Multimode Diffraction Tomography with Elastic Waves

In recent years ultrasonic imaging procedures have been developed to quantify defects [1,2,3,4] for application in QNDE or medical imaging. The demands for these purposes are high resolution images, true recovering of the scattering geometry and fast computer processing. But most of the published algorithms require certain assumptions as: plane wave excitation, measurements in the farfield of the scatterer or, which is a very serious restriction, scalar wave propagation.</p

A Finite Element Test Bed for Diffraction Tomography

Finite element analysis methods have been successfully applied to the study of ultrasonic wave propagation in elastic solids [1–4]. As a natural part of such numerical solutions. displacements are predicted for every node of the spatial discretization describing the solids geometry and at every instant of time in the temporal discretization used to define the pulse propagation through the material. All of the data constitute a solution to the forward problem and can be used to visualize wavefront propagation and interactions with defects, thus predicting displacement signals at any point in or on the solid

Surface Wave Modes on Spherical Cavities Excited by Incident Ultrasound

It has been shown both experimentally and theoretically1 that ultrasonic waves propagate circumferentially around the surface of cavities in an elastic medium, besides being reflected from its “flash points”. Surface wave returns were seen to decisively influence the time structure of the echo return from incident ultrasonic pulses. Nagase2 has solved a characteristic equation applicable to the spherical cavity problem, from which it could be shown3 that the surface of a spherical cavity supports a Rayleigh-type and two (P and S) Franz-type surface waves, of known speeds and dispersions. On the other hand, the complex eigenfrequencies of cavities were recently obtained numerically4. We have used these numerical results in order to satisfy Nagase’s solutions, presented in the form of propagation constants of the surface waves as series of fractional powers of the frequency, and have obtained in this way a mode number assignment for all the complex eigenfrequencies. Using this, we calculate dispersion curves for the Rayleigh, P and S- type surface wave phase velocities; their knowledge will permit an accurate interpretation of ultrasonic scattering experiments1, which previously could be analyzed in a qualitative way only

Optimization of Ultrasonic Defect Reconstruction with Multi-Saft

Ultrasonic nondestructive inspection (NDI) is widely applied in order to evaluate the structural integrity of steel components. The main reason for this success is that ultrasonic NDI is an excellent means for detecting inhomogeneities. Ultrasonic characterization of inhomogeneities, however, is less successful, as ultrasonic measurements do not directly provide the information, such as size and shape, needed to apply the rules of fracture mechanics. Although the location and orientation of an inhomogeneity may sometimes be estimated quite accurately from ultrasonic measurements, its size and shape are often very hard to determine. Cross-sectional images of the region containing the inhomogeneity would be particularly suitable for extracting these characteristic features. It is possible to reconstruct an image of a possible defect from ultrasonic B-scan data using the well-known Synthetic Aperture Focusing Technique (SAFT) [1]

Imaging of Flaws in Solids by Velocity Inversion

We describe the application of a method for ultrasonic imaging of flaws in solids. These methods greatly extend earlier work along these lines at Rockwell and the Langenberg group in Germany, see [1,2,3,4,5,6,7,8,9,10]. The new inversion methods allow reflector imaging and parameter estimation in progressively more complex media with progressively more realistic source/receiver configurations. This research has been carried out in the context of seismic exploration. However, the problems are sufficiently similar that these more realistic models have direct counterparts in nondestructive testing [11,12,13,14,15,16,17]. In particular, both problems are high frequency inverse scattering problems. High frequency means that the wavelengths are much smaller (by a factor of three or more) than the other length scales of the problem.</p

Association Study with 77 SNPs Confirms the Robust Role for the rs10830963/G of MTNR1B Variant and Identifies Two Novel Associations in Gestational Diabetes Mellitus Development

CONTEXT: Genetic variation in human maternal DNA contributes to the susceptibility for development of gestational diabetes mellitus (GDM). OBJECTIVE: We assessed 77 maternal single nucleotide gene polymorphisms (SNPs) for associations with GDM or plasma glucose levels at OGTT in pregnancy. METHODS: 960 pregnant women (after dropouts 820: case/control: m99'WHO: 303/517, IADPSG: 287/533) were enrolled in two countries into this case-control study. After genomic DNA isolation the 820 samples were collected in a GDM biobank and assessed using KASP (LGC Genomics) genotyping assay. Logistic regression risk models were used to calculate ORs according to IADPSG/m'99WHO criteria based on standard OGTT values. RESULTS: The most important risk alleles associated with GDM were rs10830963/G of MTNR1B (OR = 1.84/1.64 [IADPSG/m'99WHO], p = 0.0007/0.006), rs7754840/C (OR = 1.51/NS, p = 0.016) of CDKAL1 and rs1799884/T (OR = 1.4/1.56, p = 0.04/0.006) of GCK. The rs13266634/T (SLC30A8, OR = 0.74/0.71, p = 0.05/0.02) and rs7578326/G (LOC646736/IRS1, OR = 0.62/0.60, p = 0.001/0.006) variants were associated with lower risk to develop GDM. Carrying a minor allele of rs10830963 (MTNR1B); rs7903146 (TCF7L2); rs1799884 (GCK) SNPs were associated with increased plasma glucose levels at routine OGTT. CONCLUSIONS: We confirmed the robust association of MTNR1B rs10830963/G variant with GDM binary and glycemic traits in this Caucasian case-control study. As novel associations we report the minor, G allele of the rs7578326 SNP in the LOC646736/IRS1 region as a significant and the rs13266634/T SNP (SLC30A8) as a suggestive protective variant against GDM development. Genetic susceptibility appears to be more preponderant in individuals who meet both the modified 99'WHO and the IADPSG GDM diagnostic criteria

Formation of Complexes at Plasmodesmata for Potyvirus Intercellular Movement Is Mediated by the Viral Protein P3N-PIPO

Intercellular transport of viruses through cytoplasmic connections, termed plasmodesmata (PD), is essential for systemic infection in plants by viruses. Previous genetic and ultrastructural data revealed that the potyvirus cyclindrical inclusion (CI) protein is directly involved in cell-to-cell movement, likely through the formation of conical structures anchored to and extended through PD. In this study, we demonstrate that plasmodesmatal localization of CI in N. benthamiana leaf cells is modulated by the recently discovered potyviral protein, P3N-PIPO, in a CI:P3N-PIPO ratio-dependent manner. We show that P3N-PIPO is a PD-located protein that physically interacts with CI in planta. The early secretory pathway, rather than the actomyosin motility system, is required for the delivery of P3N-PIPO and CI to PD. Moreover, CI mutations that disrupt virus cell-to-cell movement compromise PD-localization capacity. These data suggest that the CI and P3N-PIPO complex coordinates the formation of PD-associated structures that facilitate the intercellular movement of potyviruses in infected plants

A combination of plasma phospholipid fatty acids and its association with incidence of type 2 diabetes: The EPIC-InterAct case-cohort study.

BACKGROUND: Combinations of multiple fatty acids may influence cardiometabolic risk more than single fatty acids. The association of a combination of fatty acids with incident type 2 diabetes (T2D) has not been evaluated. METHODS AND FINDINGS: We measured plasma phospholipid fatty acids by gas chromatography in 27,296 adults, including 12,132 incident cases of T2D, over the follow-up period between baseline (1991-1998) and 31 December 2007 in 8 European countries in EPIC-InterAct, a nested case-cohort study. The first principal component derived by principal component analysis of 27 individual fatty acids (mole percentage) was the main exposure (subsequently called the fatty acid pattern score [FA-pattern score]). The FA-pattern score was partly characterised by high concentrations of linoleic acid, stearic acid, odd-chain fatty acids, and very-long-chain saturated fatty acids and low concentrations of γ-linolenic acid, palmitic acid, and long-chain monounsaturated fatty acids, and it explained 16.1% of the overall variability of the 27 fatty acids. Based on country-specific Prentice-weighted Cox regression and random-effects meta-analysis, the FA-pattern score was associated with lower incident T2D. Comparing the top to the bottom fifth of the score, the hazard ratio of incident T2D was 0.23 (95% CI 0.19-0.29) adjusted for potential confounders and 0.37 (95% CI 0.27-0.50) further adjusted for metabolic risk factors. The association changed little after adjustment for individual fatty acids or fatty acid subclasses. In cross-sectional analyses relating the FA-pattern score to metabolic, genetic, and dietary factors, the FA-pattern score was inversely associated with adiposity, triglycerides, liver enzymes, C-reactive protein, a genetic score representing insulin resistance, and dietary intakes of soft drinks and alcohol and was positively associated with high-density-lipoprotein cholesterol and intakes of polyunsaturated fat, dietary fibre, and coffee (p < 0.05 each). Limitations include potential measurement error in the fatty acids and other model covariates and possible residual confounding. CONCLUSIONS: A combination of individual fatty acids, characterised by high concentrations of linoleic acid, odd-chain fatty acids, and very long-chain fatty acids, was associated with lower incidence of T2D. The specific fatty acid pattern may be influenced by metabolic, genetic, and dietary factors

A narrative review on the similarities and dissimilarities between myalgic encephalomyelitis/chronic fatigue syndrome (me/cfs) and sickness behavior

It is of importance whether myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a variant of sickness behavior. The latter is induced by acute infections/injury being principally mediated through proinflammatory cytokines. Sickness is a beneficial behavioral response that serves to enhance recovery, conserves energy and plays a role in the resolution of inflammation. There are behavioral/symptomatic similarities (for example, fatigue, malaise, hyperalgesia) and dissimilarities (gastrointestinal symptoms, anorexia and weight loss) between sickness and ME/CFS. While sickness is an adaptive response induced by proinflammatory cytokines, ME/CFS is a chronic, disabling disorder, where the pathophysiology is related to activation of immunoinflammatory and oxidative pathways and autoimmune responses. While sickness behavior is a state of energy conservation, which plays a role in combating pathogens, ME/CFS is a chronic disease underpinned by a state of energy depletion. While sickness is an acute response to infection/injury, the trigger factors in ME/CFS are less well defined and encompass acute and chronic infections, as well as inflammatory or autoimmune diseases. It is concluded that sickness behavior and ME/CFS are two different conditions