Clinical and electrophysiological evaluation of dysphagia in myasthenia gravis

OBJECTIVE: To evaluate dysphagia at the oropharyngeal stage of swallowing and to determine the pathophysiological mechanisms of dysphagia in patients with myasthenia gravis. METHODS: Fifteen patients with myasthenia gravis with dysphagia and 10 patients without dysphagia were investigated by a combined electrophysiological and mechanical method described previously. Laryngeal movements were detected by a piezoelectric transducer and the related submental EMG (SM-EMG) and sometimes the EMG of cricopharyngeal muscle of the upper esophageal sphincter (CP-EMG) were recorded during dry or wet swallowing. The results of these electrophysiological variables were compared with those of normal age matched control subjects. RESULTS: In patients with myasthenia gravis with dysphagia, it was found that the time necessary for the larynx to remain in its superior position during swallowing and swallowing variability in successive swallows increased significantly compared with normal subjects and with patients with myasthenia gravis without dysphagia. The total duration of SM-EMG activity was also prolonged in both groups but more severely in the dysphagic patients. Electromyographic activity of the CP sphincter was found to be normal in the dysphagic patients investigated. All the patients with myasthenia gravis with dysphagia had pathological dysphagia limits (<20 ml water) whereas other patients except two, were within normal limits. CONCLUSIONS: Because the electrophysiological variables related to oropharyngeal swallowing were prolonged even in patients with myasthenia gravis without dysphagia, it is concluded that the submental and laryngeal elevators are involved subclinically in myasthenia gravis and, because of compensating mechanisms, the patient may not be dysphagic. As the CP-EMG behaviour was found to be normal, a coordination disorder between normal CP sphincter muscle and the affected striated muscles of the laryngeal elevators may be one of the reasons for dysphagia in myasthenia gravis. This method also made it possible to investigate the myasthenic involvement in the laryngeal elevators that cannot be evaluated by other electrophysiological methods in myasthenia gravis.     

Photoluminescence and decay characteristics of cerium,gallium and vanadium - containing borate-based bioactive glass powders for bioimaging applications

Biomaterials having photoluminescent properties play a crucial role in real-time bioimaging after in vivo implantation. In this study, photoluminescence properties and decay characteristics of the borate-based 13–93B3 glasses containing different concentrations of cerium, gallium, and vanadium oxides were investigated for biomedical applications. The borate-based bioactive glass powders were prepared using melt-quench technique and size reduction was performed through planetary ball milling. Bioactivity of the prepared powders was investigated in simulated body fluid at 37 °C under static conditions. The photoluminescent properties and decay kinetics of the as-prepared and the SBF-treated bioactive glass powders were analyzed by steady-state and time-resolved photoluminescence measurements. Results revealed that the cerium activated glasses exhibited an intense luminescence centered at 538 nm. Broad-band emission of the gallium and vanadium doped samples was centered at 440 and 572 nm, respectively. All of the SBF-treated glasses exhibited enhanced lifetimes and bi-exponential decays both in nanosecond and microsecond regime measurements. It was concluded that depending on the dopant concentration, bioactive glass particles prepared in the study showed remarkable photoluminescence and have potential to be used in bioimaging applications.     

Pathways to controlled 3D deformation of graphene: Manipulating the motion of topological defects

Functional properties of 2D materials like graphene can be tailored by designing their 3D structure at the Angstrom to nanometer scale. While there are routes to tailoring 3D structure at larger scales, achieving controllable sub-micron 3D deformations has remained an elusive goal since the original discovery of graphene. In this contribution, we summarize the state-of-the-art in controllable 3D structures, and present our perspective on pathways to realizing atomic-scale control. We propose an approach based on strategic application of mechanical load to precisely relocate and position topological defects that give rise to curvature and corrugation to achieve a desired 3D structure. Realizing this approach requires establishing the detailed nature of defect migration and pathways in response to applied load. From a computational perspective, the key needed advances lie in the identification of defect migration mechanisms. These needed advances define new forward and inverse problems: when a fixed stress or strain field is applied, along which pathways will defects migrate?, and vice versa. We provide a formal statement of these forward and inverse problems, and review recent methods that may enable solving them. The forward problem is addressed by determining the potential energy surface of allowable topological configurations through Monte Carlo and Gaussian process models to determine defect migration paths through dynamic programming algorithms or Monte Carlo tree search. Two inverse models are suggested, one based on genetic algorithms and another on convolutional neural networks, to predict the applied loads that induce migration and position defects to achieve desired curvature and corrugation. The realization of controllable 3D structures enables a vast design space at multiple scales to enable new functionality in flexible electronics, soft robotics, biomimetics, optics, and other application areas.     

Vibrational Energy Transport in Hybrid Ordered/Disordered Nanocomposites: Hybridization and Avoided Crossings of Localized and Delocalized Modes

Vibrational energy transport in disordered media is of fundamental importance to several fields spanning from sustainable energy to biomedicine to thermal management. This work investigates hybrid ordered/disordered nanocomposites that consist of crystalline membranes decorated by regularly patterned disordered regions formed by ion beam irradiation. The presence of the disordered regions results in reduced thermal conductivity, rendering these systems of interest for use as nanostructured thermoelectrics and thermal device components, yet their vibrational properties are not well understood. Here, the mechanism of vibrational transport and the reason underlying the observed reduction is established in detail. The hybrid systems are found to exhibit glass‐crystal duality in vibrational transport. Lattice dynamics reveals substantial hybridization between the localized and delocalized modes, which induces avoided crossings and harmonic broadening in the dispersion. Allen/Feldman theory shows that the hybridization and avoided crossings are the dominant drivers of the reduction. Anharmonic scattering is also enhanced in the patterned nanocomposites, further contributing to the reduction. The systems exhibit features reminiscent of both nanophononic materials and locally resonant nanophononic metamaterials, but operate in a manner distinct to both. These findings indicate that such “patterned disorder” can be a promising strategy to tailor vibrational transport through hybrid nanostructures.     

Evaluation of normal-appearing white matter with perfusion and diffusion MRI in patients with treated glioblastoma

Magnetic Resonance Materials in Physics, Biology and Medicine - We tried to reveal how the normal appearing white matter (NAWM) was affected in patients with glioblastoma treated with...     

Physicochemical Characterization of Whole Egg Powder Microencapsulated by Spray Drying

Physical characterization and oxidative stability of egg powder microencapsulated by spray drying were studied in this work. The wall material (gelatin, lactose, pullulan, and their mixtures) and liquid egg mixtures were prepared by homogenization at 22,000 rpm for 60 s. The spray drying was carried out at pilot-scale spray dryer (Niro Mobile Minor, Søborg, Denmark). The spray-dried egg powders were analyzed for moisture content, water activity, peroxide value, total cholesterol oxidation products (TCOPs), particle properties, and bulk properties. Using gelatin as wall material resulted in a significant increase in the moisture content and water activity of egg powder during storage and it improved flowability. Egg powders containing pullulan as wall material showed a fibrous structure and had the lowest bulk density. Adding lactose as wall material increased the oxidative stability, which was indicated with lowest peroxide value and TCOPs level of egg powder.     

The effects of annealing temperature on the in-field Jc and surface pinning in silicone oil doped MgB2 bulks and wires

The effects of sintering temperature on the lattice parameters, full width at half maximum (FWHM), strain, critical temperature (T_c), critical current density (J_c), irreversibility field (H_irr), upper critical field (H_c2), and resistivity (ρ) of 10 wt.% silicone oil doped MgB₂ bulk and wire samples are investigated in state of the art by this article. The a-lattice parameter of the silicone oil doped samples which were sintered at different temperatures was drastically reduced from 3.0864 Å to 3.0745 Å, compared to the un-doped samples, which indicates the substitution of the carbon (C) into the boron sites. It was found that sintered samples at the low temperature of 600 °C shows more lattice distortion by more C-substitution and higher strain, lower T_c, higher impurity scattering, and enhancement of both magnetic J_c and H_c2, compared to those sintered samples at high temperatures. The flux pinning mechanism has been analyzed based on the extended normalized pinning force density f_p = F_p/F_p,max scaled with b = B/B_max. Results show that surface pinning is the dominant pinning mechanism for the doped sample sintered at the low temperature of 600 °C, while point pinning is dominant for the un-doped sample. The powder in tube (PIT) MgB₂ wire was also fabricated by using of this liquid doping and found that both transport J_c and n-factor increased which proves this cheap and abundant silicone oil doping can be a good candidate for industrial application.     

Sub-nanomolar sensing of ionic mercury with polymeric electrospun nanofibers

Ethyl cellulose (EC) based electrospun nanofibers were exploited for sub-nanomolar level optical chemical sensing of ionic mercury. An azomethine ionophore was used as Hg (I) and Hg (II) sensing material. Ethyl cellulose nanofibers with varying amounts of the ionic liquid; 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF₄) were prepared and characterized. The nanofibers were fabricated by electrospinning technique. The offered chemosensor allow determination of mercury ions in a large linear working range between 1.0 × 10⁻¹⁰ and 1.0 × 10⁻⁴ mol L⁻¹. Limit of detection was found to be 0.07 nM which makes this technique alternative to cold-vapor atomic absorption spectrometry (CV-AAS), flame emission methods and to inductively coupled plasma-mass spectrometry (ICP-MS).