Monitoring Replication Protein A (RPA) Dynamics in Homologous Recombination Through Site-specific Incorporation of Non-canonical Amino Acids

An essential coordinator of all DNA metabolic processes is Replication Protein A (RPA). RPA orchestrates these processes by binding to single-stranded DNA (ssDNA) and interacting with several other DNA binding proteins. Determining the real-time kinetics of single players such as RPA in the presence of multiple DNA processors to better understand the associated mechanistic events is technically challenging. To overcome this hurdle, we utilized non-canonical amino acids and bio-orthogonal chemistry to site-specifically incorporate a chemical fluorophore onto a single subunit of heterotrimeric RPA. Upon binding to ssDNA, this fluorescent RPA (RPAf) generates a quantifiable change in fluorescence, thus serving as a reporter of its dynamics on DNA in the presence of multiple other DNA binding proteins. Using RPAf, we describe the kinetics of facilitated self-exchange and exchange by Rad51 and mediator proteins during various stages in homologous recombination. RPAf is widely applicable to investigate its mechanism of action in processes such as DNA replication, repair and telomere maintenance

Symptom burden, palliative care need and predictors of physical and psychological discomfort in two UK hospitals

Background: The requirement to meet the palliative needs of acute hospital populations has grown in recent years. With increasing numbers of frail older people needing hospital care as a result of both malignant and nonmalignant conditions, emphasis is being placed upon understanding the physical, psychological and social burdens experienced by patients. This study explores the extent of burden in two large UK hospitals, focusing upon those patients who meet palliative care criteria. Furthermore, the paper explores the use of palliative services and identifies the most significant clinical diagnostic and demographic factors which determine physical and psychological burden. Methods: Two hospital surveys were undertaken to identify burden using the Sheffield Profile for Assessment and Referral to Care (SPARC). The Gold Standards Framework (GSF) is used to identify those patients meeting palliative care criteria. Participants were identified as being in-patients during a two-week data collection phase for each site. Data was gathered using face-to-face interviews or self-completion by patients or a proxy. Descriptive analyses highlight prevalence and use of palliative care provision. Binary logistic regression assesses clinical diagnostic predictor variables of physical and psychological burden. Results: The sample consisted of 514 patients and elevated physical, psychological and social burden is identified amongst those meeting palliative care criteria (n = 185). Tiredness (34.6%), pain (31.1%), weakness (28.8%) and psychological discomfort (low mood 19.9%; anxiety 16.1%) are noted as being prevalent. A small number of these participants accessed Specialist Palliative Care (8.2%). Dementia was identified as a predictor of physical (OR 3.94; p < .05) and psychological burden (OR 2.88; p < .05), being female was a predictor of psychological burden (OR 2.00; p < .05). Conclusion: The paper highlights elevated levels of burden experienced by patients with palliative care requirements. Moreover, the paper also indicates that a large proportion of such patients are not in receipt of palliative approaches to their care. Furthermore, the paper identifies that those with non-malignant illnesses, especially dementia, may experience high levels of physical and psychological burden

Hybrid photonic loss resilient entanglement swapping

We propose a scheme of loss-resilient entanglement swapping between two distant parties in lossy optical fibre. In this scheme, Alice and Bob each begin with a pair of entangled non-classical states; these "hybrid states" of light are entangled discrete variable (Fock state) and continuous variable (coherent state) pairs. The continuous variable halves of each of these pairs are sent through lossy optical fibre to a middle location, where these states are then mixed (using a 50:50 beam-splitter) and measured. The detection scheme we use is to measure one of these modes via vacuum detection, and to measure the other mode using balanced homodyne detection. In this work we show that the |Φ+⟩=(|00⟩+|11⟩)/2–√ Bell state can theoretically be produced following this scheme with high fidelity and entanglement, even when allowing for a small amount of loss. It can be shown that there is an optimal amplitude value (α) of the coherent state, when allowing for such loss. We also investigate the realistic circumstance when the loss is not balanced in the propagating modes. We demonstrate that a small amount of loss mismatch does not destroy the overall entanglement, thus demonstrating the physical practicality of this protocol

Weak Spin Fluctuation with Finite Wave Vector and Superconducting Gap Symmetry in KxFe2-ySe2: 77Se Nuclear Magnetic Resonance

We report $^{77}$Se-nuclear magnetic resonance (NMR) results down to sufficiently low temperatures under magnetic fields parallel to both the $ab$-plane and the c-axis in a paramagnetic/superconducting (PM/SC) phase of K$_x$Fe$_{2-y}$Se$_2$. The observation of anisotropy in the orbital part of the Knight shift results in the anisotropy of its spin part increasing on approaching the transition temperature. The anisotropy of the Korringa relation suggests the presence of the weak spin fluctuations with a finite wave vector $\bm{q}$, which induce the magnetic fluctuations along the ab-plane at the Se site. Such fluctuations do not correspond to the stripe $(\pi,0)$ correlation of the Fe moment observed in many Fe-based superconductors, and are not contradictory to weak $(\pi,\pi)$ correlations. The nuclear spin-lattice relaxation rate $1/T_1$ shows a field-independent $T_1T \sim const.$ behavior at low temperatures for $H \parallel ab$, which is attributed to the nonzero density of states at the Fermi level and can be explained by the sign-changing order parameter even for nodeless gaps. The temperature dependence of $1/T_1$ is reproduced well by nodeless models with two isotropic gaps or a single anisotropic gap. The obtained gap magnitude in the isotropic two-gap model is comparable to those obtained in the angle-resolved photoemission spectroscopy experiments.Comment: 6 pages, 6 figures, Accepted for the publication in J. Phys. Soc. Jp

Impaired postprandial skeletal muscle vascular responses to a mixed meal challenge in normoglycaemic people with a parent with type 2 diabetes

Aims/hypothesis: Microvascular blood flow (MBF) increases in skeletal muscle postprandially to aid in glucose delivery and uptake in muscle. This vascular action is impaired in individuals who are obese or have type 2 diabetes. Whether MBF is impaired in normoglycaemic people at risk of type 2 diabetes is unknown. We aimed to determine whether apparently healthy people at risk of type 2 diabetes display impaired skeletal muscle microvascular responses to a mixed-nutrient meal. Methods: In this cross-sectional study, participants with no family history of type 2 diabetes (FH-) for two generations (n = 18), participants with a positive family history of type 2 diabetes (FH+; i.e. a parent with type 2 diabetes; n = 16) and those with type 2 diabetes (n = 12) underwent a mixed meal challenge (MMC). Metabolic responses (blood glucose, plasma insulin and indirect calorimetry) were measured before and during the MMC. Skeletal muscle large artery haemodynamics (2D and Doppler ultrasound, and Mobil-O-graph) and microvascular responses (contrast-enhanced ultrasound) were measured at baseline and 1 h post MMC. Results: Despite normal blood glucose concentrations, FH+ individuals displayed impaired metabolic flexibility (reduced ability to switch from fat to carbohydrate oxidation vs FH-; p \u3c 0.05) during the MMC. The MMC increased forearm muscle microvascular blood volume in both the FH- (1.3-fold, p \u3c 0.01) and FH+ (1.3-fold, p \u3c 0.05) groups but not in participants with type 2 diabetes. However, the MMC increased MBF (1.9-fold, p \u3c 0.01), brachial artery diameter (1.1-fold, p \u3c 0.01) and brachial artery blood flow (1.7-fold, p \u3c 0.001) and reduced vascular resistance (0.7-fold, p \u3c 0.001) only in FH- participants, with these changes being absent in FH+ and type 2 diabetes. Participants with type 2 diabetes displayed significantly higher vascular stiffness (p \u3c 0.001) compared with those in the FH- and FH+ groups; however, vascular stiffness did not change during the MMC in any participant group. Conclusions/interpretation: Normoglycaemic FH+ participants display impaired postprandial skeletal muscle macro- and microvascular responses, suggesting that poor vascular responses to a meal may contribute to their increased risk of type 2 diabetes. We conclude that vascular insulin resistance may be an early precursor to type 2 diabetes in humans, which can be revealed using an MMC

Transitions to palliative care for older people in acute hospitals: a mixed-methods study

Background: Improving the provision of palliative and end-of-life care is a priority for the NHS. Ensuring an appropriately managed ‘transition’ to a palliative approach for care when patients are likely to be entering the last year of life is central to current policy. Acute hospitals represent a significant site of palliative care delivery and specific guidance has been published regarding the management of palliative care transitions within this setting.&lt;p&gt;&lt;/p&gt; Aims: (1) to explore how transitions to a palliative care approach are managed and experienced in acute hospitals and to identify best practice from the perspective of clinicians and service users; (2) to examine the extent of potentially avoidable hospital admissions amongst hospital inpatients with palliative care needs.&lt;p&gt;&lt;/p&gt; Design: A mixed-methods design was adopted in two hospitals in England, serving diverse patient populations. Methods included (1) two systematic reviews; (2) focus groups and interviews with 58 health-care professionals to explore barriers to, and facilitators of, palliative care transitions in hospital; (3) a hospital inpatient survey examining palliative care needs and aspects of management including a self-/proxy-completed questionnaire, a survey of medical and nursing staff and a case note review; (4) in-depth interviews with 15 patients with palliative care needs; (5) a retrospective case note review of all inpatients present in the hospital at the time of the survey who had died within the subsequent 12 months; and (6) focus groups with 83 key decision-makers to explore the implications of the findings for service delivery and policy.&lt;p&gt;&lt;/p&gt; Results: Of the 514 patients in the inpatient survey sample, just over one-third (n = 185, 36.0%) met one or more of the Gold Standards Framework (GSF) prognostic indicator criteria for palliative care needs. The most common GSF prognostic indicator was frailty, with almost one-third of patients (27%) meeting this criteria. Agreement between medical and nursing staff and the GSF with respect to identifying patients with palliative care needs was poor. In focus groups, health professionals reported difficulties in recognising that a patient had entered the last 12 months of life. In-depth interviews with patients found that many of those interviewed were unaware of their prognosis and showed little insight into what they could expect from the trajectory of their disease. The retrospective case note review found that 35 (7.2%) admissions were potentially avoidable. The potential annual cost saving across both hospitals of preventing these admissions was approximately £5.3M. However, a 2- or 3-day reduction in length of stay for these admissions would result in an annual cost saving of £21.6M or £32.4M respectively.&lt;p&gt;&lt;/p&gt; Conclusions: Patients with palliative care needs represent a significant proportion of the hospital inpatient population. There is a significant gap between NHS policy regarding palliative and end-of-life care management in acute hospitals in England and current practice

Spatially Explicit Data: Stewardship and Ethical Challenges in Science

Scholarly communication is at an unprecedented turning point created in part by the increasing saliency of data stewardship and data sharing. Formal data management plans represent a new emphasis in research, enabling access to data at higher volumes and more quickly, and the potential for replication and augmentation of existing research. Data sharing has recently transformed the practice, scope, content, and applicability of research in several disciplines, in particular in relation to spatially specific data. This lends exciting potentiality, but the most effective ways in which to implement such changes, particularly for disciplines involving human subjects and other sensitive information, demand consideration. Data management plans, stewardship, and sharing, impart distinctive technical, sociological, and ethical challenges that remain to be adequately identified and remedied. Here, we consider these and propose potential solutions for their amelioration

A diamond nanophotonic interface with an optically accessible deterministic electronuclear spin register

A contemporary challenge for the scalability of quantum networks is developing quantum nodes with simultaneous high photonic efficiency and long-lived qubits. Here, we present a fibre-packaged nanophotonic diamond waveguide hosting a tin-vacancy centre with a spin-1/2 $^{117}$Sn nucleus. The interaction between the electronic and nuclear spins results in a signature 452(7) MHz hyperfine splitting. This exceeds the natural optical linewidth by a factor of 16, enabling direct optical nuclear-spin initialisation with 98.6(3)% fidelity and single-shot readout with 80(1)% fidelity. The waveguide-to-fibre extraction efficiency of our device of 57(6)% enables the practical detection of 5-photon events. Combining the photonic performance with the optically initialised nuclear spin, we demonstrate a spin-gated single-photon nonlinearity with 11(1)% contrast in the absence of an external magnetic field. These capabilities position our nanophotonic interface as a versatile quantum node in the pursuit of scalable quantum networks