Imaging mechanical vibrations in suspended graphene sheets

We carried out measurements on nanoelectromechanical systems based on multilayer graphene sheets suspended over trenches in silicon oxide. The motion of the suspended sheets was electrostatically driven at resonance using applied radio-frequency voltages. The mechanical vibrations were detected using a novel form of scanning probe microscopy, which allowed identification and spatial imaging of the shape of the mechanical eigenmodes. In as many as half the resonators measured, we observed a new class of exotic nanoscale vibration eigenmodes not predicted by the elastic beam theory, where the amplitude of vibration is maximum at the free edges. By modeling the suspended sheets with the finite element method, these edge eigenmodes are shown to be the result of non-uniform stress with remarkably large magnitudes (up to 1.5 GPa). This non-uniform stress, which arises from the way graphene is prepared by pressing or rubbing bulk graphite against another surface, should be taken into account in future studies on electronic and mechanical properties of graphene

Genomics of sex allocation in the parasitoid wasp Nasonia vitripennis

This research was funded by the Netherlands Genomics Initiative (Zenith 93511041) and the by the Natural Environment Research Council (NE/J024481/1).Background Whilst adaptive facultative sex allocation has been widely studied at the phenotypic level across a broad range of organisms, we still know remarkably little about its genetic architecture. Here, we explore the genome-wide basis of sex ratio variation in the parasitoid wasp Nasonia vitripennis, perhaps the best studied organism in terms of sex allocation, and well known for its response to local mate competition. Results We performed a genome-wide association study (GWAS) for single foundress sex ratios using iso-female lines derived from the recently developed outbred N. vitripennis laboratory strain HVRx. The iso-female lines capture a sample of the genetic variation in HVRx and we present them as the first iteration of the Nasonia vitripennis Genome Reference Panel (NVGRP 1.0). This panel provides an assessment of the standing genetic variation for sex ratio in the study population. Using the NVGRP, we discovered a cluster of 18 linked SNPs, encompassing 9 annotated loci associated with sex ratio variation. Furthermore, we found evidence that sex ratio has a shared genetic basis with clutch size on three different chromosomes. Conclusions Our approach provides a thorough description of the quantitative genetic basis of sex ratio variation in Nasonia at the genome level and reveals a number of inter-related candidate loci underlying sex allocation regulation.Publisher PDFPeer reviewe

Reproductive health in adults with congenital heart disease:a review on fertility, sexual health, assisted reproductive technology and contraception

Introduction: Due to the improved survival in individuals with congenital heart disease (CHD), considering their reproductive health has become more important. Currently, this topic is still underexplored. Areas covered: We discuss fertility, sexuality, assisted reproductive technology (ART), and contraception in adults with CHD. Expert opinion: Timely counseling regarding fertility, sexuality, pregnancy, and contraception is necessary, preferably during teenage years. Due to a lack of data, whether or not to perform ART in adults with CHD is almost always based on expert opinion and follow-up in an expert center is recommended. Future research is necessary to fill the gaps in knowledge on the risks and frequency of complications of ART in adults with CHD, but also to be able to differentiate the relative risks in the different types of CHD. Only then will we be able to counsel adults with CHD correctly and not unjustly deprive someone of a chance of pregnancy.</p

Terahertz imaging and spectroscopy of large-area single-layer graphene

We demonstrate terahertz (THz) imaging and spectroscopy of a 15x15-mm^2 single-layer graphene film on Si using broadband THz pulses. The THz images clearly map out the THz carrier dynamics of the graphene-on-Si sample, allowing us to measure sheet conductivity with sub-mm resolution without fabricating electrodes. The THz carrier dynamics are dominated by intraband transitions and the THz-induced electron motion is characterized by a flat spectral response. A theoretical analysis based on the Fresnel coefficients for a metallic thin film shows that the local sheet conductivity varies across the sample from {\sigma}s = 1.7x10^-3 to 2.4x10^-3 {\Omega}^-1 (sheet resistance, {\rho}s = 420 - 590 {\Omega}/sq).Comment: 6 pages, 5 figure

The AGE reader:a non-invasive method to assess long term tissue damage

AIMS: Advanced glycation endproducts (AGEs) are sugar modified adducts which arise during non-enzymatic glycoxidative stress. These compounds may become systemically elevated in disease states, and accumulate in tissue, especially on long-lived proteins. AGEs have been implicated in various acute, and chronic diseases, stressing the need for reliable and comprehensive measuring techniques. Measurement of AGEs in tissue such as skin requires skin biopsies, which is an invasive procedure. The AGE Reader has been developed to assess skin autofluorescence (SAF) non-invasively by the fluorescent properties of several AGEs. RESULTS/CONCLUSION: Various studies have shown that SAF is a useful marker of disease processes associated with oxidative stress. It is prospectively associated with development of cardiovascular events in patients with diabetes, renal or cardiovascular disease, and it predicts diabetes, cardiovascular disease and mortality in the general population. However, when measuring SAF in individual subjects, several factors may limit the reliability of the measurement, and hamper its use as a systemic biomarker for AGEs. These include endogenous factors present in the skin that absorb emission light such as melanin in dark-skinned subjects, but also factors that lead to temporal changes in SAF such as acute diseases and strenuous physical exercise associated with glycoxidative stress. Also, exogenous factors could potentially influence SAF levels inadvertently such as nutrition, and for example the application of skin care products. This review will give an overview of the AGE Reader functionality and the intrinsic, and exogenous factors which potentially influence the SAF assessment in individual subjects

Behavioural intervention to promote the uptake of planned care in urgent dental care attenders:study protocol for the RETURN randomised controlled trial

This is the final version. Available on open access from BMC via the DOI in this recordAvailability of data and materials: As per the data controller agreement, the following organisations which have access to the final dataset are The University of Liverpool and the University of Leeds.BACKGROUND: People with disadvantaged backgrounds are less likely to visit the dentist for planned care, even though they have disproportionately poorer oral health. They are correspondingly more likely to experience dental problems and use urgent dental care, general practices and Accident and Emergency departments, which not only makes meeting their needs expensive, but, since these services often rely on prescriptions rather than addressing the clinical cause, can contribute to antimicrobial resistance. METHODS: The RETURN intervention has been developed with substantial community co-production, to be delivered opportunistically in urgent dental care settings. This brief intervention is delivered by dental nurses and involves material relevant to the 'in-group' targeted. The material includes booklets relating to barriers to planned dental visiting with corresponding short video clips featuring local people and including a modelling element. Dental nurses are trained to have supportive and non-judgemental conversations, assisting patients to set personal goals and action plans, which are reinforced in a follow-up text within a few weeks. A randomised controlled trial will be undertaken in 3 types of sites: dental practices delivering urgent care (a) within working hours, (b) out of hours, and (c) in a Dental Hospital. The trial will recruit 1180 adult urgent dental care users over 12 months, who have not visited a dentist for a planned care appointment for 2 years or more and do not have a dentist who they visit for routine care. It aims to investigate the effectiveness and cost-effectiveness of the intervention and to explore whether the intervention has different effects across the socio-economic gradient. Participants will be followed up at 6, 12 and 18 months after randomisation. Co-primary outcomes are attendance at a dental practice for planned care within 12 months and self-reported oral health-related quality of life at 12 months. DISCUSSION: This is a pragmatic trial, evaluating the effectiveness of the intervention under the usual condition in which it might be applied. Since dental practices work as independent contractors to the NHS, this brings implementation and fidelity challenges which will be explored and described in embedded qualitative work. TRIAL REGISTRATION: ISRCTN registry identifier ISRCTN84666712. Registered 12/04/2021.National Institute for Health Research (NIHR

Effects of antiplatelet therapy on menstrual blood loss in reproductive-aged women:a systematic review

Background: The effects of antiplatelet therapy on menstrual bleeding have not been well characterized. Objectives: To systematically review the effects of antiplatelet therapy on menstrual bleeding. Methods: A literature search was performed for studies of reproductive-aged women who received antiplatelet therapy. Characteristics of menstrual bleeding both before and after initiation of antiplatelet therapy and from comparison groups were collected. Two reviewers independently assessed the risk of bias in individual studies. Results: Thirteen studies with a total of 611 women who received antiplatelet therapy were included. Types of antiplatelet drugs used were aspirin (n = 8), aspirin and/or clopidogrel (n = 2), prasugrel (n = 1), and not specified (n = 2). Risk of bias was assessed at moderate (n = 1), serious (n = 8), critical (n = 2), and no information (n = 2). Three studies reported changes in menstrual blood loss volume. One of these showed no increase during antiplatelet therapy; the other 2 studies suggested that aspirin may increase menstrual blood loss volume. In 3 studies that assessed the duration of menstrual bleeding, up to 13% of women reported an increased duration of menstruation. In 5 studies that reported the intensity of menstrual flow, 13% to 38% of women experienced an increase in the intensity of flow. Five studies reported the prevalence of heavy menstrual bleeding in women who received antiplatelet therapy, with estimates ranging from 7% to 38%. Conclusion: There is lack of high-quality data on the effects of antiplatelet therapy on menstrual bleeding. Aspirin may increase menstrual blood loss, at least in a minority of women, whereas the effects of P2Y12 inhibitors are unknown.</p