Triplet superconductivity in coupled odd-gon rings

Shedding light on the nature of spin-triplet superconductivity has been a long-standing quest in condensed matter physics since the discovery of superfluidity in liquid 3 He. Nevertheless, the mechanism of spin-triplet pairing is much less understood than that of spin-singlet pairing explained by the Bardeen-Cooper-Schrieffer theory or even observed in high-temperature superconductors. Here we propose a versatile mechanism for spin-triplet superconductivity which emerges through a melting of macroscopic spin polarization stabilized in weakly coupled odd-gon (e.g., triangle, pentagon, etc) systems. We demonstrate the feasibility of sustaining spin-triplet superconductivity with this mechanism by considering a new class of quasi-one-dimensional superconductors A 2 Cr 3 As 3 (A = K, Rb, and Cs). Furthermore, we suggest a simple effective model to easily illustrate the adaptability of the mechanism to general systems consisting of odd-gon units. This mechanism provides a rare example of superconductivity from on-site Coulomb repulsion

Peierls to superfluid crossover in the one-dimensional, quarter-filled Holstein model

We use continuous-time quantum Monte Carlo simulations to study retardation effects in the metallic, quarter-filled Holstein model in one dimension. Based on results which include the one- and two-particle spectral functions as well as the optical conductivity, we conclude that with increasing phonon frequency the ground state evolves from one with dominant diagonal order---2k_F charge correlations---to one with dominant off-diagonal fluctuations, namely s-wave pairing correlations. In the parameter range of this crossover, our numerical results support the existence of a spin gap for all phonon frequencies. The crossover can hence be interpreted in terms of preformed pairs corresponding to bipolarons, which are essentially localised in the Peierls phase, and "condense" with increasing phonon frequency to generate dominant pairing correlations.Comment: 11 pages, 5 figure

Correlated singlet phase in the one-dimensional Hubbard-Holstein model

We show that a nearest-neighbor singlet phase results (from an effective Hamiltonian) for the one-dimensional Hubbard-Holstein model in the regime of strong electron-electron and electron-phonon interactions and under non-adiabatic conditions ($t/\omega_0 \leq 1$). By mapping the system of nearest-neighbor singlets at a filling $N_p/N$ onto a hard-core-boson (HCB) $t$-$V$ model at a filling $N_p/(N-N_p)$, we demonstrate explicitly that superfluidity and charge-density-wave (CDW) occur mutually exclusively with the diagonal long range order manifesting itself only at one-third filling. Furthermore, we also show that the Bose-Einstein condensate (BEC) occupation number $n_0$ for the singlet phase, similar to the $n_0$ for a HCB tight binding model, scales as $\sqrt N$; however, the coefficient of $\sqrt N$ in the $n_0$ for the interacting singlet phase is numerically demonstrated to be smaller.Comment: Corrected a few reference

Harnessing the power of complex light propagation in multimode fibers for spatially resolved sensing

The propagation of coherent light in multimode optical fibers results in a speckled output that is both complex and sensitive to environmental effects. These properties can be a powerful tool for sensing, as small perturbations lead to significant changes in the output of the fiber. However, the mechanism to encode spatially resolved sensing information into the speckle pattern and the ability to extract this information is thus far unclear. In this paper, we demonstrate that spatially dependent mode coupling is crucial to achieving spatially resolved measurements. We leverage machine learning to quantitatively extract this spatially resolved sensing information from three fiber types with dramatically different characteristics and demonstrate that the fiber with the highest degree of spatially dependent mode coupling provides the greatest accuracy.Comment: 17 pages and 7 figure

The fetal mouse is a sensitive genotoxicity model that exposes lentiviral-associated mutagenesis resulting in liver oncogenesis

This article is available open access through the publisher’s website at the link below. Copyright @ 2013 The American Society of Gene & Cell Therapy.Genotoxicity models are extremely important to assess retroviral vector biosafety before gene therapy. We have developed an in utero model that demonstrates that hepatocellular carcinoma (HCC) development is restricted to mice receiving nonprimate (np) lentiviral vectors (LV) and does not occur when a primate (p) LV is used regardless of woodchuck post-translation regulatory element (WPRE) mutations to prevent truncated X gene expression. Analysis of 839 npLV and 244 pLV integrations in the liver genomes of vector-treated mice revealed clear differences between vector insertions in gene dense regions and highly expressed genes, suggestive of vector preference for insertion or clonal outgrowth. In npLV-associated clonal tumors, 56% of insertions occurred in oncogenes or genes associated with oncogenesis or tumor suppression and surprisingly, most genes examined (11/12) had reduced expression as compared with control livers and tumors. Two examples of vector-inserted genes were the Park 7 oncogene and Uvrag tumor suppressor gene. Both these genes and their known interactive partners had differential expression profiles. Interactive partners were assigned to networks specific to liver disease and HCC via ingenuity pathway analysis. The fetal mouse model not only exposes the genotoxic potential of vectors intended for gene therapy but can also reveal genes associated with liver oncogenesis.Imperial College London, the Wellcome Trust, and Brunel University

Exploring the theories, determinants and policy-options of street vending: a demand-side approach

Street vending has been a common feature of urban centres for several decades, with a relatively high proportion of developing countries’ populations depending on it for employment, income or survival. Taking a supply-side approach, studies have shown that urban planners’ responses to street vending have followed the modernism theory. In this paper, we take a demand-side (buyer-focused) approach to studying street vending, which to date has received little attention from the academic community. Employing data from Lagos state, Nigeria, we report four explanations underpinning the demand-side of street vending: formal economy failures, social/redistributive, financial gains, and multifeature. These are, in turn, explained by individuals’ marital status, level of education, and perception. Our findings highlight the need for urban planners to embrace pragmatic policies in addressing these demand-side drivers of street vending and use of urban space, rather than criminalising its actors

National profile of foot orthotic provision in the United Kingdom, part 1 : practitioners and scope of practice.

Foot orthoses have been advocated in the management of a wide range of clinical foot and lower limb problems and are within the scope of podiatry, orthotic and physiotherapy practice. Previous reports into the provision of orthoses have consistently identified significant issues with services and devices, but data were never specific to foot orthoses. The aim of this first of a series of papers was to report the first ever national multi professional profile of foot orthosis provision in the United Kingdom. Quantitative and qualitative data were collected from podiatrists, orthotists and physiotherapists via an online questionnaire. The topics, questions and answers were developed through a series of pilot phases. The professions were targeted through electronic and printed materials. Data were captured over a 10 month period in 2016. A total of 499 responses were included in analysis, including 357 podiatrists, 93 orthotists and 49 physiotherapists. The results reveal wide ranging practices across podiatrists, orthotists and physiotherapists, provision of orthoses through different health care departments (uni and multidisciplinary), for different health conditions (acute and chronic), and involving different types of orthoses (prefabricated and customised). Foot orthoses in the United Kingdom are provided in areas of well recognised health and rehabilitation priorities. A wide range of orthotic devices and practices are employed and different professions provide foot orthoses in different ways

Evaluating the Safety of Intravenous Delivery of Autologous Activated Platelet-rich Plasma

Introduction: Autologous platelet-rich plasma (PRP) has been a growing trend in the field of medicine due to its broad range of application and is considered safe from bloodborne diseases. Furthermore, various studies have tried to optimize the use of autologous PRP through various preparation protocols, including PRP activation. However, most of the studies available have not evaluated the safety for intravenous delivery of PRP, especially autologous activated PRP (aaPRP). Therefore, this study aimed to evaluate the safety of intravenous delivery of aaPRP.Methods: Blood was drawn from each patient and aaPRP was isolated through calcium activation and light irradiation. Each aaPRP was administered intravenously to all patients. Adverse events were documented and analyzed.Results: Six hundred eleven patients participated in this study with a total of 4244 aaPRP therapies. Quality control of autologous aaPRP showed no platelets present after both calcium activation and light irradiation. No adverse events such as allergic reaction, infection, and coagulation problems were observed on all patients over the course of the study.Conclusion: Our results showed that intravenous administration of autologous aaPRP is safe even in patients with various pathological conditions

National profile of foot orthotic provision in the United Kingdom, part 2 : podiatrist, orthotist and physiotherapy practices.

Background A national survey recently provided the first description of foot orthotic provision in the United Kingdom. This article aims to profile and compare the foot orthoses practice of podiatrists, orthotists and physiotherapists within the current provision. Method Quantitative data were collected from podiatrists, orthotists and physiotherapists via an online questionnaire. The topics, questions and answers were developed through a series of pilot phases. The professions were targeted through electronic and printed materials advertising the survey. Data were captured over a 10 month period in 2016. Differences between professions were investigated using Chi squared and Fischer’s exact tests, and regression analysis was used to predict the likelihood of each aspect of practice in each of the three professions. Results Responses from 357 podiatrists, 93 orthotists and 49 physiotherapists were included in the analysis. The results reveal statistically significant differences in employment and clinical arrangements, the clinical populations treated, and the nature and volume of foot orthoses caseload. Conclusion Podiatrists, orthotists and physiotherapists provide foot orthoses to important clinical populations in both a prevention and treatment capacity. Their working context, scope of practice and mix of clinical caseload differs significantly, although there are areas of overlap. Addressing variations in practice could align this collective workforce to national allied health policy

An evidence-based review of creative problem solving tools: a practitioner’s resource

Creative problem solving (CPS) requires solutions to be useful and original. Typically, its operations span problem finding, idea generation and critical evaluation. The benefits of training CPS have been extolled in education, industry and government with evidence showing it can enhance performance. However, while such training schemes work, less is known about the specific tools used. Knowing whether a particular tool works or not would provide practitioners with a valuable resource, leading to more effective training schemes, and a better understanding of the processes involved. A comprehensive review was undertaken examining the empirical support of tools used within CPS. Despite the surprising lack of research focusing on the use and success of specific tools some evidence exists to support the effectiveness of a small set. Such findings present practitioners with a potential resource that could be used in a stand-alone setting or possibly combined to create more effective training programmes