A semi-implicit finite-difference time-domain thin-wire (TW) scheme with a relaxed stability condition is proposed for modelling effective surface plasmons in waveguide metamaterials. Its formulation ...is based on introducing the Newmark-Beta method into the TW formulation based on the contour-path integral of Maxwell's equations around a wire. The resultant scheme is magnetically implicit. Its stability, accuracy and efficiency are assessed in the application to a wire-added parallel-plate waveguide perturbed with a small gap.
For centuries, the scientific discovery process has been based on systematic human observation and analysis of natural phenomena
. Today, however, automated instrumentation and large-scale data ...acquisition are generating datasets of such large volume and complexity as to defy conventional scientific methodology. Radically different scientific approaches are needed, and machine learning (ML) shows great promise for research fields such as materials science
. Given the success of ML in the analysis of synthetic data representing electronic quantum matter (EQM)
, the next challenge is to apply this approach to experimental data-for example, to the arrays of complex electronic-structure images
obtained from atomic-scale visualization of EQM. Here we report the development and training of a suite of artificial neural networks (ANNs) designed to recognize different types of order hidden in such EQM image arrays. These ANNs are used to analyse an archive of experimentally derived EQM image arrays from carrier-doped copper oxide Mott insulators. In these noisy and complex data, the ANNs discover the existence of a lattice-commensurate, four-unit-cell periodic, translational-symmetry-breaking EQM state. Further, the ANNs determine that this state is unidirectional, revealing a coincident nematic EQM state. Strong-coupling theories of electronic liquid crystals
are consistent with these observations.
Drug resistance commonly occurs when treating immunocompromised patients who have fungal infections. Curcumin, is a compound isolated from Curcuma longa, has been reported to inhibit drug efflux in ...several human cell lines and nonpathogenic budding yeast Saccharomyces cerevisiae cells that overexpresses the ATP‐binding cassette (ABC) transporters S. cerevisiae Pdr5p and pathogenic Candida albicans Cdr1p and Cdr2p. The aim of this study was to examine the effects of curcumin on multidrug resistance in a wild‐type strain of the budding yeast with an intrinsic expression system of multidrug efflux‐related genes. The antifungal activity of dodecanol alone was temporary against S. cerevisiae; however, restoration of cell viability was completely inhibited when the cells were co‐treated with dodecanol and curcumin. Furthermore, restriction of rhodamine 6G (R6G) efflux from the cells and intracellular accumulation of R6G were observed with curcumin treatment. Reverse transcription‐polymerase chain reaction analysis revealed that curcumin reduced the dodecanol‐induced overexpression of the ABC transporter‐related genes PDR1, PDR3 and PDR5 to their control levels in untreated cells. Curcumin can directly restrict the glucose‐induced drug efflux and inhibits the expression of the ABC transporter gene PDR5, and can thereby inhibit the efflux of dodecanol from S. cerevisiae cells. Curcumin is effective in potentiating the efficacy of antifungal drugs via its effects on ABC transporters.
Significance and Impact of the Study
Drug resistance is common in immunocompromised patients with fungal infections. Curcumin, isolated from Curcuma longa, inhibits drug efflux in nonpathogenic budding yeast Saccharomyces cerevisiae cells overexpressing ABC transporters S. cerevisiae Pdr5p and pathogenic Candida albicans Cdr1p and Cdr2p. We examined the effects of curcumin on multidrug resistance in a wild‐type strain of the budding yeast with an intrinsic expression system of multidrug efflux‐related genes. Curcumin directly inhibited drug efflux and also suppressed the PDR5 expression, thereby enhancing the antifungal effects. Thus, curcumin potentially promotes the efficacy of antifungals via its effects on ABC transporters in wild‐type fungal strains.
Significance and Impact of the Study: Drug resistance is common in immunocompromised patients with fungal infections. Curcumin, isolated from Curcuma longa, inhibits drug efflux in nonpathogenic budding yeast Saccharomyces cerevisiae cells overexpressing ABC transporters S. cerevisiae Pdr5p and pathogenic Candida albicans Cdr1p and Cdr2p. We examined the effects of curcumin on multidrug resistance in a wild‐type strain of the budding yeast with an intrinsic expression system of multidrug efflux‐related genes. Curcumin directly inhibited drug efflux and also suppressed the PDR5 expression, thereby enhancing the antifungal effects. Thus, curcumin potentially promotes the efficacy of antifungals via its effects on ABC transporters in wild‐type fungal strains.
The existence of electronic symmetry breaking in the underdoped cuprates and its disappearance with increased hole density p are now widely reported. However, the relation between this transition and ...the momentum-space ($\overrightarrow{\mathrm{k}}$-space) electronic structure underpinning the superconductivity has not yet been established. Here, we visualize the $\overrightarrow{\mathrm{Q}}=0$ = 0 (intra–unit-cell) and $\overrightarrow{\mathrm{Q}}\ne 0$ (density-wave) broken-symmetry states, simultaneously with the coherent $\overrightarrow{\mathrm{k}}$-space topology, for Bi2Sr2CaCu2O8+δ samples spanning the phase diagram 0.06 ≤ p ≤ 0.23. We show that the electronic symmetry-breaking tendencies weaken with increasing p and disappear close to a critical doping pc = 0.19. Concomitantly, the coherent $\overrightarrow{\mathrm{k}}$-space topology undergoes an abrupt transition, from arcs to closed contours, at the same pc. These data reveal that the $\overrightarrow{\mathrm{k}}$-space topology transformation in cuprates is linked intimately with the disappearance of the electronic symmetry breaking at a concealed critical point.
High magnetic fields suppress cuprate superconductivity to reveal an unusual density wave (DW) state coexisting with unexplained quantum oscillations. Although routinely labeled a charge density wave ...(CDW), this DW state could actually be an electron-pair density wave (PDW). To search for evidence of a field-induced PDW, we visualized modulations in the density of electronic states
(
) within the halo surrounding Bi
Sr
CaCu
O
vortex cores. We detected numerous phenomena predicted for a field-induced PDW, including two sets of particle-hole symmetric
(
) modulations with wave vectors
and
, with the latter decaying twice as rapidly from the core as the former. These data imply that the primary field-induced state in underdoped superconducting cuprates is a PDW, with approximately eight CuO
unit-cell periodicity and coexisting with its secondary CDWs.
Neuromyelitis optica spectrum disorder is a relapsing inflammatory disorder of the central nervous system. Two thirds of patients have antibodies against aquaporin-4, and CNS damage is complement ...dependent. The inhibitor of terminal complement C5 cleavage, eculizumab, reduced relapses of NMOSD.
A nonlinear and partially implicit finite-difference time-domain scheme with a relaxed stability condition is presented for fast full-wave simulation of electrostatic discharges occurred at a short ...gap. The nonlinear spark resistance model of Rompe and Weizel is directly incorporated in this scheme. Its stability, accuracy and computational efficiency are assessed in the application to a metallic structure system.
Genealogical data are an important source of evidence for delimiting species, yet few statistical methods are available for calculating the probabilities associated with different species ...delimitations. Bayesian species delimitation uses reversible-jump Markov chain Monte Carlo (rjMCMC) in conjunction with a user-specified guide tree to estimate the posterior distribution for species delimitation models containing different numbers of species. We apply Bayesian species delimitation to investigate the speciation history of forest geckos (Hemidactylus fasciatus) from tropical West Africa using five nuclear loci (and mtDNA) for 51 specimens representing 10 populations. We find that species diversity in H. fasciatus is currently underestimated, and describe three new species to reflect the most conservative estimate for the number of species in this complex. We examine the impact of the guide tree, and the prior distributions on ancestral population sizes (θ) and root age (τ0), on the posterior probabilities for species delimitation. Mis-specification of the guide tree or the prior distribution for θ can result in strong support for models containing more species. We describe a new statistic for summarizing the posterior distribution of species delimitation models, called speciation probabilities, which summarize the posterior support for each speciation event on the starting guide tree.
The quantum condensate of Cooper pairs forming a superconductor was originally conceived as being translationally invariant. In theory, however, pairs can exist with finite momentum Q, thus ...generating a state with a spatially modulated Cooper-pair density. Such a state has been created in ultracold (6)Li gas but never observed directly in any superconductor. It is now widely hypothesized that the pseudogap phase of the copper oxide superconductors contains such a 'pair density wave' state. Here we report the use of nanometre-resolution scanned Josephson tunnelling microscopy to image Cooper pair tunnelling from a d-wave superconducting microscope tip to the condensate of the superconductor Bi2Sr2CaCu2O8+x. We demonstrate condensate visualization capabilities directly by using the Cooper-pair density variations surrounding zinc impurity atoms and at the Bi2Sr2CaCu2O8+x crystal supermodulation. Then, by using Fourier analysis of scanned Josephson tunnelling images, we discover the direct signature of a Cooper-pair density modulation at wavevectors QP ≈ (0.25, 0)2π/a0 and (0, 0.25)2π/a0 in Bi2Sr2CaCu2O8+x. The amplitude of these modulations is about five per cent of the background condensate density and their form factor exhibits primarily s or s' symmetry. This phenomenology is consistent with Ginzburg-Landau theory when a charge density wave with d-symmetry form factor and wavevector QC = QP coexists with a d-symmetry superconductor; it is also predicted by several contemporary microscopic theories for the pseudogap phase.
The State and Fate of Himalayan Glaciers Bolch, T.; Kulkarni, A.; Kääb, A. ...
Science (American Association for the Advancement of Science),
04/2012, Letnik:
336, Številka:
6079
Journal Article
Recenzirano
Odprti dostop
Himalayan gladers are a focus of public and scientific debate. Prevailing uncertainties are of major concern because some projections of their future have serious implications for water resources. ...Most Himalayan glaciers are losing mass at rates similar to glaciers elsewhere, except for emerging indications of stability or mass gain in the Karakoram. A poor understanding of the processes affecting them, combined with the diversity of climatic conditions and the extremes of topographical relief within the region, makes projections speculative. Nevertheless, it is unlikely that dramatic changes in total runoff will occur soon, although continuing shrinkage outside the Karakoram will increase the seasonally of runoff, affect irrigation and hydropower, and alter hazards.
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