Molecular Weight Tuning of Organic Semiconductors for Curved Organic-Inorganic Hybrid X-Ray Detectors

Curved X-ray detectors have the potential to revolutionize diverse sectors due to benefits such as reduced image distortion and vignetting compared to their planar counterparts. While the use of inorganic semiconductors for curved detectors are restricted by their brittle nature, organic-inorganic hybrid semiconductors which incorporated bismuth oxide nanoparticles in an organic bulk heterojunction consisting of poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl C71 butyric acid methyl ester (PC70BM) are considered to be more promising in this regard. However, the influence of the P3HT molecular weight on the mechanical stability of curved, thick X-ray detectors remains less well understood. Herein, high P3HT molecular weights (>40 kDa) are identified to allow increased intermolecular bonding and chain entanglements, resulting in X-ray detectors that can be curved to a radius as low as 1.3 mm with low deviation in X-ray response under 100 repeated bending cycles while maintaining an industry-standard dark current of mu C Gy(-1) cm(-2). This study identifies a crucial missing link in the development of curved detectors, namely the importance of the molecular weight of the polymer semiconductors used

Tissue Equivalent Curved Organic X-ray Detectors Utilizing High Atomic Number Polythiophene Analogues

Organic semiconductors are a promising material candidate for X-ray detection. However, the low atomic number (Z) of organic semiconductors leads to poor X-ray absorption thus restricting their performance. Herein, the authors propose a new strategy for achieving high-sensitivity performance for X-ray detectors based on organic semiconductors modified with high –Z heteroatoms. X-ray detectors are fabricated with p-type organic semiconductors containing selenium heteroatoms (poly(3-hexyl)selenophene (P3HSe)) in blends with an n-type fullerene derivative ([6,6]-Phenyl C71 butyric acid methyl ester (PC70BM). When characterized under 70, 100, 150, and 220 kVp X-ray radiation, these heteroatom-containing detectors displayed a superior performance in terms of sensitivity up to 600 ± 11 nC Gy−1 cm−2 with respect to the bismuth oxide (Bi2O3) nanoparticle (NP) sensitized organic detectors. Despite the lower Z of selenium compared to the NPs typically used, the authors identify a more efficient generation of electron-hole pairs, better charge transfer, and charge transport characteristics in heteroatom-incorporated detectors that result in this breakthrough detector performance. The authors also demonstrate flexible X-ray detectors that can be curved to a radius as low as 2 mm with low deviation in X-ray response under 100 repeated bending cycles while maintaining an industry-standard ultra-low dark current of 0.03 ± 0.01 pA mm−2

Provision of obstetrics and gynaecology services during the COVID-19 pandemic:a survey of junior doctors in the UK National Health Service

Objective: The COVID-19 pandemic is disrupting health services worldwide. We aimed to evaluate the provision of obstetrics and gynaecology services in the UK during the acute-phase of the COVID-19 pandemic. Design: Interview-based national survey. Setting: Women’s healthcare units in the National Health Service. Population: Junior doctors in obstetrics and gynaecology. Methods: Participants were interviewed by members of the UKARCOG trainees’ collaborative between 28th March and 7th of April 2020. We used a quantitative analysis for closed-ended questions and a thematic framework analysis for open comments. Results: We received responses from 148/155 units (95%), majority of the participants were in years 3-7 of training (121/148, 82%). Most completed specific training drills for managing obstetric and gynaecological emergencies in women with COVID-19 (89/148, 60.1%) and two-persons donning and doffing of Personal Protective Equipment (PPE) (96/148, 64.9%). The majority of surveyed units implemented COVID-19 specific protocols (130/148, 87.8%), offered adequate PPE (135/148, 91.2%) and operated dedicated COVID-19 emergency theatres (105/148, 70.8%). Most units reduced face-to-face antenatal clinics (117/148, 79.1%), and suspended elective gynaecology services (131/148, 88.5%). The two-week referral pathway for oncology gynaecology was not affected in half of the units (76/148, 51.4%), while half reported a planned reduction in oncology operating (82/148, 55.4%). Conclusion: The provision of obstetrics and gynaecology services in the UK during the acute phase of the COVID-19 pandemic seems to be in line with current guidelines, but strategic planning is needed to restore routine gynaecology services and ensure safe access to maternity care on the longterm

Optimising platelet secretomes to deliver robust tissue specific regeneration

Promoting cell proliferation is the cornerstone of most tissue regeneration therapies. As platelet‐based applications promote cell division and can be customised for tissue‐specific efficacy, this makes them strong candidates for developing novel regenerative therapies. Therefore, the aim of this study was to determine if platelet releasate could be optimised to promote cellular proliferation and differentiation of specific tissues. Growth factors in platelet releasate were profiled for physiological and supra‐physiological platelet concentrations. We analysed the effect of physiological and supra‐physiological releasate on C2C12 skeletal myoblasts, H9C2 rat cardiomyocytes, human dermal fibroblasts (HDF), HaCaT keratinocytes and chondrocytes. Cellular proliferation and differentiation were assessed through proliferation assays, mRNA and protein expression. We show that supra‐physiological releasate is not simply a concentrated version of physiological releasate. Physiological releasate promoted C2C12, HDF and chondrocyte proliferation with no effect on H9C2 or HaCaT cells. Supra‐physiological releasate induced stronger proliferation in C2C12 and HDF cells compared to physiological releasate. Importantly, supra‐physiological releasate induced proliferation of H9C2 cells. The proliferative effects of skeletal and cardiac muscle cells were in part driven by VEGFα. Furthermore, supra‐physiological releasate induced differentiation of H9C2 and C2C12, HDF and keratinocyte differentiation. This study provides insights into the ability of releasate to promote muscle, heart, skin and cartilage cell proliferation and differentiation and highlights the importance of optimising releasate composition for tissue‐specific regeneration

Comparative study of in situ N2 rotational Raman spectroscopy methods for probing energy thermalisation processes during spin-exchange optical pumping

Spin-exchange optical pumping (SEOP) has been widely used to produce enhancements in nuclear spin polarisation for hyperpolarised noble gases. However, some key fundamental physical processes underlying SEOP remain poorly understood, particularly in regards to how pump laser energy absorbed during SEOP is thermalised, distributed and dissipated. This study uses in situ ultra-low frequency Raman spectroscopy to probe rotational temperatures of nitrogen buffer gas during optical pumping under conditions of high resonant laser flux and binary Xe/N2 gas mixtures. We compare two methods of collecting the Raman scattering signal from the SEOP cell: a conventional orthogonal arrangement combining intrinsic spatial filtering with the utilisation of the internal baffles of the Raman spectrometer, eliminating probe laser light and Rayleigh scattering, versus a new in-line modular design that uses ultra-narrowband notch filters to remove such unwanted contributions. We report a ~23-fold improvement in detection sensitivity using the in-line module, which leads to faster data acquisition and more accurate real-time monitoring of energy transport processes during optical pumping. The utility of this approach is demonstrated via measurements of the local internal gas temperature (which can greatly exceed the externally measured temperature) as a function of incident laser power and position within the cell

A conceptual thematic framework of psychological adjustment in caregivers of children with craniofacial microsomia

Objective: Children with craniofacial microsomia (CFM) have complex healthcare needs, resulting in evaluations and interventions from infancy onward. Yet, little is understood about families’ treatment experiences or the impact of CFM on caregivers’ well-being. To address this gap, the NIH-funded ‘Craniofacial microsomia: Accelerating Research and Education (CARE)’ program sought to develop a conceptual thematic framework of caregiver adjustment to CFM. Design: Caregivers reported on their child's medical and surgical history. Narrative interviews were conducted with US caregivers (n = 62) of children aged 3-17 years with CFM. Transcripts were inductively coded and final themes and subthemes were identified. Results: Components of the framework included: 1) Diagnostic Experiences, including pregnancy and birth, initial emotional responses, communication about the diagnosis by healthcare providers, and information-seeking behaviors; 2) Child Health and Healthcare Experiences, including feeding, the child's physical health, burden of care, medical decision-making, surgical experiences, and the perceived quality of care; 3) Child Development, including cognition and behavior, educational provision, social experiences, and emotional well-being; and 4) Family Functioning, including parental well-being, relationships, coping strategies, and personal growth. Participants also identified a series of “high” and “low” points throughout their journey and shared their priorities for future research. Conclusions: Narrative interviews provided rich insight into caregivers’ experiences of having a child with CFM and enabled the development of a conceptual thematic framework to guide clinical care and future research. Information gathered from this study demonstrates the need to incorporate evidence-based psychological support for families into the CFM pathway from birth onward

Outstanding challenges in the transferability of ecological models

Predictive models are central to many scientific disciplines and vital for informing management in a rapidly changing world. However, limited understanding of the accuracy and precision of models transferred to novel conditions (their ‘transferability’) undermines confidence in their predictions. Here, 50 experts identified priority knowledge gaps which, if filled, will most improve model transfers. These are summarized into six technical and six fundamental challenges, which underlie the combined need to intensify research on the determinants of ecological predictability, including species traits and data quality, and develop best practices for transferring models. Of high importance is the identification of a widely applicable set of transferability metrics, with appropriate tools to quantify the sources and impacts of prediction uncertainty under novel conditions

XeNA: an automated ‘open-source’ 129Xe hyperpolarizer for clinical use

Here we provide a full report on the construction, components, and capabilities of our consortium’s “open-source” large-scale (~ 1 L/h) 129Xe hyperpolarizer for clinical, pre-clinical, and materials NMR/MRI (Nikolaou et al., Proc. Natl. Acad. Sci. USA, 110, 14150 (2013)). The ‘hyperpolarizer’ is automated and built mostly of off-the-shelf components; moreover, it is designed to be cost-effective and installed in both research laboratories and clinical settings with materials costing less than $125,000. The device runs in the xenon-rich regime (up to 1800 Torr Xe in 0.5 L) in either stopped-flow or single-batch mode—making cryo-collection of the hyperpolarized gas unnecessary for many applications. In-cell 129Xe nuclear spin polarization values of ~ 30%–90% have been measured for Xe loadings of ~ 300–1600 Torr. Typical 129Xe polarization build-up and T1 relaxation time constants were ~ 8.5 min and ~ 1.9 h respectively under our spin-exchange optical pumping conditions; such ratios, combined with near-unity Rb electron spin polarizations enabled by the high resonant laser power (up to ~ 200 W), permit such high PXe values to be achieved despite the high in-cell Xe densities. Importantly, most of the polarization is maintained during efficient HP gas transfer to other containers, and ultra-long 129Xe relaxation times (up to nearly 6 h) were observed in Tedlar bags following transport to a clinical 3 T scanner for MR spectroscopy and imaging as a prelude to in vivo experiments. The device has received FDA IND approval for a clinical study of chronic obstructive pulmonary disease subjects. The primary focus of this paper is on the technical/engineering development of the polarizer, with the explicit goals of facilitating the adaptation of design features and operative modes into other laboratories, and of spurring the further advancement of HP-gas MR applications in biomedicine