50 research outputs found
Is aspirin effective in women undergoing in vitro fertilization (IVF)? Results from an individual patient data meta-analysis (IPD MA)
No full textBACKGROUND Aspirin is believed to improve the outcome of IVF, but previous conventional meta-analyses on the subject are conflicting. Therefore, we performed a meta-analysis with individual patient data (IPD MA) of randomized clinical trials (RCTs) on the subject. METHODS A systematic literature search was conducted to identify RCTs assessing the effectiveness of aspirin in IVF. Authors were asked to share their original data. In a one step meta-analytic approach, the treatment effect of aspirin was estimated with odds ratios (ORs) and 95% confidence intervals (CIs) using logistic regression, based on the intention to treat principle. RESULTS Ten studies fulfilled the inclusion criteria. Authors of six studies provided IPD, including 1119 patients (562 placebo and 557 aspirin). There were 160 clinical pregnancies in the aspirin (28.8%) and 179 (31.9%) in the placebo group [OR 0.86, 95% CI (0.69–1.1)]. There were 129 ongoing pregnancies in the aspirin (23.6%) and 147 in the placebo group (26.7%) [OR 0.85, 95% CI (0.65–1.1)]. Whereas the conventional meta-analysis limited to studies that could provide IPD showed an OR of 0.89 (95% CI 0.69–1.2), the conventional meta-analysis limited to the eight studies of which method of randomization could be confirmed showed an OR of 0.94 (95% CI 0.76–1.17) and the conventional meta-analysis including all 10 eligible RCTs identified with our search changed the OR to 1.07 (95% CI 0.81–1.41). This difference in direction of effect, derived from the studies not able to share IPD of which quality of randomization could not be confirmed. CONCLUSIONS Aspirin does not improve pregnancy rates after IVF.E. Groeneveld, K.A. Broeze, M.J. Lambers, M. Haapsamo, K. Dirckx, B.C. Schoot, B. Salle, C.I. Duvan, R. Schats, B.W. Mol, and P.G.A. Hompes, for the IPD MARIA study grou
Medical entries in 18th-century encyclopaedias : the lexicographic construction of knowledge
No full textThe aim of applying new technical and scientific discoveries to benefit mankind is the main purpose of early modern research in Britain, and is typical of a process well established since the 17th century (Jardine 1999; Hunter 1981). The experimental method based on observation, collection of data, reproducibility of phenomena, deduction and application to the world around, with a view to making progress possible, can therefore be considered as representative of the principles inspiring 18th-century encyclopaedias. Their content and form are an evident and perhaps necessary expression of a great change in the interpretation of the world: the research and discovery path has as its ultimate aim utility, beyond any speculative, purely theoretical attitude. This means that concrete facts should therefore be transformed through language into written texts which everybody can take advantage of (Formigari 1974; Banks 2008; Gotti 2011). Alongside the development of the encyclopaedic genre, the 18th century witnessed great changes in the medical field and in the social approach to medicine as well (French & Wear 1991; Lane 2001; Loudon 1986 and 1992; Riley 1987): new concepts, new processes and new techniques, besides the layman’s interest in them, emerged with force. Medical research, which directly goes back to the outstanding approaches and discoveries of the preceding century (Lindemann 2010; Wear 1989 and 2000), urged experts and non-experts alike to develop new communicative strategies both to categorize, organize, describe and discuss advanced issues, and to apply pioneering approaches to well-known and completely new situations. Medical writing thus became an expanding phenomenon and an essential one to record medical debate and experience, both in the early modern English period (Taavitsainen & Pahta 2011a; McConchie & Curzan 2011; McConchie 1997; Dirckx 1976) and later, particularly after 1750 when the English Medical reform was definitely taking place (Bynum & Porter 1992; Fissel 2007; Warren 1951). The present analysis focuses on the first editions of the three most relevant 18th-century ‘dictionaries of arts and sciences’: John Harris’s Lexicon Technicum (LT, 1704), Ephraïm Chambers’s Cyclopaedia (Cy, 1728), and the Encyclopaedia Britannica (Br, 1768-1771).
The percentage covered by medical terminology in LT, Cy and Br (approximately between 8% and 13%) takes on notable significance, considering the high number of branches of knowledge included in the three works. In particular, in Cy, an elaborate tree of knowledge is included in the preface, whereas in Br the most important branches of arts and science are organized into treatises (amongst which MEDICINE and SURGERY). The tendency to increase the number of medical entries from LT to Br testifies to the great interest in medicine and in medical vocabulary, and also guarantees a great variety of examples (for a general survey of this topic, Lonati 2002 and 2007)
Ontwerpend onderzoek als versneller voor transities opgaven: Reflectie op en aanbevelingen voor ontwerpend onderzoek aan Platform Ontwerp NL
No full textPlatform Ontwerp NL heeft ons, de auteurs van dit stuk, gevraagd om te reflecteren op ontwerpend onderzoek in de ateliers over de grote transitie opgaven die vlak voor de zomer zijn georganiseerd in het kader van Ontwerpend onderzoek NOVEX. Vanaf november 2023 loopt er een ontwerpend onderzoek traject, dat het ministerie van BZK faciliteert. Dit traject is bedoeld om de provincies te ondersteunen, die aan de Ruimtelijke voorstellen werken. In een aantal stappen gingen ontwerpbureaus aan de slag met beleidsinventarisatie, de analyse van prangende vraagstukken (hot topics) en van nationale overzichten die laten zien welke vraagstukken waar spelen en waar er provincieoverschrijdende kansen liggen om thema’s te verbinden. De ontwerpbureaus werken met de notities die de provincies produceren, waardoor de kaartbeelden die ontstaan, steeds preciezer worden.Landscape Architectur
Demolding of hot embossed polymer microstructures
No full textThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from PDF version of thesis.Includes bibliographical references (p. 219-229).Polymer-based microfluidic "lab on a chip" technology promises to reduce cost and extend access to medical diagnostic tests that formerly required expensive and labor-intensive lab work. The predominant methods for manufacturing these devices are miniaturized molding processes including casting, injection molding, and hot embossing. These techniques have in common the use of a mold to define the shape of functional features (fluidic channels), the separation of the part from the mold as a process step (demolding), and the intended re-use of the mold to produce additional parts. The demolding step in particular poses significant challenges for mass production. Demolding affects several issues including production rate, part quality, and mold lifetime, and demolding-related defects are frequently observed. Despite its importance, there has been no comprehensive effort to analyze demolding theoretically or experimentally. This thesis aims to deepen the understanding of demolding of polymer microstructures in order to facilitate mass manufacturing of polymer-based devices with micro-scale functional features, such as microfluidic chips. A theory of demolding mechanics has been proposed that combines the effects of thermal stress, friction, and adhesion in a unified framework. A metric by which demolding can be characterized experimentally--the demolding work--has been proposed by analogy with interfacial fracture and has been related to underlying physical mechanisms. Finite element simulations based on this theory of demolding have been performed to investigate the effects of important parameters, including demolding temperature and feature geometry. A test method for characterizing demolding by directly measuring the demolding work for individual microstructures has been developed and applied to hot embossing to study the effects of process parameters such as demolding temperature, the effects of feature geometry and layout, and the impacts of mitigation strategies such as low-adhesion mold coatings. The results of these demolding experiments broadly agree with expected trends based on the theory of demolding mechanics proposed herein. A dimensionless parameter aggregating the effects of feature geometry and layout has been identified and related to the occurrence of demolding-related defects, the demolding process window, and the demolding temperature that minimizes the demolding work. These findings have been generalized to provide processing and design guidance for industrial application of polymer micro-molding.by Matthew E. Dirckx.Ph.D
The effect of nasal shape on the thermal conditioning of inhaled air : using clinical tomographic data to build a large-scale statistical shape model
No full textAbstract: In this paper, we investigate the heating function of the nasal cavity qualitatively, using a high-quality, large-scale statistical shape model. This model consists of a symmetrical and an asymmetrical part and provides a new and unique way of examining changes in nasal heating function resulting from natural variations in nasal shape (as obtained from 100 clinical CT scans). Data collected from patients suffering from different nasal or sinus-related complaints are included. Parameterized models allow us to investigate the effect of continuous deviations in shape from the mean nasal cavity. This approach also enables us to avoid many of the compounded effects on flow and heat exchange, which one would encounter when comparing different patient-specific models. The effects of global size, size-related features, and turbinate size are investigated using the symmetrical shape model. The asymmetrical model is used to investigate different types of septal deviation using Mladina's classification. The qualitative results are discussed and compared with findings from the existing literature
High quality statistical shape modelling of the human nasal cavity and applications
No full textThe human nose is a complex organ that shows large morphological variations and has many important functions. However, the relation between shape and function is not yet fully understood. In this work, we present a high quality statistical shape model of the human nose based on clinical CT data of 46 patients. A technique based on cylindrical parametrization was used to create a correspondence between the nasal shapes of the population. Applying principal component analysis on these corresponded nasal cavities resulted in an average nasal geometry and geometrical variations, known as principal components, present in the population with a high precision. The analysis led to 46 principal components, which account for 95% of the total geometrical variation captured. These variations are first discussed qualitatively, and the effect on the average nasal shape of the first five principal components is visualized. Hereafter, by using this statistical shape model, two application examples that lead to quantitative data are shown: nasal shape in function of age and gender, and a morphometric analysis of different anatomical regions. Shape models, as the one presented here, can help to get a better understanding of nasal shape and variation, and their relationship with demographic data.Applied Ergonomics and Desig
LDV measurement of bird ear vibrations to determine inner ear impedance and middle ear power flow
No full textAbstract: The mechanical behavior of the middle ear structures in birds and mammals is affected by the fluids in the inner ear (IE) that are present behind the oval window. In this study, the aim was to gather knowledge of the acoustic impedance of the IE in the ostrich, to be able to determine the effect on vibrations and power flow in the single-ossicle bird middle ear for future studies. To determine the IE impedance, vibrations of the ossicle were measured for both the quasi-static and acoustic stimulus frequencies. In the acoustic regime, vibrations were measured with a laser Doppler vibrometer and electromagnetic stimulation of the ossicle. The impedance of the inner ear could be determined by means of a simple RIX model in series, which resulted in a stiffness reactance of K-IE = 0.20.10(12) Pa/m(3), an inertial impedance of M-IE = 0.652.10(6) Pa s(2)/m(3), and a resistance of R-IE = 1.57.10(9) Pa s/m. The measured impedance is found to be considerably smaller than what is found for the human IE
Energy localisation and frequency analysis in the locust ear
No full textAnimal ears are exquisitely adapted to capture sound energy and perform signal analysis. Studying the ear of the locust, we show how frequency signal analysis can be performed solely by using the structural features of the tympanum. Incident sound waves generate mechanical vibrational waves that travel across the tympanum. These waves shoal in a tsunami like fashion, resulting in energy localisation that focuses vibrations onto the mechanosensory neurons in a frequency dependent manner. Using finite element analysis, we demonstrate that two mechanical properties of the locust tympanum, distributed thickness and tension, are necessary and sufficient to generate frequency-dependent energy localisation. <br/
Digital image correlation for full-field high resolution assessment of leaf growth
No full textAbstract: Changes in shape and size of the leaves are driven by several transient growth parameters. Being able to assess resulting changes at a high temporal and spatial resolution is a necessary tool for studying biochemical principles of leaf development, and for construction of leaf growth models. In this short communication, a technique based on the use of 2D digital image correlation (DIC) is presented to track leaf growth. A speckle pattern with orange fluorescent paint was applied on three leaves of the sycamore maple (Acer pseudoplatanus) at an arbitrary point in growth. For ten consecutive days, images of the growing leaves were analyzed with DIC, revealing leaf growth patterns. The patterns were similar for three leaves, and results corresponded both with literature data of leaf growth and with leaf area measurements using manual segmentation of leaf images. We demonstrate that DIC can be applied for tracking leaf growth. Based on the results, a detailed macro-model for leaf growth can be developed or environmental effects on leaf growth can be assessed, amongst other possible applications
