An epidemiologic, clinical, and therapeutic study of childhood Guillain-Barré syndrome in Kuwait: is it related to the oral polio vaccine?

We studied Guillain-Barré syndrome, affecting children 12 years old or less, throughout Kuwait, in the period between January 1, 1992, and March 31, 1997. Nineteen children had the diagnostic criteria of Guillain-Barré syndrome, with an overall annual incidence rate of 0.95/100,000 population at risk. Female patients outnumbered male patients with a sex ratio of 1.4:1. There was a clustering of cases in winter and spring and in the year 1996. The disease symptoms were relatively severe in our patients because only 16% (3 of 19) of them were able to walk at the height of their illness, whereas the rest were bed or chair bound or needed assisted ventilation. Two patients had the electrodiagnostic features of axonal neuropathy and both had residual deficits on follow-up, whereas the rest recovered fully. All the patients received intravenous immunoglobulin. The mean time to walk unaided was 23.5 days (range, 2-84 days) after intravenous immunoglobulin and excluding the two patients with axonal neuropathy, and full recovery was achieved in a mean time of 103 days (range, 30-300 days). Contrary to previous studies, we found no correlation between oral polio vaccine administration and Guillain-Barré syndrome in 2 successive years (1995 and 1996) during a nationwide campaign targeting children less than 5 years old.     

Ionization coefficient of monolayer graphene nanoribbon

A semi-analytical model for impact ionization coefficient of graphene nanoribbon (GNR) is presented. The model is derived by calculating probability of electrons reaching ionization threshold energy E_t and the distance travelled by electron gaining E_t. In addition, ionization threshold energy is semi-analytically modelled for GNR. During modelling, we justify our assumptions using analytical modelling and comparison with simulation. Furthermore, it is shown that conventional silicon models are not valid for calculation of ionization coefficient of GNR. Finally, the profile of ionization is presented using the proposed models and the results are compared with that of silicon.     

Native Liquid Chromatography and Mass Spectrometry to Structurally and Functionally Characterize Endo-Xylanase Proteoforms

Xylanases are of great value in various industries, including paper, food, and biorefinery. Due to their biotechnological production, these enzymes can contain a variety of post-translational modifications, which may have a profound effect on protein function. Understanding the structure–function relationship can guide the development of products with optimal performance. We have developed a workflow for the structural and functional characterization of an endo-1,4-β-xylanase (ENDO-I) produced by Aspergillus niger with and without applying thermal stress. This workflow relies on orthogonal native separation techniques to resolve proteoforms. Mass spectrometry and activity assays of separated proteoforms permitted the establishment of structure–function relationships. The separation conditions were focus on balancing efficient separation and protein functionality. We employed size exclusion chromatography (SEC) to separate ENDO-I from other co-expressed proteins. Charge variants were investigated with ion exchange chromatography (IEX) and revealed the presence of low abundant glycated variants in the temperature-stressed material. To obtain better insights into the effect on glycation on function, we enriched for these species using boronate affinity chromatography (BAC). The activity measurements showed lower activity of glycated species compared to the non-modified enzyme. Altogether, this workflow allowed in-depth structural and functional characterization of ENDO-I proteoforms.     

Electromagnetic and semiconductor device simulation usinginterpolating wavelets

A MESFET and a two-dimensional cavity enclosing a cylinder are simulated using a nonuniform mesh generated by an interpolating wavelet scheme. A self-adaptive mesh is implemented and controlled by the wavelet coefficient threshold. A fine mesh can therefore be used in domains where the unknown quantities are varying rapidly and a coarse mesh can be used where the unknowns are varying slowly. It is shown that good accuracy can be achieved while compressing the number of unknowns by 50% to 80% during the whole simulation. In the case of the MESFET, the I-V characteristics are obtained and the accuracy is compared with the basic finite difference scheme. A reduction of 83% in the number of discretization points at steady state is obtained with 3% error on the drain current. The performance of the scheme is investigated using different values of threshold and two types of interpolating wavelet, namely, the second-order and fourth-order wavelets. Due to the specific problem analyzed, a tradeoff appears between good compression, accuracy, and order of the wavelet. This represents the ongoing effort toward a numerical technique that uses wavelets to solve both Maxwell's equations and the semiconductor equations. Such a method is of great interest to deal with the multiscale problem that is the full-wave simulation of active microwave circuits     

Synthesis, characterization and electrical resistivity of graphite bi-intercalation compounds G-FeCl3-MCl3 (M = Al, Ga, In) and the related binaries

We present new chemical, crystallographic and electrical conductivity data concerning the title compounds. It is found that the axis repeat distances of the bi-intercalation compounds (GBC) are almost identical to the sum of the interplanar distances of the associated binary compounds. The basal plane resistivity ρ_a decreases upon intercalation of the second halide into the stage two, binary host: ρ_a 5 ± 1 μΩ cm at 295 K and for the GaCl₃₋ and AlCl₃-containing GBC. The axis resistivity possesses a positive temperature coefficient for all compounds examined except the 4th stage FeCl₃ GIC. The room temperature anisotropy is 10⁶ for 1st and 4th stage GaCl₃ GIC as for low stage AsF₅ materials. Chemically determined values of the charge transfer are about twice as great as those evaluated from analysis of the C-C bond distances.     

Evolution in the surface modification of textiles: a review

The development of technical textiles allows the introduction of new, interesting and original multi-functionalities in textiles through development of the architecture of fibres, yarns and fabrics, their morphology and surface functionalization without altering their physico-chemical proprieties. This issue of Textile Progress reports different techniques used to impart new functionalities to the surfaces of textiles during the last decade. Following a short, context-setting historical introduction, the preparatory processes which need to be applied to textile matrices to make them clean and ready for functionalization are examined prior to a comprehensive review of techniques and research related to the development of functional textiles ranging from the more-traditional techniques through to more-recent developments. The challenge now is to bring new performance features to bear whilst maintaining environmental sustainability, chemical toxicological acceptability, high performance and cost effectiveness. In this context, the review reports on developments in the use of polymerization, nanotechnologies, plasma treatment, electrospinning, microencapsulation and sol gel techniques to impart novel properties to a textile surface such as water-repellent, flame-retardant and antibacterial properties.     

Development of an analytical 3D-simulation model of the levelling process

Sheet metal often shows shape defects, which is not complying with the increasing requirements for the quality of the products needed to satisfy the highest demands on finer tolerances. Due to the market's high requirements on the quality of products, new high-technology levelling machines were developed. The adjustment of these levellers is very complicated and a successful adjustment depends mainly on the experience of the line operator. As the computational power has developed over the past years, simulation becomes more important in the production process and is used in analysing the effects of leveller adjustments on the unflattened sheet metal. In this study, edge- and centre waves are investigated. In order to find a suitable adjustment of the leveller to reach a flat sheet metal, an analytical 3D simulation model has been developed using the Matlab programming environment. The sheet metal will be firstly analyzed and visualized before and after deformation. A user-friendly interface has been developed to enter the required parameters before starting the simulation. Different methods have been used to investigate the effect of the levelling process on the sheet metal and to calculate the remaining shape defects after levelling. The simulation results were validated by experiments and are represented in this paper.     

Time-domain optical response of an electrooptic modulator usingFDTD

A time-domain analysis of an LiNbO₃ electrooptic modulator using the finite-difference time-domain (FDTD) technique is performed. This allows for the calculation of optical modulation and the time-domain optical response of an electrooptic modulator. The electromagnetic fields computed by FDTD are coupled to standard electrooptic relations that characterize electrooptic interactions inside the embedded Ti diffused LiNbO₃ optical waveguides. The electric field-dependent change in the index of refraction inside these optical waveguides and resulting minute phase shifts imparted to optical signals propagating along the device are determined in time, allowing for the simulation of optical intensity modulation. This novel approach to LiNbO₃ electrooptic modulators using a coupled FDTD technique allows for previously unattainable investigations into device operating bandwidth and data transmission speed     

A model for length of saturation velocity region in double-gate Graphene nanoribbon transistors

Length of saturation region (LVSR) as an important parameter in nanoscale devices, which controls the drain breakdown voltage is in our focus. This paper presents three models for surface potential, surface electric field and LVSR in double-gate Graphene nanoribbon transistors. The Poisson equation is used to derive surface potential, lateral electric field and LVSR. Using the proposed models, the effect of several parameters such as drain-source voltage, oxide thickness, doping concentration and channel length on the LVSR is studied.