Coupling effect between two adjacent chiral structure layers

Cataloged from PDF version of article.A pair of mutually twisted metallic cross-wires can produce giant optical activity. When this single chiral layer is stacked layer by layer in order to build a thick chiral metamaterial, strong coupling effects are found between the two adjacent chiral layers. We studied these coupling effects numerically and experimentally. The results show that the existing coupling between chiral layers can make the chiral properties of a two-layered chiral metamaterial different from the constituting single chiral layers. It is explained qualitatively that the coupling effects are generated from the coupling of metallic cross-wires belonging to different chiral layers. Our experimental results are in good agreement with the simulation results. ©2010 Optical Society of Americ

Bilateral Talus and Navicular Fractures accompanied with Unilateral Calcaneal Fracture: A Case Report

An 18-year old male patient, with a history of paragliding accident, sustaining a coronal shear fracture of the body of the talus, an anterior process fracture of the calcaneus extending to the calcaneocuboid joint and a nondisplaced navicular body fracture at the right foot and a displaced fracture of the navicular body accompanied with posteromedial process fracture of the talus at the left side was referred to our emergency clinic. For the right foot, the coronal plane fracture of the talar body was anatomically reduced and fixed with screws. For the left foot, screw fixation was performed through the lateral aspect to fix the large posteromedial fragment. Small bone fragments were removed from the left navicular fracture, and the main fragments were also fixed with screw. The talo-navicular joint was stabilised with a Kirschner wire. At 36 months follow-up, bilateral foot and ankle functions were satisfactory, Maryland scores of the right and left foot were 85 (good) and 90 (excellent), respectively, and the patient regained his full activity level by the 5th month postoperatively. With reference to the number and types of fractures in this one patient, we present a standard protocol for treatment of isolated talus, navicular and calcaneal fractures presenting together in a single foot injury

Enhanced transmission and directivity from metallic subwavelength apertures with nonuniform and nonperiodic grooves

Nonuniform and nonperiodic grooves are used to enhance the transmission and directivity of emissions from a single metallic subwavelength aperture. By using nonuniform and nonperiodic grooves, the amplitude and phase of the diffracted power flow from each groove can be adjusted properly. As a result, the transmission and emission directivity can be further improved when compared to apertures with uniform and periodic grooves. Our experimental results are in good agreement with the finite difference time domain simulation results. © 2008 American Institute of Physics

Strength Development in Overmolded Structures

Overmolding of thermoplastic composites is a technology in which a thermoplastic composite is thermoformed and subsequently injection overmolded. Although the feasibility of the process is increasingly demonstrated, it is acknowledged that there is a lack of proper design tools that can be used for a right-the-first-time design strategy. Here, a modelling strategy is proposed for the prediction of the bond strength between a composite insert and an injected polymer. The development of the interface strength is affected by the process history as well, where the temperature and polymer chain mobility play an important role. In the model, the melting behavior of the polymer interface is described using the temperature evolution on the interface combined with experimentally determined polymer melting kinetics via flash differential scanning calorimetry (DSC). Dedicated test geometries were developed and manufactured to evaluate the bond strength under different loading conditions. Short beam strength experiments were used to study the flow length dependency of the interface strength and were correlated with the predicted melting evolution on the interface. The outcome was critically reviewed leading to preliminary guidelines for design, materials and processing as well as routes to further mature this technology

Automated Prediction of CMEs Using Machine Learning of CME – Flare Associations

YesIn this work, machine learning algorithms are applied to explore the relation between significant flares and their associated CMEs. The NGDC flares catalogue and the SOHO/LASCO CMEs catalogue are processed to associate X and M-class flares with CMEs based on timing information. Automated systems are created to process and associate years of flares and CMEs data, which are later arranged in numerical training vectors and fed to machine learning algorithms to extract the embedded knowledge and provide learning rules that can be used for the automated prediction of CMEs. Different properties are extracted from all the associated (A) and not-associated (NA) flares representing the intensity, flare duration, duration of decline and duration of growth. Cascade Correlation Neural Networks (CCNN) are used in our work. The flare properties are converted to numerical formats that are suitable for CCNN. The CCNN will predict if a certain flare is likely to initiate a CME after input of its properties. Intensive experiments using the Jack-knife techniques are carried out and it is concluded that our system provides an accurate prediction rate of 65.3%. The prediction performance is analysed and recommendation for enhancing the performance are provided

Clinical, genetic, and functional characterization of the glycine receptor β-subunit A455P variant in a family affected by hyperekplexia syndrome

Hyperekplexia is a rare neurological disorder characterized by exaggerated startle response affecting newborns with the hallmark characteristics of hypertonia, apnea, and noise or touch-induced non-epileptic seizures. The genetic causes of the disease can vary and several associated genes and mutations have been reported to affect glycine receptors (GlyRs); however, the mechanistic links between GlyRs and hyperekplexia are not yet understood. Here, we describe a patient with hyperekplexia from a consanguineous family. Extensive genetic screening using exome sequencing coupled with autozygome analysis and iterative filtering supplemented by in silico prediction identified that the patient carries the homozygous missense mutation A455P in GLRB, which encodes the GlyR β-subunit. To unravel the physiological and molecular effects of A455P on GlyRs, we used electrophysiology in a heterologous system as well as immunocytochemistry, confocal microscopy, and cellular biochemistry. We found a reduction in glycine-evoked currents in N2A cells expressing the mutation compared to wild type cells. Western blot analysis also revealed a reduced amount of GlyR β protein both in cell lysates and isolated membrane fractions. In line with the above observations, co-immunoprecipitation assays suggested that the GlyR α1-subunit retained co-assembly with βA455P to form membrane-bound heteromeric receptors. Finally, structural modelling showed that the A455P mutation affected the interaction between the GlyR β-subunit transmembrane domain 4 and the other helices of the subunit. Taken together, our study identifies and validates a novel loss-of-function mutation in GlyRs whose pathogenicity is likely to cause hyperekplexia in affected individuals

A novel extracellular role for tissue transglutaminase in matrix-bound VEGF-mediated angiogenesis

The importance of tissue transglutaminase (TG2) in angiogenesis is unclear and contradictory. Here we show that inhibition of extracellular TG2 protein crosslinking or downregulation of TG2 expression leads to inhibition of angiogenesis in cell culture, the aorta ring assay and in vivo models. In a human umbilical vein endothelial cell (HUVEC) co-culture model, inhibition of extracellular TG2 activity can halt the progression of angiogenesis, even when introduced after tubule formation has commenced and after addition of excess vascular endothelial growth factor (VEGF). In both cases, this leads to a significant reduction in tubule branching. Knockdown of TG2 by short hairpin (shRNA) results in inhibition of HUVEC migration and tubule formation, which can be restored by add back of wt TG2, but not by the transamidation-defective but GTP-binding mutant W241A. TG2 inhibition results in inhibition of fibronectin deposition in HUVEC monocultures with a parallel reduction in matrix-bound VEGFA, leading to a reduction in phosphorylated VEGF receptor 2 (VEGFR2) at Tyr1214 and its downstream effectors Akt and ERK1/2, and importantly its association with b1 integrin. We propose a mechanism for the involvement of matrix-bound VEGFA in angiogenesis that is dependent on extracellular TG2-related activity

Genetic and phenotypic characterization of NKX6‐2‐related spastic ataxia and hypomyelination

Background and purpose Hypomyelinating leukodystrophies are a heterogeneous group of genetic disorders with a wide spectrum of phenotypes and a high rate of genetically unsolved cases. Bi‐allelic mutations in NKX6‐2 were recently linked to spastic ataxia 8 with hypomyelinating leukodystrophy. Methods Using a combination of homozygosity mapping, exome sequencing, and detailed clinical and neuroimaging assessment a series of new NKX6‐2 mutations in a multicentre setting is described. Then, all reported NKX6‐2 mutations and those identified in this study were combined and an in‐depth analysis of NKX6‐2‐related disease spectrum was provided. Results Eleven new cases from eight families of different ethnic backgrounds carrying compound heterozygous and homozygous pathogenic variants in NKX6‐2 were identified, evidencing a high NKX6‐2 mutation burden in the hypomyelinating leukodystrophy disease spectrum. Our data reveal a phenotype spectrum with neonatal onset, global psychomotor delay and worse prognosis at the severe end and a childhood onset with mainly motor phenotype at the milder end. The phenotypic and neuroimaging expression in NKX6‐2 is described and it is shown that phenotypes with epilepsy in the absence of overt hypomyelination and diffuse hypomyelination without seizures can occur. Conclusions NKX6‐2 mutations should be considered in patients with autosomal recessive, very early onset of nystagmus, cerebellar ataxia with hypotonia that rapidly progresses to spasticity, particularly when associated with neuroimaging signs of hypomyelination. Therefore, it is recommended that NXK6‐2 should be included in hypomyelinating leukodystrophy and spastic ataxia diagnostic panels