965 research outputs found
Genetic Approaches to Metabolic Bone Diseases
Metabolic bone diseases comprise a diverse group of disorders characterized by alterations in skeletal homeostasis, and are often associated with abnormal circulating concentrations of calcium, phosphate or vitamin D metabolites. These diseases commonly have a genetic basis and represent either a monogenic disorder due to a germline or somatic single gene mutation, or an oligogenic or polygenic disorder that involves variants in more than one gene. Germline single gene mutations causing Mendelian diseases typically have a high penetrance, whereas the genetic variations causing oligogenic or polygenic disorders are each associated with smaller effects with additional contributions from environmental factors. Recognition of familial monogenic disorders is of clinical importance to facilitate timely investigations and management of the patient and any affected relatives. The diagnosis of monogenic metabolic bone disease requires careful clinical evaluation of the large diversity of symptoms and signs associated with these disorders. Thus, the clinician must pursue a systematic approach beginning with a detailed history and physical examination, followed by appropriate laboratory and skeletal imaging evaluations. Finally, the clinician must understand the increasing number and complexity of molecular genetic tests available to ensure their appropriate use and interpretation
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Indentation of a layer on foam substrate
There is a practical need to elevate both the indentation strength and level of energy absorption of engineering foams by the addition of a stiff and strong face sheet for applications such as packaging and crash mitigation. In this study, the enhancement in plane strain indentation resistance of a polyvinyl chloride (PVC) foam by the presence of a
polycarbonate (PC) face sheet is determined by experiment, finite element analysis and by an analytical model. Plane strain indentation is by a flat-bottom punch or by a cylindrical roller, and the strain distribution within the PC face sheet and in the foam substrate are measured by digital image correlation. With increasing indent depth, the face sheet bends
and stretches elastically and then plastically until face sheet or substrate fail. The
generation of membrane tension in the face sheet plays a major role in supporting the indentation load when the indent depth exceeds the thickness of the face sheet, and leads to a strong hardening behaviour beyond the initial collapse load for indentation. Finite element predictions of the full indentation response are based upon the measured tensile
and compressive responses of the PVC foam and PC layer. An analytical model is developed by matching the stretching response of the PC face sheet to the indentation response of the underlying foam, with due consideration for load diffusion from membrane tension of the PC face sheet into the underlying foam substrate. The indentation model is calibrated by
ancillary finite element simulations of the load diffusion problem, and they emphasise the role of a shear lag zone in dictating the large indentation resistance. The indentation response of the bi-layer is also compared with that of a sandwich beam in 3-point bending. Experiments, finite element simulations and an additional analytical model for indentation of the sandwich beam in 3-point bending reveal that strong hardening of the post-yield load versus displacement response is now absent, in contrast to that of the bi-layer. The lack of hardening in 3-point bending is traced to the relatively low value of plastic bending moment of the beam section.We acknowledge financial support from the ERC MULTILAT, grant number 669764. This work was also supported by the Engineering and Physical Sciences Research Council, award number 1463953. The authors are grateful for the financial support from SABIC and the technical assistance from Dr. Martin van Es
A Review of Lithium-Ion Battery Electrode Drying: Mechanisms and Metrology
Lithium-ion battery manufacturing chain is extremely complex with many controllable parameters especially for the drying process. These processes affect the porous structure and properties of these electrode films and influence the final cell performance properties. However, there is limited available drying information and the dynamics are poorly understood due to the limitation of the existing metrology. There is an emerging need to develop new methodologies to understand the drying dynamics to achieve improved quality control of the electrode coatings. A comprehensive summary of the parameters and variables relevant to the wet electrode film drying process is presented, and its consequences/effects on the finished electrode/final cell properties are mapped. The development of the drying mechanism is critically discussed according to existing modeling studies. Then, the existing and potential metrology techniques, either in situ or ex situ in the drying process are reviewed. This work is intended to develop new perspectives on the application of advanced techniques to enable a more predictive approach to identify optimum lithium-ion battery manufacturing conditions, with a focus upon the critical drying process
Interactions in vivo between the Vif protein of HIV-1 and the precursor (Pr55GAG) of the virion nucleocapsid proteins
The abnormality of viral core structure seen in vif-defective HIV-1 grown in PBMCs has suggested a role for Vif in viral morphogenesis. Using an in vivo mammalian two-hybrid assay, the interaction between Vif and the precursor (Pr55GAG) of the virion nucleocapsid proteins has been analysed. This revealed the amino-terminal (aa 1â22) and central (aa 70â100) regions of Vif to be essential for its interaction with Pr55GAG, but deletion of the carboxy-terminal (aa 158â192) region of the protein had only a minor effect on its interaction. Initial deletion studies carried out on Pr55GAG showed that a 35-amino-acid region of the protein bridging the MA(p17)âCA(p24) junction was essential for its ability to interact with Vif. Site-directed mutagenesis of a conserved tryptophan (Trp21) near the amino terminus of Vif showed it to be important for the interaction with Pr55GAG. By contrast, mutagenesis of the highly conserved YLAL residues forming part of the BC-box motif, shown to be important in Vif promoting degradation of APOBEC3G/3F, had little or no effect on the VifâPr55GAG interaction
Are people who participate in cultural activities more satisfied with life?
The influence of various aspects of life on wellbeing has been extensively researched. However, despite little empirical evidence, participation in leisure activities has been assumed to increase subjective wellbeing. Leisure is important because it is more under personal control than other sources of life satisfaction. This study asked whether people who participate in cultural leisure activities have higher life satisfaction than people who do not, if different types of leisure have the same influence on life satisfaction and if satisfaction is dependent on the frequency of participation or the number of activities undertaken. It used data from UKHLS Survey to establish associations between type, number and frequency of participation in leisure activities and life satisfaction. Results showed an independent and positive association of participation in sport, heritage and active-creative leisure activities and life satisfaction but not for participation in popular entertainment, theatre hobbies and museum/galleries. The association of reading hobbies and sedentary-creative activities and life satisfaction was negative. High life satisfaction was associated with engaging in a number of different activities rather than the frequency of participation in each of them. The results have implications for policy makers and leisure services providers, in particular those associated with heritage recreation. Subjective wellbeing measures, such as life satisfaction, and not economic measures alone should be considered in the evaluation of services. The promotion of leisure activities which are active and promote social interaction should be considered in programmes aimed at improving the quality of life
Towards optimised cell design of thin film silicon-based solid-state batteries via modelling and experimental characterisation
To realise the promise of solid-state batteries, negative electrode materials exhibiting large volumetric expansions, such as Li and Si, must be used. These volume changes can cause significant mechanical stresses and strains that affect cell performance and durability, however their role and nature in SSBs are poorly understood. Here, a 2D electro-chemo-mechanical model is constructed and experimentally validated using steady-state, transient and pulsed electrochemical methods. The model geometry is taken as a representative cross-section of a non-porous, thin-film solid-state battery with an amorphous Si (a-Si) negative electrode, lithium phosphorous oxynitride (LiPON) solid electrolyte and LiCoO2 (LCO) positive electrode. A viscoplastic model is used to predict the build-up of strains and plastic deformation of a-Si as a result of (de)lithiation during cycling. A suite of electrochemical tests, including electrochemical impedance spectroscopy, the galvanostatic intermittent titration technique and hybrid pulse power characterisation are carried out to establish key parameters for model validation. The validated model is used to explore the peak interfacial (a-SiâŁLiPON) stress and strain as a function of the relative electrode thickness (up to a factor of 4), revealing a peak volumetric expansion from 69% to 104% during cycling at 1C. The validation of this electro-chemo-mechanical model under load and pulsed operating conditions will aid in the cell design and optimisation of solid-state battery technologies
Improving patient outcomes in fibrous dysplasia/McCune-Albright syndrome: an international multidisciplinary workshop to inform an international partnership.
Bone and mineral researc
Childhood loneliness as a predictor of adolescent depressive symptoms: an 8-year longitudinal study
Childhood loneliness is characterised by childrenâs perceived dissatisfaction with aspects of their social relationships. This 8-year prospective study investigates whether loneliness in childhood predicts depressive symptoms in adolescence, controlling for early childhood indicators of emotional problems and a sociometric measure of peer social preference. 296 children were tested in the infant years of primary school (T1 5 years of age), in the upper primary school (T2 9 years of age) and in secondary school (T3 13 years of age). At T1, children completed the loneliness assessment and sociometric interview. Their teachers completed externalisation and internalisation rating scales for each child. At T2, children completed a loneliness assessment, a measure of depressive symptoms, and the sociometric interview. At T3, children completed the depressive symptom assessment. An SEM analysis showed that depressive symptoms in early adolescence (age 13) were predicted by reports of depressive symptoms at age 8, which were themselves predicted by internalisation in the infant school (5 years). The interactive effect of loneliness at 5 and 9, indicative of prolonged loneliness in childhood, also predicted depressive symptoms at age 13. Parent and peer-related loneliness at age 5 and 9, peer acceptance variables, and duration of parent loneliness did not predict depression. Our results suggest that enduring peer-related loneliness during childhood constitutes an interpersonal stressor that predisposes children to adolescent depressive symptoms. Possible mediators are discussed
Loneliness, social support and cardiovascular reactivity to laboratory stress
Self-reported or explicit loneliness and social support have been inconsistently associated with cardiovascular reactivity (CVR) to stress. The present study aimed to adapt an implicit measure of loneliness, and use it alongside the measures of explicit loneliness and social support, to investigate their correlations with CVR to laboratory stress. Twenty-five female volunteers aged between 18 and 39 years completed self-reported measures of loneliness and social support, and an Implicit Association Test (IAT) of loneliness. The systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) reactivity indices were measured in response to psychosocial stress induced in the laboratory. Functional support indices of social support were significantly correlated with CVR reactivity to stress. Interestingly, implicit, but not explicit, loneliness was significantly correlated with DBP reactivity after one of the stressors. No associations were found between structural support and CVR indices. Results are discussed in terms of validity of implicit versus explicit measures and possible factors that affect physiological outcomes
Keyboard Contamination in Intensive Care Unit: Is Cleaning Enough? Prospective Research of In Situ Effectiveness of a Tea Tree Oil (KTEO) Film
After the SARS-CoV-2 pandemic, disinfection practices and microbial load reduction have become even more important and rigorous. To determine the contamination of keyboard surface and the relative risk to transfer healthcare-associated pathogens to susceptible patients, as it frequently happens in Intensive Care Unit (ICU), a standard keyboard (SK), a cleanable keyless keyboard (KK) with smooth surface and a standard keyboard coated with a 3M Tegaderm film added with active essential oil (tea tree oil) (KTEO) were tested. S. aureus, including MRSA strains, were detected in ICU, with values ranging from 15% to 57%. Gram negative strains belonging to the Enterobacteriaceae family were also found with values ranging from 14% to 71%. Similar Gram positive and Gram negative strains were found on all surfaces, but with low percentage, and only environmental bacteria were detected using the settling plates method. The Microbial Challenge Test performed on KTEO showed high rates of decrease for all the pathogens with statistical significance both at 24 and 48h (p=0.003* and p=0.040*, respectively). Our results suggest that the use of KTEO may be a feasible strategy for reducing the transmission of pathogens in health care setting and may be complementary to surface cleaning protocols
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