High Wall Shear Stress can Predict Wall Degradation in Ascending Aortic Aneurysms: An Integrated Biomechanics Study

Background: Blood flow patterns can alter material properties of ascending thoracic aortic aneurysms (ATAA) via vascular wall remodeling. This study examines the relationship between wall shear stress (WSS) obtained from image-based computational modelling with tissue-derived mechanical and microstructural properties of the ATAA wall using segmental analysis.Methods: Ten patients undergoing surgery for ATAA were recruited. Exclusions: bicuspid aortopathy, connective tissue disease. All patients had pre-operative 4-dimensional flow magnetic resonance imaging (4D-MRI), allowing for patient-specific computational fluid dynamics (CFD) analysis and anatomically precise WSS mapping of ATAA regions (6–12 segments per patient). ATAA samples were obtained from surgery and subjected to region-specific tensile and peel testing (matched to WSS segments). Computational pathology was used to characterize elastin/collagen abundance and smooth muscle cell (SMC) count.Results: Elevated values of WSS were predictive of: reduced wall thickness [coef −0.0489, 95% CI (−0.0905, −0.00727), p = 0.022] and dissection energy function (longitudinal) [−15,0, 95% CI (−33.00, −2.98), p = 0.048]. High WSS values also predicted higher ultimate tensile strength [coef 0.136, 95% CI (0 0.001, 0.270), p = 0.048]. Additionally, elevated WSS also predicted a reduction in elastin levels [coef −0.276, 95% (CI −0.531, −0.020), p = 0.035] and lower SMC count ([oef −6.19, 95% CI (−11.41, −0.98), p = 0.021]. WSS was found to have no effect on collagen abundance or circumferential mechanical properties.Conclusions: Our study suggests an association between elevated WSS values and aortic wall degradation in ATAA disease. Further studies might help identify threshold values to predict acute aortic events.

Anatomy of the Heart with the Highest Heart Rate

Shrews occupy the lower extreme of the seven orders of magnitude mammals range in size. Their hearts are large relative to body weight and heart rate can exceed a thousand beats a minute. To investigate whether cardiac traits that are typical mammalian scale to these extremes, we assessed the heart of three species of shrew (genus Sorex) following the sequential segmental analysis developed for human hearts. Using micro-computed tomography we describe the overall structure and find, in agreement with previous studies, a large and elongate ventricle. The atrial and ventricular septums and the atrioventricular and arterial valves are typically mammalian. The ventricular walls comprise mostly compact myocardium and especially the right ventricle has few trabeculations on the luminal side. A developmental process of compaction is thought to reduce trabeculations in mammals, but in embryonic shrews the volume of trabeculations increase for every gestational stage, only slower than the compact volume. By expression of Hcn4, we identify a sinus node and an atrioventricular conduction axis which is continuous with the ventricular septal crest. Outstanding traits include pulmonary venous sleeve myocardium that reaches farther into the lungs than in any other mammals. Typical proportions of coronary arteries-to-aorta do not scale and the shrew coronary arteries are proportionally enormous, presumably to avoid the high resistance to blood flow of narrow vessels. In conclusion, most cardiac traits do scale to the miniscule shrews. The shrew heart, nevertheless, stands out by its relative size, elongation, proportionally large coronary vessels, and extent of pulmonary venous myocardium.

Application of Parallel Difference Tests to Resolve the Axial Activation–Deactivation Profile of Copper–Zinc Oxide Catalyst During Hydrogenation of Methyl Acetate

The deactivation of a copper–zinc oxide catalyst has been studied in a set of parallel tests which covered a range of space-times with equal flow and variable catalyst quantity, from 1/8th bed to full bed. The activation–deactivation trends over time in different segments of the full catalyst bed have been determined by two alternative parallel difference methods. The relative trends in segmental activity over time were followed by (a) using a pre-determined reaction model, and (b) by referencing the axial conversion profile against the initial profile. The trends estimated by both methods were in broad agreement. The results show that the front segment of the catalyst bed experienced a more rapid process of deactivation than the rest of the catalyst bed. This process is consistent with the known susceptibility of this type of catalyst to deactivation by chlorine and sulfur impurities in the feedstock. The main part of the catalyst bed appeared to undergo a process of activation during the first 150 h, followed by a slow process of deactivation which was more rapid during periods at increased temperature. The slow deactivation is most likely associated with sintering of copper particles. The conversion parallel difference method provides a convenient and rapid tool for segmental analysis of parallel life tests, and is well-suited to resolving the impact of a poison front within a catalyst bed.

Distribution profiles of diphenhydramine and lidocaine in scalp, axillary, and pubic hairs measured by micro-segmental hair analysis: good indicator for discrimination between administration and external contamination of the drugs

Purpose Drug distribution in scalp hair can provide historical information about drug use, such as the date and frequency of drug ingestion. We previously developed micro-segmental hair analysis, which visualizes drug distribution at 0.4-mm intervals in individual hairs. The present study examines whether the distribution profiles of drugs can be markers for the administration or external contamination of the drugs using scalp, axillary, and pubic hairs. Methods A single dose of anti-itch ointment containing diphenhydramine (DP) and lidocaine (LD) was topically applied to the axillary or pubic areas of two volunteers; DP was also orally administered; and LD was intra-gingivally injected. Scalp, axillary, and pubic hairs were assessed using our micro-segmental analysis. Results The localization of DP and LD differed within individual scalp hair strands, implying DP and LD were predominantly incorporated into scalp hair via the bloodstream and via sweat/sebum, respectively, showing double-peak profiles. However, DP and LD were distributed along the shafts of axillary and pubic hairs without appearance of the double-peak profiles when the ointment had been applied to the axillary and pubic areas. The distributions of DP and LD in scalp hairs did not significantly differ according to administration routes, such as oral administration, gingival injection, and topical application. Conclusions Micro-segmental analysis revealed differences in the distribution profiles of drugs in hairs, and distinguished hairs with and without external contamination. These findings will be useful for understanding of the mechanism of drug uptake into hair and for estimating the circumstances for a drug use.

A Contrastive Study of English and Arabic Vowel Phonemes

Consequently, the present study sheds light on a very important aspect that is a contrastive analysis of segmental vowel phonemes of both L1 and L2. As one of the Problems, that is affecting the teaching/learning process of ELT. Then to clarify the different areas between the segmental vowel phonemes of Arabic and English. It also aims at making a comparative segmental analysis in the vowel phonemes of both L1 - L2, in order to shed light on the areas of difficulties. Taking into account the different forms of sounds in relation to their spellings. Also the sound systems of both languages L1 and L2. Particular the areas of common mistakes. Thus, it encourages teachers to check English pronunciation before teaching and predict problems before they happen. Also the use of advanced methods and pronunciation dictionary for (IPA). It also helps learners to master all the significant sound features and basic structural patterns. On the phonological levels, differences cause difficulties e.g. The areas of Arabic /p/ and /v/ ,and English front vowels phonemes /i:/-/i/- /e/- /æ/, central /ə:/- /ə/-/Λ/,and back/a:/-/o/-/ ﬤ:/-/u/-/u:/ phonemes in English, they do not exist in Arabic. In addition to the English vowel /e/ which doesn’t exist in Arabic. This observation can't be only linguistically, but it will also confirm by L2 learners. These theories need to be clarified in order to allow rules to be expressed. In the English language, there are 26 alphabetical letters which are totally different than their sounds. Another drawback is the alphabetical method which is intended to teach reading by means of spelling. There is no one –to- one correspondence between sounds and letters. That is to say, each different sound cannot be represented by the same letter. There are also words which are spelt differently but sound the same. Therefore, the present study concentrates on the difficulties that Learners and beginners face in using English segmental vowel phonemes. It also tries to get new methods and new ideas. This study is based on the practical experience of the writer, being specialized in English phonology, a lecturer and an author of a phonetics textbook for beginner learners who learn English as a foreign language. And as a supervisor who follows undergraduate students in the field of experience. That is, in order to find out possible remedial solutions, better suggestion and recommendations. Then follows a descriptive method to achieve this purpose. With the sample of twenty student girls. As a case study of undergraduate trainees of Majmaah Universitiy in the training field, to collect data from the subjects’ real environment during talks, speeches, presentations and teaching in the Field Experience. The results were recorded to be analyzed. In particular, the areas of English vowels and diphthongs that are totally different than in Arabic.

Congenitally Malformed Hearts: Aspects of Teaching and Research Involving Medical Students

To appreciate congenital heart disease fully, a detailed understanding of the anatomical presentation, as well as the physiology, is required. This is often introduced at an advanced stage of training. Professor Anderson has been influential in the Clinical Anatomy Intercalated BSc programme at the University of Birmingham, in particular in his teaching on Sequential Segmental Analysis. This article describes the experiences of the latest cohort of students on this programme, who undertook varying research projects using the Birmingham Cardiac Archive, with the guidance of Professor Anderson. The projects outlined include various aspects of isomerism, encompassing both the cardiac and abdominal manifestations, as well as details of congenitally corrected transposition of the great arteries and prenatally diagnosed right aortic arch and double arch. These studies all aimed to increase the knowledge base of their respective cardiac malformations and provide a basis for further research.

Segmental and global longitudinal strain differences between children with paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 pandemic and Kawasaki disease

Funding Acknowledgements Type of funding sources: None. Introduction The paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) and Kawasaki disease (KD) have overlapping features. This study aimed to describe the strain segmental analysis among both entities. Methods Retrospective review of strain segmental analysis within 4 weeks of presentation of symptoms among children diagnosed with PIMS-TS between April and June 2020 and a historic cohort of typical KD from the Royal Brompton Hospital, London. Results We included 33 PIMS-TS patients (23 males, 69.7%) at a mean age of 8 ± 4,9 years old and 45 KD patients (31 males, 68,9%) at a mean age of 5,8 ± 4,5 years old. PIMS-TS patients were older at presentation (p = 0.038). Left ventricle ejection fraction (LVEF) was normal in both groups (63,3% vs 63,5%; p= 0,89), 4/33 PIMS-TS children (12,1%) had coronary arteries abnormalities (CAA), whereas 100% of KD cohort had CAA. Both groups had a normal global longitudinal strain (GLS),but in PIMS-TS it was significantly reduced compared to the KD group (-20% vs -22%; p = 0,008). Basal segments were the most affected in PIMS-TS with significant difference in the basal anterior and anterolateral strain compared to KD (respectively -18,2% vs -23,4%; p < 0,001 and - 16,7% vs -22,7%; p < 0,001). PIMS-TS had a greater anterior, anterolateral and posterior segments involvement with a significant reduction in the anterolateral mid-wall longitudinal strain (-18,3% vs -22%; p = 0,002). Apical segments were less involved, with significant difference only in the septal and inferior apical strain (respectively p = 0.001 and p = 0,032). Conclusions These preliminary data showed that after 4 weeks from the onset of symptoms, all PIMS-TS patients had a normal LVEF but they had a significant reduction in GLS and different segmental involvement compared to KD cohort. We hypothesize that these findings may be related to direct myocardial damage in PIMS-TS rather than caused by coronaries perfusion abnormalities. Abstract Figure. Bull"s eye

A Pictorial Account of Heart Development: Spatial and Temporal Aspects of The Human Embryonic Heart Between 3.5 and 8 Weeks of Development

Heart development is topographically complex and requires visualization to understand its progression. No comprehensive 3-dimensional primer of human cardiac development is currently available. We prepared detailed reconstructions of 12 hearts between 3.5 and 8 weeks post fertilization, using Amira® 3D-reconstruction and Cinema4D®-remodeling software. The models were visualized as calibrated interactive 3D-PDFs. We describe the developmental appearance and subsequent remodeling of 70 different structures incrementally, using sequential segmental analysis. Pictorial timelines of structures highlight age-dependent events, while graphs visualize growth and spiraling of the wall of the heart tube. The basic cardiac layout is established between 3.5 and 4.5 weeks. Septation at the venous pole is completed at 6 weeks. Between 5.5 and 6.5 weeks, as the outflow tract becomes incorporated in the ventricles, the spiraling course of its subaortic and subpulmonary channels is transferred to the intrapericardial arterial trunks. The remodeling of the interventricular foramen is complete at 7 weeks.