Elastic waves scattered by randomly rough surfaces in solid media play an important role across research topics including ultrasonic wave detection and imaging, seismic wave exploration and phonon ...boundary interaction. Previous attention has focused upon the mean/expected scattering intensity for both compressional (P) and shear (S) waves. In this article, the variance or the standard deviation (sd) of elastic wave scattering from randomly rough surfaces is studied, which so far has been neglected despite their practical importance in elastic wave applications, via an analytical approach. Theoretical formulae are derived with the aid of the elastodynamic Kirchhoff approximation (KA), to rapidly predict the variance of the scattering amplitude and the intensity, once the statistical parameters of the roughness are known. Theoretical formulae are then successfully validated against high-fidelity Monte Carlo finite element (FE) simulations at different scattering angles across a range of roughness. With the analytical approach the effects of rms roughness, the correlation length and the surface length on the standard deviation of the scattering amplitude are analysed. The significance for applications is illustrated in one important example taken from the field of ultrasonic wave detection of planar rough defects. The theoretical formulae accurately predict the lower bound of the scattering amplitude, which helps set an amplitude threshold confidently, for detecting any possible rough crack in a single inspection while minimising the risk of false alarm. The significantly improved accuracy and confidence of detection enable reliable decisions to be made about whether it is safe to continue using an engineering component.
We investigate the ultrafast terahertz response of electrostatically gated graphene upon optical excitation. We observe that the photoinduced terahertz absorption increases in charge neutral graphene ...but decreases in highly doped graphene. We show that this transition from semiconductor-like to metal-like response is unique for zero bandgap materials such as graphene. In charge neutral graphene photoexcited hot carriers effectively increase electron and hole densities and increase the conductivity. In highly doped graphene, however, photoexcitation does not change net conducting carrier concentration. Instead, it mainly increases electron scattering rate and reduce the conductivity.
We demonstrate efficient terahertz (THz) modulation by coupling graphene strongly with a broadband THz metasurface device. This THz metasurface, made of periodic gold slit arrays, shows near unity ...broadband transmission, which arises from coherent radiation of the enhanced local-field in the slits. Utilizing graphene as an active load with tunable conductivity, we can significantly modify the local-field enhancement and strongly modulate the THz wave transmission. This hybrid device also provides a new platform for future nonlinear THz spectroscopy study of graphene.
We achieve direct electrical readout of the wavelength and polarization dependence of the plasmon resonance in individual gold nanogap antennas by positioning a graphene nanoconstriction within the ...gap as a localized photodetector. The polarization sensitivities can be as large as 99%, while the plasmon-induced photocurrent enhancement is 2−100. The plasmon peak frequency, polarization sensitivity, and photocurrent enhancement all vary between devices, indicating the degree to which the plasmon resonance is sensitive to nanometer-scale irregularities.
In this paper, our aim is to present some characterizations of M-fuzzifying convex matroids. First we discuss the relation between M-fuzzifying convex matroids and M-fuzzy families of dependent sets. ...Secondly, we give characterizations of M-fuzzifying convex matroids by M-fuzzifying rank functions. Finally we discuss the relation between two concept of M-fuzzifying hull (closure) operators.
Application of nuclear magnetic resonance (NMR) spectroscopy to nanoscale samples has remained an elusive goal, achieved only with great experimental effort at subkelvin temperatures. We demonstrated ...detection of NMR signals from a (5-nanometer)(3) voxel of various fluid and solid organic samples under ambient conditions. We used an atomic-size magnetic field sensor, a single nitrogen-vacancy defect center, embedded ~7 nanometers under the surface of a bulk diamond to record NMR spectra of various samples placed on the diamond surface. Its detection volume consisted of only 10(4) nuclear spins with a net magnetization of only 10(2) statistically polarized spins.
Summary
Deficiency of CARD9 (caspase recruitment domain‐containing protein 9) has been reported in individuals with recurrent and invasive fungal infections. We report on a patient who first had ...Trichosporon asahii affecting the skin then Candida albicans infections involving the digestive tract and knee joint, along with elevated serum IgE. After stimulation with C. albicans, peripheral blood mononuclear cells of this patient produced less tumour necrosis factor‐α, interferon‐γ and interleukin‐17 than those of healthy controls. Furthermore, the serum IgE levels of this patient were positively correlated with the severity of fungal infection during the course of treatment. Sanger sequencing identified one homozygous frameshift mutation (p.D274fsX60) in CARD9. We further performed a review including 48 cases with CARD9 deficiency. According to the data published previously, CARD9‐deficient patients demonstrated obviously elevated IgE in serum (median 1300 IU mL−1), which could distinguish them from otherwise healthy people with fungal infections (area under the curve 0·94, P < 0·001). Patients carrying the mutations Q289X and Q295X had a higher mortality rate (24% vs. 0%, P < 0·05). Patients with the mutations R18W, R35Q, R70W, G72S or Y91H in the CARD domain, and the nonsense mutation Q295X in the coiled‐coil domain, seemed to be more prone to Candida infections (90% vs. 20%, P < 0·005) and central nervous system infections (60% vs. 12%, P < 0·005).
What's already known about this topic?
CARD9 deficiency is a rare autosomal recessive genetic defect in T helper 17 immunity, resulting in susceptibility to recurrent and invasive fungal infections.
Patients with genetic defects in T helper 17 immunity are prone to hyper‐IgE syndrome.
What does this study add?
We report a patient with CARD9 p.D274fsX60 mutation manifested as multiple organs infections by Trichosporon asahii and Candida albicans.
This study enriches the phenotypic spectrum of CARD9 deficiency.
IgE level seems to be a possible clue for diagnosis or therapeutic effect of fungal infection in CARD9‐deficient patients.
The cerebellum plays an important role in motor and cognitive functions. However, whether and how the normal-appearing cerebellum is impaired in patients with neuromyelitis optica spectrum disorders ...remain unknown. We aimed to identify the occult structural damage of the cerebellum in neuromyelitis optica spectrum disorder and its possible causes at the level of substructures.
Normal-appearing gray matter volume of the cerebellar lobules and nuclei and normal-appearing white matter volume of the cerebellar peduncles were compared between patients with neuromyelitis optica spectrum disorder and healthy controls.
The cerebellar damage of patients with neuromyelitis optica spectrum disorder in the hemispheric lobule VI, vermis lobule VI, and all cerebellar nuclei and peduncles was related only to spinal lesions; and cerebellar damage in the hemispheric lobules VIII and X was related only to the aquaporin-4 antibody. The mixed cerebellar damage in the hemispheric lobules V and IX and vermis lobule Crus I was related mainly to spinal lesions; and mixed cerebellar damage in the hemispheric lobule VIIb was related mainly to the aquaporin-4 antibody. Other cerebellar substructures showed no significant cerebellar damage.
We have shown that the damage in cerebellar normal-appearing white matter and normal-appearing gray matter is associated with aquaporin-4-mediated primary damage or axonal degeneration secondary to spinal lesions or both. The etiologic classifications of substructure-specific occult cerebellar damage may facilitate developing neuroimaging markers for assessing the severity and the results of therapy of neuromyelitis optica spectrum disorder occult cerebellar damage.
Amphibole‐rich rocks constitute significant components of the mid‐ to lower continental crust, particularly in active orogens characterized with thick and hot crusts. Nevertheless, experimental data ...on their viscosity remain scarce. We conducted axial compression deformation experiments on synthetic amphibolites under temperature and pressure conditions resembling deep sections of overthickened crust. A novel flow law for a calcic‐amphibole‐rich rock (80% amphibole +20% garnet) in the dislocation creep regime is derived from these experiments. Contrary to common assumptions, our results reveal that calcic‐amphibolite is 1‐2 orders of magnitude weaker than plagioclase‐rich amphibolite, granulite, or gabbro. A calcic‐amphibole‐rich, low viscosity deep crust may not only support the “channel flow” model proposed for the Tibetan Plateau but also explain the observed high crustal seismic anisotropy in the region.
Plain Language Summary
The rarity of earthquakes despite strong deformation in the deep crust of mountain belts produced by continental collisions, such as the Himalayas, implies that the deep continental crust is rather weak, easily dissipating imposed stresses by ductile deformation. The major components of the orogenic lower crust are plagioclase, amphibole, pyroxene, and garnet. Experimental data on the ductile deformation of coarse‐grained amphibole‐rich rocks was until now missing. We present new deformation experiments, from which we derive a flow law for an amphibolitic aggregate (80% amphibole +20% garnet). These data show high volumes of amphibole should result in high ductility and, hence, low strength in the deep crust, which should be considered when modeling the mechanical behavior of the lower crust during continental collisional. An amphibole‐rich deep crust also accounts for the high crustal seismic anisotropy in southern Tibet.
Key Points
Experimentally based flow law for dislocation creep of calcic‐amphibole‐rich (80 wt.%) rocks
A calcic‐amphibole‐rich deep crust supports the “channel flow” model in southern Tibet
Experimental amphibole crystal preferred orientations (CPO) may explain deep crustal seismic anisotropy
PDF
