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Romantic Attachment and Support Preferences in New Mothers: The Moderating Role of Stress
No full textIn the present research, we examined whether attachment anxiety and avoidance in support recipients were related to preferences for specific types of support. In addition, we examined whether stress moderated the relationship between attachment and support needs. Two-hundred and forty-five first-time mothers, currently involved in romantic relationships, participated in study 1, in which support needs and stress were appraised over the previous month using self-reports. High levels of attachment avoidance were related to needing less support, but attachment anxiety was not associated with support needs. There was no hyperactivation or deactivation of the attachment system in response to stress. It is possible that recall bias, associated with cross-sectional methods, may have confounded the results. In study 2, we sought to replicate these hypotheses using an ambulatory method to examine the association between attachment and momentary support needs in the daily life of mothers with babies (N = 40). Results revealed that attachment anxiety was associated with a preference for high levels of momentary support, but attachment avoidance was not related to any support needs. Stress experienced in the moment was found to moderate the relationships between attachment and support needs, with mothers high in anxiety and avoidance needing more support
Real-Time Fluctuations in Single-Molecule Rotaxane Experiments Reveal an Intermediate Weak Binding State During Shuttling
No full textWe report on the use of AFM to identify and characterize an intermediate state in macrocycle shuttling in a hydrogen bonded amide-based molecular shuttle. The [2]rotaxane consists of a benzylic amide macrocycle mechanically locked onto a thread that bears both fumaramide and succinic amide-ester sites, each of which can bind to the macrocycle through up to four intercomponent hydrogen bonds. Using AFM-based single-molecule force spectroscopy we mechanically triggered the translocation of the ring between the two principal binding sites (‘stations’) on the axle. Equilibrium fluctuations reveal another interacting site involving the two oxygen atoms in the middle of the thread. We characterized the ring occupancy distribution over time, which confirms the intermediate in both shuttling directions. The study provides evidence of weak hydrogen bonds that are difficult to detect using other methods and shows how the composition of the thread can significantly influence the shuttling dynamics by slowing down the ring motion between the principal binding sites. More generally the study illustrates the utility that single-molecule experiments, such as force spectroscopy, can offer for elucidating the structure and dynamics of synthetic molecular machines
Realization of 3D Epoxy resin/Ti3C2Tx MXene Aerogel Composites for Low-Voltage Electrothermal Heating
No full textAcoustic Emission Analysis for Wind Turbine Blade Bearing Fault Detection Under Time-Varying Low-Speed and Heavy Blade Load Conditions
No full textThis article uses acoustic emission (AE) analysis to diagnose an industrial-scale and slow-speed wind turbine blade bearing. The main challenge for AE analysis is that the fault signals are mingled with heavy noise. As a result, the objective of this paper is to filter the raw AE signals and extract weak fault signals. To achieve this goal, a general linear and nonlinear auto-regressive (GLNAR) model is firstly developed to exploitthe nonlinear characteristics of the AE signals. Then, the Sparse Augmented Lagrangian (SAL) algorithm is applied to learn the built GLNAR model and filter the raw AE signals. The characteristics of SAL is that it is a novel sparse representation technique which can convert the original filtering problem into a number of sub-optimization problems, and these sub-problems can be solved separately. Finally, as the blade bearing rotatesat fluctuating speeds, the filtered signals are resampled so that the bearing fault type can be diagnosed in the order domain. The proposed diagnostic framework was validated in several experiments under time-varying low-speed and heavy-blade-load conditions. The results indicate that our proposed methods are effective and accurate
Double-D2Q9 lattice Boltzmann models with extended equilibrium for two-dimensional magnetohydrodynamic flows
No full textThe vast majority of the existing lattice Boltzmann methods (LBMs) suggest to relax relevant quantities to a second-order truncated equilibrium state. Despite its simplicity and popularity, this choice does not fully exploit the potential of any lattice discretization. In this paper, an extended equilibrium state is adopted to evaluate the suitability of different LBMs (i.e., the Bhatnagar-Gross-Krook, the multiple-relaxation-time in terms of raw and central moments, and the simplified one) to simulate two-dimensional magnetohydrodynamic flows by means of the D2Q9 velocity space. Two sets of particle distribution functions are employed: one for the flow field and the other for the magnetic one. Even if the minimal ve-velocities discretization is sufficient to represent the evolution of the latter, a nine-velocities model enhances the capability to enforce the divergence-free condition of the magnetic field, as shown. Therefore, a double-D2Q9 approach is herein devised. Eventually, the computational cost involved by all the schemes is discussed both in terms of virtual memory and run time. Interestingly, the simplified LBM for magnetohydrodynamic flows is herein presented for the first time
How do electrostatic perturbations of the protein affect the bifurcation pathways of substrate hydroxylation versus desaturation in the nonheme iron-dependent viomycin biosynthesis enzyme?
No full textThe viomycin biosynthesis enzyme VioC is a non-heme iron and α-ketoglutarate-dependent dioxygenase involved in the selective hydroxylation of L-arginine at the C3-position for antibiotics biosynthesis. Interestingly, experimental studies showed that using the substrate analogue, namely L-homo-arginine, a mixture of products was obtained originating from C3-hydroxylation, C4-hydroxylation and C3‒C4 desaturation. To understand how the addition of one CH2 group to a substrate can lead to such a dramatic change in selectivity and activity, we decided to do a computational study using QM cluster models. We set up a large active-site cluster model of 245 atoms that includes the oxidant with its first- and second-coordination sphere influence as well as the substrate-binding pocket. The model was validated against experimental work on related enzymes and previous computational studies. Thereafter, possible pathways leading to products and byproducts were investigated for a model containing L-Arg and one for L-homo-Arg as substrate. The calcu-lated free energies of activation predict product distributions that match experimental observation and give a low-energy C3-hydroxylation pathway for L-Arg, while for L-homo-Arg several barriers are found to be close in energy leading to a mixture of products. We then analyzed the origins of the differences in product distributions using thermochemical, va-lence bond and electrostatic models. Our studies show that the C3-H and C4-H bond strengths of L-Arg and L-homo-Arg are similar; however, external perturbations from an induced electric field of the protein affect the relative C-H bond strengths of L-Arg dramatically and make the C3-H bond the weakest and guide the reaction to a selective C3-hydroxylation channel. Therefore, the charge distribution in the protein and the induced electric dipole field of the active site of VioC guides the L-Arg substrate activation to C3-hydroxylation and disfavors the C4-hydroxylation pathway, while this does not happen for L-homo-Arg. Tight substrate positioning and electrostatic perturbations from the second-coordination sphere residues in VioC also result in a slower overall reaction for L-Arg; however, they enable a high sub-strate selectivity. Our studies highlight the importance of the second-coordination sphere in proteins that position the substrate and oxidant, perturb charge distributions and enable substrate selectivity
Adverse outcomes associated with rapid linear and non-linear patterns of chronic kidney disease progression
No full textBackground Patients with rapidly declining renal function face the dual threat of end-stage renal disease (ESRD) and mortality prior to ESRD. What is less well characterised is whether the pattern of the renal trajectory, linear or non-linear, unmasks subgroups of rapidly progressing patients that face adverse outcomes in a differential manner. Methods An individual eGFR slope was applied to all outpatient estimated glomerular filtration rate (eGFR) values for each patient in the Salford Kidney Study from 2002 to 2018 who had at least 2years follow-up, ≥4 eGFR values and baseline eGFR 15 to <60ml/min/1.73m2. Rapid progression was defined as an annual eGFR slope of ≤-3ml/min/1.73m2/yr and patients were categorised as linear or non-linear progressors based on the nature of their eGFR-time graphs. A Fine-Gray competing risk hazard model was used to determine factors associated with progression ESRD and with mortality prior to ESRD. Cumulative incidence function curves highlighted differences in outcomes between linear and non-linear patients. Results There were 211 rapidly deteriorating patients with linear eGFR trajectories and 61 rapid non-linear patients in the study cohort. Factors associated with ESRD included younger age, male gender, lower baseline eGFR and higher serum phosphate, whilst older age, history of myocardial infarction and anaemia predicted mortality prior to ESRD. Over a median follow-up of 3.7years, linear progressors reached ESRD sooner whilst those with non-linear progression faced significantly higher rates of mortality prior to ESRD. Conclusions Patients with rapid eGFR decline have high rates of adverse outcomes that are differentially expressed in those progressing linearly and non-linearly as a result of differing phenotypic profiles. Consequently, addressing individual risk factor profiles is important to deliver optimal personalised patient care
Five year follow-up on the prevalence and intensity of infections of Schistosoma mansoni in a hard-to-reach district of Madagascar
No full textSchistosomiasis is a major public health problem in Madagascar. World Health Organization recommends preventive chemotherapy by mass drug administration (MDA) with praziquantel as the primary approach to control Schistosoma mansoni related morbidity in endemic populations, alongside complementary interventions such as health education. The impact of annual MDA and health education programs was assessed in the hard-to-reach Marolambo District of eastern Madagascar, an area endemic for S. mansoni. Repeated cross-sectional studies undertaken 2015–2019 examined between 300 and 381 school-aged children (aged 5–14 years) annually. The prevalence and infection intensity of S. mansoni were assessed by urine-circulating cathodic antigen (CCA) dipsticks and coproscopy using Kato-Katz (KK) methodologies. After four rounds of annual MDA, a reduction in S. mansoni prevalence was seen in CCA (93.9% in Year 1 to 87.7% in Year 5; p=0.007) and KK (73.9% in Year 1 to 59.4% in Year 5; p<0.0001). Prevalence of heavy-intensity infections roughly halved from 23.7% to 10.1% (p<0.0001), and the mean intensity of infection fell by 55.0% (480.2 to 216.3 eggs per gram of feces). A malacological survey found Biomphalaria pfeifferi snail intermediate hosts in multiple water contact sites including rice paddies, streams and Nosivolo River. Despite reductions in infection prevalence and intensity, schistosomiasis still poses a significant public health challenge in Marolambo District. Twice yearly MDA cycles and/or community-wide MDA are suggested to better reduce infections. Expanding health education, improving standards of water, sanitation and hygiene, and attention on snail-related control will also be important, especially in rice paddy irrigated areas
What health policy makers need to know about mismatches between public perceptions of disease risk, prevalence and severity: A national survey
No full textOBJECTIVES To assess people’s perceptions of their personal risk, population prevalence and perceived severity in relation to three key health conditions (cancer, heart disease and hearing loss), gauge the size of any misperceptions, and identify correlates of such misperceptions. DESIGN Cross-sectional survey. STUDY SAMPLE 10,401 adults representative of the UK population. RESULTS Clear majorities of people incorrectly believe that they are at greater personal risk of cancer (>75%), that cancer is more prevalent in the population (>50%) and that cancer is more disabling (>65%), than either heart disease or hearing loss. In turn, people consistently regard their personal risk of hearing loss, the population prevalence of hearing loss and the severity of hearing loss as lower than either cancer or heart disease. Multiple regression analyses showed inconsistent patterns of relationships between people’s beliefs, sociodemographic characteristics and their health behaviours. CONCLUSIONS Accuracy in beliefs about cancer, heart disease and hearing loss is low, and the relationships between these beliefs, their potential antecedents and consequences are complex. Policy makers should ensure close adherence to evidence or risk making decisions that are costly both in financial terms and in terms of suboptimal population subjective well-being