Models of venous return and their application to estimate the mean systemic filling pressure

Mean systemic filling pressure is the equilibrium pressure in the systemic circulation when the heart is arrested and there is no flow. This pressure is a measure of the stressed volume of the systemic circulation and regarded as the driving pressure for the venous return during steady states [1-3]. In this thesis the terms stationary level and steady state refer to a state in which the mean pressure and flow, averaged over a heart cycle, do not change. Dynamic conditions refer to changes in averaged pressure and flow between heart beats. The property of mean systemic filling pressure as driving pressure fat venous return has been explained by Guyton [1] and others [2,3]. Most methods that are used to determine mean systemic filling pressure require a total stop of the circulation by inflating a balloon in the right atrium [4] or arresting the heart by fibrillation [5-9]. In 1985 Versprille & Jansen developed a method to determine mean systemic filling pressure in the intact circulation [10]. Their method required seven different steady states of central venous pressure and cardiac output. The total procedure lasted approximately 45 min. If circulatory conditions are nor stable for such a time span, this method is not useful. A main purpose of the research described in this thesis was to develop faster methods to determine the mean systemic filling pressure in the intact circulation

Abundances of the elements in the solar system

A review of the abundances and condensation temperatures of the elements and their nuclides in the solar nebula and in chondritic meteorites. Abundances of the elements in some neighboring stars are also discussed.Comment: 42 pages, 11 tables, 8 figures, chapter, In Landolt- B\"ornstein, New Series, Vol. VI/4B, Chap. 4.4, J.E. Tr\"umper (ed.), Berlin, Heidelberg, New York: Springer-Verlag, p. 560-63

Solar System Abundances of the Elements

Representative abundances of the chemical elements for use as a solar abundance standard in astronomical and planetary studies are summarized. Updated abundance tables for solar system abundances based on meteorites and photospheric measurements are presented.Comment: 46 pages; 5 figures; 8 tables; In: Principles and Perspectives in Cosmochemistry.Lecture Notes of the Kodai School on 'Synthesis of Elements in Stars' held at Kodaikanal Observatory, India, April 29 - May 13, 2008 (Aruna Goswami and B. Eswar Reddy eds.) Astrophysics and Space Science Proceedings, Springer-Verlag Berlin Heidelberg, 2010, p. 379-417 (ISBN 978-3-642-10351-3), 201

Clopidogrel in noncarriers of CYP2C19 loss-of-function alleles versus ticagrelor in elderly patients with acute coronary syndrome: a pre-specified sub analysis from the POPular Genetics and POPular Age trials CYP2C19 alleles in elderly patients

Background: Patients with acute coronary syndrome (ACS) who are carrying CYP2C19 loss-of-function alleles derive less benefit from clopidogrel treatment. Despite this, in elderly patients, clopidogrel might be preferred over more potent P2Y12 inhibitors due to a lower bleeding risk. Whether CYP2C19 genotype-guided antiplatelet treatment in the elderly could be of benefit has not been studied specifically.Methods: Patients aged 70 years and older with known CYP2C19*2 and *3 genotype were identified from the POPular Genetics and POPular Age trials. Noncarriers of loss-of-function alleles treated with clopidogrel were compared to patients, irrespective of CYP2C19 genotype, treated with ticagrelor and to clopidogrel treated carriers of loss-of-function alleles. We assessed net clinical benefit (all-cause death, myocardial infarction, stroke and Platelet Inhibition and Patient Outcomes (PLATO) major bleeding), atherothrombotic outcomes (cardiovascular death, myocardial infarction, stroke) and bleeding outcomes (PLATO major and minor bleeding).Results: A total of 991 patients were assessed. There was no significant difference in net clinical benefit (17.2% vs. 15.1%, adjusted hazard ratio (adjHR) 1.05, 95% confidence interval (CI) 0.77-1.44), atherothrombotic outcomes (9.7% vs. 9.2%, adjHR 1.00, 95%CI 0.66-1.50), and bleeding outcomes (17.7% vs. 19.8%, adjHR 0.80, 95%CI 0.62-1.12) between clopidogrel in noncarriers of loss-of-function alleles and ticagrelor respectively.Conclusion: In ACS patients aged 70 years and older, there was no significant difference in net clinical benefit and atherothrombotic outcomes between noncarriers of a loss-of-function allele treated with clopidogrel and pa-tients treated with ticagrelor. The bleeding rate was numerically; though not statistically significant, lower in pa-tients using clopidogrel.(c) 2021 Published by Elsevier B.V.Cardiolog

Endometrial scratching in women with one failed IVF/ICSI cycle-outcomes of a randomised controlled trial (SCRaTCH)

STUDY QUESTION: Does endometrial scratching in women with one failed IVF/ICSI treatment affect the chance of a live birth of the subsequent fresh IVF/ICSI cycle? SUMMARY ANSWER: In this study, 4.6% more live births were observed in the scratch group, with a likely certainty range between -0.7% and +9.9%. WHAT IS KNOWN ALREADY: Since the first suggestion that endometrial scratching might improve embryo implantation during IVF/ICSI, many clinical trials have been conducted. However, due to limitations in sample size and study quality, it remains unclear whether endometrial scratching improves IVF/ICSI outcomes. STUDY DESIGN, SIZE, DURATION: The SCRaTCH trial was a non-blinded randomised controlled trial in women with one unsuccessful IVF/ICSI cycle and assessed whether a single endometrial scratch using an endometrial biopsy catheter would lead to a higher live birth rate after the subsequent IVF/ICSI treatment compared to no scratch. The study took place in 8 academic and 24 general hospitals. Participants were randomised between January 2016 and July 2018 by a web-based randomisation programme. Secondary outcomes included cumulative 12-month ongoing pregnancy leading to live birth rate. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women with one previous failed IVF/ICSI treatment and planning a second fresh IVF/ICSI treatment were eligible. In total, 933 participants out of 1065 eligibles were included (participation rate 88%). MAIN RESULTS AND THE ROLE OF CHANCE: After the fresh transfer, 4.6% more live births were observed in the scratch compared to control group (110/465 versus 88/461, respectively, risk ratio (RR) 1.24 [95% CI 0.96-1.59]). These data are consistent with a true difference of between -0.7% and +9.9% (95% CI), indicating that while the largest proportion of the 95% CI is positive, scratchin

Predicting temperature timit values for cold touchable surfaces

During some occupational activities, workers have to handle objects or tools in cold environments. In other circumstances, contact between the hand and the cold surface might be accidental (e.g., when a worker touches a cold surface, a cooler, etc). In both cases, contact between the hands and the cold material can induce discomfort, pain or frostbite, and exposure to cold may negatively influence the dexterity and the manual sensitivity of the subject [1]. Four years ago the EU started to finance a research project to determine the maximum duration of touching and gripping materials in the cold. In four different European labs, six male and six female students participated in the study. All subjects touched 10cm x 10cm blocks of different materials: wood, nylon, steel and aluminium. The 5 materials chosen were representative of a wide range of thermal properties that are relevant to cold surfaces. The subjects were asked to touch with their index finger the materials maintained at temperatures ranging between -40°C and -5°C. Thermocouples were placed on the back of the hand and on the touching surface of the finger. The subjects scored their subjective ratings on scales of pain and numbness with 5 levels (0 to 4; from total absence to intolerable level). From all the experiments, an extensive data set was collected on cooling curves of the fingers touching the mentioned cold materials. From this data set general safety limits could be derived for touching cold surfaces of various materials. Additional modelling allowed extending the duration limits beyond the range of the data. Furthermore, recent developments in the modelling showed that the actual limits are leaning on the safe side, due to the measurement technique that has been used. In conclusion, touching experiments were conducted to determine the maximum allowable tolerable exposure duration at different temperatures and for different materials. This duration varies inversely as a function of the material constants and linearly as a function of the temperature of the material. Modelling this problem allows the development of exposure limits outside the experimental range and to improve the validity of the experimental limits