169 research outputs found

    Texture profile analysis reveals a stiffer ovarian cortex after testosterone therapy : a pilot study

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    Purpose: The importance of the surrounding ovarian stromal cells and extracellular matrix in the development and maturation of follicles has recently gained attention. An aberrant extracellular matrix has been described in ovaries of patients with polycystic ovary syndrome where a more rigid structural environment, possibly induced by endogenous testosterone, impairs normal folliculogenesis. In this context, we describe the textural parameters of the ovarian cortex of transgender men after prolonged testosterone administration compared to the textural parameters of the non-exposed ovarian cortex originating from female oncological patients. Methods: Texture profile analysis (TPA) was performed on ovarian cortex (5 x 5 mm) of oncological and transgender patients in order to measure stiffness, hardness, cohesiveness, and springiness of the ovarian cortex (LRXplus universal testing system). Statistical analysis was performed using repeated measurements mixed models and the Spearman rank order correlation test (IBM SPSS Statistics 23). Results: A total of 36 frozen-thawed cortical strips (5 x 5 mm) were subjected to TPA. The superficial part of cortex fragments originating from transgender persons (fragments < 1.4 mm; N = 10) appeared to be significantly stiffer compared to cortex derived from oncology patients (fragments < 1.4 mm; N = 7) (6.78 +/- 1.38 N/mm versus 5.41 +/- 0.9 N/mm respectively, p = 0.036). Conclusions: This is the first application of TPA in ovarian cortex to study the physical properties. Comparing the physical properties, we objectively describe an increased cortical stiffness in the most outer part of the ovarian cortex following prolonged testosterone administration in transgender men compared to the ovarian cortex of oncological patients. This preliminary and novel approach could be the start of future research to understand the physical properties of ovarian tissue

    Dry High Speed Orthogonal Turning of Titanium Alloy Wear Evolution and Chip Morphology

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    The present work is an experimental study on the dry high-speed turning of Ti-6Al-4 V titanium alloy. The objective of this study is to see for high cutting speeds, how wear occurs on the face of insert and how to evolve cutting forces and chip formation. Cutting speeds tested is 600, 800, 1000 and 1200 m/min in orthogonal turning with a carbide insert tool H13A uncoated and coated TiN on a cylindrical titanium alloy part. Investigation on the wear inserts with 3D microscope scanning revered the crater formation is instantaneous and a chip adhesion. Welded chip causes detachment of carbide particles. In these experiments the chip shape was systematically investigated at each cutting conditions using optical microscopy. The chips produced were collected and polished to measure the thicknesses t2max and t2min. The distance between each segments dch and ɸseg inclination angle as described in the introduction part, the shear angle ɸ and the inclination angle of a segment ɸseg are differentiated. ɸseg angle is actually measured on the collected chips while the shear angle ɸ cannot be. The angle ɸ represents the initial shear similar to the one that describes the formation of a continuous chip in the primary shear zone. Cutting forces increase and stabilize before removing the tool. The chip reaches a very high temperature

    Flash temperature measurement during dry friction process at high sliding speed

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    An experimental method is presented in this paper to measure flash temperatures of sliding surfaces. High sliding velocities are reached by using a ballistic set-up equipped with a high speed camera. The temperature field on the friction surface was recorded during the process. Tests were conducted under dry sliding conditions by using an identical material for the rubbing bodies, which are of middle hard steel (C22). Experiments showed that the temperature distribution generated by frictional heating is made up of small hot spots that correspond to the friction of asperities located on the sliding surface during very short time. Deduced from observations, maximum local surface temperatures can exceed about 1100 °C around an area less than 100 μm in diameter

    A qualitative interpretation of challenges associated with helping patients with multiple chronic diseases identify their goals

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    Background Patients with multiple chronic diseases are usually treated according to disease-specific guidelines, with outcome measurements focusing mostly on biomedical indicators (e.g. blood sugar levels or lung function). However, for multimorbidity, a goal-oriented approach focusing on the goals defined by the individual patient, may be more suitable. Despite the clear theoretical and conceptual advantages of including patient-defined goals in clinical decision-making for multimorbidity, it is not clear how patients define their goals and which aspects play a role in the process of defining them. Objective To explore goal-setting in patients with multimorbidity. Design Qualitative analysis of interviews with 19 patients diagnosed with chronic obstructive pulmonary disease and comorbidities. Results Patients do not naturally present their goals. Their goals are difficult to elicit, even when different interviewing techniques are used. Four underlying hypotheses which may explain this finding were identified from the interviews: (1) patients cannot identify with the concept of goal-setting; (2) goal-setting is reduced due to acceptation; (3) actual stressors predominate over personal goal-setting; and (4) patients may consider personal goals as selfish. Conclusions Our findings advocate for specific attention to provider skills and strategies that help patients identify their personal goals. The hypotheses on why patients may struggle with defining goals may be useful to prompt patients in this process and support the development of a clinical method for goal-oriented care

    Bowling Together: Scientific Collaboration Networks of Demographers at European Population Conferences

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    Studies of collaborative networks of demographers are relatively scarce. Similar studies in other social sciences provide insight into scholarly trends of both the fields and characteristics of their successful scientists. Exploiting a unique database of metadata for papers presented at six European Population Conferences, this report explores factors explaining research collaboration among demographers. We find that (1) collaboration among demographers has increased over the past 10 years, however, among co-authored papers, collaboration across institutions remains relatively unchanged over the period, (2) papers based on core demographic subfields such as fertility, mortality, migration and data and methods are more likely to involve multiple authors and (3) multiple author teams that are all female are less likely to co-author with colleagues in different institutions. Potential explanations for these results are discussed alongside comparisons with similar studies of collaboration networks in other related social sciences

    Patients with coronary artery disease and diabetes need improved management: a report from the EUROASPIRE IV survey: a registry from the EuroObservational Research Programme of the European Society of Cardiology

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    BACKGROUND: In order to influence every day clinical practice professional organisations issue management guidelines. Cross-sectional surveys are used to evaluate the implementation of such guidelines. The present survey investigated screening for glucose perturbations in people with coronary artery disease and compared patients with known and newly detected type 2 diabetes with those without diabetes in terms of their life-style and pharmacological risk factor management in relation to contemporary European guidelines. ----- METHODS: A total of 6187 patients (18-80 years) with coronary artery disease and known glycaemic status based on a self reported history of diabetes (previously known diabetes) or the results of an oral glucose tolerance test and HbA1c (no diabetes or newly diagnosed diabetes) were investigated in EUROASPIRE IV including patients in 24 European countries 2012-2013. The patients were interviewed and investigated in order to enable a comparison between their actual risk factor control with that recommended in current European management guidelines and the outcome in previously conducted surveys. ----- RESULTS: A total of 2846 (46%) patients had no diabetes, 1158 (19%) newly diagnosed diabetes and 2183 (35%) previously known diabetes. The combined use of all four cardioprotective drugs in these groups was 53, 55 and 60%, respectively. A blood pressure target of 9.0% (>75 mmol/mol). Of the patients with diabetes 69% reported on low physical activity. The proportion of patients participating in cardiac rehabilitation programmes was low (≈40 %) and only 27% of those with diabetes had attended diabetes schools. Compared with data from previous surveys the use of cardioprotective drugs had increased and more patients were achieving the risk factor treatment targets. ----- CONCLUSIONS: Despite advances in patient management there is further potential to improve both the detection and management of patients with diabetes and coronary artery disease

    CropPol: a dynamic, open and global database on crop pollination

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    Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop yield, as well as to anticipate changes in this service, develop predictions, and inform management actions. Here, we present CropPol, a dynamic, open and global database on crop pollination. It contains measurements recorded from 202 crop studies, covering 3,394 field observations, 2,552 yield measurements (i.e. berry weight, number of fruits and kg per hectare, among others), and 47,752 insect records from 48 commercial crops distributed around the globe. CropPol comprises 32 of the 87 leading global crops and commodities that are pollinator dependent. Malus domestica is the most represented crop (32 studies), followed by Brassica napus (22 studies), Vaccinium corymbosum (13 studies), and Citrullus lanatus (12 studies). The most abundant pollinator guilds recorded are honey bees (34.22% counts), bumblebees (19.19%), flies other than Syrphidae and Bombyliidae (13.18%), other wild bees (13.13%), beetles (10.97%), Syrphidae (4.87%), and Bombyliidae (0.05%). Locations comprise 34 countries distributed among Europe (76 studies), Northern America (60), Latin America and the Caribbean (29), Asia (20), Oceania (10), and Africa (7). Sampling spans three decades and is concentrated on 2001-05 (21 studies), 2006-10 (40), 2011-15 (88), and 2016-20 (50). This is the most comprehensive open global data set on measurements of crop flower visitors, crop pollinators and pollination to date, and we encourage researchers to add more datasets to this database in the future. This data set is released for non-commercial use only. Credits should be given to this paper (i.e., proper citation), and the products generated with this database should be shared under the same license terms (CC BY-NC-SA). This article is protected by copyright. All rights reserved

    Pollination supply models from a local to global scale

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    Ecological intensification has been embraced with great interest by the academic sector but is still rarely taken up by farmers because monitoring the state of different ecological functions is not straightforward. Modelling tools can represent a more accessible alternative of measuring ecological functions, which could help promote their use amongst farmers and other decision-makers. In the case of crop pollination, modelling has traditionally followed either a mechanistic or a data-driven approach. Mechanistic models simulate the habitat preferences and foraging behaviour of pollinators, while data-driven models associate georeferenced variables with real observations. Here, we test these two approaches to predict pollination supply and validate these predictions using data from a newly released global dataset on pollinator visitation rates to different crops. We use one of the most extensively used models for the mechanistic approach, while for the data-driven approach, we select from among a comprehensive set of state-of-the-art machine-learning models. Moreover, we explore a mixed approach, where data-derived inputs, rather than expert assessment, inform the mechanistic model. We find that, at a global scale, machine-learning models work best, offering a rank correlation coefficient between predictions and observations of pollinator visitation rates of 0.56. In turn, the mechanistic model works moderately well at a global scale for wild bees other than bumblebees. Biomes characterized by temperate or Mediterranean forests show a better agreement between mechanistic model predictions and observations, probably due to more comprehensive ecological knowledge and therefore better parameterization of input variables for these biomes. This study highlights the challenges of transferring input variables across multiple biomes, as expected given the different composition of species in different biomes. Our results provide clear guidance on which pollination supply models perform best at different spatial scales – the first step towards bridging the stakeholder–academia gap in modelling ecosystem service delivery under ecological intensification

    A practice-based analysis of combinations of diseases in patients aged 65 or older in primary care

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    BACKGROUND: Most evidence on chronic diseases has been collected for single diseases whereas in reality, patients often suffer from more than one condition. There is a growing need for evidence-based answers to multimorbidity, especially in primary care settings where family doctors (FD's) provide comprehensive care for a high variety of chronic conditions. This study aimed to define which disease and problem combinations would be most relevant and useful for the development of guidelines to manage multimorbidity in primary care. METHODS: A practice-based cross sectional analysis of clinicians' chart reviews in 543 patients aged over 65 registered within two family practices in Ghent, Belgium. Main outcome measures were prevalence of disease and problem combinations and association strengths. RESULTS: The prevalence of multimorbidity (Cumulative Illness Rating Scale >1) in the study sample is 82.6%. The most prevalent combination is hypertension-osteoarthritis (132/543). Moderate to strong associations (Yules Q > 0.50) are reported for 14 combinations but the corresponding prevalences are mostly below 5%. More than half of these associations show a contribution of a psychiatric problem or a social problem. CONCLUSIONS: This study confirms the high prevalence of multimorbidity in patients aged over 65 in primary care. Hypertension-osteoarthritis is defined as a frequent combination however 94% of these patients have more than two disorders. The low prevalence of specific combinations, the high prevalence of psychiatric and social problems and the general complexity of multimorbidity will hamper the usefulness of randomized trials or guidelines at practice level. There is a need to explore new paradigms for addressing multimorbidity

    Temperature fields in a chip during high-speed orthogonal cutting-An experimental investigation

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    International audienceDuring the cutting process, the temperature field in the chip is measured by using the principle of pyrometry in the visible spectral range. The mechanical device developed to reproduce orthogonal cutting conditions and to reach very high cutting speed (up to 120 m/s) is used for a range of velocities from 10 to 70 m/s. The presented experimental results concern two materials chosen following the form of chip generated: a low carbon steel (C15) and a low alloyed medium carbon steel (42CrMo4). The performances of the measurement set-up are completed by the possibility of recording real time photographs of the chip formation. These records make the analysis of temperature maps easier and allow specific parameters as the contact length at the tool-chip interface or the shear angle to be determined. The non-uniform heating in the chip is emphasized by the presence of a maximal temperature area. The temperature fields measured for a cutting speed around 20 m/s present maximums of 870 °C for 42CrMo4 and 630 °C for C15 located near the tool-chip interface. The effects of cutting velocity on the maximum temperature value in the chip and the location of this heat zone are presented. This maximum increases with the cutting velocity contrary to its location which presents few variations. The experimental results are compared with an analytical approach
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