bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving the preoperative classification of adnexal masses as benign or malignant by second‐stage tests
Authors: Daemen A. , Valentin L. , Fruscio R. , Van Holsbeke C. , Melis G. B. , Guerriero S. , Czekierdowski A. , Jurkovic D. , Ombelet W. , Rossi A. , Vergote I. , Bourne T. , De Moor B. , Timmerman D.
Published: September 2010

Objective

The aim of this study was to establish when a second‐stage diagnostic test may be of value in cases where a primary diagnostic test has given an uncertain diagnosis of the benign or malignant nature of an adnexal mass.

Methods

The diagnostic performance with regard to discrimination between benign and malignant adnexal masses for mathematical models including ultrasound variables and for subjective evaluation of ultrasound findings by an experienced ultrasound examiner was expressed as area under the receiver–operating characteristics curve (AUC), sensitivity and specificity. These were calculated for the total study population of 1938 patients with an adnexal mass as well as for subpopulations defined by the certainty with which the diagnosis of benignity or malignancy was made. The effect of applying a second‐stage test to the tumors where risk estimation was uncertain was determined.

Results

The best mathematical model (LR1) had an AUC of 0.95, sensitivity of 92% and specificity of 84% when applied to all tumors. When model LR1 was applied to the 10% of tumors in which the calculated risk fell closest to the risk cut‐off of the model, the AUC was 0.59, sensitivity 90% and specificity 21%. A strategy where subjective evaluation was used to classify these 10% of tumors for which LR1 performed poorly and where LR1 was used in the other 90% of tumors resulted in a sensitivity of 91% and specificity of 90%. Applying subjective evaluation to all tumors yielded an AUC of 0.95, sensitivity of 90% and specificity of 93%. Sensitivity was 81% and specificity 47% for those patients where the ultrasound examiner was uncertain about the diagnosis (n = 115; 5.9%). No mathematical model performed better than did subjective evaluation among the 115 tumors where the ultrasound examiner was uncertain.

Conclusion

When model LR1 is used as a primary test for discriminating between benign and malignant adnexal masses, the use of subjective evaluation of ultrasound findings by an experienced examiner as a second‐stage test in the 10% of cases for which the model yields a risk of malignancy closest to its risk cut‐off will improve specificity without substantially decreasing sensitivity. However, none of the models tested proved suitable as a second‐stage test in tumors where subjective evaluation yielded an uncertain result. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
Temporal and spatial performance of vector velocity imaging in the human fetal heart
Authors: Matsui H. , Germanakis I. , Kulinskaya E. , Gardiner H. M.
Published: September 2010

Objectives

To assess the spatial and temporal performance of fetal myocardial speckle tracking, using high‐frame‐rate (HFR) storing and Lagrangian strain analysis.

Methods

Dummy electrocardiographic signaling permitted DICOM HFR in 124 normal fetuses and paired low‐frame‐rate (LFR) video storing at 25 Hz in 93 of them. Vector velocity imaging (VVI) tracking co‐ordinates were used to compare time and spatial domain measures. We compared tracking success, Lagrangian strain, peak diastolic velocity and positive strain rate values in HFR vs. LFR video storing. Further comparisons within an HFR subset included Lagrangian vs. natural strain, VVI vs. M‐mode annular displacement, and VVI vs. pulsed‐wave tissue Doppler imaging (TDI) peak velocities.

Results

HFR (average 79.4 Hz) tracking was more successful than LFR (86 vs. 76%, P = 0.024). Lagrangian and natural HFR strain correlated highly (left ventricle (LV): r = 0.883, P < 0.001; right ventricle (RV): r = 0.792, P < 0.001) but natural strain gave 20% lower values, suggesting reduced reliability of measurement. Lagrangian HFR strain was similar in LV and RV and decreased with gestation (P = 0.015 and P < 0.001, respectively). LV Lagrangian LFR strain was significantly lower than the values for the RV (P < 0.001) and those using paired LV‐HFR recordings (P = 0.007). Annular displacement methods correlated highly (LV = 1.046, r = 0.90, P < 0.001; RV = 1.170, r = 0.88, P < 0.001). Early diastolic waves were visible in 95% of TDI, but in only 26% of HFR and 0% of LFR recordings, and HFR‐VVI velocities were significantly lower than those for TDI (P < 0.001).

Conclusions

Doppler estimation of velocities remains superior to VVI but image gating and use of original co‐ordinates should improve offline VVI assessment of fetal myocardial function. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Semi‐automated adjusted measurement of nuchal translucency: feasibility and reproducibility
Authors: Grangé G. , Althuser M. , Fresson J. , Bititi A. , Miyamoto K. , Tsatsaris V. , Morel O.
Published: September 2010

Objective

The variability of nuchal translucency thickness (NT) measurements in the first trimester appears to be associated in part with caliper placement. Methods for obtaining semi‐automated adjusted measurements (SAAMs) can provide several NT values (maximum, minimum, mean and median) automatically within a manually set frame in the zone of interest. This study sought to assess the feasibility and reproducibility of these SAAM‐NTs.

Methods

Three readers, two experts and one less experienced, examined archive images of 160 patients and obtained SAAM‐NTs from them, on two separate occasions. The intra‐ and interobserver reproducibility were assessed by calculating the intraclass correlation coefficients (ICCs) for maximum, mean and median SAAM‐NTs, and Bland–Altman plots were constructed.

Results

SAAM‐NTs were technically feasible for all 160 images. The range of ICCs for intraobserver reproducibility was 0.76–0.93 for mean SAAM‐NT, 0.76–0.95 for median SAAM‐NT and 0.74–0.95 for maximum SAAM‐NT. Interobserver ICCs were 0.85, 0.85 and 0.84 for mean SAAM‐NT, median SAAM‐NT and maximum SAAM‐NT, respectively. There were no significant differences for intra‐ and interobserver reproducibility of median, mean and maximum SAAM‐NTs.

Conclusions

SAAM‐NT is feasible with a high level of intra‐ and interobserver reproducibility. This easy‐to‐use method has the potential to simplify screening during the first trimester. It should be evaluated further and compared with the manual measurement method. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Cardiac function in trisomy 21 fetuses
Authors: Clur S. A. B. , Oude Rengerink K. , Ottenkamp J. , Bilardo C. M.
Published: September 2010

Objectives

Trisomy 21 is associated with an increased nuchal translucency thickness (NT), abnormal ductus venosus (DV) flow at 11–14 weeks' gestation and congenital heart defects (CHD), and cardiac dysfunction has been hypothesized as the link between them. We therefore aimed to investigate whether cardiac function is altered in trisomy 21 fetuses.

Methods

Between December 2003 and June 2009, we performed echocardiography on 46 trisomy 21 fetuses (28 with structurally normal heart and 18 with CHD) and on 191 chromosomally/phenotypically normal fetuses with a confirmed normal heart (87 with normal NT and 104 with NT ≥ 95th percentile), between 11 and 35 weeks' gestation. Measurements included: E‐ and A‐wave peak velocity, E/A velocity ratio and E/time velocity integral (TVI) ratio over atrioventricular valves; myocardial performance index (MPI); semilunar valve peak velocity and acceleration time; stroke volume (SV); cardiac output; and DV pulsatility index for veins (PIV) at 11–14 weeks' gestation. Data were categorized into three different age groups for analysis (11 to 13 + 6, 14 to 21 + 6 and 22 to 35 weeks' gestation).

Results

The tricuspid valve (TV) A‐wave velocity and aortic valve peak velocity were significantly reduced in trisomy 21 compared with normal fetuses. Other highly significant differences found in trisomy 21 fetuses at 11–14 weeks' were increased TV‐E/A ratio and DV‐PIV, and decreased pulmonary valve peak velocity. We also observed evidence of left ventricular (LV) systolic dysfunction, reduced SV and increased MPI. After 14 weeks' gestation, the mitral valve A‐wave peak velocity and E/TVI ratio were significantly reduced in the trisomy 21 fetuses with normal hearts compared with the controls with increased NT.

Conclusions

In comparison with controls with normal or increased NT, cardiac function in trisomy 21 fetuses is abnormal irrespective of the presence of CHD. Evidence for cardiac loading (increased preload and afterload) and LV systolic (in the first trimester) and later diastolic dysfunction was observed. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Paleoclimates: what do we learn from deep ice cores?
Authors: Jouzel Jean , Masson‐Delmotte Valérie
Published: September 2010

Since the early 1960s, the ice core community has produced a wealth of scientific results from a still relatively limited number of deep drilling sites in Greenland and Antarctica with the longest record extending back to the last interglacial in Greenland and covering eight glacial–interglacial cycles in Antarctica. Although measurements performed on the first ice cores, Camp Century and Byrd, largely focused on the isotopic composition of the ice as an indicator of climate change, the number of studied parameters has steadily increased encompassing numerous measurements performed on the entrapped air bubbles, on various impurities as well as on the ice itself. The climatic information provided by these various paleodata time is extremely rich. The relationships between forcing factors and climate, about the importance of carbon cycle feedbacks, about the occurrence of abrupt climate variability, and about the interplay between polar climate, ice sheet dynamics, and sea‐level variations are examples that are highly relevant to future climate change. Copyright © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

Paleoclimates and Current Trends > Paleoclimate
Energy digestibility of giant pandas on bamboo‐only and on supplemented diets
Authors: Finley Tommy G. , Sikes Robert S. , Parsons Jennifer L. , Rude Brian J. , Bissell Heidi A. , Ouellette John R.
Published: September 2010

Endangered giant pandas (Ailuropoda melanoleuca) are bears (Family Ursidae), within the order Carnivora. They specialize on an herbivorous diet of bamboo yet retain a gastrointestinal tract typical of their carnivorous ancestry. The evolutionary constraints of their digestive tract result in a low extraction efficiency from bamboo (<40% in reported studies). The goal of this study was to determine the energy digestibility of bamboo by giant pandas used in digestibility trials and through subsequent analyses with bomb calorimetry. Seven digestibility trials were conducted (three with bamboo‐only diets and four with supplemental diets). Energy digestibilities ranged from 7.5–38.9% for mixed diets and 9.2–34.0% for bamboo‐only diets. The bamboo‐only trials summarized here represent, to our knowledge, the first empirical data available for energy digestibility on a bamboo diet for giant pandas. Zoo Biol 30:121–133, 2011. © 2010 Wiley‐Liss, Inc.
The Public Debate on Clerical Marriage in the Late Eleventh Century
Authors: MELVE LEIDULF
Published: September 2010

The article offers an analysis of the public debate on priestly marriage, conducted in the last decades of the eleventh century. This was the first debate on the subject in six hundred years, erupting in the context of the reform movement. Although the theme of priestly marriage was mentioned in the Carolingian period as well as in the tenth and first half of the eleventh century, it was the anonymous defence of clerical marriage, the Epistola de continentia clericorum, that gave rise to a wide-ranging public debate. The article examines this debate in terms of the argumentative approaches used by the participants, the aim being to emphasise an important undercurrent in the understanding of priestly marriage contrary to the official – or Gratian – view on the issue.
Syed Ahmad and His Two Books Called ‘Asar-al-Sanadid’
Authors: NAIM C. M.
Published: September 2010

The earliest writings of Sir Syed Ahmad Khan (1817–1898), the famous Muslim social reformer and educationist, were in the field of History, including two books on the monuments and history of Delhi that bear the same title, Asar-al-Sanadid. This paper compares the first book, published in 1847, with the second, published in 1854, to discover the author's ambitions for each. How do the two books differ from some of the earlier books of relatively similar nature in Persian and Urdu? How radically different are the two books from each other, and why? How and why were they written, and what particular audiences could the author have had in mind in each instance? How were the two books actually received by the public? And, finally, what changes do the two books reflect in the author's thinking? These are the chief questions that this paper seeks to explore.
What is Christian orthodoxy according to Justin'sDialogue?
Authors: Choi Michael J.
Published: September 2010

This article suggests that Christian orthodoxy according to Justin'sDialoguecan be understood if one considers Justin's christology as stemming not merely from an opposition to Judaism (as Boyarin argues), but rather from the recognition of inadequate soteriology according to rabbinic teachings of Justin's time. This is most clearly delineated in Trypho's response as well as Justin's emphasis on the inclusive salvific efficacy of the crucifixion. Trypho's most enduring objection is not that there is another god explicated by Justin through Logos theology, nor that the Messiah is divine. Trypho resists the Christian message because he is most troubled by Justin's assertion that this Messiah died the death cursed by the Law of Moses.
Habermas and Ratzinger on the Future of Religion
Authors: Welker Michael
Published: September 2010

The article investigates the encounter between Joseph Cardinal Ratzinger and Jürgen Habermas in Munich 2004. The event was widely regarded as a conversation about the topic ‘The Pre-Political Moral Foundations of a Liberal State’. It was praised as a dialogue between the ‘personification of the Catholic faith’ and ‘the personification of liberal, individual and secular thought’ with far-reaching consequences. A close analysis of the texts, however, shows that Ratzinger and Habermas think in quite incompatible frameworks with very different concerns. They both share a sceptical attitude towards scientific ideology and they both show a remarkable lack of cultural and political realism. Habermas assumes that civil-societal elites will transform moral concerns into political and legal power. Ratzinger hopes for a revival of natural law tradition which would overcome the ‘pathologies of reason’ and political and religious fanaticism.
Wastewater use in crop production in peri-urban areas of Addis Ababa: impacts on health in farm households
Authors: WELDESILASSIE ALEBEL B. , BOELEE ELINE , DRECHSEL PAY , DABBERT STEPHAN
Published: September 2010

Using stream water polluted with untreated wastewater in agriculture is controversial due to its combination of benefits and negative health impacts. Using data from a household survey, ‘wastewater’ and ‘freshwater’ farmers were analysed comparatively to examine the perceived impacts of irrigation water quality on farmers' health and to evaluate the extent of health damage. Probability of illness was estimated using the theory of utility-maximising behaviour of households subject to the conventional farm household production model, augmented by adding a health production function. Reduced model and instrumental variable probit specifications both show that perceived illness prevalence is significantly higher for household members working on wastewater irrigation farms than for those working with freshwater. Our data entails econometric complications (e.g., endogeneity of farmers' behaviour, unobserved location-specific characteristics). Ignoring these will result in underestimation of the value of policy interventions designed to reduce potential health damage of wastewater use in irrigation.
The regulation of oestrous cycles in groups of post-pubertal female pigs using allyl-trenbolone
Authors: Varley M. A.
Published: September 2010

Sixty Landrace × Large White gilts were allocated at random to one of three treatments. Treatment A gilts were fed 16 mg allyl-trenbolone once a day for 18 days. Treatment B gilts were fed 20 mg allyl-trenbolone per day for 18 days. Treatment C gilts were controls. The gilts were allocated to treatment at 111·3 ± 1·91 kg live weight, moved to a pen with individual feeders and put into groups of four gilts to a pen with a sexually mature boar in the adjacent pen. Treatment A and B gilts were tested for heat with a boar for 20 min each day beginning on the day after the last allyl-trenbolone feed. Treatment C gilts were tested with a boar in the same way after allocation. The time from the last allyl-trenbolone feed to oestrus for treatments A and B was 7·05 ± 0·44 and 8·4 ± 0·49 days. The time from the beginning of heat detection to oestrus for group C gilts was 22·4 ± 4·5 days. At oestrus, all gilts were mated twice on successive days with a fertile boar. The mean litter size at farrowing for treatment A was 9·1 ± 0·62; B, 11·2 ± 0·75 and C, 9·3 ± 0·65 piglets born alive (P < 0·05). It is concluded that giving 20 mg of allyl-trenbolone for 18 days to groups of peripubertal gilts is a very effective means of controlling oestrus and ovulation.
The effect of selection for altered body weight on the ultrastructural components of skeletal muscle fibres
Authors: Hooper A. C. B. , Hurley M. P.
Published: September 2010

Ultrastructural parameters of muscle growth were measured in lines of mice which had undergone 15 generations of selection for high and low body weight. Previous light microscopic studies of these lines had shown that selection for altered body weight evokes correlated responses in the weight of skeletal muscles as a result of changes in both the number and the longitudinal and transverse dimensions of the fibres.

The length of the myosin filaments and of the actin filaments (including the Z disc) did not differ significantly from the controls in themm. sternomastoideus, biceps brachiiandtibialis anteriorof mature male mice from the two selection lines. The mean cross-sectional area of the myofibrils of themm. sternomastoideusandbiceps brachiiwere also unaltered by selection for high and low body weight. Changes in the area of the fibres were brought about by increases and decreases in the number of their constituent myofibrils and corresponding changes in the non-contractile elements.

Selection for high and low body weight did not affect the dimensions of the contractile elements of the muscle fibres. The genetically determined alterations in the length and cross-sectional area of the fibres were due to changes in the number of their constituent sarcomeres and myofibrils. These changes are similar to those which occur during growth.
Treatment of barley straw with urea or anhydrous ammonia for growing cattle
Authors: Mira J. J. F. , Kay M. , Hunter E. A.
Published: September 2010

In experiment 1, nine Hereford × Friesian steers weighing 325 kg were used in a changeover design and offered long barley straw that had been treated with 30 g anhydrous ammonia per kg for 8 weeks, a solution providing 25 g urea per kg straw dry matter or a solution providing 23 g urea and 3 g ammonium sulphate per kg straw dry matter. In addition they were offered 3 kg/day of mineralized rolled barley. In experiment 2, 30 Hereford × Friesian steers weighing 380 kg were used in a continuous growth trial of 10 weeks duration. They were allocated to one of the following barley straw treatments, straw that had been exposed to 30 g anhydrous ammonia per kg for 4 weeks, untreated straw with a urea supplement in the barley or untreated straw. The straw was fed ad libitum with either 2·8 or 4·4 kg rolled barley daily.

The barley straw contained 43 and 27 g crude protein per kg dry matter in experiment 1 and 2 respectively. In both experiments, ammonia treatment increased the crude protein content of the straw and resulted in improved straw intakes and higher live-weight gains. The results of experiment 2 cast doubt on the practice of providing supplementary nitrogen with food based on long barley straw and barley when steers weighing about 400 kg are used.
Usefulness of some components of the lactation curve for selection in Murrah buffaloes
Authors: Cheema J. S. , Basu S. B.
Published: September 2010

The study was based on 1156 lactation records of 545 Murrah buffaloes. Initial milk yield, peak yield, ascending phase milk yield and days to attain peak daily production, the means of which were 26·7 kg, 10·3 kg, 407 kg and 58·9 days respectively, were all affected by period, season and parity of calving. Heifers recorded the least initial milk yield and peak yield and took the longest time to reach peak production. Peak yield was the most important single factor (R2 = 0·41) in causing variation in 43-week milk yield. The heritability estimates for initial, peak and ascending phase milk yields and days to attain peak yield were 0·35, 0·51, 0·27 and 0·13 respectively, whilst that for 43-week milk yield was 0·18. Peak yield had the highest phenotypic (rP = 0·64) and genetic correlations (ra = 0·68 ± 0·19) with the 43-week milk yield. Other genetic correlations with the 43-week milk yield were low and non-significant. The results indicated that indirect selection for peak yield would be more effective than direct selection for improving the 43-week milk yield in buffaloes.
A note on the concentration of energy in the milk of Friesian and Jersey cows
Authors: Grainger C. , Holmes C. W. , Bryant A. M. , Moore Y.
Published: September 2010

The relations between the gross energy concentration of milk and its concentration of fat and protein were calculated for samples of Jersey and Friesian milk. Stage of lactation and level of feeding had no consistent effects on the relations.

The calculated equations can be used to predict the energy concentrations of milk from Jersey or Friesian cows fed on pasture, from the concentrations of fat alone or from the concentrations of fat and protein. The predicted values agree with those predicted by earlier published equations.
A note on the assessment of down production in Australian ‘cashmere’ goats
Authors: Couchman R. C. , McGregor B. A.
Published: September 2010

Down production of 93 feral, F1 and F2 cashmere-producing goats run in Victoria was investigated. The goats were visually assessed for down production and shorn. Their fleeces were evaluated for total fibre, down yield, fibre diameter, grease and moisture content. Analyses on down yield and fleece characteristics indicated that they compared favourably with those of traditional cashmere-producing countries. Mean down production ranged from 330 g for males to 148 g for females. Sampling at three body sites was accurate in determining total fleece measures and visual assessment proved a reliable screening technique for on-farm selection. Large variation was found in down production indicating the possibility of rapid genetic gain through selection.
The Audacity of Justice: Recession, Redundancy, Rights and Legal Aid
Authors: Pleasence Pascoe , Balmer Nigel J.
Published: September 2010

The 2008 recession presents a double challenge to legal aid. Unemployment extends legal aid eligibility. It is also associated with increased vulnerability to problems involving legal rights, feeding demand for legal services. Job loss, as distinct from unemployment, might be expected to increase vulnerability further still. In this paper, we set out findings from a first analysis of the relationship between job loss and the experience of rights problems. In the context of the current recession, we set out the likely scale of the recession's impact on the incidence of rights problems and demand for legal (and legal aid) services.
Investing in Children, Regulating Parents, Thinking Family: A Decade of Tensions and Contradictions
Authors: Morris Kate , Featherstone Brid
Published: September 2010

This article describes the contested and underdeveloped backdrop to ‘“whole family” approaches’, whereby families with care and protection needs are caught in a conflicting set of policy and practice expectations concerning responsibility to care whilst being positioned as families that fail. Questions are raised about how supported families are to navigate their way through these permissive and punitive policies and practices. We suggest that there is an urgent need for more ‘bottom–up’ research informed by the ethic of care to develop the kinds of policies and practices that might make it more possible for them to do so.
Parent Abuse: Opening Up a Discussion of a Complex Instance of Family Power Relations
Authors: Tew Jerry , Nixon Judy
Published: September 2010

In the UK, the issue of parent abuse remains an unacknowledged and under-researched form of family violence receiving little recognition within social policy and professional practice. This may in part be due to the way it transgresses conventional notions of family power relations in which children are seen as potential victims but not as perpetrators. In this paper, we develop a framework for analysing the complexity of family power relations and explore how these may inform the context in which parent abuse and victimisation occurs. This may help to inform constructive policy and practice responses to this issue.
Reliabilität und Validität des Wender-Reimherr-Interviews (WRI)
Authors: Corbisiero Salvatore , Buchli-Kammermann Jacqueline , Stieglitz Rolf-Dieter
Published: September 2010

Grundlage der Diagnostik der ADHS (Aufmerksamkeitsdefizit-/Hyperaktivitätsstörung) im Erwachsenenalter ist in der Regel die DSM-IV- oder ICD-10-Klassifikation. Für die Psychopathologie der Erwachsenen sind diese Systeme nur bedingt geeignet. Die Utah-Kriterien, die mit dem Wender-Reimher-Interview (WRI) erfasst werden können, beziehen sich explizit auf das Erwachsenenalter. Ziel der vorliegenden Studie war, die psychometrischen Charakteristiken sowie die Verteilung und Kombination der sieben Bereiche des WRI zu untersuchen und zudem einen Vergleich mit anderen Selbst- und Fremdbeurteilungsverfahren der ADHS-Diagnostik zu ziehen. Die Skalenhomogenität des WRI lag mit einem Cronbachs α von .88 hoch. Die Interrater-Reliabilität lag auf Itemebene zwischen .45 und .95. Hohe Korrelationen mit anderen Instrumenten bestätigten die konvergente Validität des Interviews. Das WRI erwies sich als ein reliables und valides Instrument, das über das dreidimensionale Modell der ADHS Unaufmerksamkeit, Hyperaktivität und Impulsivität hinausgeht und dabei die Symptomatik der erwachsenen ADHS-Patienten besser berücksichtigt.
Unusually large magmatic CO2 gas emissions prior to a basaltic paroxysm
Authors: Aiuppa Alessandro , Burton Mike , Caltabiano Tommaso , Giudice Gaetano , Guerrieri Sergio , Liuzzo Marco , Murè Filippo , Salerno Giuseppe
Published: September 2010

The low‐intensity activity of basaltic volcanoes is occasionally interrupted by short‐lived but energetic explosions which, whilst frequently observed, are amongst the most enigmatic volcanic events in Nature. The combination of poorly understood and deep, challenging to measure, source processes make such events currently impossible to forecast. Here we report increases in quiescent degassing CO2 emissions (>10,000 t/day) prior to a powerful explosive event on Stromboli volcano on 15 March 2007. We interpret such large CO2 flux as being sourced by passive gas leakage from a deeply (>4 km) stored magma, whose depressurization, possibly caused by the onset of an effusive eruption on 28 February 2007, was the explosion trigger. Our observations suggest that continuous CO2 flux monitoring may allow anomalously large explosions to be accurately forecast at basaltic volcanoes.
Role of the RNA/DNA kinase Grc3 in transcription termination by RNA polymerase I
Authors: Braglia Priscilla , Heindl Katrin , Schleiffer Alexander , Martinez Javier , Proudfoot Nick J
Published: September 2010

Transcription termination by RNA polymerase I in Saccharomyces cerevisiae is mediated by a ‘torpedo’ mechanism: co‐transcriptional RNA cleavage by Rnt1 at the ribosomal DNA 3′‐region generates a 5′‐end that is recognized by the 5′–3′ exonuclease Rat1; this degrades the downstream transcript and eventually causes termination. In this study, we identify Grc3 as a new factor involved in this process. We demonstrate that GRC3, an essential gene of previously unknown function, encodes a polynucleotide kinase that is required for efficient termination by RNA polymerase I. We propose that it controls the phosphorylation status of the downstream Rnt1 cleavage product and thereby regulates its accessibility to the torpedo Rat1.
Functional dissection of the N-terminal degron of human thymidylate synthase
Authors: Melo Sandra P. , Yoshida Asami , Berger Franklin G.
Published: September 2010

Human thymidylate synthase (hTS; EC 2.1.1.45) is one of a small group of proteasomal substrates whose intracellular degradation occurs in a ubiquitin-independent manner. Previous studies have shown that proteolytic breakdown of the hTS polypeptide is directed by an intrinsically disordered 27-residue domain at the N-terminal end of the molecule. This domain, in co-operation with an α-helix spanning amino acids 31–45, functions as a degron, in that it has the ability to destabilize a heterologous polypeptide to which it is attached. In the present study, we provide evidence indicating that it is the 26S isoform of the proteasome that is responsible for intracellular degradation of the hTS polypeptide. In addition, we have used targeted in vitro mutagenesis to show that an Arg–Arg motif at residues 10–11 is required for proteolysis, an observation that was confirmed by functional analysis of the TS N-terminus from other mammalian species. The effects of stabilizing mutations on hTS degradation are maintained when the enzyme is provided with an alternative means of proteasome association; thus such mutations perturb one or more post-docking steps in the degradation pathway. Surprisingly, deletion mutants missing large segments of the disordered domain still function as proteasomal substrates; however, degradation of such mutants occurs by a mechanism that is distinct from that for the wild-type protein. Taken together, our results provide information on the roles of specific subregions within the intrinsically disordered N-terminal domain of hTS in regulation of degradation, leading to a deeper understanding of mechanisms underlying the ubiquitin-independent proteasomal degradation pathway.
Aberrant methylation of hMLH1 and p16INK4a in Tunisian patients with sporadic colorectal adenocarcinoma
Authors: Miladi-Abdennadher Imen , Abdelmaksoud-Damak Rania , Ayadi Lobna , Khabir Abdelmajid , Frikha Foued , Kallel Lamia , Frikha Mounir , Sellami-Boudawara Tahia , Gargouri Ali , Mokdad-Gargouri Raja
Published: September 2010

The methylation of CpG islands in the promoters is associated with loss of protein via repression of gene transcription. Several studies have demonstrated that tumour suppressor and DNA repair genes are often aberrantly hypermethylated in colorectal cancer. The present study was conducted to examine whether the methylation profile of p16INK4a and hMLH1 (human mutL homologue 1) promoters was associated with clinical features and patients’ survival in CRC (colorectal carcinoma). Aberrant methylation of p16INK4a and hMLH1 promoters was found in 47.2 and 53.4% of tumours respectively. For adjacent non-tumoral mucosa, p16INK4a was fully unmethylated in 30% of the cases, whereas hMLH1 was predominantly unmethylated (76%). Methylation of p16INK4a correlated with gender and tumour size (P=0.005 and 0.035 respectively), whereas those of hMLH1 significantly correlated with overall survival (P log rank = 0.007). Concomitant methylation of p16INK4a and hMLH1 was associated with TNM (tumour, lymph node and metastases) stage and tumour size (P=0.024 and 0.021 respectively). Our data show that loss of hMLH1 expression through aberrant methylation could be used as a marker of poor prognosis in CRC.
Curcumin regulates miR-21 expression and inhibits invasion and metastasis in colorectal cancer
Authors: Mudduluru Giridhar , George-William Jonahunnatha N. , Muppala Santoshi , Asangani Irfan A. , Kumarswamy Regalla , Nelson Laura D. , Allgayer Heike
Published: September 2010

Curcumin has promising potential in cancer prevention and therapy by interacting with proteins and modifying their expression and activity, which includes transcription factors, inflammatory cytokines and factors of cell survival, proliferation and angiogenesis. miR-21 is overexpressed in many tumours, promoting progression and metastasis. In the present study, we examined the potential of curcumin to regulate miR-21, tumour growth, invasion and in vivo metastasis in colorectal cancer. In Rko and HCT116 cells, we identified two new transcriptional start sites of the miR-21 gene and delineated its promoter region. PMA stimulation induced miR-21 expression via motifs bound with AP-1 (activator protein 1) transcription factors. Curcumin treatment reduced miR-21 promoter activity and expression in a dose-dependent manner by inhibiting AP-1 binding to the promoter, and induced the expression of the tumour suppressor Pdcd4 (programmed cell death protein 4), which is a target of miR-21. Curcumin-treated Rko and HCT116 cells were arrested in the G2/M phase with increasing concentrations. Furthermore, curcumin inhibited tumour growth, invasion and in vivo metastasis in the chicken-embryo-metastasis assay [CAM (chorionallantoic membrane) assay]. Additionally, curcumin significantly inhibited miR-21 expression in primary tumours generated in vivo in the CAM assay by Rko and HCT116 cells (P<0.00006 and P<0.035 respectively). Taken together, this is the first paper to show that curcumin inhibits the transcriptional regulation of miR-21 via AP-1, suppresses cell proliferation, tumour growth, invasion and in vivo metastasis, and stabilizes the expression of the tumour suppressor Pdcd4 in colorectal cancer.
Light scattering from human corneal grafts: Bulk and surface contribution
Authors: Latour Gaël , Georges Gaëlle , Lamoine Laure Siozade , Deumié Carole , Conrath John , Hoffart Louis
Published: September 2010

The cornea is the only transparent tissue in the body. The transparency is the main characteristic of the corneal tissue, and depends not only on the transmission coefficient but also on the losses by scattering and absorption. The scattering properties of the cornea tissues become one of the most important parameters in the case of the corneal graft. These scattering properties are studied in this paper in the reflected half area, similar to the diagnosis configuration. We quantify the influence of the cornea thickness and of the epithelial layer on scattering level. The technique of ellipsometry on scattered field is also used to analyze the polarization properties in order to determine the origin of scattering (surface and/or bulk).
On the interplay between quantum confinement and dielectric mismatch in high-k based quantum wells
Authors: Pereira T. A. S. , de Sousa J. S. , Freire J. A. K. , Farias G. A.
Published: September 2010

In this work we investigate the confinement properties of quantum systems with high dielectric mismatch between barriers and quantum well layers, focusing on the role of image charges. We demonstrate that the combination of high dielectric mismatch, band offset, and carrier’s effective mass strongly modifies the electronic and optical properties of those systems in such a way that the ideal confinement model is no longer suitable.
Au/Fe/Au multilayer transducers for magneto-optic surface plasmon resonance sensing
Authors: Regatos D. , Fariña D. , Calle A. , Cebollada A. , Sepúlveda B. , Armelles G. , Lechuga L. M.
Published: September 2010

In this paper, we analyze the magnetoplasmonic (MP) features and sensing capabilities of Au/Fe/Au trilayer structures, as transducers of the magneto-optic surface plasmon resonance (MOSPR) biosensor. This biosensor, which can surpass the sensitivity of the standard SPR sensor, is based on a MP modulation technique generated by the simultaneous stimulation of the surface plasmon polaritons (SPP) and the transversal magneto-optical Kerr effect (TMOKE). We study the magneto-optical activity of the trilayers as a function of the thickness and position of the Fe layer. We first demonstrate that this kind of structure allows modulating the SPP through an external magnetic field and moreover, induce a strong enhancement of the TMOKE effect. The modulation of the SPP is linearly proportional to the thickness of Fe layer and inversely proportional to the distance between the Fe layer and the external dielectric medium. Finally, we experimentally confirm a twofold increase in the MOSPR sensitivity with respect to the intensity-interrogated SPR biosensor in bulk refractive-index changes, keeping a similar chemical resistance and stability, unprecedented in other MP transducers, and biofunctionalization protocols.
Application of the cBΩ model for the calculation of oxygen self-diffusion coefficients in minerals
Authors: Zhang Baohua , Wu Xiaoping , Xu Junshan , Zhou Rulong
Published: September 2010

The cBΩ model, which suggests the defect Gibbs energy is proportional to the isothermal bulk modulus and the mean volume per atom, is first introduced to predict self-diffusion coefficients of oxygen in various silicate and oxide minerals in terms of available elastic data. We develop a new approach to determine constant c in the cBΩ model on the basis of the observed compensation effect between the activation energies and pre-exponential factors, which is critical to the diffusivity prediction. Under anhydrous conditions, the validity of this model is tested by the experimentally determined oxygen self-diffusion coefficients. Our results show that the absolute oxygen diffusion rates derived from the cBΩ model are in agreement with experimental data in a variety of rock-forming minerals including olivine, MgSiO3 perovskite, spinel, and zircon.
Bulk acoustic wave delay line in acoustic superlattice
Authors: Yin Ruo-Cheng , Yu Si-Yuan , He Cheng , Lu Ming-Hui , Chen Yan-Feng
Published: September 2010

The bulk acoustic wave delay lines are demonstrated both theoretically and experimentally based on the acoustic superlattices. In one bulk acoustic wave delay line, two collinear acoustic superlattices are separately located, where the generation and detection of the bulk acoustic waves are executed, respectively. A basic bulk acoustic wave delay line working at 819 MHz with the delay time of 2.46 μs was realized. Furthermore, by employing two enantiomorphous aperiodic acoustic superlattices, a broadband dispersive bulk acoustic wave delay line with the center frequency at 295 MHz has also been fabricated and investigated.
First-principles studies of interlayer exchange coupling in (Ga, Mn)As-based diluted magnetic semiconductor multilayers
Authors: Luo M. , Tang Z. , Zheng J. , Zhu Z. Q. , Chu J. H.
Published: September 2010

Interlayer exchange coupling (IEC) in a series model diluted magnetic semiconductor multilayers consisting of two magnetic (Ga, Mn)As layers separated by nondoped or Be-doped GaAs nonmagnetic spacers is studied by first-principles calculations. For the GaAs spacers without Be doping, the IEC is always ferromagnetic and is well described by the Ruderman–Kittle–Kasuya–Yoshida interaction based on a two-band model for a gaped system. For the Be-doped GaAs spacers, the IEC is found to be tunable and the antiferromagnetic IEC is achieved via Be-doping in the interfaces between the (Ga, Mn)As layers and the spacers.
Structure determination in 55-atom Li–Na and Na–K nanoalloys
Authors: Aguado Andrés , López José M.
Published: September 2010

The structure of 55-atom Li–Na and Na–K nanoalloys is determined through combined empirical potential (EP) and density functional theory (DFT) calculations. The potential energy surface generated by the EP model is extensively sampled by using the basin hopping technique, and a wide diversity of structural motifs is reoptimized at the DFT level. A composition comparison technique is applied at the DFT level in order to make a final refinement of the global minimum structures. For dilute concentrations of one of the alkali atoms, the structure of the pure metal cluster, namely, a perfect Mackay icosahedron, remains stable, with the minority component atoms entering the host cluster as substitutional impurities. At intermediate concentrations, the nanoalloys adopt instead a core-shell polyicosahedral (p-Ih) packing, where the element with smaller atomic size and larger cohesive energy segregates to the cluster core. The p-Ih structures show a marked prolate deformation, in agreement with the predictions of jelliumlike models. The electronic preference for a prolate cluster shape, which is frustrated in the 55-atom pure clusters due to the icosahedral geometrical shell closing, is therefore realized only in the 55-atom nanoalloys. An analysis of the electronic densities of states suggests that photoelectron spectroscopy would be a sufficiently sensitive technique to assess the structures of nanoalloys with fixed size and varying compositions.
On the role of fluctuations, cathode placement, and collisions on the transport of electrons in the near-field of Hall thrusters
Authors: Smith A. W. , Cappelli M. A.
Published: September 2010

The performance of Hall thrusters can be highly sensitive to the position and operational parameters of the external cathode, hinting that the electron transport in the near-field is strongly dependent on the emitted electrons’ initial properties. In addition, the plasma plumes of Hall discharges often exhibit fluctuations which are expected to alter electron trajectories. By implementing recent near-field plasma potential measurements made on a low-power Hall thruster in 3D electron-trajectory simulations, it is shown that electron transport from the external cathode to the thruster channel is strongly sensitive to cathode parameters including position, orientation, and electron emission divergence. Periodic, low-frequency (i.e., 25 kHz) plasma potential fluctuations reduce electron transport to the channel of the thruster by more than 65% compared to the transport achieved with static 3D fields and substantially homogenize the electron density distribution. Additional gas-phase collisions are found to have only marginal effects, even when prescribed to occur at exaggerated rates (reaching 10 MHz). The three-dimensionality of the E and B fields, together with electron-wall collisions, appear to be important drivers of cross-field transport in this region of the discharge, yielding sufficient levels of electron transport to the channel without invoking plasma turbulence.
Temperature dependence of energies and broadening parameters of near band edge interband excitonic transitions in wurtzite ZnCdMgSe
Authors: Dumcenco D. O. , Huang Y. S. , Hsu H. P. , Tiong K. K. , Firszt F. , Strzałkowski K. , Łęgowski S. , Męczyńska H.
Published: September 2010

An optical characterization of two wurtzite ZnCdMgSe crystalline alloys grown by the modified high-pressure Bridgman method was carried out by temperature-dependent photoluminescence (PL) and contactless electroreflectance (CER) in the temperature range of 10–300 K and photoreflectance (PR) measurements between 300–400 K. Low temperature PL spectra of the investigated samples consisted of the excitonic line, the “edge-emission” due to radiative recombination of shallow donor-acceptor pairs and a broad band related to recombination through deep level defects. Three excitonic features, A, B, and C, in the vicinity of band edge were observed in the CER and PR spectra. The peak positions of band edge excitonic features in the PL spectra were shifted slightly toward lower energies as compared to the lowest corresponding transition energies of A exciton determined from CER and PR data. The increase in the CER-PL shift with the increasing of Mg content in the investigated crystals was explained by the rising of compositional disorder causing the smearing of the band edge energies. In addition, the parameters that describe the temperature dependence of the transition energies and broadening parameters of the band edge excitonic transitions were evaluated and discussed.
Electron and impurity states in GaN/AlGaN coupled quantum dots: Effects of electric field and hydrostatic pressure
Authors: Xia Congxin , Zeng Zaiping , Wei Shuyi
Published: September 2010

Based on the effective mass approximation, the ground-state donor binding energy of impurity located at the surface of the zinc-blende (ZB) GaN/AlGaN symmetric coupled quantum dots (SCQDs) is investigated variationally, considering the combined effects of the electric field to the right (along the growth direction) and the hydrostatic pressure. Numerical results show that the impurity localized inside the left dot, the donor binding energy is insensitive to the middle barrier width of the ZB GaN/AlGaN SCQDs if the middle barrier width is large. While the hydrostatic pressure increases the donor binding energy for any electric field and impurity position. Moreover, the hydrostatic pressure has a remarkable influence on the donor binding energy of impurity localized inside left dot. In addition, the competition effects between the electric field and hydrostatic pressure (between the electric field and quantum confinement) on the donor impurity states in the ZB GaN/AlGaN SCQDs have also been investigated in detail, which may be very interesting to understand the impurity states in semiconducting nanostructures.
Plasma shaping effects on the geodesic acoustic mode in the large orbit drift width limit
Authors: Gao Zhe
Published: September 2010

Plasma shaping effects on the geodesic acoustic mode (GAM) are revisited analytically in the large orbit drift width limit. Comparing with results from the small orbit drift width expansion method [Z. Gao et al., Phys. Plasmas 15, 074502 (2008)] the behavior of the real frequency is almost the same but the effect on the damping rate is different due to the change of dominant resonant mechanism, from low order harmonic transit resonance to high order harmonic resonance, or equivalently, to the magnetic drift resonance. As a result, although the GAM frequency decreases with an increasing elongation κ by dependence of [2/(κ2+1)]1/2, the damping is weakened mildly in the large orbit drift width limit, which is quite different from the result in the low small orbit drift limit, where the damping is enhanced exponentially with the decrease in frequency. Also, in the large orbit drift width limit, the dependence of the GAM damping rate on inverse aspect ratio ε is analytically obtained for the first time. As ε increases, the frequency behaves as a weakly decreasing parabola function of ε, and the damping rate increases parabolically, but more rapidly than the frequency decreases. The GAM with longer radial wavelength is more easily damped by the finite aspect ratio effect. It is also found that the Shafranov shift gradient has the similar effect as the inverse aspect ratio.
Phenomenological theory of bistability in polariton diodes
Authors: Bajoni Daniele , Semenova Elizaveta , Lemaître Aristide , Barbay Sylvain , Kuszelewicz Robert , Bloch Jacqueline
Published: September 2010

Polariton diodes have been recently shown to exhibit pronounced bistability induced by the control of the light-matter coupling via an external bias and optical pumping [D. Bajoni, E. Semenova, A. Lemaître, S. Bouchoule, E. Wertz, P. Senellart, S. Barbay, R. Kuszelewicz, and J. Bloch, Phys. Rev. Lett. 101, 266402 (2008)]. In the present paper, we detail the phenomenological theory developed to describe the observed hysteresis cycles and present additional experimental data confirming the validity of the present model.