Measurements Of Ep Research Articles

Machine-learning guided differentiation between photoplethysmography waveforms of supraventricular and ventricular origin

Abstract Aims To test, whether a neural network-based classifier could aid in distinguishing photoplethysmographic (PPG) pulse waveforms of ventricular from those of supraventricular origin. Methods Thirty patients undergoing invasive electrophysiological studies for documented narrow complex tachycardias between May and December 2021 at a university medical centre were included in the trial. PPG waveforms were recorded using a PPG wristband (Empatica E4) in parallel to 12-lead surface electrograms (ECGs) and intracardiac electrograms from diagnostic catheters. Pulse waves were then annotated to either supraventricular (sinus rhythm, atrial pacing) or ventricular origin (ventricular pacing) based on invasive electrogram recordings, ECGs and stimulation protocols. 21147 data sets were split into test, training and validation data sets and used to develop, train and validate a convolutional neural network (CNN) for classifying PPG waveforms according to their origin into sinus rhythm, atrial or ventricular pacing. Results Datasets were complete for 27 patients. 74% were female and median age was 53 (range 18, 78) years, median BMI was 27±5, 19% had arterial hypertension, 11% had diabetes and 15% had coronary artery disease. During the electrophysiological study, typical AV-nodal re-entrant tachycardias could be induced in 63% of patients, 15% had inducible atrial tachycardias and the other patients had no inducible tachyarrhythmias. Our CNN-based classifier was able to correctly predict the origins of pulse waves in 95±1% for sinus rhythm, 96±1% for atrial paced rhythms and 95±1% for ventricular rhythms. Conclusion A neural network-based classifier trained on ground truth PPG data obtained by using invasive EP measurements for annotation could accurately predict atrial or ventricular origin from PPG waveforms alone.Graphical abstract

Defining cardiac stability during Langendorff perfusion

The Langendorff heart preparation is a valuable ex vivo technique for studying cardiac electrophysiology. For the past century it has been used in toxicology studies, drug testing, and disease modeling and has contributed significantly to understanding cardiac physiology, development, and pathological states. This study aimed to investigate the stability and reproducibility of the modern Langendorff heart preparation under various experimental conditions and to establish cardiac metric standards with corresponding exclusion criteria. Isolated hearts were extracted from adult Sprague Dawley rats and retrograde perfused with a modified Krebs-Henseleit buffer. A cohort of isolated hearts were used to establish a control baseline of multiple physiological parameters measured over time (e.g., electrocardiogram, flow rate, electrophysiology, electrical and calcium dynamics). These control baseline values were then compared to hearts exposed to the most common media additives in Langendorff studies (e.g., blebbistatin(−/−), bovine serum albumin, and voltage and calcium indicator dye). Over a three-hour period, cardiac metrics were monitored in stable Langendorff-perfused hearts. The addition of blebbistatin, DMSO or dyes did not change EP or ECG measurements as compared to control baseline. The most significant drift in all the EP values was ventricular effective refractory period (VERP). With or without blebbistatin, VERP increased from 40 to 60ms over the course of three hours. In that time heart rate and flow also decreased slightly. Blebbistatin was associated with an increased action potential duration but did not alter calcium transient duration. It was also observed that 1% circulating bovine serum albumin quenched the rh237 voltage dye signal 80% as measured by signal to noise. Constant pressure Langendorff-perfusion with a crystalloid buffer provides a reliable and reproducible model for cardiac electrophysiology research with a few caveats. The total length of study should be carefully considered to account for adaptations in cardiac physiology during longer perfusion times. As an excitation-contraction uncoupler, blebbistatin reduces motion artifact but delays action potential duration. Although BSA is used to minimize cardiac edema, it interferes with membrane bound voltage dyes. This study sets physiological parameters as a useful guide for future cardiac studies that use the isolated heart as a research model. American Physiological Society, R01HD108839 to N.G.P. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Potential use of optical coherence tomography in oral potentially malignant disorders: in-vivo case series study

BackgroundEvidence confirms that the use of Optical Coherence Tomography (OCT) in oral medicine can be a reliable aid for the diagnosis and management of Oral Potentially Malignant Disorders (OPMDs). Several authors described the ability of this system to detect the structural changes of the epithelia involved by the OPMDs. The purpose of this case series is to provide a suggestion for interpretation of OCT images from different OPMDs, compared to OCT images of healthy tissues.MethodsA sample of 11 OPMDs patients was recruited and analyzed with OCT. The images obtained were then compared with an OCT repertoire image. In this work the reflectance degree was considered, together with the analysis of the increased/decreased thicknesses of the various layers. Keratin Layer (KL), Epithelial Layer (EP), Lamina Propria (LP), Basal Membrane (BM) assessment, for each lesion, was performed.ResultsOCT measurements of KL, EP and LP layers, together with BM assessing, should aid the physicians to recognize and describe different oral lesions, relating them to the corresponding oral pathology.ConclusionMore studies like this, on larger samples, are needed to validate the results and provide, in the future, a kind of manual that could guide clinicians to correctly interpret the OCT images in relation to the causing pathologies.

Abstract 15505: Aortic Stiffening in L-NAME Treated C57bl6 Mice Precedes Peripheral Hypertension and Cardiac Hypertrophy: Early Endothelial Dysfunction Shifts to Late-term Vascular Smooth Muscle Cell Disease

Introduction: Endothelial dysfunction (ED) acts as a common player in most cardiovascular (CV) risk factors (e.g. hypertension, smoking) underlining its importance in CV ageing. Therefore, this study aims to characterize ex vivo aortic function changes in Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME) treated mice. Methods: C57Bl6 mice (male, n=10) received 0.5 mg/mL L-NAME through the drinking water for 1, 2, 4, 8, and 16 weeks, followed by in-depth ex vivo thoracic aorta isometric reactivity studies and arterial stiffness (Peterson modulus, Ep) measurements in the Rodent Oscillatory Tension set-up for Arterial Compliance (ROTSAC). In addition, peripheral blood pressure (BP, Coda), aortic pulse wave velocity (aPWV, Vevo2100), and echocardiography (Vevo2100) were measured in vivo . (Data are represented as mean±SEM) Results: L-NAME treated mice display fast-onset aortic stiffening after 1-week L-NAME (Fig. A, B), followed by the development of peripheral hypertension (Fig. C) and cardiac disease (Fig. D-F) after 4-weeks L-NAME. Ex vivo aorta studies reveal different stages of disease. Early on (1-4 weeks), mice show elevated phenylephrine (PE) contractions (Fig. G) and impaired acetylcholine (ACh) relaxations (Fig. H), consistent with L-NAME related ED. After 8 weeks, endothelial function and PE contractions normalize. Relaxations to exogenous NO remain unaltered (Fig. I). In contrast to the recovery of ACh relaxations, stiffness analysis in the ROTSAC reveals constantly reduced basal NO levels (Fig. J), and a late-term shift (16 weeks) towards vascular smooth muscle cell (VSMC) disease. This involves basal cytoplasmic calcium loading (Fig. K) and a sharply increasing contribution of voltage-gated calcium channels (Fig. L). Conclusions: NOS inhibition by L-NAME treatment causes a distinct time-dependent aortic disease phenotype, underlying fast-onset arterial stiffening which precedes peripheral hypertension and cardiac disease.

Sex Differences In Arterial Stiffness Following Acute Resistance Exercise

During resistance exercise there is an increase in blood pressure, with systolic pressure rising up to 400 mmHg. This transient elevation in pressure has been shown to result in acutely stiffer vessels in young males, however, this has not been well studied in young females. It is possible that the sex hormones of young females may be protective against this pressure load, resulting in differential responses following resistance exercise. PURPOSE: The purpose of this study was to determine if there are sex differences in arterial stiffness following an acute resistance exercise bout in young, healthy males and females who are not currently resistance training. METHODS: Carotid beta stiffness (β), arterial compliance (AC), and elastic modulus (Ep) measurements were taken in 23 young participants (10 males, 13 females; 26 ± 1 years) before, immediately after, and 30 minutes following full body resistance exercise. Exercise consisted of 2 sets of 10-12 repetitions performed on 8 resistance machines completed at 40% 1RM for the upper body and 60% 1RM for the lower body. Females were tested during the early follicular phase of their menstrual cycle to control for sex hormones. Exercise values (pre, post, post30) were compared between sexes using a repeated measures ANOVA, with significance set at p < 0.05. When the interaction was significant, the responses were evaluated with paired samples t-tests within each sex and independent t-tests between sexes. RESULTS: There were no sex differences in stiffness values prior to exercise, but males displayed significantly higher β and Ep and lower AC post and post30 compared to females. Males demonstrated significant increases in β (4.2 ± 0.4 to 6.6 ± 0.5 to 5.8 ± 0.5 AU) and Ep (48 ± 5 to 73 ± 6 to 65 ± 6 kPa) and decreases in AC (1.5 ± 0.2 to 0.9 ± 0.1 to 1.1 ± 0.1 mm2/kPa) both immediately and 30 min post resistance exercise compared to baseline values, while females had no change in AC (1.4 ± 0.1 to 1.2 ± 0.1 to 1.5 ± 0.1 mm2/kPa) or Ep (46 ± 4 to 52 ± 5 to 44 ± 5 kPa) with exercise and an immediate increase in β that returned to baseline at 30 min post (4.2 ± 0.3 to 5.1 ± 0.5 to 4.3 ± 0.4 AU). CONCLUSION: Acute resistance exercise in females does not result in the elevation of stiffness as seen in males. It appears females may be protected from this increased pressure load, which may be due to the vasodilatory effects of estrogen.

Impact of large volume paracentesis on respiratory parameters including transpulmonary pressure and on transpulmonary thermodilution derived hemodynamics: A prospective study.

IntroductionAppropriate mechanical ventilation and prevention of alveolar collaps is mainly dependent on transpulmonary pressure TPP. TPP is assessed by measurement of esophageal pressure EP, largely influenced by pleural and intraabdominal pressure IAP. Consecutively, TPP-guided ventilation might be particularly useful in patients with high IAP.This study investigates the impact of large volume paracentesis LVP on TPP, EP, IAP as well as on hemodynamic and respiratory function in patients with liver cirrhosis and tense ascites.Material and methodsWe analysed 23 LVP-procedures in 11 cirrhotic patients ventilated with the AVEA Viasys respirator (CareFusion, USA) which is capable to measure EP via an esophageal tube.ResultsLVP of a mean volume of 4826±1276 mL of ascites resulted in marked increases in inspiratory (17.9±8.9 vs. 5.4±13.3 cmH2O; p<0.001) as well as expiratory TPP (-3.0±4.7 vs. -15.9±10.9 cmH2O; p<0.001; primary endpoint). In parallel, the inspiratory (2.4±8.7 vs. 14.1±14.5 cmH2O; p<0.001) and expiratory EP (12.4±6.0 vs. 24.9±11.3 cmH2O; p<0.001) significantly decreased. The effects were most pronounced for the release of the first 500 mL of ascites. LVP evoked substantial decreases in IAP and central venous pressure CVP. By contrast, mean arterial pressure, cardiac index, global end-diastolic volume index, extravascular lung water index and systemic vascular resistance index did not change.Among the respiratory parameters we observed an increase in paO2/FiO2 (247.7±60.9 vs. 208.3±46.8 mmHg; p<0.001) and a decrease in Oxygenation Index OI (4.8±2.0 vs. 5.8±3.1 cmH2O/mmHg; p = 0.002). Tidal volume (510±100 vs. 452±113 mL; p = 0.008) and dynamic respiratory system compliance Cdyn (46.8±15.9 vs. 35.1±14.6 mL/cmH20; p<0.001) increased, whereas paCO2 (47.3±10.7 vs. 51.2±12.3mmHg; p = 0.046) and the respiratory rate decreased (17.1±7.3 vs. 19.6±7.8 min-1; p = 0.010).ConclusionsIn mechanically ventilated patients with decompensated cirrhosis, intraabdominal hypertension resulted in a substantially decreased TPP despite PEEP-setting according to the ARDSNet.In these patients LVP markedly increased TPP and improved respiratory function in parallel with a decline of EP. Furthermore, LVP induced a decrease in IAP and CVP, while other hemodynamic parameters did not change.

OP.1C.02] SPECTRAL ESTIMATION OF PETERSON'S MODULUS VARIABILITY FROM ARTERIAL BLOOD PRESSURE AND WAVELET ANALYSIS

Objective: Arterial stiffness is mainly characterized by its Peterson's Modulus (EP). Increased values of EP are associated with a reduced heart function and an increased arterial blood pressure. Assessment of EP requires simultaneous measurements of arterial diameter and pressure signals. However, instantaneous determination of arterial diameter signals implies optical and ultrasonic techniques and neither of them are portables. Aims: To evaluate a novel method for estimating the Ep spectral variability of arterial stiffness, without arterial diameter signals. Design and method: Arterial pressure (Konigsberg micro-transducer) was measured in 10 sheeps (25–35 kg) during 24 hours. Instantaneous cardiac cycle of pressure signals were determined using five–level multi-resolution wavelet analysis and decomposition. A state machine processed and analysed different linear combinations of details d3, d4 and d5 of mother wavelet Symlet11. EP spectral estimation assessment involved the study of various temporal locations of the fiducial elasticity starting point within each beat. Moreover, discard criteria were added from the heart rate variability studio and coherence index between systolic pressure and beat to beat intervals around 0.1 Hz. Agreement between the actual direct measurement of EP and the proposed method of spectral stiffness estimation was analyzed according to the Bland–Altman approach. Results: Results showed a high coherence (more than 70%) between the actual and proposed method for a wide frequency range (0 to 0.5 Hz). Bland & Altman test showed a standard deviation of the mean less of 10% between the proposed methodology and the direct assessment of EP. Conclusions: The methodology presented in this work evidenced high levels of spectral coherence in EP variability studios and no significantly difference between the actual and the proposed estimation method. So, this novel method is able to estimate the Peterson's modulus spectral variability by solely using the arterial blood pressure signal.

Contribution of mental training to the improvement of sports performance

The aim of this study was to assess the influence of mental training on the increase in attention and manual response in certain athletes (skiers). The subjects within are samples are aged 12±5 and 16±1. The athletes who participated in this study are part of ski groups within School sports clubs. The experimental group comprises athletes from Gheorgheni, Baia-Sprie, while the control group includes of athletes from Topliţa, Sibiu, Predeal and Sinaia. We applied the ACRM (focused attention with manual response) test, because it provides information on the ability of remaining focused during activities with imposed pace and with dynamic field of observations. We conducted these tests after applying certain mental training techniques in the experimental group and after comparing the scores with those obtained by the control group. For the analysis, we used the SPSS 15.0 software. For the comparison of means between the groups of subjects, we applied ANOVA for the VP, EP and EX posttest measurements. The purpose was to determine whether the two groups have similar scores before the intervention. We applied mental imagery techniques on certain components of alpine skiing technique, based on hand-eye coordination. We also calculated a t test for dependent samples for VP, EP and EX, in posttest, to the end of establishing whether the intervention led to any alterations. The means and standard deviation for VP are as follows: for the control group 10.00±6.04 and for the experimental group 4.04±3.85; for EP test, the values for control group are 18.54±9.12 and for the experimental group 9.83±4.40; EX – the values obtained for the control group 0.86±0.07 and for the experimental group 0.92±0.05. The values for (t) Student Test were the following: for VP t=4.074, p&lt;0.000; EP t=4.203, p&lt;0.000; EX t=3.279, p&lt;0.002. Considering both the comparative analysis of scores to the tests.Keywords: attention, skiing, mental training, manual response

Contribution of mental training to the improvement of sports performance

The aim of this study was to assess the influence of mental training on the increase in attention and manual response in certain athletes (skiers). The subjects within are samples are aged 12±5 and 16±1. The athletes who participated in this study are part of ski groups within School sports clubs. The experimental group comprises athletes from Gheorgheni, Baia-Sprie, while the control group includes of athletes from Topliţa, Sibiu, Predeal and Sinaia. We applied the ACRM (focused attention with manual response) test, because it provides information on the ability of remaining focused during activities with imposed pace and with dynamic field of observations. We conducted these tests after applying certain mental training techniques in the experimental group and after comparing the scores with those obtained by the control group. For the analysis, we used the SPSS 15.0 software. For the comparison of means between the groups of subjects, we applied ANOVA for the VP, EP and EX posttest measurements. The purpose was to determine whether the two groups have similar scores before the intervention. We applied mental imagery techniques on certain components of alpine skiing technique, based on hand-eye coordination. We also calculated a t test for dependent samples for VP, EP and EX, in posttest, to the end of establishing whether the intervention led to any alterations. The means and standard deviation for VP are as follows: for the control group 10.00±6.04 and for the experimental group 4.04±3.85; for EP test, the values for control group are 18.54±9.12 and for the experimental group 9.83±4.40; EX – the values obtained for the control group 0.86±0.07 and for the experimental group 0.92±0.05. The values for (t) Student Test were the following: for VP t=4.074, p&lt;0.000; EP t=4.203, p&lt;0.000; EX t=3.279, p&lt;0.002. Considering both the comparative analysis of scores to the tests.Keywords: attention, skiing, mental training, manual response

Contribution of mental training to the improvement of sports performance

The aim of this study was to assess the influence of mental training on the increase in attention and manual response in certain athletes (skiers). The subjects within are samples are aged 12±5 and 16±1. The athletes who participated in this study are part of ski groups within School sports clubs. The experimental group comprises athletes from Gheorgheni, Baia-Sprie, while the control group includes of athletes from Topliţa, Sibiu, Predeal and Sinaia. We applied the ACRM (focused attention with manual response) test, because it provides information on the ability of remaining focused during activities with imposed pace and with dynamic field of observations. We conducted these tests after applying certain mental training techniques in the experimental group and after comparing the scores with those obtained by the control group. For the analysis, we used the SPSS 15.0 software. For the comparison of means between the groups of subjects, we applied ANOVA for the VP, EP and EX posttest measurements. The purpose was to determine whether the two groups have similar scores before the intervention. We applied mental imagery techniques on certain components of alpine skiing technique, based on hand-eye coordination. We also calculated a t test for dependent samples for VP, EP and EX, in posttest, to the end of establishing whether the intervention led to any alterations. The means and standard deviation for VP are as follows: for the control group 10.00±6.04 and for the experimental group 4.04±3.85; for EP test, the values for control group are 18.54±9.12 and for the experimental group 9.83±4.40; EX – the values obtained for the control group 0.86±0.07 and for the experimental group 0.92±0.05. The values for (t) Student Test were the following: for VP t=4.074, p<0.000; EP t=4.203, p<0.000; EX t=3.279, p<0.002. Considering both the comparative analysis of scores to the tests. Keywords: attention, skiing, mental training, manual response

The Economic Impact of Environmentally Responsible Practices

ABSTRACTThe objective of this paper is to present a dynamic analysis of the relationship between environmental (EP) and financial performance (FP). More precisely, we have analysed this relationship by considering the measurement of EP lagged by one, two, and three periods. The introduction of lagged variables at both an aggregate and non‐aggregate level, aims to capture the effects of EP on FP over time. Our results show that the aggregate measure of the lagged EP has a persistent positive effect on FP, extended over three years. This effect appears to be more marked for large size companies, for companies with low risk levels and for those spending less on investment. Results for non‐aggregate measurements reveal an asymmetric relationship between FP and KLD's concerns score, of which the impact is negative and persistent, and between FP and KLD's strengths score, where the effect is positive and limited to one year. Copyright © 2015 John Wiley &amp; Sons, Ltd and ERP Environment

Plasma resonance of binary amorphous and crystalline Al-transition metal alloys: Experiments and ab initio calculations

We report on measurements of the volume plasmon loss energy EP by electron energy loss spectroscopy of binary amorphous Al–(Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Y, Pd, Ce) alloys. In these systems the measured EP can be described by an effective valence of the transition metal independent of the particular transition metal. By exploiting ab initio calculations for the crystalline counterparts in the case of Al–(Ti, V, Fe, Ni) we show that this behavior can be understood in terms of the full dielectric function taking into account intra- and interband transitions mainly due to the presence of d-states close to the Fermi energy. This is validated by the comparison with published experimental data on binary Al systems with the non-transition metals Be, Mg, Ca, and Zn. Due to the absence of composition-dependent structural phase changes, amorphous alloys are found to be model-like systems for studying the influence of interband transitions on the plasma resonance.

INVESTIGATING THE &lt;em&gt;E&lt;/em&gt;&lt;sub&gt;p, i&lt;/sub&gt; –&lt;em&gt;E&lt;/em&gt;&lt;sub&gt;iso&lt;/sub&gt; CORRELATION

The correlation between the spectral peak photon energy, Ep, and the radiated energy or luminosity (i.e., the “Amati relation” and other correlations derived from it) is one of the central and most debated topics in GRB astrophysics, with implications for physics and the geometry of prompt emission, the identification and understanding of various classes of GRBs (short/long, XRFs,sub-energetic), and GRB cosmology. Fermi is exceptionally suited to provide, also in conjunction with Swift observations, a significant step forward in this field of research. Indeed, one of the main goals of Fermi/GBM is to make accurate measurements of Ep, by exploiting its unprecedented broad energy band from ~8 keV to ~30MeV; in addition, for a small fraction of GRBs, the LAT can extend the spectral measurements up to the GeV energy range, thus allowing a reliable estimate of the bolometric radiated energy/luminosity. We provide a review, an update and a discussion of the impact of Fermi observations in the investigation, understanding and testing of the Ep,i –Eiso (“Amati”) relation.

A precision measurement of the inclusive ep scattering cross section at HERA

A measurement of the inclusive deep-inelastic neutral current e+p scattering cross section is reported in the region of four-momentum transfer squared, 12<=Q^2<=150 GeV^2, and Bjorken x, 2x10^-4<=x<=0.1. The results are based on data collected by the H1 Collaboration at the ep collider HERA at positron and proton beam energies of E_e=27.6 GeV and E_p=920 GeV, respectively. The data are combined with previously published data, taken at E_p=820 GeV. The accuracy of the combined measurement is typically in the range of 1.3-2%. A QCD analysis at next-to-leading order is performed to determine the parton distributions in the proton based on H1 data.

Measurement of the inclusive ep scattering cross section at low Q2 and x at HERA

A measurement of the inclusive ep scattering cross section is presented in the region of low momentum transfers, 0.2 GeV^2 < Q^2 < 12 GeV^2, and low Bjorken x, 5x10^-6 < x < 0.02. The result is based on two data sets collected in dedicated runs by the H1 Collaboration at HERA at beam energies of 27.6 GeV and 920 GeV for positrons and protons, respectively. A combination with data previously published by H1 leads to a cross section measurement of a few percent accuracy. A kinematic reconstruction method exploiting radiative ep events extends the measurement to lower Q^2 and larger x. The data are compared with theoretical models which apply to the transition region from photoproduction to deep inelastic scattering.

Measurement of the Inclusive ep Scattering Cross Section at HERA

Measurements of the inclusive ep scattering cross section are presented in the wide region of four-momentum transfers squared, 0.2 GeV 2 ⩽ Q 2 ⩽ 30000 GeV 2 , and Bjorken x, 4 ⋅ 10 −6 ≲ x ≲ 0.8 . The results are based on data sets collected by the H1 and ZEUS collaborations at HERA. The data include the region of high inelasticity y up to 0.9, which is sensitive to the longitudinal proton structure function F L ( x , Q 2 ) .

Measurement of the neutral current DIS cross section at H1

New preliminary measurements of the inclusive neutral current ep scattering cross sections from the H1 experiment at HERA are presented.The inclusive ep scattering cross ection is measured in the region of low negative four-momentum transfer squared, 0.2 ≤ Q2 ≤ 12 GeV2, and low Bjorken x, 5·10-6 ≤ x ≤ 0.02. The result is based on two data sets collected in dedicated runs at beam energies of 27.5 GeV for positrons and 920 GeV for protons and covers the transition region from quasi-real photoproduction to deep inelastic scattering. A combination with data used in results previously published by H1 leads to an accuracy of a few percent on the resulting cross section measurement. Measurements of the e±p inclusive cross sections are presented in the region of high inelasticity y > 0.6 at low (8 ≤ Q2 ≤ 50 GeV2) and medium (65 ≤ Q2 ≤ 800 GeV2) values of Q2. At high values of inelasticity the cross section is sensitive to the longitudinal structure function F land thus provides additional constraints on DGLAP evolution. These results are based on data collected during the years 2003-2007 (HERA-II) which correspond to an integrated luminosity of 315 pb-1. About equal luminosities obtained for the e+p and e−p samples allow for a high precision control of background processes.

Aortic Compliance Following EVAR and the Influence of Different Endografts:Determination Using Dynamic MRA

To utilize dynamic magnetic resonance angiography (MRA) to characterize aortic stiffness (beta) and elastic modulus (Ep) as indexes of wall compliance during the cardiac cycle and determine any influence of different endograft designs or the presence of endoleaks on these indexes. Eleven consecutive patients (11 men; median age 74 years, range 63-78) with abdominal aortic aneurysm (AAA) selected for endovascular repair were scanned pre- and postoperatively. Aortic area and diameter changes during the cardiac cycle were determined using dynamic MRA at 4 levels: 3 cm above the renal arteries, between the renal arteries, 1 cm below the renal arteries, and at the level of maximum aneurysm sac diameter. Ep and beta were calculated. Data are presented as median (range); p<0.05 was considered significant. Preoperatively, Ep and beta were significantly higher at the level of the aneurysm sac compared to all other levels (p<0.05). Following EVAR, stiffness increased at this level (p<0.05). After implantation, patients with an Excluder endograft demonstrated Ep and beta measurements at the aneurysm neck that were 94% and 60% higher, respectively, compared to those with a Talent (p<0.05) endograft. The presence of an endoleak had no effect on Ep or beta. This study introduces the feasibility of dynamic MRA imaging-based calculations of aortic elastic modulus and stiffness. AAA patients demonstrate increased Ep and beta at the level of the aneurysm sac. EVAR results in increased aneurysm sac Ep and beta. Stent-graft design seems to alter Ep and beta within the aneurysm neck, which may have consequences for endograft durability. The presence of an endoleak does not seem to have an effect on Ep or beta.

Eta and two pion electroproduction with CLAS

We present new measurements of the reactions ep → epη and ep → e′pπ +π − using data from the CLAS detector at Jefferson Laboratory. In the η channel we present a precise measurement of the proton- S 11 (1535) coupling over a wider range of Q 2 than any previous experiment. In the two-pion channel, the data show resonant structure not visible in previous experiments.

Inclusive diffraction at HERA

New precision measurements of inclusive diffractive deep-inelastic ep scattering interactions, performed by the H1 and ZEUS collaborations at the HERA collider, are discussed. A new set of diffractive parton distributions, determined from recent high precision H1 data, is presented.