bluuebunny/crossref_metadata_2025 huggingface dataset:
Measuring engagement of the fetal head: validity and reproducibility of a new ultrasound technique
Authors: Dietz H. P. , Lanzarone V.
Published: November 2004

Objective

Fetal head engagement can be assessed by translabial ultrasound and has been shown to be predictive of delivery mode. We attempted to validate the technique by comparing ultrasound with abdominal and vaginal palpation. Reproducibility was tested in a blinded test–retest series.

Methods

In a prospective clinical study, 139 nulliparous women between 35 + 3 and 40 + 4 weeks' gestation were assessed by translabial ultrasound, abdominal palpation of the fetal head (n = 139) and vaginal examination (n = 112). Ultrasound was performed using two methods, with the symphysis pubis as reference. A test–retest series was performed in 90 women.

Results

Ultrasound of head engagement correlated strongly with abdominal palpation, full Bishop scores and vaginal assessment (all P < 0.001 for Kendall's tau‐b). Intraclass correlation coefficients (n = 90) for the two methods were 0.75 and 0.92, signifying excellent interobserver agreement. Reproducibility was higher for the method using the central symphyseal axis as reference.

Conclusion

Quantitation of head engagement by translabial ultrasound is highly reproducible and correlates strongly with clinical measures of head engagement. We are now undertaking a prospective study to assess the predictive value of this new parameter for intrapartum events. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.
The short‐term effect of nifedipine tocolysis on placental, fetal cerebral and atrioventricular Doppler waveforms
Authors: Guclu S. , Saygili U. , Dogan E. , Demir N. , Baschat A. A.
Published: November 2004

Objective

To evaluate the effect of nifedipine on placental and fetal middle cerebral and atrioventricular Doppler waveforms.

Methods

Doppler waveforms of uterine (UtA), umbilical (UA) and middle cerebral (MCA) arteries and both atrioventricular valves were measured from 21 pregnant women/fetuses prior to and during nifedipine therapy for preterm labor. Maternal and fetal heart rates (FHR), maternal systolic and diastolic blood pressure, the Doppler pulsatility index and systolic/diastolic ratio of the UtA, UA and MCA were measured. The total time velocity integrals (TVI) of tricuspid and mitral valves and their E‐wave/A‐wave (E/A) TVI ratios were measured. Wilcoxon signed pairs test was used to compare the differences in Doppler parameters before and at 3 h after nifedipine loading up to a maximum dose of 40 mg.

Results

Fetal arterial and UtA Doppler parameters were not different before and after nifedipine therapy. Blood flow across the atrioventricular valves and the TVI were equally unaffected by nifedipine. The TVI × FHR product was also unchanged following nifedipine therapy.

Conclusions

In women with otherwise uncomplicated pregnancies, nifedipine loading and tocolysis are generally well tolerated by the mother. Placental and fetal cerebral arterial blood flow, fetal systolic and diastolic cardiac function and downstream distribution of fetal cardiac output are unaffected by nifedipine loading. These results apply to women with unchanged vital parameters. Further studies are necessary to show long‐term effects of nifedipine therapy and may help to refine choice of tocolytic agents. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.
Evaluation of interference due to UWB hot spot on fixed wireless access systems
Authors: Giuliano Romeo , Guidoni Gianluca , Habib Ibrahim , Mazzenga Franco
Published: November 2004

Ultra Wide Bandwidth (UWB) techniques are getting an increased importance due to their many features such as high bit rates availability, low power consumption and location capabilities. UWB technology enables the development of advanced wireless local area networks providing integrated multimedia services to nomadic users over hot‐spot areas. The assessment of the possible interference caused by UWB devices on already existing narrowband and wideband systems is fundamental to ensure not‐conflicting coexistence and, therefore, the acceptance of UWB technology worldwide. In this paper we analyze coexistence between an indoor UWB system and an outdoor fixed wireless access (FWA) system operating in the 3.5–5.0 GHz band. We consider a realistic UWB master/slave system architecture using pulse amplitude modulated spread spectrum signals for multiple access and we evaluate the UWB system interfering power in the FWA band accounting for the UWB power spectrum shape. Both upstream and downstream communication directions are analyzed. We show through computer simulation, that in many practical cases UWB system can coexist with FWA without causing any dangerous interference. Copyright © 2004 John Wiley & Sons, Ltd.
Uncertainty and traceability in alloy analysis by borate fusion and XRF
Authors: Sieber John R. , Yu Lee L. , Marlow Anthony F. , Butler Theresa A.
Published: November 2004

Owing to the increasing demand for compliance with quality system standards, analytical laboratories may need to demonstrate the traceability of their results to the International System of Units (SI) or to the values of a certified reference material. To do that, they need to demonstrate the components of uncertainty in their analytical work. At NIST, the goal is to demonstrate traceability to SI units to ensure that results are accepted on a worldwide basis. For XRF spectrometry with borate fusion, traceability to SI is achieved through calibration with spectrometric solution standards or high‐purity compounds. The method is capable of achieving relative expanded uncertainty estimates (95% confidence level) of 1% or lower. In this paper, the capability is demonstrated for low alloy‐steel and an AlTiNbW aerospace alloy. XRF results are compared with certified values and with results from atomic emission methods through a simple bias test. NIST uses the borate fusion/XRF method as part of the value assignment process for Standard Reference Materials®. Copyright © 2004 John Wiley & Sons, Ltd.
The effect of aspirin on the ventilatory response to exercise in chronic heart failure
Authors: Witte Klaus K.A. , Clark Andrew L.
Published: November 2004

Introduction:

Patients with chronic heart failure (CHF) experience breathlessness and fatigue on exercise. One of the abnormalities seen on maximal exercise testing is an increased ventilatory response to exercise (Ve/Vco2 slope). The cause of this is unknown, but is likely to be due to a combination of interacting peripheral and central factors. Recent data have demonstrated a relation between Ve/Vco2 slope and prostaglandin levels in contracting muscles. The present study examined the influence of the presence of a potent non‐selective prostaglandin inhibitor, aspirin, on the ventilatory response to exercise in a group of patients with CHF.

Methods:

We investigated the ventilatory response to exercise of 120 consecutive patients in sinus rhythm attending a specialist heart failure clinic. We excluded those taking clopidogrel (six patients) and those on both warfarin and aspirin or taking other non‐steroidal anti‐inflammatory agents (five patients). The other 109 patients were grouped according to whether they were taking aspirin (n=52 (48%)) or not (n=57 (52%)). Each patient underwent echocardiography to assess left ventricular function, and exercise testing with metabolic gas exchange to derive peak oxygen consumption (pVo2) and the Ve/Vco2 slope.

Results:

The groups were similar in terms of age, (67 (13) vs. 66 (12) years; P=0.34) drug use, heart failure aetiology, left ventricular function (ejection fraction; 33.3 (9.4) vs. 31.8 (9.9)%; P=0.05)) and exercise tolerance (pVo2; 20.4 (5.3) vs. 19.9 (6.0); P=0.68, and Ve/Vco2 slope; 35.4 (6.2) vs. 35.7 (9.3); P=0.73). There was no difference in the ventilatory response to exercise or the symptoms of breathlessness between the two groups.

Conclusions:

Aspirin does not appear to affect exercise performance in CHF.
Clinico‐pathological evaluation of restrictive cardiomyopathy (endomyocardial fibrosis and idiopathic restrictive cardiomyopathy) in India
Authors: Seth Sandeep , Thatai Deepak , Sharma Sanjeev , Chopra Prem , Talwar K.K.
Published: November 2004

Background:

Restrictive heart disease is characterized by impairment of ventricular filling during diastole with preserved systolic function. The clinical and histopathological profile on endomyocardial biopsy of a cohort of patients with restrictive cardiomyopathy (RCM) is presented.

Methodology:

The medical records of patients presenting with heart failure with systemic congestion, subsequently diagnosed as restrictive heart disease after evaluation including cardiac catheterisation, were studied retrospectively to determine the clinical spectrum of restrictive cardiomyopathy. The diagnosis of RCM was made, based on systemic congestion with dilated atria and near normal ventricular size and function. Only patients who had an endomyocardial biopsy were included in the study. Patients with chronic constrictive pericarditis and secondary restrictive heart disease mainly amyloidosis were excluded from the study.

Results:

All 52 patients had heart failure with normal or near normal left ventricular size and function. Based on right and left ventricle angiography, patients were classified into two groups. Group I with findings suggestive of EMF (n=30) and Group II no evidence of EMF on angiography i.e. ‘idiopathic RCM’ (IRCM) (n=22). Baseline characteristics were similar in the two groups. Echocardiography revealed typical features of endomyocardial fibrosis in Group I patients, with apical obliteration of right and left ventricular apices. Group II patients had no apex obliteration (except in four patients, who were misclassified and in whom angiography did not show apex obliteration). The Group II patients had features of IRCM in the form of normal left and right ventricular size and function with restrictive features of doppler filling along with dilated left and right atria. Angiocardiography in EMF patients showed isolated RV involvement in only two patients. In the remaining 28 patients, the obliterative changes were biventricular with RV involvement more severe than LV involvement. Angiographic findings in Group II (IRCM) patients were unremarkable with preservation of normal trabecular pattern and absence of obliterative changes. Mild atrioventricular regurgitation was present in 10/22 patients. Histopathological examination revealed that endocardial thickening was more common (77% vs. 23%) in EMF patients. The presence of myocyte hypertrophy (70–80%), myocytolysis (40–50%) and interstitial fibrosis (46–56%) were similar in both groups.

Conclusions:

The majority of our patients had biventricular EMF. A significant number of patients had clinical hemodynamic features of restrictive heart disease but no evidence of EMF on angiography. These IRCM patients had similar clinical profiles to EMF but on endomyocardial biopsy the endocardial thickening was minimal and seen in few patients (5/22).
Evaluation of the performance and concordance of clinical questionnaires for the diagnosis of heart failure in primary care
Authors: Fonseca Cândida , Oliveira António G. , Mota Teresa , Matias Fernando , Morais Humberto , Costa Catarina , Ceia Fátima ,   on behalf of the EPICA Investigators
Published: November 2004

Aim:

To validate and estimate the performance statistics and concordance of seven clinical questionnaires for the diagnosis of chronic heart failure (HF).

Methods:

Community‐based epidemiological survey of patients aged >25 years attending a random sample of primary health care centers in Portugal. Heart failure was identified according to the Guidelines of the European Society of Cardiology (ESC).

Results:

A total of 5434 subjects evaluated by 365 investigators were eligible for analysis, 551 of which had criteria for heart failure. Overall, the questionnaires had high specificity, usually above 90%, but low sensitivity, providing an increase in the likelihood of heart failure from 4.3% pre‐test to 25–35% post‐test in most cases. The Göteborg questionnaire was the most balanced regarding sensitivity (84%) and specificity (81%) but this may reflect its use of prescription of digoxin or diuretics as diagnostic criteria for diagnosis. The Walma, Framingham and NHANES‐I questionnaires performed similarly (Sensitivity: 63%, Specificity: 93%), while the Boston and the Gheorghiade questionnaires had a somewhat lower sensitivity (55%). Concordance was good between the Boston, Framingham, Gheorghiade, NHANES‐I and Walma questionnaires.

Conclusions

This study evaluated seven clinical questionnaires for the diagnosis of heart failure in the community. Their low sensitivity impairs their usefulness as diagnostic instruments, but their high specificity makes them useful for the identification of patients with fluid retention and/or exercise intolerance from non‐cardiac causes.
Clinical trials update from the European Society of Cardiology: SENIORS, ACES, PROVE‐IT, ACTION, and the HF‐ACTION trial
Authors: Cleland John G.F. , Loh P. Huan , Freemantle Nick , Clark Andrew L. , Coletta Alison P.
Published: November 2004

This article provides information and a commentary on landmark trials presented at the European Society of Cardiology Congress in August 2004, relevant to the pathophysiology, prevention or treatment of heart failure. The SENIORS trial suggests that nebivolol is well tolerated and effective in older patients with heart failure, even if left ventricular systolic function is not markedly depressed. However, patients aged >75 years appeared to gain less benefit. Further data on the effects of nebivolol on symptoms and quality of life are awaited. Two new trials of long‐term antibiotic prophylaxis after myocardial infarction (ACES and PROVE‐IT) showed no benefit. The ACTION trial showed no reduction in serious cardiovascular events with nifedipine GITS in patients with chronic stable angina, despite a substantial reduction in blood pressure. The HF‐ACTION trial announced that the first 700 patients of a projected 3000 had been randomised to either an exercise program or encouragement to exercise but without a formal program. The primary outcome measure is death or hospitalisation for any reason.
Aetiology, comorbidity and drug therapy of chronic heart failure in the real world: the EPICA substudy
Authors: Ceia Fátima , Fonseca Cândida , Mota Teresa , Morais Humberto , Matias Fernando , Costa Catarina , Oliveira António G.
Published: November 2004

Background:

Chronic heart failure (CHF) is common and is frequently managed by primary care physicians (PCPs). Despite the European Society of Cardiology (ESC) Guidelines, standard treatments for CHF are frequently underutilised, particularly in primary care.

Aim:

To evaluate current drug therapy for CHF in adults with HF diagnosed according to ESC guidelines in the context of the EPICA study. Aetiological features and therapy relevant comorbidities were also analysed.

Methods:

EPICA was a community‐based epidemiological study conducted in mainland Portugal. The study involved 365 primary care physicians, who evaluated 6300 primary care attendees aged over 25 years. CHF was diagnosed by clinical and echocardiography criteria according to ESC guidelines.

Results:

Total of 551 cases of CHF were identified, with a mean age of 65±9 years. The estimated overall prevalence of CHF in the Portuguese population was 4.4%; 1.3% with and 1.7% without left ventricular systolic dysfunction (LVSD). There are 6,280,792 people aged >25 years in Portugal, which extrapolates to 261,400 cases of heart failure. About 80% of patients had a history of hypertension, 39% had a history of coronary artery disease and 15% had atrial fibrillation. Only 58% of patients were on angiotensin‐converting enzyme (ACE) inhibitors and 7% on beta‐blockers. The type of ventricular dysfunction, age and presence of renal failure had little effect on prescription rates. Diuretics were prescribed in 78%. Thiazides were used more frequently in those with preserved systolic function and frusemide in those with left ventricular systolic dysfunction. Digoxin was prescribed more often to patients with than without left ventricular systolic dysfunction (34% vs. 17%; p=0.02). Long‐acting nitrates were prescribed to 20% and amiodarone to 8% of patients.

Conclusion:

The EPICA study, as in other studies in primary care in Europe, particularly the IMPROVEMENT study, suggests that greater efforts are required to improve training of primary care teams in the management of CHF.
Ultrasound vocalisation by rodents does not correlate with behavioural measures of persistent pain
Authors: Wallace Victoria C.J. , Norbury Timothy A. , Rice Andrew S.C.
Published: November 2004

Three well‐established rodent models of somatic, visceral and neuropathic pain were used to test the hypothesis that a stress and anxiety evoked behaviour, namely ultrasound vocalisation, correlates with other well‐characterised indices of pain behaviour, such as limb withdrawal and stereotypical behaviour.

Persistent pain presents a significant clinical problem for which there remains relatively ineffective clinical management and animal models of pain are commonly employed to investigate the underlying pathophysiology and for pre‐clinical evaluation of novel therapies. At present, the assessment of such animal models largely relies on the observation of simple reflex responses which may not entirely represent the full range of rodent pain behaviour. Therefore, additional integrated behavioural indices for the quantification of pain could improve the veracity of animal models. In stressful or harmful situations, it is thought that rodents produce ultrasound vocalisations to communicate within the social group. In this study, the number of ultrasound vocalisations (22 kHz) was measured during both evoked and ongoing pain. Ultrasound vocalisation was not associated with other pain behaviour in any of the inflammatory, visceral or neuropathic pain models examined and is therefore not a useful integrated correlate of pain behaviour.
Protein kinase Akt/PKB phosphorylates heme oxygenase‐1 in vitro and in vivo
Authors: Salinas Marta , Wang Jinling , Rosa de Sagarra María , Martín Daniel , Rojo Ana I. , Martin-Perez Jorge , Ortiz de Montellano Paul R. , Cuadrado Antonio
Published: November 2004

Heme oxygenase‐1 (HO‐1) is a stress response protein that protects cells against diverse noxious stimuli. Although regulation of HO‐1 occurs mainly at the transcriptional level, its posttranslational modifications remain unexplored. We have identified a putative consensus sequence for phosphorylation by Akt/PKB of HO‐1 at Ser188. Recombinant human and rat HO‐1, but not mutant HO‐1(S188A), are phosphorylated in vitro by Akt/PKB. Isotopic 32P‐labeling of HEK293T cells confirmed that HO‐1 is a phosphoprotein and that the basal HO‐1 phosphorylation is increased by Akt1 activation. HO‐1(S188D), a single point mutant equivalent to the phosphorylated protein, exhibited over 1.6‐fold higher activity than wild type HO‐1. Fluorescence resonance energy transfer (FRET) studies indicated that HO‐1(S188D) bound to cytochrome P450 reductase (CPR) and biliverdin reductase (BVR) with a slightly lower K
d than wild‐type HO‐1. Although the changes in activity are small, this study provides the first evidence for a role of the survival kinase Akt in the regulation of HO‐1.
All‐trans retinoic acid inhibits proliferation of intestinal epithelial cells by inhibiting expression of the gene encoding Krüppel‐like factor 5
Authors: Chanchevalap Sengthong , Nandan Mandayam O. , Merlin Didier , Yang Vincent W.
Published: November 2004

Retinoids are known inhibitors of epithelial cell proliferation. Previous studies indicate that Krüppel‐like factor 5 (KLF5) is a pro‐proliferative transcription factor. Here, we examined the effect of all‐trans retinoid acid (ATRA) on proliferation of the intestinal epithelial cell line, IEC6. Treatment of IEC6 cells with ATRA inhibited their proliferation due to G1 cell cycle arrest. This inhibition was correlated with a decrease in the levels of KLF5 mRNA and promoter activity. In contrast, constitutive expression of KLF5 in stably transfected IEC6 cells with a KLF5‐expressing plasmid driven by a viral promoter abrogated the growth inhibitory effect of ATRA. Moreover, ATRA inhibited proliferation of several human colon cancer cell lines with high levels of KLF5 expression but not those with low levels of KLF5 expression. Our results indicate that KLF5 is a potential mediator for the inhibitory effect of ATRA on intestinal epithelial cell proliferation.
Impact of pH on Bax α conformation, oligomerisation and mitochondrial integration
Authors: Cartron Pierre François , Oliver Lisa , Mayat Ebrahim , Meflah Khaled , Vallette François M.
Published: November 2004

The change in the conformation of Bax at the onset of apoptosis is a determinant for the execution of this cell death programme. However, very few models can account for this modification and the factors involved in this process remain elusive. We have analysed the modifications in the conformation induced by a variation in pH using a cell‐free assay. We show that a moderate basic or acidic pH can induce apoptotic‐like changes in the conformation of Bax, such as the exposure of the N‐terminal or the BH3 domain. These changes in the conformation are associated with the binding of Bax to mitochondria and an enhanced Bax homo‐ and oligomerisation. Our results suggest that variations in the pH, in a range consistent with that often observed during apoptosis, are sufficient to trigger Bax translocation to mitochondria and the subsequent release of apoptogenic factors from this organelle.
Providing Care for Hand Disorders a Re-Appraisal of Need
Authors: BURKE F.D. , DIAS J.J. , PALOU C. HERAS , BRADLEY M.J. , WILDIN C.
Published: November 2004

An audit of hand surgery activity in Derby during the period 1989–1990 produced manpower and resource recommendations for the speciality per 100,000 of population per year for the United Kingdom. The decade that followed the audit has seen major changes in health care provision, including reduced service activity by trainee doctors through restricted hours of work and less unsupervised surgery. A further audit of hand surgery activity was performed during 2000–2001 to assess the effects of these and other changes. This showed that there has been a 2% rise in trauma attendances, though trauma bed utilization had reduced by 12% and surgery time by 38%. Trauma out-patient visits had also reduced by 11%. Day-case trauma surgery rates were virtually unchanged at 63%. Women attend more frequently with traumatic hand injuries than they did 10 years ago and there is arising incidence of hand injuries in the home, with a falling incidence at work. Elective referrals have risen by 36% and operations by 34%. The top ten diagnoses relate to the same conditions although their rankings have changed. Elective day-case surgery rates have risen from 64% to 94% over the decade. The 34% increase in elective operations has been absorbed within a 5% reduction in elective bed use and a 23% reduction in surgery time. Elective out-patient visits have also dropped 14% overall. This audit indicates that in 2000–2001 one whole time equivalent hand surgeon can service a population of 125,000. The national requirement for a 56 million population would be 448 whole time equivalent hand surgeons.
The Consolidated Standards of Reporting Trials (CONSORT): Better Presentation of Surgical Trials in the Journal of Hand Surgery
Authors: SAUERLAND S. , DAVIS T. R. C.
Published: November 2004

To assure readers that study results are scientifically valid, the methods of a clinical trial should be described adequately. Since randomization, blinding, and intention-to-treat-analysis are major bias-reducing techniques, these aspects should be reported most accurately. The Consolidated standards of reporting trials (CONSORT) are recommendations to improve the reporting of trials. CONSORT requires that trial authors describe basic methodological aspects that readers need to appraise the strengths of report ed clinical trials. This article presents the CONSORT recommendations and explains some of their main aspects. From now on, the Journal of Hand Surgery will use CONSORT to assist authors of randomized controlled trials in improving the description of their studies. We believe that this decision increases the scientific validity of study reports and helps readers when critically appraising articles.
Asymmetrical valleys created by the geomorphic response of rivers to strike-slip fault
Authors: Zhang Ke , Liu Kaiyu , Yang Jinchun
Published: November 2004

Offset fluvial valleys, including rivers beheaded and deflected by strike-slip faults, have long been used to estimate horizontal displacements on the faults. Larger rivers crossing such faults, however, sometimes show either no offset or only a small amount of offset compared to smaller rivers crossing the same faults. The larger rivers with higher erosional rates may widen their valleys asymmetrically downstream of strike-slip faults, rather than being beheaded or deflected. Examples are described from the Yellow River near the NE margin of the Tibetan Plateau. River beheading and asymmetrical widening are two end-members of a fluvial valley's response to strike-slip faulting, whereas deflection is a combination of both. Recognition of the formation of such asymmetrical valleys related to strike-slip faulting will help to understand fault activity better over longer time spans and enable a re-evaluation of many fault histories worldwide.
On the structure of water vapour feedbacks in climate models
Authors: Colman Rob
Published: November 2004

This paper quantifies the structure of water vapour feedback in a model by evaluating its meridional and vertical distribution and decomposing it into conceptually simplified components. First is a division into changes from fixed and varying relative humidity (RH). The first term is further divided into responses associated with the global mean surface temperature change, changes in horizontal gradients, and changes to the lapse rate. The uniform global temperature change component explains the majority of water vapour feedback. The horizontal gradient and varying RH terms are small. The component of water vapour feedback associated with lapse rate changes makes a significant contribution to the global water vapour feedback. However, there is a roughly equal and opposite temperature feedback from the lapse rate changes themselves. These results suggest both a very simple conceptual model for the bulk of the global water vapour feedback, as well as a relative insensitivity of combined temperature and water vapour feedbacks to the details of lapse rate changes. The effect of clouds on all feedback contributions is also quantified.
Geologic evolution of the Martian dichotomy in the Ismenius area of Mars and implications for plains magnetization
Authors: Smrekar S. E. , McGill G. E. , Raymond C. A. , Dimitriou A. M.
Published: November 2004

The origin of the Martian dichotomy, which divides highlands from lowlands, is unknown. We examine a section of the dichotomy (50–90E) defined by steep scarps and normal faults. Stratigraphy and age relationships preclude the formation of the 2.5 km high boundary via erosion. The abrupt disappearance of topographic knobs ∼300–500 km to the northeast is interpreted as a buried fault. Alignment of the buried fault with grabens, stratigraphy, and age determinations using crater counts indicate that the lowland bench is down faulted highlands crust. The estimated local strain (3.5%) and fault pattern are broadly consistent with gravitational relaxation of a plateau boundary. Magnetic and gravity anomalies occur on either side of the buried fault. Admittance analysis indicates isostatic compensation. Although nonunique, a model with a 10 km thick intracrustal block under the lowland bench, a 20 km thick block under the plains, and an excess density of 200 kg/m3 provides a good fit to the isostatic anomaly. A good fit to a profile of the magnetic field perpendicular to the dichotomy is produced using uniformly polarized intracrustal blocks 10–20 km thick, an intensity of 6 Am/m, a field inclination of −30°, and gaps aligned with the isostatic anomalies. One interpretation is that high‐density intrusions demagnetized the crust after dynamo cessation and that low‐lying magnetized areas could be down faulted highlands crust. Another model (inclination of 30°) has magnetized crust beneath the isostatic anomalies, separated by gaps. The gaps could result from hydrothermal alteration of the crust along fault zones.
Global dynamics of low immersion high-speed milling
Authors: Szalai Róbert , Stépán Gábor , Hogan S. John
Published: November 2004

In the case of low immersion high-speed milling, the ratio of time spent cutting to not cutting can be considered as a small parameter. In this case the classical regenerative vibration model of machine tool vibrations reduces to a simplified discrete mathematical model. The corresponding stability charts contain stability boundaries related to period doubling and Neimark–Sacker bifurcations. The subcriticality of both types of bifurcations is proved in this paper. Further, global period-2 orbits are found and analyzed. In connection with these orbits, the existence of chaotic motion is demonstrated for realistic high-speed milling parameters.
Dissipative relaxed states in two-fluid plasma with external drive
Authors: Bhattacharyya R. , Janaki M. S.
Published: November 2004

In this work the principle of minimum dissipation rate is applied to an externally driven two-fluid plasma. The definition of generalized helicity has been modified to a gauge invariant form to incorporate open systems. The relaxed state is represented by a double-curl equation and supports nonzero flow. In the limit of vanishingly small dissipation, the equation is shown to retain the double-curl form that represents a steady state configuration supported by a two-fluid plasma.
Measurement of a release adiabat from ∼8 Mbar in lead using magnetically driven flyer impact
Authors: Rothman S. D. , Parker K. , Robinson C. , Knudson M. D.
Published: November 2004

Using magnetically driven aluminium flyers to generate ∼8 Mbar shocks in lead, which were then transmitted into lower-impedance material samples, points on a lead release adiabat have been measured. The pressure–particle-velocity points were calculated from known sample principal Hugoniots and from shock velocities measured using arrays of fiber-optic active and passive shock breakout diagnostics, and point and line velocity interferometer for a surface of any reflectivity (VISARs). The measured points agree closely with adiabats calculated using models which do not include ionization, or do include it both with, and without, atomic shell effects. Though the data are not sufficient to discriminate between widely different models we may qualitatively identify errors within these models. This is the first attempt to measure a release adiabat from such high pressures.
Property of an X-point generated velocity-space hole in a diverted tokamak plasma edge
Authors: Ku Seunghoe , Baek Hoyul , Chang C. S.
Published: November 2004

Due to vanishingly small poloidal magnetic field in the vicinity of a divertor X point in a tokamak geometry, there exists a significant ion velocity space hole at the thermal energy level in the absence of a radial electric field. Physical property of the loss orbits and loss hole is studied in a lower single null geometry using a Hamiltonian guiding center particle code. The loss occurs through both high and low field sides of the X point, and in both trapped and passing velocity regions in the conventional sense. Loss holes between forward and backward ∇B drift cases are compared to find that there is little difference in velocity space. However, the loss hole in the forward ∇B plasma occupies a much larger real space volume due to flux expansion near the X point. A radial electric field shifts the velocity hole to a higher energy and, thus, reduces the orbit loss flux from the plasma near the X point (in the forward ∇B case) or at the vertically opposite side (in the backward ∇B case) by the same amount. On the midplane, however, the orbit loss hole disappears to an extremely high energy. The loss hole boundary shows a modification by an electrostatic fluctuation.
A broadband waveguide for protein crystallography under intense microwave fields
Authors: Weissenborn R. , Reinhardt T. , Hansen V. , Maret G. , Gisler T.
Published: November 2004

We present a slab-line waveguide whose geometry is optimized for wide-angle x-ray diffraction (XRD) experiments on protein crystals during irradiation with intense microwave fields. Characterization of the waveguide transmission and reflectivity (using time-domain reflectometry) and of the electric field distribution inside the waveguide (using finite-difference time-domain calculations) shows that the present device has a broad bandwidth from below 0.5 to 18 GHz, allowing one to perform frequency-dependent XRD studies with a well-defined transverse mode structure and negligible reflection losses. As shown with a specific example, our device provides a simple way to couple microwave irradiation experiments with high-resolution x-ray diffraction measurements from millimeter-size crystalline samples. The present design might prove useful for systematic studies of microwave effects on protein structure and dynamics.
Phase contrast radiography: Image modeling and optimization
Authors: Arhatari Benedicta D. , Mancuso Adrian P. , Peele Andrew G. , Nugent Keith A.
Published: November 2004

We consider image formation for the phase-contrast radiography technique where the radiation source is extended and spatially incoherent. A model is developed for this imaging process which allows us to define an objective filtering criterion that can be applied to the recovery of quantitative phase images from data obtained at different propagation distances. We test our image model with experimental x-ray data. We then apply our filter to experimental neutron phase radiography data and demonstrate improved image quality.
Radial P32 ion implantation using a coaxial plasma reactor: Activity imaging and numerical integration
Authors: Fortin M. A. , Dufresne V. , Paynter R. , Sarkissian A. , Stansfield B.
Published: November 2004

Beta-emitting biomedical implants are currently employed in angioplasty, in the treatment of certain types of cancers, and in the embolization of aneurysms with platinum coils. Radioisotopes such as P32 can be implanted using plasma-based ion implantation (PBII). In this article, we describe a reactor that was developed to implant radioisotopes into cylindrical metallic objects. The plasma first ionizes radioisotopes sputtered from a target, and then acts as the source of particles to be implanted into the biased biomedical device. The plasma therefore plays a major role in the ionization/implantation process. Following a sequence of implantation tests, the liners protecting the interior walls of the reactor were changed and the radioactivity on them measured. This study demonstrates that the radioactive deposits on these protective liners, adequately imaged by radiography, can indicate the distribution of the radioisotopes that are not implanted. The resulting maps give unique information about the activity distribution, which is influenced by the sputtering of the P32-containing fragments, their ionization in the plasma, and also by the subsequent ion transport mechanisms. Such information can be interpreted and used to significantly improve the efficiency of the implantation procedure. Using a surface barrier detector, a comparative study established a relationship between the gray scale of radiographs of the liners, and activity measurements. An integration process allows the quantification of the activities on the walls and components of the reactor. Finally, the resulting integral of the P32 activity is correlated to the sum of the radioactivity amounts that were sputtered from radioactive targets inside the implanter before the dismantling procedure. This balance addresses the issue of security regarding PBII technology and confirms the confinement of the radioactivity inside the chamber.
Possible Influence of Cell Walls upon Ion Concentrations at Plasma Membrane Surfaces. Toward a Comprehensive View of Cell-Surface Electrical Effects upon Ion Uptake, Intoxication, and Amelioration
Authors: Kinraide Thomas B.
Published: November 2004

Plant uptake of ions, intoxication by ions, and the alleviation of intoxication by other ions often correlate poorly with ion concentrations in the rooting medium. By contrast, uptake, intoxication, and alleviation correlate well with ion concentrations at the plasma membrane (PM) surface computed as though the PM were bathed directly in the rooting medium with no effect from the cell wall (CW). According to two separate lines of analysis, a close association of CWs and PMs results in a slight increase in cation concentrations and a slight decrease in anion concentrations at the PM surface compared with concentrations when the CW is separated or has no effect. Although slightly different, the ion concentrations at the PM surface computed with and without close association with the CW are highly correlated. Altogether, the CW would appear to have a small effect upon ion uptake by the PM or upon intoxication or alleviation of intoxication originating at the PM surface. These analyses have been enabled by the recent evaluation of parameters required for the electrostatic models (Gouy-Chapman-Stern and Donnan-plus-binding) used to compute electrical potentials and ion concentrations in CWs and at PM surfaces.
Maize Starch-Branching Enzyme Isoforms and Amylopectin Structure. In the Absence of Starch-Branching Enzyme IIb, the Further Absence of Starch-Branching Enzyme Ia Leads to Increased Branching
Authors: Yao Yuan , Thompson Donald B. , Guiltinan Mark J.
Published: November 2004

Previous studies indicated that the deficiency of starch-branching enzyme (SBE) Ia in the single mutant sbe1a∷Mu (sbe1a) has no impact on endosperm starch structure, whereas the deficiency of SBEIIb in the ae mutant is well known to reduce the branching of starch. We hypothesized that in maize (Zea mays) endosperm, the function of SBEIIb is predominant to that of SBEIa, and SBEIa would have an observable effect only on amylopectin structure in the absence of SBEIIb. To test this hypothesis, the mutant sbe1a was introgressed into lines containing either wx (lacking the granule-bound starch synthase GBSSI) or ae wx (lacking both SBEIIb and GBSSI) in the W64A background. Both western blotting and zymogram analysis confirmed the SBEIa deficiency in sbe1a wx and sbe1a ae wx, and the SBEIIb deficiency in ae wx and sbe1a ae wx. Using zymogram analysis, no pleiotropic effects of sbe1a genes on SBEIIa, starch synthase, or starch-debranching enzyme isoforms were observed. High-performance size exclusion chromatography analysis shows that the chain-length profiles of amylopectin as well as β-limit dextrin were indistinguishable between wx and sbe1a wx, whereas significant differences for both were observed between ae wx and sbe1a ae wx, suggesting an effect of SBEIa on amylopectin biosynthesis that is observable only in the absence of SBEIIb. The amylopectin branch density and the average number of branches per cluster were both higher in endosperm starch from sbe1a ae wx than from ae wx. These results indicate possible functional interactions between SBE isoforms that may involve enzymatic inhibition. Both the cluster repeat distance and the distance between branch points on the short intracluster chains were similar for all genotypes however, suggesting a similar pattern of individual SBE isoforms in cluster initiation and the determination of branch point location.
AtGA3ox2, a Key Gene Responsible for Bioactive Gibberellin Biosynthesis, Is Regulated during Embryogenesis by LEAFY COTYLEDON2 and FUSCA3 in Arabidopsis
Authors: Curaba Julien , Moritz Thomas , Blervaque Renaud , Parcy François , Raz Vered , Herzog Michel , Vachon Gilles
Published: November 2004

Embryonic regulators LEC2 (LEAFY COTYLEDON2) and FUS3 (FUSCA3) are involved in multiple aspects of Arabidopsis (Arabidopsis thaliana) seed development, including repression of leaf traits and premature germination and activation of seed storage protein genes. In this study, we show that gibberellin (GA) hormone biosynthesis is regulated by LEC2 and FUS3 pathways. The level of bioactive GAs is increased in immature seeds of lec2 and fus3 mutants relative to wild-type level. In addition, we show that the formation of ectopic trichome cells on lec2 and fus3 embryos is a GA-dependent process as in true leaves, suggesting that the GA pathway is misactivated in embryonic mutants. We next demonstrate that the GA-biosynthesis gene AtGA3ox2, which encodes the key enzyme AtGA3ox2 that catalyzes the conversion of inactive to bioactive GAs, is ectopically activated in embryos of the two mutants. Interestingly, both β-glucuronidase reporter gene expression and in situ hybridization indicate that FUS3 represses AtGA3ox2 expression mainly in epidermal cells of embryo axis, which is distinct from AtGA3ox2 pattern at germination. Finally, we show that the FUS3 protein physically interacts with two RY elements (CATGCATG) present in the AtGA3ox2 promoter. This work suggests that GA biosynthesis is directly controlled by embryonic regulators during Arabidopsis embryonic development.
nip, a Symbiotic Medicago truncatula Mutant That Forms Root Nodules with Aberrant Infection Threads and Plant Defense-Like Response
Authors: Veereshlingam Harita , Haynes Janine G. , Penmetsa R. Varma , Cook Douglas R. , Sherrier D. Janine , Dickstein Rebecca
Published: November 2004

To investigate the legume-Rhizobium symbiosis, we isolated and studied a novel symbiotic mutant of the model legume Medicago truncatula, designated nip (numerous infections and polyphenolics). When grown on nitrogen-free media in the presence of the compatible bacterium Sinorhizobium meliloti, the nip mutant showed nitrogen deficiency symptoms. The mutant failed to form pink nitrogen-fixing nodules that occur in the wild-type symbiosis, but instead developed small bump-like nodules on its roots that were blocked at an early stage of development. Examination of the nip nodules by light microscopy after staining with X-Gal for S. meliloti expressing a constitutive GUS gene, by confocal microscopy following staining with SYTO-13, and by electron microscopy revealed that nip initiated symbiotic interactions and formed nodule primordia and infection threads. The infection threads in nip proliferated abnormally and very rarely deposited rhizobia into plant host cells; rhizobia failed to differentiate further in these cases. nip nodules contained autofluorescent cells and accumulated a brown pigment. Histochemical staining of nip nodules revealed this pigment to be polyphenolic accumulation. RNA blot analyses demonstrated that nip nodules expressed only a subset of genes associated with nodule organogenesis, as well as elevated expression of a host defense-associated phenylalanine ammonia lyase gene. nip plants were observed to have abnormal lateral roots. nip plant root growth and nodulation responded normally to ethylene inhibitors and precursors. Allelism tests showed that nip complements 14 other M. truncatula nodulation mutants but not latd, a mutant with a more severe nodulation phenotype as well as primary and lateral root defects. Thus, the nip mutant defines a new locus, NIP, required for appropriate infection thread development during invasion of the nascent nodule by rhizobia, normal lateral root elongation, and normal regulation of host defense-like responses during symbiotic interactions.
Oxalate Production by Sclerotinia sclerotiorum Deregulates Guard Cells during Infection
Authors: Guimarães Rejane L. , Stotz Henrik U.
Published: November 2004

Oxalic acid is a virulence factor of several phytopathogenic fungi, including Sclerotinia sclerotiorum (Lib.) de Bary, but the detailed mechanisms by which oxalic acid affects host cells and tissues are not understood. We tested the hypothesis that oxalate induces foliar wilting during fungal infection by manipulating guard cells. Unlike uninfected leaves, stomatal pores of Vicia faba leaves infected with S. sclerotiorum are open at night. This cellular response appears to be dependent on oxalic acid because stomatal pores are partially closed when leaves are infected with an oxalate-deficient mutant of S. sclerotiorum. In contrast to oxalate-deficient S. sclerotiorum, wild-type fungus causes an increase in stomatal conductance and transpiration as well as a decrease in plant biomass. Green fluorescent protein-tagged S. sclerotiorum emerges through open stomata from the uninfected abaxial leaf surface for secondary colonization. Exogenous application of oxalic acid to the detached abaxial epidermis of V. faba leaves induces stomatal opening. Guard cells treated with oxalic acid accumulate potassium and break down starch, both of which are known to contribute to stomatal opening. Oxalate interferes with abscisic acid (ABA)-induced stomatal closure. The Arabidopsis (Arabidopsis thaliana) L. Heynh. mutants abi1, abi3, abi4, and aba2 are more susceptible to oxalate-deficient S. sclerotiorum than wild-type plants, suggesting that Sclerotinia resistance is dependent on ABA. We conclude that oxalate acts via (1) accumulation of osmotically active molecules to induce stomatal opening and (2) inhibition of ABA-induced stomatal closure.
Untranslated Regions from C4 Amaranth AhRbcS1 mRNAs Confer Translational Enhancement and Preferential Bundle Sheath Cell Expression in Transgenic C4Flaveria bidentis
Authors: Patel Minesh , Corey Amy C. , Yin Li-Ping , Ali Shahjahan , Taylor William C. , Berry James O.
Published: November 2004

Many aspects of photosynthetic gene expression are posttranscriptionally regulated in C4 plants. To determine if RbcS mRNA untranslated regions (UTRs) in themselves could confer any characteristic C4 expression patterns, 5′- and 3′-UTRs of AhRbcS1 mRNA from the C4 dicot amaranth were linked to a gusA reporter gene. These were constitutively transcribed from a cauliflower mosaic virus promoter and assayed for posttranscriptional expression patterns in transgenic lines of the C4 dicot Flaveria bidentis. Three characteristic C4 expression patterns were conferred by heterologous AhRbcS1 UTRs in transgenic F. bidentis. First, the AhRbcS1 UTRs conferred strong translational enhancement of gusA expression, relative to control constructs lacking these UTRs. Second, while the UTRs did not appear to confer tissue-specific expression when analyzed by β-glucuronidase activity assays, differences in gusA mRNA accumulation were observed in leaves, stems, and roots. Third, the AhRbcS1 UTRs conferred preferential gusA expression (enzyme activity and gusA mRNA accumulation) in leaf bundle sheath cells. AhRbcS1 UTR-mediated translational enhancement was also observed in transgenic C3 plants (tobacco [Nicotiana tabacum]) and in in vitro translation extracts. These mRNAs appear to be translated with different efficiencies in C4 versus C3 plants, indicating that processes determining overall translational efficiency may vary between these two categories of higher plants. Our findings suggest that the AhRbcS1 5′-UTR functions as a strong translational enhancer in leaves and other tissues, and may work synergistically with the 3′-UTR to modulate overall levels of Rubisco gene expression in different tissues and cell types of C4 plants.