bluuebunny/crossref_metadata_2025 huggingface dataset:
Filtered deconvolution of a simulated and an in vivo phase model of the human brain
Authors: Grabner Günther , Trattnig Siegfried , Barth Markus
Published: July 2010

Purpose:

To remove spatial patterns in gradient echo phase images which are caused by susceptibility differences between different tissue types using filtered deconvolution and to evaluate deconvolution effects.

Materials and Methods:

A realistic simulated susceptibility map of the human brain was built and used to evaluate the effects of filtered deconvolution. The simulated susceptibility map was convolved with a filter kernel representing a magnetic dipole resulting in a simulated phase map. The artificial phase map was superimposed with different noise levels and deconvolved using different deconvolution kernels. The resulting contrast‐to‐noise ratios between white and gray matter of the deconvolved data provide an estimate for an optimal deconvolution kernel for a given noise level. These results were used to deconvolve an in vivo phase model representing the average of 30 phase data sets and also individual phase data acquired at 7 Tesla.

Results:

The deconvolved phase model shows a better anatomical agreement with the corresponding magnitude than the original phase model (5% higher κ coefficient). Visual inspection of the deconvolved individual phase shows a more consistent delineation of blood vessels.

Conclusion:

Filtered deconvolution of SWI phase is possible when an appropriate filter kernel is used. This helps to improve region of interest definition as unrealistic phase patterns are removed. J. Magn. Reson. Imaging 2010;32:289–297. © 2010 Wiley‐Liss, Inc.
Intra‐renal oxygenation in rat kidneys during water loading: Effects of cyclooxygenase (COX) inhibition and nitric oxide (NO) donation
Authors: Ji Lin , Li Lu‐Ping , Schnitzer Thomas , Du Hongyan , Prasad Pottumarthi V.
Published: July 2010

Purpose:

To evaluate intra‐renal oxygenation by blood oxygenation level dependent (BOLD) MRI in rat kidneys during water loading and to investigate if the NO donating moiety in naproxcinod could compensate for the effect of cyclooxygenase (COX) inhibition of naproxen.

Materials and Methods:

Nineteen male Sprague Dawley rats were divided into three groups and dosed with vehicle, naproxen or naproxcinod by gavage for two weeks. On the day of the experiment, hypotonic saline with glucose was infused intravenously to induce water diuresis. BOLD MRI data to monitor renal oxygenation and timed urine samples for estimation of prostaglandins (PGs) and urine flow were obtained.

Results:

The data in this study is consistent with previous experience in humans in that pre‐treatment with naproxen abolished the improvement in medullary oxygenation during water loading. In addition, the inhibition of PGs by naproxcinod reached similar levels as naproxen but maintained the improvement in oxygenation in renal medulla during water loading.

Conclusion:

This suggests that naproxcinod may have less nephrotoxicity and that the NO donating moiety partially compensates for the hemodynamic effects of prostaglandin inhibition by naproxen. J. Magn. Reson. Imaging 2010;32:383–387. © 2010 Wiley‐Liss, Inc.
Comparison of the high relaxivity Gd chelates P1152 and Gd‐BOPTA for contrast‐enhanced MR angiography in rabbits at 1.5 Tesla and 3.0 Tesla
Authors: Peldschus Kersten , Hamdorf Mareike , Robert Philippe , Port Marc , Adam Gerhard , Herborn Christoph U.
Published: July 2010

Purpose:

To compare signal‐enhancing properties of the high relaxivity Gd chelates P1152 and Gd‐BOPTA for contrast‐enhanced MR angiography (CE‐MRA) in rabbits at 1.5 Tesla (T) and 3.0T.

Materials and Methods:

Three‐dimensional CE‐MRA of the abdominal vasculature was performed in six rabbits using both contrast agents at a dose of 0.1 mmol/kg. Data acquisition was carried out during first pass and up to 10 min after contrast material administration. CNR was determined in aorta, vena cava, and renal cortex. Image quality (5‐point scale, 5 = best) of first pass MR angiograms was rated by two radiologists.

Results:

During first pass CNR of the aorta was 55.1 ± 5.8 (P1152) and 40.3 ± 3.9 (Gd‐BOPTA) at 1.5T (P < 0.05), and 114.9 ± 9.9 (P1152) and 73.5 ± 8.1 (Gd‐BOPTA) at 3.0T (P < 0.05). Both contrast agents showed a comparable decline of CNR within 10 min. Image quality was rated 4.8 ± 0.40 (P1152) and 4.5 ± 0.50 (Gd‐BOPTA) at 1.5T (P = 0.17), and 4.8 ± 0.37 (P1152) and 4.7 ± 0.47 (Gd‐BOPTA) at 3.0T (P = 0.61).

Conclusion:

The high relaxivity Gd‐chelate P1152 offers potential to improve image contrast for CE‐MRA compared with a clinically approved high relaxivity contrast agent. J. Magn. Reson. Imaging 2010;32:459–465. © 2010 Wiley‐Liss, Inc.
Individual voxel‐based analysis of brain magnetization transfer maps shows great variability of gray matter injury in the first stage of multiple sclerosis
Authors: Jure Lorena , Zaaraoui Wafaa , Rousseau Celia , Reuter Françoise , Rico Audrey , Malikova Irina , Confort‐Gouny Sylviane , Cozzone Patrick J. , Pelletier Jean , Ranjeva Jean‐Philippe , Audoin Bertrand
Published: July 2010

In multiple sclerosis (MS), it seems likely that the variability of the long‐term disability might be partly due to the variability of the early gray matter (GM) injury. In the present study, we assessed the variability of GM injury in early MS, using a method designed to determine individual pathological GM patterns. Eighteen patients presenting with a clinically isolated syndrome and 24 healthy matched control subjects were included in this study. Patients were explored using a 1.5 Tesla MR scanner (Magnetom Vision Plus; Siemens). Brain MR protocol included magnetization transfer ratio imaging (MTR). Statistical mapping analyses were performed to compare each subject's GM MTR maps with those of the whole group of control subjects (SPM5). The statistical threshold was taken to be the maximum P value showing no significant cluster when any control individual was compared with the whole control population. GM abnormalities were observed in 83% of the patients, ranging in size from 0.3 to 125 cm3. Among the patients with GM abnormalities, 87% had abnormalities located in the temporal cortex, 80% in the frontal cortex, 80% in the limbic cortex, 73% in the posterior fossa, 53% in the deep GM, 47% in the parietal cortex, and 47% in the occipital cortex. Individual statistical mapping of MTR data, which gives a quantitative assessment of individual GM lesions, demonstrates great variability of grey matter injury in the first stage of multiple sclerosis. J. Magn. Reson. Imaging 2010;32:424–428. © 2010 Wiley‐Liss, Inc.
Value of delayed hypointensity and delayed enhancing rim in magnetic resonance imaging diagnosis of small hepatocellular carcinoma in the cirrhotic liver
Authors: Khan Asra S. , Hussain Hero K. , Johnson Timothy D. , Weadock William J. , Pelletier Shawn J. , Marrero Jorge A.
Published: July 2010

Purpose:

To determine the diagnostic utility of delayed hypointensity and delayed enhancing rim on magnetic resonance imaging (MRI) as indicators of hepatocellular carcinoma (HCC) in arterially enhancing nodules ≤5 cm in the cirrhotic liver and determine the features that best predict HCC.

Materials and Methods:

Gadolinium‐enhanced MRI studies performed from January 2001 to December 2004 in patients with cirrhosis were evaluated for arterially enhancing nodules measuring ≤5 cm. Verification was via explant correlation, biopsy, or imaging follow‐up. Sensitivity and specificity of diagnostic features of HCC were calculated. Features predictive of HCC were determined using the Generalized Estimating Equation approach.

Results:

In all, 116 arterially enhancing nodules were identified in 80 patients (<2 cm: n = 79, 2–5 cm n = 37). Sensitivity and specificity of delayed hypointensity for HCC measuring ≤5 cm, 2–5 cm, and <2 cm were 0.54 (40 of 74) and 0.86 (36 of 42); 0.72 (23 of 32) and 0.80 (4 of 5); and 0.41 (17 of 42) and 0.87 (32 of 37). For the delayed enhancing rim sensitivity and specificity were 0.64 (47 of 74) and 0.86 (36 of 42); 0.75 (24 of 32) and 1.0 (5 of 5); and 0.55 (23 of 42) and 0.83 (31 of 37), respectively. Lesion size (≥2 cm) and delayed enhancing rim, as main features and their interaction, were the most significant predictors of HCC.

Conclusion:

Delayed hypointensity and enhancing rim improve the specificity of diagnosis of HCC of all sizes but are seen less frequently in small (<2 cm) HCC. Nodule size (≥2 cm) and delayed enhancing rim are the strongest predictors of HCC. J. Magn. Reson. Imaging 2010;32:360–366. © 2010 Wiley‐Liss, Inc.
Effective use of flow‐spoiled FBI and time‐SLIP methods in the diagnostic study of an aberrant vessel of the head and neck: “Left jugular venous steal by the right jugular vein”
Authors: Kogure Taroh , Kogure Kyuya , Iizuka Mitsumasa , Ino Azusa , Ishii Masako
Published: July 2010

Three‐dimensional (3D) time‐of‐flight (TOF) is now commonly used in routine magnetic resonance angiography (MRA) studies of the head and neck. However, there are limits to its diagnostic abilities in the clinical field and, in some instances, a more invasive supplementary examination may be required. We incidentally discovered a patient with an aberrant vessel of the head and neck that ran alongside the left carotid artery and contained a constant, slowly pulsating efferent blood flow. 3D‐TOF and carotid ultrasonography could not determine the nature and origin of this vessel. Additional studies using flow‐spoiled fresh blood imaging (flow‐spoiled FBI) and time spatial labeling inversion pulse (time‐SLIP) methods were effective in determining that the vessel was the left jugular vein, and that the continuous venous reflux was a result of a venous steal by the right jugular vein. We show that by combining different MRA techniques we can effectively achieve diagnosis without resorting to more invasive examinations. J. Magn. Reson. Imaging 2010;32:429–433. © 2010 Wiley‐Liss, Inc.
Efficient flow suppressed MRI improves interscan reproducibility of carotid atherosclerosis plaque burden measurements
Authors: Dong Li , Wang Jinnan , Yarnykh Vasily L. , Underhill Hunter R. , Neradilek Moni B. , Polissar Nayak , Hatsukami Thomas S. , Yuan Chun
Published: July 2010

Purpose:

To determine if better flow suppression can meaningfully improve the reproducibility of measurements associated with carotid atherosclerotic disease, particularly for lumen and wall areas.

Materials and Methods:

Eighteen subjects with carotid artery stenosis identified by duplex ultrasound (11 with 16%–49% stenosis; 7 with 50%–79% stenosis) underwent two carotid magnetic resonance imaging (MRI) examinations on a 3T scanner with a 4‐channel phased array coil. High‐resolution intermediate‐weighted TSE (TR/TE = 4000/8.5 msec, 0.55 mm in‐plane resolution, 2 mm slice thickness, 16 slices, 3‐minute scan time) with two different flow‐suppression techniques (multislice double inversion recovery [mDIR] and motion‐sensitized driven‐equilibrium [MSDE]) were obtained separately. For each subject, bilateral arteries were reviewed. One radiologist blinded to timepoints, flow suppression techniques, and clinical information measured the arterial lumen area, wall area, and total vessel wall area.

Results:

Compared to mDIR, the MSDE technique had a smaller interscan standard deviation (SD) in lumen (SD: 3.6 vs. 5.2 mm2, P = 0.02), wall area measurements (SD: 4.5 vs. 6.4 mm2, P = 0.02), and a trend towards smaller SD in total vessel area measurement (SD: 4.4 vs. 4.9 mm2, P = 0.07).

Conclusion:

The results from this study demonstrate that vessel wall imaging could quantify atherosclerotic plaque measurements more reliably with an improved blood suppression technique. This relationship between flow‐suppression efficiency and reproducibility of plaque measurements is important, as more reliable area measurements will be useful in clinical diagnosis and in serial MRI studies that monitor carotid atherosclerotic lesion progression and regression. J. Magn. Reson. Imaging 2010;32:452–458. © 2010 Wiley‐Liss, Inc.
The First Half‐Century of Laser Development
Authors: Hecht Jeff
Published: July 2010

The laser was born on May 16, 1960 at Hughes Research Laboratories in Malibu, California. Instead of enjoying the view of the Pacific from his new office window, Theodore Maiman closeted himself in a windowless lab, where he slipped a spring‐shaped photographic flashlamp over a stubby ruby rod, then put the assembly inside a reflective cylinder. Firing pulses with higher and higher voltage through the lamp, he carefully studied oscilloscope traces of the rise and fall of the ruby's red fluorescence. Once the voltage exceeded 950 volts, the lamp flashed bright enough to excite the ruby above laser threshold. The red light suddenly flashed so bright that Maiman's colorblind assistant Irnee D'Haenens saw red light for the first time [1]! The instruments recorded what Maiman had predicted would happen above laser threshold – the pulse rose and fell faster, and the range of red wavelengths narrowed. This article provides an overview of the first 50 years of laser development as well as a brief outlook what's coming next.
Nächste Generation des Laserselektivlötens
Authors: Deininger Christoph
Published: July 2010

Das Löten von Elektronikkomponenten moderner Produkte nimmt im Produktionsalltag vieler Hersteller stetig zu. Durch eine stetige Entwicklung hin zu komplexeren Bauteilen werden dabei Selektivlötprozesse immer wichtiger. Dieser Artikel beschreibt einen neuen laserbasierten Ansatz zum Selektivlöten, der durch Kombination intelligenter Systemkomponenten eine neue Dimension des Laserlötens eröffnet.
Amelioration of an acid ultisol by agricultural by‐products
Authors: Wang N. , Xu R.‐K. , Li J.‐Y.
Published: July 2010

Ultisols are widely distributed in the subtropical regions of China as well as in the world. High acidity of Ultisols limits plant growth and reduces crop yields. Amelioration of an acid Ultisol was investigated by incorporating the residues of canola (Brassica campestris L.), wheat (Triticum aestivum L.), rice (Oryza sativa), corn (Zea mays), soybean (Glycine max), peanut (Arachis hypogaea), faba bean (Vicia faba L.) and pea (Pisum sativum) and Chinese milk vetch (Astragalus sinicus L.) shoots after incubation of the agricultural by‐products for a maximum of 75 days, soil pH was increased by each of the plant materials. The degree of amelioration of the soil acidity by the plant materials was found to depend on the ash alkalinity and N content of the materials; the legumes of higher ash alkalinities and lower N contents, such as peanut straw and faba bean straw, led to the largest increases in soil pH, while the legumes of higher N contents showed less amelioration of the acidity to a certain degree, because of the release of protons during nitrification of NH from mineralisation of organic N. The non‐leguminous materials have medium amelioration effects and increased soil pH by 0·42–0·56 units at the end of incubation. The incorporation of the plant materials also increased exchangeable base status and reduced exchangeable Al, and thus decreased the toxicity of Al in the soil. This study demonstrates that plant materials, especially crop residues, can be used as amendments for acidic soils to restore degraded land in subtropical regions. Copyright © 2010 John Wiley & Sons, Ltd.
Population structure of three woody species in four ethnic domains of the sub‐sahel of Burkina Faso
Authors: Sop T. K. , Oldeland J. , Schmiedel U. , Ouedraogo I. , Thiombiano A.
Published: July 2010

In developing countries many people depend on woody resources for their livelihoods. Monitoring human impact on the populations of socio‐economically important species is therefore important for the conservation of vulnerable plants.

In order to assess and compare the population structure and regeneration patterns of three multipurpose species, namely Acacia seyal Del., Balanites aegyptiaca Delile and Pterocarpus lucens Lepr. in four ethnic areas of the sub‐Sahel of Burkina Faso (Samo, Gourmantché, Fulani and Mossi), we used the size‐class distribution method (SCD) (Condit et al., 1998). Diameter at breast height (Dbh) of adult individuals of each species were sampled on 1000 m2 (20 m × 50 m) plots in each ethnic domain. Recorded Dbhs were distributed among eight size‐classes of 5 cm intervals. For each species, the slope of the regression of the SCD was considered to be an indicator of the population structure. Seedlings and saplings were recorded on five nested 25 m2 plots and fell into five height classes of 0·5 m intervals.

The target species had significant (p < 0·001) negative SCD slopes with an inverse J‐shape distribution in all ethnic areas; indicating stable populations with good regeneration. Kruskal–Wallis test for the SCDs of A. seyal, B. aegyptiaca and P. lucens did not differ significantly among the ethnic areas (p > 0·1). This suggests that the dynamics of each of the three species is similar across ethnic domains and the sub‐Sahel. Data from P. lucens depicted an apparent stable population structure which contrasted with our field observations, perception of local people and previous studies. Copyright © 2010 John Wiley & Sons, Ltd.
Highly tuned gas atomization for controlled preparation of coarse powder
Authors: Anderson I. E. , Byrd D. , Meyer J.
Published: July 2010

While close‐coupled gas atomization has been demonstrated for highly controlled production of fine powders in many alloy systems, defense applications for Mg powder demand that such an atomization system also be capable of producing a narrow standard deviation for coarse Mg powders. To develop this capability, a series of 5 gas atomization experiments were conducted with Al, as a less hazardous surrogate for Mg, over a range of a very low atomization gas pressures. The optimum result produced an average particle diameter of about 460 μm with a standard deviation of 1.53 using Ar atomization gas, sufficiently close to the 500 μm target size. These experiments achieved the process uniformity needed for this narrow standard deviation by stabilizing melt filming with an expanded discrete jet, close‐coupled atomization nozzle and a slotted trumpet bell pour tube. Initial analysis of the size results indicated that decreased atomization gas velocity, acting within the acceleration wave model, was the key controlling variable in this low‐pressure regime. No consistent influence of gas/melt mass flow ratio was detected in the data. Experimental observation of the atomization spray images also indicated that a practical lower limit to atomization gas pressure is about 69 kPa for achieving atomization process uniformity with the method of this study.
Spray forming of stainless steel matrix composites with injection of hard particulates
Authors: Cui C. , Schulz A. , Uhlenwinkel V. , Zobel F. , Zoch H.‐W.
Published: July 2010

To produce new types of wear resistant and corrosion resistant materials for the manufacture of knives, hard particles (TiC and VC, size 1–10 μm) have been injected into martensitic stainless steel (X46Cr13) and austenitic stainless steel (X2CrNiMo17‐12‐2) during spray forming, respectively. To eliminate porosity in the deposits and prepare semi‐finished materials for subsequent applications, the spray‐formed billets (diameter 130 mm–160 mm after peeling) have been hot worked to bars (75 mm×25 mm or 75 mm×15 mm) and thin plates (7–8 mm thickness). The microstructures and properties of the spray‐formed and hot worked steel matrix composites have been investigated and evaluated. A porosity level less than 1% in the as‐deposited composites can be achieved under proper carbide powder feeding and spray forming conditions. The carbide particles are more homogeneously distributed in the steel matrices after hot working. The hardness of the spray‐formed composites, particularly the austenitic steel matrix composites, increases significantly with increasing carbide content. The abrasive wear resistance of the composites is also improved.

Neue Arten von verschleißfesten und korrosionsbeständigen Materialien wurden erzeugt, indem beim Sprühkompaktieren Refraktärmetallcarbide (MC), speziell TiC und VC (Partikelgröße 1–10 μm), in den rostfreien martensitischen Stahl (X46Cr13) und den austenitischen Stahl (X2CrNiMo17‐12‐2) eingebracht wurden. Zur Verdichtung und Formgebung zu Halbzeugen für spätere Anwendungen als Schneidwerkzeuge wurden die sprühkompaktierten, bolzenförmigen Deposits zunächst zu Platinen (75×25 bzw. 75×15 mm2) geschmiedet und dann weiter zu 7–8 mm dünnen Blechen warmgewalzt. Gefüge und Eigenschaften der sprühkompaktierten Stahl‐Verbundwerkstoffe wurden untersucht und bewertet. Unter geeigneten Bedingungen bei der Pulverzufuhr und beim Sprühkompaktieren kann die Porosität in den Deposits unter 1% liegen. Die Karbidpartikel sind nach der Warmumformung in der Stahl‐Matrix homogener verteilt. Die Härte der sprühkompaktierten Verbundwerkstoffe, insbesondere der austenitischen Matrix‐Composites, steigt signifikant mit zunehmendem Hartstoffgehalt. Die Verschleißfestigkeit der Verbundwerkstoffe wird ebenfalls gesteigert.
Why is spray forming a rapid solidification process?
Authors: Henein H.
Published: July 2010

Since the invention of spray forming by Prof. Singer in the early 80's, many researchers have attempted to explain the rapid solidification features of the spray deposit through mathematical modelling of the process. The break‐up of the stream into atomized drops followed by the deposition of these semi‐solid droplets into a rotating deposit have been simulated using both the energy and the momentum equations. These models, however, do not explain the fineness of structure observed in spray formed products when compared to cast structures of similar dimensions and experiencing similar cooling rates. A single fluid technique provides an ideal tool to study the effect of atomization variables on the structure evolution of a spray formed deposit. It will be shown based on Cu‐6Sn, Al‐Cu and Al‐Fe alloys that the undercooling of second and subsequent phases in the deposit accounts for the rapid solidified structure in spray forming.
Wear and microstructural characteristics of spray atomized zircon sand reinforced LM13 alloy
Authors: Kaur K. , Pandey O. P.
Published: July 2010

The requirement of the high performance light weight materials demands the development of varieties of materials within the economical range to get it commercialized. Light weight aluminium alloys are used in several structural applications like automotive, aerospace, defense industry and other fields of engineering. The ceramic particle reinforced aluminium metal matrix composites (AMCs) have emerged as a suitable candidate for commercial applications. A variety of processing routes have been adopted to manufacture AMCs. In the present work LM13 alloy reinforced with zircon sand is formed via spray forming. During experimentation a self prepared convergent‐divergent nozzle is used for inert gas atomization of the melt which is subsequently deposited on copper substrate placed vertically below the atomizer. The zircon sand particles are injected in the atomization zone by external injectors aligned perpendicular to the gas atomization axis. Zircon sand has been found to have new promising economical commercial candidate due to its easy availability and good mechanical properties like high hardness, high modulus of elasticity and good thermal stability. The microhardness of cast alloy and spray formed composite shows that the spray formed zircon sand reinforced composite has higher hardness. Also the lower wear rate has been observed in case of the zircon sand reinforced AMC as compared to LM13 alloy. This behaviour is further analyzed in light of microstructural features of the spray deposited composite using optical and scanning electron microscope (SEM). A comparative study of this material (LM13/Zircon sand) with the parent alloy (LM13) is presented in this work.
Redoxregulierte Phosphatasen
Authors: Groß Michael
Published: July 2010

Phosphatasen mit einer Thiolgruppe im aktiven Zentrum sind extrem empfindlich gegenüber Oxidation. Diese kann schädlich sein, aber auch zur Regulierung der Enzyme beitragen.
Sparsam in großem Maßstab
Authors: Pakusch Anne
Published: July 2010

Neue Anlagen und Herstellungstechniken senken den Energieverbrauch und die Kosten bei der Produktion von Polyurethan‐Grundstoffen.
Mit China reden, handeln und forschen
Authors: Bulmahn Maren
Published: July 2010

Die von der Dechema seit 1989 alle drei Jahre organisierte Achemasia wies in diesem Jahr Rekordzahlen auf. Mehr Aussteller zeigten mehr Besuchern ihre Exponate auf einer größeren Fläche und beide Gruppen waren internationaler besetzt als im Jahr 2004.
Erythromycin für Elritzen
Authors: Schmid‐Ruzicka Susanne , Gans Oliver
Published: July 2010

Experten im österreichischen Umweltbundesamt haben Gewässer auf Rückstände von Arzneimittelwirkstoffen untersucht.
Der heimliche Katalysator
Authors: Guggolz Ernst
Published: July 2010

Ohne großes Aufheben wuchs ein in Bayern verwurzelter Konzern in weltweite Dimensionen: Die Süd‐Chemie, eines der ältesten deutschen Chemieunternehmen, sieht mit Katalysatoren und Adsorbentien seine gute Zukunft weiter in der Spezialchemie.
The redox‐sensing regulator YodB senses quinones and diamide via a thiol‐disulfide switch in Bacillus subtilis
Authors: Chi Bui Khanh , Albrecht Dirk , Gronau Katrin , Becher Dörte , Hecker Michael , Antelmann Haike
Published: July 2010

The MarR/DUF24‐type repressor YodB controls the azoreductase AzoR1, the nitroreductase YodC and the redox‐sensing regulator Spx in response to quinones and diamide in Bacillus subtilis. Previously, we showed using a yodBCys6‐Ala mutant that the conserved Cys6 apparently contributes to the DNA‐binding activity of YodB in vivo. Here, we present data that mutation of Cys6 to Ser led to a form of the protein that was reduced in redox‐sensing in response to diamide and 2‐methylhydroquinone (MHQ) in vivo. DNA‐binding experiments indicate that YodB is regulated by a reversible thiol‐modification in response to diamide and MHQ in vitro. Redox‐regulation of YodB involves Cys6‐Cys101' intermolecular disulfide formation by diamide and quinones in vitro. Diagonal Western blot analyses confirm the formation of intersubunit disulfides in YodB in vivo that require the conserved Cys6 and either of the C‐terminal Cys101' or Cys108' residues. This study reveals a thiol‐disulfide switch model of redox‐regulation for the YodB repressor to sense electrophilic compounds in vivo.
Application of analytical solutions in trapezoidal compound channel flow
Authors: Zeng Y. H. , Guymer I. , Spence K. J. , Huai W. X.
Published: July 2010

The accuracy of predictions using an analytical model for a lateral depth varying open channel flow can be affected by the friction factor and the dimensionless eddy viscosity. In this paper, different approaches to determine these two parameters are discussed by comparing analytical results with experimental data obtained from a symmetrical trapezoidal compound open channel. To reflect different hydraulic characteristics along the wetted perimeter, the trapezoidal cross‐section was divided into several sub‐sections, and the friction factor in each sub‐section was calculated with Manning's formula by adopting local hydraulic parameters. The wetted perimeters of main channel and side slope included the interface between panels to reflect the effects of the lateral momentum exchange. This approach is shown to be effective once the roughness coefficients and hydraulic radius in different sub‐regions have been determined. The results show that the friction factor is the major parameter affecting the accuracy of the analytical solution. The effect of dimensionless eddy viscosity on the precision of predictions is much smaller, which means that for practical applications, the dimensionless eddy viscosity can be determined empirically. Inclusion of a term for secondary flows in the model can improve the prediction, especially in the transition from main channel to the floodplain. A reasonable prediction of the lateral distribution of depth mean Reynolds' stress in this region is obtained. Copyright © 2010 John Wiley & Sons, Ltd.
Western hemispheric trade agreements and sustainability: Lesson from butterflies, hummingbirds, and salty anchovies
Authors: Miller Van V. , Crespy Charles T. , Loess Kurt H. , Renau José A.
Published: July 2010

The relationship between international commerce and sustainable development is the subject of much controversy that is exacerbated by geographic boundaries that are co‐jointly developed, shaped, and sustained by regional trade agreements. The outcomes of three Americas trade agreements – NAFTA, CAFTA, and USPTPA – are analyzed across three dimensions: economic, ecological, and labor. The three dimensions collectively form for each trade region a specific ECOL niche that is concurrently subject to national variation. We propose and find that low‐ECOL niches in the Americas appear to attract more foreign trade with investment. Nevertheless, this tentative finding seems not to hold for those corporations that seek out strong ECOL niche countries like Costa Rica. Copyright © 2010 John Wiley & Sons, Ltd and ERP Environment.
Concise Review: Kidney Stem/Progenitor Cells: Differentiate, Sort Out, or Reprogram?
Authors: Pleniceanu Oren , Harari-Steinberg Orit , Dekel Benjamin
Published: July 2010

End-stage renal disease (ESRD) is defined as the inability of the kidneys to remove waste products and excess fluid from the blood. ESRD progresses from earlier stages of chronic kidney disease (CKD) and occurs when the glomerular filtration rate (GFR) is below 15 ml/minute/1.73 m2. CKD and ESRD are dramatically rising due to increasing aging population, population demographics, and the growing rate of diabetes and hypertension. Identification of multipotential stem/progenitor populations in mammalian tissues is important for therapeutic applications and for understanding developmental processes and tissue homeostasis. Progenitor populations are ideal targets for gene therapy, cell transplantation, and tissue engineering. The demand for kidney progenitors is increasing due to severe shortage of donor organs. Because dialysis and transplantation are currently the only successful therapies for ESRD, cell therapy offers an alternative approach for kidney diseases. However, this approach may be relevant only in earlier stages of CKD, when kidney function and histology are still preserved, allowing for the integration of cells and/or for their paracrine effects, but not when small and fibrotic end-stage kidneys develop. Although blood- and bone marrow-derived stem cells hold a therapeutic promise, they are devoid of nephrogenic potential, emphasizing the need to seek kidney stem cells beyond known extrarenal sources. Moreover, controversies regarding the existence of a true adult kidney stem cell highlight the importance of studying cell-based therapies using pluripotent cells, progenitor cells from fetal kidney, or dedifferentiated/reprogrammed adult kidney cells.
Ten Tips for Teaching in the Theatre Tearoom: Shifting the Focus from Teaching to Learning
Authors: Jeffree Rosalind L. , Clarke Rufus M.
Published: July 2010

Educational encounters between surgeons and trainees are often brief, spontaneous, opportunistic events. In spite of their vast teaching experience, very few surgeons have had educational training that enables them to optimise such opportunities. This article reviews the literature on medical education and adult learning, and makes practical suggestions about how surgeons can best help trainees to learn. The most important ideas, such as creating a supportive learning environment, actively engaging the learner, and providing constructive feedback, are relevant to any teaching and learning, but are particularly applicable to informal, on‐the‐job educational encounters such as teaching in the theatre tearoom.
Estimating the extent of degradation of ruminant feeds from a description of their gas production profiles observedin vitro:derivation of models and other mathematical considerations
Authors: France J. , Dijkstra J. , Dhanoa M. S. , Lopez S. , Bannink A.
Published: July 2010

Equations to describe gas production profiles, obtained using manual or automated systems forin vitrofermentation of ruminant feeds, were derived from first principles by considering a simple three-pool scheme. The pools represented were the potentially degradable and undegradable feed fractions, and accumulated gases. The equations derived and investigated mathematically were the generalized Mitscherlich, generalized Michaelis–Menten, Gompertz, and logistic. They were obtained by allowing the fractional rate of degradation to vary with time. The equations permit the extent of ruminal degradation (hence the supply of microbial protein to the duodenum) to be evaluated, thus linking the gas production technique to animal production.
Evaluation of potential nonisothermal processes and heat transport during CO2 sequestration
Authors: Han Weon Shik , Stillman Greg A. , Lu Meng , Lu Chuan , McPherson Brian J. , Park Eungyu
Published: July 2010

Injection of CO2 may perturb subsurface temperatures, leading to a dynamic temperature system in the storage formation and adjacent seal strata. In most cases, the individual effects from wellbore dynamics, solvation reactions, and phase changes are incremental, but collectively these relevant processes may cause significant temperature changes compared to ambient conditions. In this work, we evaluated several potential nonisothermal effects resulting from CO2 injection activity. These include the Joule‐Thomson (heating and cooling) effect, exothermic CO2 dissolution, and heat changes associated with concomitant water vaporization. Results suggest that three effects: a) the adiabatic (de‐) compression of CO2, b) the frictional energy losses, and c) conductive heat exchange between the injected CO2 and surrounding fluid/rock, govern the resulting CO2 thermal profiles within an injection well. In addition, as supercritical‐phase CO2 comes into contact with formation brine, the CO2 will dissolve into the aqueous phase, and such dissolution is exothermic at typical conditions for CO2 sequestration. However, we still seek a better understanding of heat effects associated with water vaporization into the supercritical‐phase CO2. Finally, sensitivity studies, simulating supercritical‐phase CO2 injection into a 1‐D radially symmetric domain, are conducted to evaluate the magnitude of different heat disequilibrium potentials and spatial location in the CO2 plume affected by thermal processes. In addition, time‐scales associated with migration rates of temperature fronts, pressure pulses, and dissolved‐ and supercritical‐phase CO2 profiles are investigated with a function of heat capacities of rock, different effective thermal conductivities, permeabilities, and porosities. Our results demonstrate that adiabatic CO2 compression occurring in injection wells could have the most significant impact on the temperature change whilst the exothermic CO2 dissolution occurred at the largest spatial domain.
Drilling Into Faults Quickly After Earthquakes
Authors: Brodsky Emily E. , Mori Jim , Fulton Patrick M.
Published: July 2010

What will it take to advance from current empirical models of earthquake initiation and fault slip to a full physics‐based understanding of rupture processes? The most important requirements include knowledge of absolute stress levels on the fault during an earthquake, how stresses recover afterward to prepare for the next event, how one earthquake promotes or inhibits another, and how material properties of a particular fault affect its propensity to fail catastrophically rather than creep.

Immediately after a large earthquake, an opportunity exists to fill these knowledge gaps. For a few years after a major earthquake, the fault is observably changing and a deep borehole can capture measurable signals to address the key questions.
A new petrological and geophysical investigation of the present‐day plumbing system of Mount Vesuvius
Authors: Pommier A. , Tarits P. , Hautot S. , Pichavant M. , Scaillet B. , Gaillard F.
Published: July 2010

A model of the electrical resistivity of Mt. Vesuvius has been elaborated to investigate the present structure of the volcanic edifice. The model is based on electrical conductivity measurements in the laboratory, on geophysical information, in particular, magnetotelluric (MT) data, and on petrological and geochemical constraints. Both 1‐D and 3‐D simulations explored the effect of depth, volume and resistivity of either one or two reservoirs in the structure. For each configuration tested, modeled MT transfer functions were compared to field transfer functions from field magnetotelluric studies. The field electrical data are reproduced with a shallow and very conductive layer (∼0.5 km depth, 1.2 km thick, 5 ohm.m resistive) that most likely corresponds to a saline brine present beneath the volcano. Our results are also compatible with the presence of cooling magma batches at shallow depths (<3–4 km depth). The presence of a deeper body at ∼8 km depth, as suggested by seismic studies, is consistent with the observed field transfer functions if such a body has an electrical resistivity > ∼100 ohm.m. According to a petro‐physical conductivity model, such a resistivity value is in agreement either with a low‐temperature, crystal‐rich magma chamber or with a small quantity of hotter magma interconnected in the resistive surrounding carbonates. However, the low quality of MT field data at long periods prevent from placing strong constraints on a potential deep magma reservoir. A comparison with seismic velocity values tends to support the second hypothesis. Our findings would be consistent with a deep structure (8–10 km depth) made of a tephriphonolitic magma at 1000°C, containing 3.5 wt%H2O, 30 vol.% crystals, and interconnected in carbonates in proportions ∼45% melt −55% carbonates.
Role of Antarctic circumpolar wave in modulating the extremes of Indian summer monsoon rainfall
Authors: Prabhu Amita , Mahajan P. N. , Khaladkar R. M. , Chipade M. D.
Published: July 2010

Sea ice extent (SIE) over different sectors of Antarctica displays intra‐seasonal and inter‐annual variability. It is reflected in different atmospheric and oceanic parameters, which are characterized as the manifestation of Antarctic circumpolar wave (ACW). Due to its large areal extent, ACW is linked to the global climate. Another global phenomenon, which is instrumental for the well being of vast population of the Asian sub‐continent, is the Indian summer monsoon season (June–September). The quantum of all India summer monsoon rainfall (AISMR) received during the season decides the overall economic health of the country with the extremes causing disastrous situation, in either way. In the present study, the cases of the excess monsoon and drought years of the recent decades are considered to determine the possible role played by the ACW in influencing the monsoon rainfall. The correlation analyses, carried out for a period of 26 years from 1980 to 2005, show that the SIE over the Bellingshausen and Amundsen Sea Sector (BASS) during the austral summer (October–December) has an inverse relationship with the AISMR of the following year. Further, it is revealed that the sea surface temperature and the upper tropospheric meridional transport of heat over the southeast Pacific, during the period preceding the monsoon season, show contrasting behavior with respect to the extremes of AISMR. These parameters bring out the role of both the oceanic and the atmospheric modes of the ACW in modulating the AISMR. The study has a potential application in forecasting of the monsoon rainfall a few months in advance.
Second-harmonic generation in conjugated polymer films: A sensitive probe of how bulk polymer crystallinity changes with spin speed
Authors: Craig Ian M. , Tassone Christopher J. , Tolbert Sarah H. , Schwartz Benjamin J.
Published: July 2010

In this paper, we examine the second-harmonic generation (SHG) from spin-cast films of the conjugated polymer poly(2-methoxy-5-(2′-ethylhexyloxy)para-phenylenevinylene) (MEH-PPV). We find that the SHG intensity depends strongly on the speed used to spin cast the films. Two-dimensional grazing incidence x-ray diffraction (XRD) experiments show that the bulk crystallinity of the MEH-PPV films varies in the same way with spin speed as the SHG intensity. This strongly suggests that instead of being interface specific, the second-harmonic signal from conjugated polymer films is dominated by the crystalline domains in the bulk. The nonmonotonic dependence of both the SHG intensity and the degree of MEH-PPV crystallinity results from a competition between the shear forces and the solvent evaporation rate during spin coating, which produces a maximum degree of crystallinity for MEH-PPV films spin cast at around 1400 rpm. We also use XRD to show that thermal annealing produces MEH-PPV films with a single degree of bulk crystallinity, independent of how they were originally cast. This allows us to model the angle- and thickness-dependent SHG from annealed MEH-PPV films with a single polarizability tensor. We find that the SHG from MEH-PPV films fits best to a bulk-allowed electric quadrupole mechanism, consistent with the bulk SHG seen in other π-stacked aromatic molecules. Thus, rather than providing information about conjugated polymer interfaces, SHG can be used as a sensitive probe of the local degree of crystallinity in the bulk of conjugated polymer films.
A thermodynamically consistent determination of surface tension of small Lennard-Jones clusters from simulation and theory
Authors: Julin Jan , Napari Ismo , Merikanto Joonas , Vehkamäki Hanna
Published: July 2010

We have determined the surface tension of small Lennard-Jones clusters using molecular dynamics and Monte Carlo simulation methods as well as density functional theory calculations. For the two simulation methods the surface tension is calculated via a rigorous thermodynamic route using simulation data as input. The capillary approximation of the classical nucleation theory, where the surface tension of a planar surface is used for cluster surface, is found to be quite reasonable even when the cluster size is as small as 100–150 atoms. For smaller cluster sizes the cluster surface tension is considerably lower than the planar value. We have also obtained an approximative value for the Tolman length by extrapolating to the planar limit the difference between the equimolar radius and the radius of the surface of tension. A negative Tolman length is suggested by all the methods used.
Dissociation energy of the ground state of NaH
Authors: Huang Hsien-Yu , Lu Tsai-Lien , Whang Thou-Jen , Chang Yung-Yung , Tsai Chin-Chun
Published: July 2010

The dissociation energy of the ground state of NaH was determined by analyzing the observed near dissociation rovibrational levels. These levels were reached by stimulated emission pumping and fluorescence depletion spectroscopy. A total of 114 rovibrational levels in the ranges 9≤v″≤21 and 1≤J″≤14 were assigned to the X Σ1+ state of NaH. The highest vibrational level observed was only about 40 cm−1 from the dissociation limit in the ground state. One quasibound state, above the dissociation limit and confined by the centrifugal barrier, was observed. Determining the vibrational quantum number at dissociation vD from the highest four vibrational levels yielded the dissociation energy De=15 815±5 cm−1. Based on new observations and available data, a set of Dunham coefficients and the rotationless Rydberg–Klein–Rees curve were constructed. The effective potential curve and the quasibound states were discussed.
An efficient density-functional-theory force evaluation for large molecular systems
Authors: Reine Simen , Krapp Andreas , Iozzi Maria Francesca , Bakken Vebjørn , Helgaker Trygve , Pawłowski Filip , Sałek Pawel
Published: July 2010

An efficient, linear-scaling implementation of Kohn–Sham density-functional theory for the calculation of molecular forces for systems containing hundreds of atoms is presented. The density-fitted Coulomb force contribution is calculated in linear time by combining atomic integral screening with the continuous fast multipole method. For higher efficiency and greater simplicity, the near-field Coulomb force contribution is calculated by expanding the solid-harmonic Gaussian basis functions in Hermite rather than Cartesian Gaussians. The efficiency and linear complexity of the molecular-force evaluation is demonstrated by sample calculations and applied to the geometry optimization of a few selected large systems.
Quantum entanglement distribution with 810 nm photons through telecom fibers
Authors: Meyer-Scott E. , Hübel H. , Fedrizzi A. , Erven C. , Weihs G. , Jennewein T.
Published: July 2010

We demonstrate the distribution of polarization entangled photons of wavelength 810 nm through standard telecom fibers. This technique allows quantum communication protocols to be performed over established fiber infrastructure, and makes use of the smaller and better performing setups available around 800 nm, as compared to those which use telecom wavelengths around 1550 nm. We examine the excitation and subsequent quenching of higher-order spatial modes in telecom fibers up to 6 km in length, and perform a distribution of high quality entanglement (visibility 95.6%). Finally, we demonstrate quantum key distribution using entangled 810 nm photons over a 4.4 km long installed telecom fiber link.
Real-time optical system for observing crystallization in levitated silicate melt droplets
Authors: Inatomi Yuko , Srivastava Atul , Satoh Hisao , Maki Takao , Tsukamoto Katsuo
Published: July 2010

In this study, a real-time optical system was developed to observe crystallization in a small spherical melt droplet (few millimeters in diameter) by containerless processing. This system can be used to simultaneously observe the inside and the surface of a transparent melt droplet, as well as its ambient gas atmosphere at high temperatures. A silicate melt with a diameter of ∼2 mm and a composition of MgO:SiO2=48:52 was levitated using a gas-jet levitation system, and its crystallization process was successfully observed from 2385 K in real time with good contrast using the developed optical setup.
Improved photoinduced charge carriers separation in organic-inorganic hybrid photovoltaic devices
Authors: Vaynzof Yana , Kabra Dinesh , Zhao Lihong , Ho Peter K. H. , Wee Andrew T.-S. , Friend Richard H.
Published: July 2010

We demonstrate enhanced performance of a hybrid photovoltaic device, where poly[3-hexylthiophene] (P3HT) is used as active material and a solution-processed thin flat film of ZnO modified by a self-assembled monolayer (SAM) of phenyl-C61-butyric acid (PCBA) is used as electron extracting electrode. Ultraviolet photoemission spectroscopy measurements reveal an increase in the substrate work function from 3.6 to 4.1 eV upon PCBA SAM deposition due to an interfacial dipole pointing away from the ZnO. External quantum efficiency (EQE) of the SAM modified devices reached 9%, greatly improved over the 3% EQE of the unmodified devices. This corresponds to full charge separation of all photoexcitations generated in the P3HT within an exciton diffusion range from the interface.