We use an effective one-dimensional Gross-Pitaevskii equation to study bright matter-wave solitons held in a tightly confining toroidal trapping potential, in a rotating frame of reference, as they ...are split and recombined on narrow barrier potentials. In particular, we present an analytical and numerical analysis of the phase evolution of the solitons and delimit a velocity regime in which soliton Sagnac interferometry is possible, taking account of the effect of quantum uncertainty.
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In this Letter, we show that it is possible to structure the longitudinal polarization component of light. We illustrate our approach by demonstrating linked and knotted longitudinal vortex lines ...acquired upon nonparaxially propagating a tightly focused subwavelength beam. The remaining degrees of freedom in the transverse polarization components can be exploited to generate customized topological vector beams.
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We propose a method of atom interferometry using a spinor Bose-Einstein condensate with a time-varying magnetic field acting as a coherent beam splitter. Our protocol creates long-lived ...superpositional counterflow states, which are of fundamental interest and can be made sensitive to both the Sagnac effect and magnetic fields on the sub-μG scale. We split a ring-trapped condensate, initially in the m_{f}=0 hyperfine state, into superpositions of internal m_{f}=±1 states and condensate superflow, which are spin-orbit coupled. After interrogation, the relative phase accumulation can be inferred from a population transfer to the m_{f}=±1 states. The counterflow generation protocol is adiabatically deterministic and does not rely on coupling to additional optical fields or mechanical stirring techniques. Our protocol can maximize the classical Fisher information for any rotation, magnetic field, or interrogation time and so has the maximum sensitivity available to uncorrelated particles. Precision can increase with the interrogation time and so is limited only by the lifetime of the condensate.
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Bright solitons are non-dispersive wave solutions, arising in a diverse range of nonlinear, one-dimensional systems, including atomic Bose-Einstein condensates with attractive interactions. In ...reality, cold-atom experiments can only approach the idealized one-dimensional limit necessary for the realization of true solitons. Nevertheless, it remains possible to create bright solitary waves, the three-dimensional analogue of solitons, which maintain many of the key properties of their one-dimensional counterparts. Such solitary waves offer many potential applications and provide a rich testing ground for theoretical treatments of many-body quantum systems. Here we report the controlled formation of a bright solitary matter-wave from a Bose-Einstein condensate of (85)Rb, which is observed to propagate over a distance of ∼1.1 mm in 150 ms with no observable dispersion. We demonstrate the reflection of a solitary wave from a repulsive Gaussian barrier and contrast this to the case of a repulsive condensate, in both cases finding excellent agreement with theoretical simulations using the three-dimensional Gross-Pitaevskii equation.
Rising global demand for fossil resources has prompted a renewed interest in catalyst technologies that increase the efficiency of conversion of hydrocarbons from petroleum and natural gas to ...higher-value materials. Styrene is currently produced from benzene and ethylene through the intermediacy of ethylbenzene, which must be dehydrogenated in a separate step. The direct oxidative conversion of benzene and ethylene to styrene could provide a more efficient route, but achieving high selectivity and yield for this reaction has been challenging. Here, we report that the Rh catalyst (FIDAB)Rh(TFA)(η2–C2H4) FIDAB is N,N′-bis(pentafluorophenyl)-2,3-dimethyl-1,4-diaza-1,3-butadiene; TFA is trifluoroacetate converts benzene, ethylene, and Cu(II) acetate to styrene, Cu(I) acetate, and acetic acid with 100% selectivity and yields ≥95%. Turnover numbers >800 have been demonstrated, with catalyst stability up to 96 hours.
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Recent technological advancements have made a tremendous impact in the fields of biological anthropology and archaeology. Although advancements in DNA analysis have overshadowed other areas of ...progress in the subfields of biological anthropology, bioarchaeologists are now utilizing many other new forms of technology in their work. In particular, three-dimensional (3D) laser scanning offers a sophisticated method of documenting and studying prehistoric human skeletons. In recent years, portable laser scanning devices capable of creating high resolution images have become available, enabling researchers to scan and archive skeletal collections from archaeological sites and museum collections around the world. 3D laser scanners are inexpensive, simple to operate, and completely non-destructive to human skeletal material. A major benefit is that they offer a cost-effective method of creating a digital record of skeletal collections for museum archives. Since published research using 3D methods typically focuses on sophisticated analyses used to analyze 3D data that are difficult for the novice user to follow, in this paper we provide a simple and straightforward overview of 3D scanning methods aimed at non-specialists. We discuss how these methods can be used to preserve and document osteological material in museums, develop research ideas in the subfields of biological anthropology, and increase the potential for scholarly collaboration.
► A straightforward explanation of 3D laser scanning uses for non-specialists. ► Examples of 3D projects employing prehistoric and modern skeletal samples. ► We discuss the importance of integrating 3D scanning in museum curation procedures. ► We highlight ways that researchers can use 3D methods in collaborative projects.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Partitioning space into cells with certain extreme geometrical properties is a central problem in many fields of science and technology. Here we investigate the Quantizer problem, defined as the ...optimisation of the moment of inertia of Voronoi cells, i.e., similarly-sized 'sphere-like' polyhedra that tile space are preferred. We employ Lloyd's centroidal Voronoi diagram algorithm to solve this problem and find that it converges to disordered states associated with deep local minima. These states are universal in the sense that their structure factors are characterised by a complete independence of a wide class of initial conditions they evolved from. They moreover exhibit an anomalous suppression of long-wavelength density fluctuations and quickly become effectively hyperuniform. Our findings warrant the search for novel amorphous hyperuniform phases and cellular materials with unique physical properties.
Human papillomaviruses (HPVs) are involved in the pathogenesis of cancer of the cervix (CaCx). MicroRNA (miRNA) expression analysis using Ambion (Austin, TX, USA) arrays showed that three miRNAs were ...overexpressed and 24 underexpressed in cervical cell lines containing integrated HPV-16 DNA compared to the normal cervix. Furthermore, nine miRNAs were overexpressed and one underexpressed in integrated HPV-16 cell lines compared to the HPV-negative CaCx cell line C-33A. Based on microarray and/or quantitative real-time PCR and northern blot analyses, microRNA-218 (miR-218) was specifically underexpressed in HPV-positive cell lines, cervical lesions and cancer tissues containing HPV-16 DNA compared to both C-33A and the normal cervix. Expression of the E6 oncogene of high-risk HPV-16, but not that of low-risk HPV-6, reduced miR-218 expression, and conversely, RNA interference of E6/E7 oncogenes in an HPV-16-positive cell line increased miR-218 expression. We also demonstrate that the epithelial cell-specific marker LAMB3 is a target of miR-218. We also show that LAMB3 expression is increased in the presence of the HPV-16 E6 oncogene and this effect is mediated through miR-218. These findings may contribute to a better understanding of the molecular mechanisms involved in cervical carcinogenesis.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Summary
Renal blood flow, local tissue perfusion and blood oxygen content are the major determinants of oxygen delivery to kidney tissue. Arterial pressure and segmental vascular resistance influence ...kidney oxygen consumption through effects on glomerular filtration rate and sodium reabsorption.
Diffusive shunting of oxygen from arteries to veins in the cortex and from descending to ascending vasa recta in the medulla limits oxygen delivery to renal tissue. Oxygen shunting depends on the vascular network, renal haemodynamics and kidney oxygen consumption. Consequently, the impact of changes in renal haemodynamics on tissue oxygenation cannot necessarily be predicted intuitively and, instead, requires the integrative approach offered by computational modelling and multiple measuring modalities.
Tissue hypoxia is a hallmark of acute kidney injury (AKI) arising from multiple initiating insults, including ischaemia–reperfusion injury, radiocontrast administration, cardiopulmonary bypass surgery, shock and sepsis. Its pathophysiology is defined by inflammation and/or ischaemia resulting in alterations in renal tissue oxygenation, nitric oxide bioavailability and oxygen radical homeostasis. This sequence of events appears to cause renal microcirculatory dysfunction, which may then be exacerbated by the inappropriate use of therapies common in peri‐operative medicine, such as fluid resuscitation.
The development of new ways to prevent and treat AKI requires an integrative approach that considers not just the molecular mechanisms underlying failure of filtration and tissue damage, but also the contribution of haemodynamic factors that determine kidney oxygenation. The development of bedside monitors allowing continuous surveillance of renal haemodynamics, oxygenation and function should facilitate better prevention, detection and treatment of AKI.
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BFBNIB, DOBA, FSPLJ, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
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