way, it can create an ideal environment to explore common misconceptions about size and scale within astronomy. We present how the common tabletop activities based upon the Orion constellation miss out on this opportunity. Transforming them into a walkthrough Orion installation that includes the position of our solar system allows the students to fully immerse themselves within the model and experience parallax. It enables participants to explore within the installation many other aspects of astronomy relating to sky culture, stellar evolution, and stellar sizes, establishing an innovative learning and teaching environment.
Analyzing radial acceleration with a smartphone acceleration sensor
Authors: Vogt Patrik , Kuhn Jochen
Published: February 2013

This paper continues the sequence of experiments using the acceleration sensor of smartphones (for description of the function and the use of the acceleration sensor, see Ref. 1) within this column, in this case for analyzing the radial acceleration.
Over 50 years of teaching physics — Some advice for young teachers
Authors: Hubisz John L.
Published: February 2013

Many beginning teachers choose to teach because they were strongly influenced by favorite teachers and believe they can be successful if they attempt to emulate the practices they so admired in those teachers. I was fortunate to have several teachers whose practices I tried to bring into my teaching career that has spanned over 50 years. I've been successful in modifying some of those practices, and I would like to share with you the evolution of my teaching style as I attempted to meet the needs of my students.
Information-criterion based selection of models for community noise annoyance
Authors: Keith Wilson D. , Valente Dan , Nykaza Edward T. , Pettit Chris L.
Published: February 2013

Statistical evidence for various models relating day-night sound level (DNL) to community noise annoyance is assessed with the Akaike information criterion. In particular, community-specific adjustments such as the community tolerance level (CTL, the DNL at which 50% of survey respondents are highly annoyed) and community tolerance spread (CTS, the difference between the DNL at which 90% and 10% are highly annoyed) are considered. The results strongly support models characterizing annoyance on a community-by-community basis, rather than with complete pooling and analysis of all available surveys. The most likely model was found to be a 2-parameter logistic model, with CTL and CTS fit independently to survey data from each community.
Ultrafast Tryptophan-to-Heme Electron Transfer in Myoglobins Revealed by UV 2D Spectroscopy
Authors: Consani Cristina , Auböck Gerald , van Mourik Frank , Chergui Majed
Published: February 2013

Fretting About Electrons

The FRET technique (Fluorescence Resonance Energy Transfer) is widely used to probe structural dynamics in large macromolecules such as proteins. Essentially, the technique relies on photoexciting a donor chromophore and then watching for signs of energy transfer to an acceptor chromophore elsewhere in the framework.

Consani
et al.

(p.
1586
, published online 7 February; see the Perspective by

Winkler

) now show, using a sophisticated type of broadband time-resolved ultraviolet spectroscopy, that in myoglobin, an excited tryptophan residue relaxes by electron, rather than energy, transfer. The distinction is generally difficult to observe but has strong bearing on the applicability of FRET in this and analogous systems.
Unraveling the Mechanism of Protein Disaggregation Through a ClpB-DnaK Interaction
Authors: Rosenzweig Rina , Moradi Shoeib , Zarrine-Afsar Arash , Glover John R. , Kay Lewis E.
Published: February 2013

Dissecting Disaggregation

The excessive accumulation of misfolded protein aggregates can overwhelm the cell's "quality control" machinery, leading to cell death. The yeast Hsp104 protein and its bacterial homolog ClpB are molecular chaperones that can "rescue" aggregated proteins by coupling the force generated from adenosine triphosphate hydrolysis to the progressive unfolding and threading of extended polypeptide segments through axial channels in these large molecular machines. Unfolded polypeptides emerging from the channel are refolded with the aid of a second chaperone system, DnaK/DnaJ/GrpE. DnaK also plays an important role in bringing regions of polypeptides within aggregates to ClpB to begin the solubilization process.

Rosenzweig
et al.

(p.
1080
, published online 7 February; see the Perspective by
Saibil
) describe a nuclear magnetic resonance–derived structure of the ClpB-DnaK complex, and verified it through mutagenesis and functional assays. The work clarifies the roles of each of the molecular players in the disaggregation reaction and provides a structural basis for the DnaK-ClpB interaction.
Draft Genome Sequence of Catellicoccus marimammalium, a Novel Species Commonly Found in Gull Feces
Authors: Weigand Michael R. , Ryu Hodon , Bozcek Laura , Konstantinidis Konstantinos T. , Santo Domingo Jorge W.
Published: February 2013

Catellicoccus marimammalium
is a relatively uncharacterized Gram-positive facultative anaerobe with potential utility as an indicator of waterfowl fecal contamination. Here, we report an annotated draft genome sequence that suggests that this organism may be a symbiotic gut microbe.
Genome Sequence of Lactobacillus saerimneri 30a (Formerly
Lactobacillus
sp. Strain 30a), a Reference Lactic Acid Bacterium Strain Producing Biogenic Amines
Authors: Romano Andrea , Trip Hein , Campbell-Sills Hugo , Bouchez Olivier , Sherman David , Lolkema Juke S. , Lucas Patrick M.
Published: February 2013

Lactobacillus
sp. strain 30a (
Lactobacillus saerimneri
) produces the biogenic amines histamine, putrescine, and cadaverine by decarboxylating their amino acid precursors. We report its draft genome sequence (1,634,278 bases, 42.6% G+C content) and the principal findings from its annotation, which might shed light onto the enzymatic machineries that are involved in its production of biogenic amines.
Complete Genome Sequence of
emm
1 Streptococcus pyogenes A20, a Strain with an Intact Two-Component System, CovRS, Isolated from a Patient with Necrotizing Fasciitis
Authors: Zheng Po-Xing , Chung Kun-Ta , Chiang-Ni Chuan , Wang Shu-Ying , Tsai Pei-Jane , Chuang Woei-Jer , Lin Yee-Shin , Liu Ching-Chuan , Wu Jiunn-Jong
Published: February 2013

Here, we announce the complete sequence of
Streptococcus pyogenes
A20. This strain was isolated from a patient with necrotizing fasciitis. Given that A20 harbors an intact two-component system, CovRS, the discovery of its genome sequence provides more insight into the pathogenesis of a pandemic
emm
1 strain.
Draft Genome Sequence of Pediococcus lolii NGRI 0510Q
T
Isolated from Ryegrass Silage
Authors: Doi Katsumi , Mori Kazuki , Tashiro Kosuke , Fujino Yasuhiro , Nagayoshi Yuko , Hayashi Yoshiharu , Kuhara Satoru , Ohshima Toshihisa
Published: February 2013

Pediococcus lolii
NGRI 0510Q
T
was isolated from ryegrass silage produced on Ishigaki Island, Okinawa Prefecture, Japan. Here we present a draft genome sequence for this strain, consisting of 103 contigs for a total of 2,047,078 bp, 2,154 predicted coding sequences, and a G+C content of 42.1%.
Complete Genome Sequence of a Human Coxsackievirus B3 from a Child with Myocarditis in Beijing, China
Authors: Du Jiang , Wu Zhiqiang , Xue Ying , Zhang Ting , Yang Fan , Jin Qi
Published: February 2013

A human coxsackievirus B3 (CVB3), designated strain Beijing0811, was isolated from a child diagnosed with hospital-acquired infectious acute myocarditis in Beijing, China, and propagated in human rhabdomyosarcoma cells. The complete genome sequence of this virus was 7,402 nucleotides, excluding the 3′ poly(A) tail, which encoded a large polyprotein with 2,185 amino acids. This report will help us to analyze the evolutionary and epidemic characteristics of CVB3.
Sugammadex rescue following prolonged rocuronium neuromuscular blockade with ‘recurarisation’ in a patient with severe renal failure
Authors: Lobaz Steven , Sammut Mario , Damodaran Anand
Published: February 2013

We describe our experience of a 71-year-old patient with severe renal failure, who exhibited an unusually prolonged rocuronium-induced neuromuscular blockade (>4 h) and apparent recurarisation, following emergency rapid sequence induction (RSI). At the end of operation, 45 min post induction, train-of-four (TOF) testing had been 4/4 prior to wake up. No respiratory effort was seen 150 min postinduction, despite further neostigmine/glycopyrrolate and repeat TOF 4/4. The patient was resedated and transferred to the intensive care unit (ICU). At 180 min postinduction, fade was evident on TOF, suggestive of rocuronium reblockade. At 285 min, the patient was extubated safely following sugammadex administration and discharged uneventfully from the ICU. An important lesson to recognise is the potential for extremely prolonged neuromuscular blockade following rocuronium in patients with severe renal failure, particularly when using the higher doses (1.2 mg/kg) required for RSI, and that TOF in such cases may not be reliable in detecting residual blockade.
Eosinophilic oesophagitis in children: responders and non-responders to swallowed fluticasone
Authors: Boldorini Renzo , Mercalli Francesca , Oderda Giuseppina
Published: February 2013

Eosinophilic Oesophagitis (EO) is characterised by large numbers of eosinophils in oesophageal mucosa in response to food or inhaled antigens. Treatment with elimination diet or corticosteroids lead to improvement in some children, but their efficacy is not optimal.

Aim

of this study is to identify clinical, endoscopic and/or histological features associated with response to treatment with swallowed fluticasone propionate.

Patients and methods

In the last 12 years 34 children (M/F 25/9) with EO were treated with fluticasone propionate spray 250 μg/puff by inhaler without spacer, three puffs three times a day for 6 weeks, and returned for a follow-up endoscopy. At histology 25 of them were found to be responders to therapy (73.5%) and 9 were non-responders. Anthropometric characteristics, symptoms at presentation, endoscopic and histological data at baseline between responders and non-responders were compared.

Results

Age, sex, height, duration and type of main symptom at presentation, type of allergy and number of allergens, peripheral eosinophil counts an serum IgE were similar in responders and non-responders. At baseline histology findings responders had a more severe inflammation: median peak eosinophils/high power field was higher (76 vs 44 in non responders p=0.04), eosinophilic microabscesses were present in a significantly higher number of responders (p=0.04) and peak mast cells/ high power field was significantly higher (p=0.001).

Conclusions

Clinical characteristics of children with EO at baseline were similar in responders and non-responders, but a more severe inflammation in oesophageal mucosa was associated with a higher response rate to fluticasone treatment.