Whole-body magnetic resonance neurography in patients with chronic inflammatory demyelinating polyneuropathy

INTRODUCTION/AIMS

Whole-body magnetic resonance neurography (MRN) is an imaging modality that shows peripheral nerve signal change in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). We aimed to explore the diagnostic potential of whole-body MRN and its potential as a monitoring tool after immunotherapy in treatment-naïve CIDP patients.

METHODS

Whole-body MRN using coronal 3-dimensional short tau inversion recovery (STIR) sampling perfection with application-optimized contrasts by using different flip angle evolution (SPACE) techniques was performed in patients being investigated for CIDP and in healthy controls. Baseline clinical neuropathy scales and electrophysiologic parameters were collected, and MRN findings were compared before and after CIDP treatment.

RESULTS

We found highly concordant symmetrical thickening and increased T2 signal intensities in the brachial/lumbosacral plexus, femoral, or sciatic nerves in five of the eight patients with a final diagnosis of CIDP and none of the healthy controls. There were no treatment-related imaging changes in five patients with CIDP who completed a follow-up study. Diffuse, symmetrical thickening, and increased T2 signal in root, plexus, and peripheral nerves were found in two patients ultimately excluded due to a diagnosis of polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes (POEMS) syndrome in addition to signal changes in the muscles, bony lesions, organomegaly, and lymphadenopathy.

DISCUSSION

Whole-body MRN imaging shows promise in detecting abnormalities in proximal nerve segments in patients with CIDP. Future studies evaluating the role of MRN in assessing treatment response should consider follow-up scans after treatment durations of more than 4 months.

New nanostructure perovskite-based light-emitting diode with superior light extraction efficiency enhancement

The external quantum efficiency (EQE) of a perovskite-based light-emitting diode (PELED) is a key indicator, comprising the internal quantum efficiency (IQE) and light extraction efficiency (LEE). Currently, enhancing EQE faces a major challenge in optimizing LEE. This study introduces an innovative structure to boost LEE, exploring various influencing parameters. The transition from a planar to a domical architecture leverages factors like the waveguiding effect, resulting in a remarkable tenfold increase in LEE, from 6 to 59%. Additionally, investigations into factors affecting LEE, such as altering dipole orientation, material-substrate contact angle, and layer thickness, reveal the potential for further improvement. The optimized structure attains an impressive LEE value of 74%.

Refractive index sensor based on fano-magnetic toroidal quadrupole resonance enabled by bound state in the continuum in all-dielectric metasurface

For the first time, an all-dielectric metasurface ultra-sensitive refractive index (RI) sensor with very high quality factor (QF) and figure of merit (FOM), with Fano-magnetic toroidal quadrupole (MTQ) resonance enabled by bound state in continuum (BIC) in terahertz (THz) region was designed. Furthermore, the MTQ resonance in the THz due to a distortion of symmetry-protected bound states in the continuum in the designed structure was investigated. Also, to achieve the dark mode, a combination of three methods including (i) breaking the symmetry, (ii) design of complex structures, and (iii) changing the incident angle was utilized. The broken symmetry in the structure caused a new mode to be excited, which is suitable for sensing applications. The designed metasurface was able to sense a wide range of RI in MTQ resonance, where its properties were improved for the value of sensitivity (S) from 217 GHz/RIU to 625 GHz/RIU, for FOM from 197 RIU-1 to 2.21 × 106 RIU-1 and for QF from 872 to 5.7 × 106.

Morphological investigation and 3D simulation of plasmonic nanostructures to improve the efficiency of perovskite solar cells

The light absorption process is a key factor in improving the performance of perovskite solar cells (PSCs). Using arrays of metal nanostructures on semiconductors such as perovskite (CH3NH3PbI3), the amount of light absorption in these layers is significantly increased. Metal nanostructures have been considered for their ability to excite plasmons (collective oscillations of free electrons). Noble metal nanoparticles placed inside solar cells, by increasing the scattering of the incident light, effectively increase the optical absorption inside PSCs; this in turn increases the electric current generated in the photovoltaic device. In this work, by calculating the cross-sectional area of dispersion and absorption on gold (Au) nanoparticles, the effects of the position of nanoparticles in the active layer (AL) and their morphology on the increase of absorption within the PSC are investigated. The optimal position of the plasmonic nanoparticle was obtained in the middle of the AL using a three-dimensional simulation method. Then, three different morphologies of nano-sphere, nano-star and nano-cubes were investigated, where the short-circuit currents (Jsc) for these three nanostructures were obtained equal to 19.01, 18.66 and 20.03 mA/cm2, respectively. In our study, the best morphology of the nanostructure according to the Jsc value was related to the nano-cube, in which the device power conversion efficiency was equal to 16.20%, which is about 15% better than the PSC with the planar architecture.

Design of Single-Mode Single-Polarization Large-Mode-Area Multicore Fibers

In laser science and industry, considerable effort is directed toward designing fibers for fiber laser and fiber amplifier applications, each of which offers a particular advantage over the others. Evanescently coupled multicore fibers, however, have been studied less extensively due to the relatively small mode area in the single-mode regime. Here, by proposing a new structure with stress-applying parts in a 37-core fiber and optimizing this structure through a comprehensive framework, we present 21 solutions characterized by large-mode-area and high beam quality in the single-mode, single-polarization regime. Different fiber designs are optimal for different output parameters. In one design, the mode area can significantly increase to above 880 μm2, which is comparable with that of photonic-crystal fibers. Moreover, besides the single-mode operation, the beam quality factor (M2 factor) of the fundamental mode is considered an output parameter in the bent state and is improved up to 1.05 in another design. A comprehensive tolerance analysis is then performed to assess the performance of the designs under deviations from normal conditions. Moreover, in spite of the shifts in the loss of modes, the proposed high beam quality LMA fibers maintain single-polarization, single-mode operation across a wide range of core pitches, bending orientation angles, and bending radius deviations. Our results highlight the potential of multicore fibers for the efficient operation of fiber lasers and amplifiers.

Design of optimized photonic-structure and analysis of adding a SiO2 layer on the parallel CH3NH3PbI3/CH3NH3SnI3 perovskite solar cells

So far, remarkable achievements have been obtained by optimizing the device architecture and modeling of solar cells is a precious and very effective way to comprehend a better description of the physical mechanisms in solar cells. As a result, this study has inspected two-dimensional simulation of perovskite solar cells (PSCs) to achieve a precise model. The solution which has been employed is based on the finite element method (FEM). First, the periodically light trapping (LT) structure has been replaced with a planar structure. Due to that, the power conversion efficiency (PCE) of PSC was obtained at 14.85%. Then, the effect of adding an SiO2 layer to the LT structure as an anti-reflector layer was investigated. Moreover, increasing the PCE of these types of solar cells, a new structure including a layer of CH3NH3SnI3 as an absorber layer was added to the structure of PSCs in this study, which resulted in 25.63 mA/cm2 short circuit current (Jsc), 0.96 V open circuit voltage (Voc), and 20.48% PCE.

Marcus Theory and Tunneling Method for the Electron Transfer Rate Analysis in Quantum Dot Sensitized Solar Cells in the Presence of Blocking Layer

In this research study, the effects of different parameters on the electron transfer rate from three quantum dots (QDs), CdSe, CdS, and CdTe, on three metal oxides (MOs), TiO2, SnO2, and SnO2, in quantum-dot-sensitized solar cells (QDSSCs) with porous structures in the presence of four types of blocking layers, ZnS, ZnO, TiO2, and Al2O3, are modeled and simulated using the Marcus theory and tunneling between two spheres for the first time. Here, the studied parameters include the change in the type and thickness of the blocking layer, the diameter of the QD, and the temperature effect. To model the effect of the blocking layer on the QD, the effective sphere method is used, and by applying it into the Marcus theory equation and the tunneling method, the electron transfer rate is calculated and analyzed. The obtained results in a wide range of temperatures of 250-400 °K demonstrate that, based on the composition of the MO-QD, the increase in the temperature could reduce or increase the electron transfer rate, and the change in the QD diameter could exacerbate the effects of the temperature. In addition, the results show which type and thickness of the blocking layer can achieve the highest electron transfer rate. In order to test the accuracy of the simulation method, we calculate the electron transfer rate in the presence of a blocking layer for a reported sample of a QDSSC manufacturing work, which was obtained with an error of ~3%. The results can be used to better interpret the experimental observations and to assist with the design and selection of the appropriate combination of MO-QD in the presence of a blocking layer effect.

Oocyte quality evaluation: a review of engineering approaches toward clinical challenges

Although assisted reproductive technology has been very successful for the treatment of infertility, its steps are still dependent on direct human opinion. An important step of assisted reproductive treatments in lab for women is choosing an oocyte that has a better quality. This step would predict which oocyte has developmental competence leading to healthy baby. Observation of the oocyte morphological quality indicators under microscope by an embryologist is the most common evaluation method of oocyte quality. Such subjective method which relies on embryologist's experience may vary and leads to misdiagnosis. An alternative solution to eliminate human misjudging in traditional methods and overcome the limitations of them is always using engineering-based procedure. In this review article, we deeply study and categorize engineering-based methods applied for the evaluation of oocyte quality. Then, the challenges in laboratories and clinics settings move forward with translational medicine perspective in mind for all those methods which had been studied were discussed. Finally, a standardized process was presented, which may help improving and focusing the research in this field. Moreover, effective suggestion techniques were introduced that are expected they would be complementary methods to accelerate future researches. The aim of this review was to create a new prospect with the engineering approaches to evaluate oocyte quality and we hope this would help infertile couples to get a baby.

Design and fabrication of aspiration microfluidic channel for oocyte characterization

The development potential for oocytes can be predicted by their mechanical properties. One important parameter that is measured to calculate oocyte hardness is Cortical Tension (CT). In this work, for the first time, we present the design, simulation, and fabrication of a new aspiration microfluidic chip to measure the CT of oocytes and then predict their maturation capability in the Germinal Vesicle (GV) stage. This high-performance technique facilitates oocyte characterization and is a promising alternative to traditional methods such as MicroPipette Aspiration (MPA). The proposed technique involves considerably simpler operation, less specialized equipment, and less technical skill than MPA. The proposed microfluidic channel also promises faster measurements. It is shown that in order to completely continue the growth process of oocytes in GV stage, the CT should be in a certain range: very low or very high CTs lead to unsuccessful growth. The obtained results show that 79% of oocytes with the CT between 1.5 and 3 nN/μm reach the Metaphase II (MII) stage, whereas the growth for 78% of oocytes with the CT less than 1.5 nN/μm or higher than 3 nN/μm stops at the GV or Germinal Vesicle Break Down (GVBD) stages. Another property, k_vis, that points to the viscous behavior of oocytes is also measured. It is seen that 80% of GV oocytes with the k_vis values between 15 and 30 k Pa s/m reach the MII stage.

Clinical and Molecular Findings of Autosomal Recessive Spastic Ataxia of Charlevoix Saguenay: an Iranian Case Series Expanding the Genetic and Neuroimaging Spectra

Autosomal recessive spastic ataxia of Charlevoix Saguenay (ARSACS) is now increasingly identified from all countries over the world, possibly rendering it one of the most common autosomal recessive ataxias. Here, we selected patients harboring SACS variants, the causative gene for ARSACS, in a large cohort of 137 patients with early-onset ataxia recruited from May 2019 to May 2021 and were referred to the ataxia clinic. Genetic studies were performed for 111 out of 137 patients (81%) which led to a diagnostic rate of 72.9% (81 out of 111 cases). Ten patients with the molecular diagnosis of ARSACS were identified. We investigated the phenotypic and imaging spectra of all confirmed patients with ARSACS. We also estimated the frequency of ARSACS in this cohort and described their clinical and genetic findings including seven novel variants as well as novel neuroimaging findings. While the classic clinical triad of ARSACS is progressive cerebellar ataxia, spasticity, and sensorimotor polyneuropathy, it is not a constant feature in all patients. Sensorimotor axonal-demyelinating neuropathy was detected in all of our patients, but spasticity and extensor plantar reflex were absent in 50% (5/10). In all patients, brain magnetic resonance imaging (MRI) showed symmetric linear hypointensities in the pons (pontine stripes) and anterior superior cerebellar atrophy as well as a hyperintense rim around the thalami (thalamic rim). Although infratentorial arachnoid cyst has been reported in ARSACS earlier, we report anterior temporal arachnoid cyst in two patients for the first time, indicating that arachnoid cyst may be an associated imaging feature of ARSACS. We also extended molecular spectrum of ARSACS by presenting 8 pathogenic and one variant of unknown significance (VUS) sequence variants, which 7 of them have not been reported previously. MetaDome server confirmed that the identified VUS variant was in the intolerant regions of sacsin protein encoded by SACS.

Fibroblast Growth Factor-2 Levels are Elevated in The Serum of Patients with Multiple Sclerosis

BACKGROUND

Various factors contribute to the pathogenesis of Multiple Sclerosis (MS), one of which is Fibroblast Growth Factor 2 (FGF2). The function of FGF2 is pleiotropic. The investigation of the role of this factor in the myelination has produced conflicting results.

OBJECTIVE

To investigate the serum levels of FGF2 in patients with MS.

SUBJECTS AND METHODS

Eighty patients with MS and eighty healthy volunteers with no history of inflammation or demyelinating disorders were included, and serum samples were collected to evaluate serum levels of FGF2 using the ELISA technique. Both groups had the same age and gender distribution. For analysis, the Mann-Whitney U test was used.

RESULTS

Patients with MS had considerably greater serum FGF2 levels than the control group (p = 0.005). There was no difference between the FGF2 level in men and women.

CONCLUSION

Our data indicate that FGF2 levels may be related to the susceptibility of Iranian patients with MS. Further studies are required to analyze the involvement of FGF2 in enhancing the inflammatory process in MS.

Telephone consultation for myasthenia gravis care during the COVID-19 pandemic: Assessment of a novel virtual myasthenia gravis index

INTRODUCTION/AIMS

The aim of the study was to determine the association between the virtual Myasthenia Gravis Impairment Index (vMGII) with other patient-reported outcomes (PROs) of myasthenia gravis (MG) and its usefulness in telephone consultations with MG patients.

METHODS

This was a retrospective case series in which vMGII score along with virtual Single Simple Question (vSSQ), virtual Patient-Acceptable Symptom State PASS (vPASS) response, and patient disease status based on Myathenia Gravis Foundation of America postintervention status were collected during telephone consultation along with the MGII, SSQ, and PASS responses during the preceding in-person clinic visits.

RESULTS

In 214 patients, the mean difference of vMGII between the vPASS "Yes" and "No" groups was -14.2 ± 1.4 (95% confidence interval, -16.9 to -11.3; P < .001) with mean vMGII for vPASS "Yes" group being 6.4 ± 7.7 and vPASS "No" being 20.5 ± 11.5. A vMGII of 11.5 or higher predicted vPASS "yes" response with a sensitivity of 78.7% and specificity of 81.4%. A strong negative correlation was found between the vMGII and vSSQ (r = -.667; P < .001). The mean vMGII was 0.48 ± 1.42 for patients in remission, and 9.31 ± 10.93 for improved, 9.32 ± 8.79 for stable, and 22.58 ± 14.04 for worsened groups (P < .001). These associations were the same as those obtained during the preceding in-person clinic visit and the direction of change in MGII scores also indicated change in disease status.

DISCUSSION

vMGII is an effective measure to assess an MG patient's disease status in telephone consultations and relates well with other PRO measures. The vMGII remains reliable for assessing MG disease status even with removal of the physical examination component.

The correlation of the serum level of L-carnitine with disease severity in patients with Amyotrophic lateral sclerosis

BACKGROUND

The relationship between reserve of L-carnitine and severity in patients with Amyotrophic lateral sclerosis (ALS) is not studied sufficiently. We decided to measure the serum levels of L-carnitine in patients and the relationship with ALS severity.

METHOD

This cross-sectional study evaluated the serum levels of L-carnitine in 30 patients with ALS (total-case) divided into two groups included 15 patients in the Oral-Fed (OF) group and 15 patients in the Enteral-Fed (EF) group, compared with 15 healthy people matched in age and sex in the control group. We measured the body mass index (BMI), daily intake of L-carnitine, amyotrophic lateral sclerosis functional rating scale (ALSFRS), and serum L-carnitine level in all participants and compared among groups.

RESULTS

Serum L-carnitine (p < 0.001) and BMI (p = 0.03) were significantly lower in the total-case group compared to the control group. Alternatively, the serum level of L-carnitine (p = 0.001), ALSFRS (p < 0.001), BMI (p = 0.007), and dietary L-carnitine intake (p = 0.002) were significantly higher in OF group compared with EF. Higher serum L-carnitine levels were associated with a higher score of ALSFRS (β = 0.46, P = 0.01) in the total-case group.

CONCLUSION

Our study's results showed that serum levels of L-carnitine were lower in patients with ALS in comparison to healthy people. Also, the lower serum level of L-carnitine was associated with the higher severity of the disease.

Central nervous system manifestations in COVID-19 patients: A systematic review and meta-analysis

BACKGROUND

At the end of December 2019, a novel respiratory infection, initially reported in China, known as COVID-19 initially reported in China, and later known as COVID-19, led to a global pandemic. Despite many studies reporting respiratory infections as the primary manifestations of this illness, an increasing number of investigations have focused on the central nervous system (CNS) manifestations in COVID-19. In this study, we aimed to evaluate the CNS presentations in COVID-19 patients in an attempt to identify the common CNS features and provide a better overview to tackle this new pandemic.

METHODS

In this systematic review and meta-analysis, we searched PubMed, Web of Science, Ovid, EMBASE, Scopus, and Google Scholar. Included studies were publications that reported the CNS features between 1 January 2020 and 20 April 2020. The data of selected studies were screened and extracted independently by four reviewers. Extracted data analyzed by using STATA statistical software. The study protocol registered with PROSPERO (CRD42020184456).

RESULTS

Of 2,353 retrieved studies, we selected 64 studies with 11,687 patients after screening. Most of the studies were conducted in China (58 studies). The most common CNS symptom of COVID-19 was headache (8.69%, 95%CI: 6.76%-10.82%), dizziness (5.94%, 95%CI: 3.66%-8.22%), and impaired consciousness (1.90%, 95%CI: 1.0%-2.79%).

CONCLUSIONS

The growing number of studies has reported COVID-19, CNS presentations as remarkable manifestations that happen. Hence, understanding the CNS characteristics of COVID-19 can help us for better diagnosis and ultimately prevention of worse outcomes.

Persian adaptation of Edinburgh Cognitive and Behavioural Screen (ECAS)

Objectives: To adapt the Edinburgh Cognitive and Behavioral screen (ECAS) English version into Persian. Methods: The ECAS test was adapted and implemented to 30 ALS patients and 31 healthy volunteers in Tehran, Iran. The ECAS results were compared to MoCA and ALS-FRS-r, the other standard tools to determine whether the translated version is reliable and valid in the new language. In addition, the patients' caregivers were interviewed for behavioral and psychiatric changes. Results: The Persian version of ECAS revealed high internal consistency (α = 0.791), alongside the strong correlation of ECAS and its subscales with MoCA and ALS-FRS. Moreover, Persian ECAS discriminated against the patients and the healthy population well. Sensitivity analysis revealed promising results of Persian ECAS with an area under the curve of 0.871 in ROC curve analysis. Cognitive impairment was observed in 43.33% of patients. Conclusion: The Persian version of the ECAS, exclusively designed for the Iranian population, is the first screening tool to assess multiple neuropsychological functions, which provides a rapid and inclusive screen of cognitive and behavioral impairments specifically in ALS patients.

Efficiency enhancement of perovskite solar cells by designing GeSe nanowires in the structure of the adsorbent layer

In this paper, coupled optical and electrical simulations of perovskite solar cells (PSCs) are performed to optimize their basis output parameters and obtain the best power conversion efficiency (PCE) based on both the light absorption and carrier transport mechanisms. Due to the limitations of perovskite absorption in longer wavelengths, we used an extra photo-active material of GeSe with a narrower bandgap and a broader absorbing spectrum to increase the efficiency of the PSC. To prevent carrier transmission disorder that exists in the planar structure with two absorbing materials, GeSe was inserted into the main active layer in the form of nanowires (NWs). As a result, it improved the carrier transfer and open-circuit voltage (V_oc ) in addition to the short-circuit current density (J_sc ). The behavior of PSC with different sizes of GeSe NWs at the same density was investigated to determine the appropriate size of NWs and achieve the highest PCE. In the optimal structure with 50 nm diameter NWs, J_sc and PCE of the cell are 22.96 mA cm^-2 and 18.97%, which are improvements of 39% and 50%, respectively, compared to the planar structure studied at the beginning of the paper.

Numerical study of a highly efficient light trapping nanostructure of perovskite solar cell on a textured silicon substrate

In this paper, a nanostructured perovskite solar cell (PSC) on a textured silicon substrate is examined, and its performance is analyzed. First, its configuration and the simulated unit cell are discussed, and its fabrication method is explained. In this proposed structure, poly-dimethylsiloxane (PDMS) is used instead of glass. It is shown that the use of PDMS dramatically reduces the reflection from the cell surface. Furthermore, the light absorption is found to be greatly increased due to the light trapping and plasmonic enhancement of the electric field in the active layer. Then, three different structures, are compared with the main proposed structure in terms of absorption, considering the imperfect fabrication conditions and the characteristics of the built PSC. The findings show that in the worst fabrication conditions considered structure (FCCS), short-circuit current density (Jsc) is 22.28 mA/cm2, which is 27% higher than that of the planar structure with a value of 17.51 mA/cm2. As a result, the efficiencies of these FCCSs are significant as well. In the main proposed structure, the power conversion efficiency (PCE) is observed to be improved by 32%, from 13.86% for the planar structure to 18.29%.

Application of muscle ultrasound for the evaluation of patients with amyotrophic lateral sclerosis: An observational cross-sectional study

INTRODUCTION

We evaluated the association between muscle ultrasound, number of motor units, and clinical parameters, and assessed their utility for distinguishing amyotrophic lateral scleorisis (ALS) patients from healthy individuals.

METHODS

Three muscle pairs (abductor pollicis brevis, abductor digiti minimi, and tibialis anterior) of 18 ALS patients and 18 controls underwent muscle ultrasound (echointensity and thickness) and assessment of motor unit number index (MUNIX). The clinical and functional status of participants were also assessed.

RESULTS

Mean age of the patients was 53.8 ± 12.1 years, and score on the ALS Functional Rating Scale-Revised was 38.9 ± 4.1. Echointensity of all tested muscles of ALS participants was significantly higher than that of controls, but there was no significant difference in muscle thickness. Muscle echointensity correlated significantly with clinical and electrophysiological parameters.

CONCLUSION

Echointensity of muscles was highly associated with clinical scales and MUNIX, confirming its relevance as an ancillary diagnostic test in ALS patients.

High-performance perovskite solar cell using photonic-plasmonic nanostructure

In this paper, a coupled optical-electrical modeling method is applied to simulate perovskite solar cells (PSCs) to find ways to improve light absorption by the active layer and ensure that the generated carriers are collected effectively. Initially, a planar structure of the PSC is investigated and its optical losses are determined. To reduce the losses and enhance collection efficiency, a convex light-trapping configuration of PSC is used and the impacts of these nanostructures on all parts of the cell are investigated. In this convex nanostructured PSC, the power conversion efficiency (PCE) is found to be increased when the thickness of the absorbing layer remained unchanged. Then, a plasmonic reflector is applied to trap light inside the perovskite. In this structure, by scattering light through the surface plasmon resonance (SPR) effect of the Au back-contact, the electromagnetic field is found to concentrate in the active layer. This results in increased perovskite absorption and, consequently, a high current density of the cell. In the final structure, which is the integration of these two structures, optical losses are found to be greatly diminished and the short-circuit current density (Jsc) is increased from 18.63 mA/cm2 for the planar structure to 23.5 mA/cm2 for the proposed structure. Due to the increased Jsc and open-circuit voltage (Voc) caused by the improved carrier collection, the PCE increases from 14.62 to 19.54%.

Fast optimal design of optical components using the cultural algorithm

Design of the guided-mode resonance (GMR) grating filter, as one of the most important optical components, using the cultural algorithm (CA) is presented, for the first time. CA is an evolutionary algorithm (EA) which is easy-to-implement, flexible, inspired by the human cultural evolution, upon using the domain knowledge for reducing the search space as a metaheuristic optimization method. Reflection spectra of the designed GMR filter based on the CA is in good agreement with the previous simulation results. CA has both acceptable accuracy and enough high speed to optimize the complicated structures; therefore, a novel double-line asymmetrical transmitter (DLAT) is introduced and optimized as a complex grating-based optical component using the mentioned algorithm. The results show the transmittance at two different communication wavelengths (1.5039 and 1.6113 µm) using the combination of binary diffraction grating and customized photonic crystal (PhC) structure. Also, the DLAT shows the characteristics of a perfect transverse magnetic (TM) polarizer. Furthermore, we demonstrated the Talbot effect at the DLAT output which is so applicable in the optical usage, especially for the integrated optics.

An overview of motor unit number index reproducibility in amyotrophic lateral sclerosis

Motor unit number index (MUNIX) is an electrophysiological technique to give an estimate of functioning motor neurons in a muscle. For any given neurophysiological technique for the use in clinical or research studies, reproducibility between different operators and in a single operator in different times is one of the most important qualities, which must be evaluated and approved by different examiners and centers. After its introduction, testing the reproducibility of MUNIX was the aim of many studies to show this quality of the technique. In this review, we aimed to summarize all the studies, which have been performed up to now to approve MUNIX reproducibility in amyotrophic lateral sclerosis comparing healthy individuals.

The utility of motor unit number index: A systematic review

The need for a valid biomarker for assessing disease progression and for use in clinical trials on amyotrophic lateral sclerosis (ALS) has stimulated the study of methods that could measure the number of motor units. Motor unit number index (MUNIX) is a newly developed neurophysiological technique that was demonstrated to have a good correlation with the number of motor units in a given muscle, even though it does not necessarily accurately express the actual number of viable motor neurons. Several studies demonstrated the technique is reproducible and capable of following motor neuron loss in patients with ALS and peripheral polyneuropathies. The main goal of this review was to conduct an extensive review of the literature using MUNIX. We conducted a systematic search in English medical literature published in two databases (PubMed and SCOPUS). In this review, we aimed to answer the following queries: Comparison of MUNIX with other MUNE techniques; the reproducibility of MUNIX; the utility of MUNIX in ALS and preclinical muscles, peripheral neuropathies, and other neurological disorders.

Dielectric metalenses with engineered point spread function

High-index silicon nanoblocks support excitation of both electric and magnetic resonance modes at telecommunication wavelengths. At frequencies where both electric and magnetic resonance modes are excited simultaneously, changing the geometrical dimensions of the silicon cubes creates a 2π full span over the phase of the transmitted light in different amplitude ranges. We take advantage of the additional power-flux modulation of the scattered signal to focus the incident light with desired full width at half maximum (FWHM) and side lobe levels (SLLs) in both the lateral and axial directions. By implementing proper amplitude filters within the telecommunication working wavelength (1.55 μm), a FWHM less than half of the wavelength (0.42λ_eff) and apodization with nearly faded SLLs are achievable. Our approach introduced in this paper provides a new way to design high efficiency metalenses with desired FWHM and SLL of focal spot.

Combination of Myelin Basic Protein Gene Polymorphisms with HLA-DRB1*1501 in Iranian Patients with Multiple Sclerosis

BACKGROUND

Multiple sclerosis (MS), as a multifactorial autoimmune disease with complex genetic basis, causes demyelination in the central nervous system via cytokine responses to myelin antigens. Myelin basic protein (MBP) is the main protein component of the myelin sheath. HLA-DRB (human leukocyte antigen-DR beta) alleles, particularly HLA-DRB1*1501, may be of significance in the pathogenesis of MS.

OBJECTIVE

To examine the association of HLA-DRB1*1501 alleles and MBP VNTR (variable number tandem repeat) polymorphism with the MS susceptibility in Iranian population.

METHODS

Genomic DNA was extracted from peripheral blood. The alleles were determined by the Polymerase Chain Reaction (PCR) method in 259 MS patients and 312 healthy control individuals and analyses were carried out using Fisher's exact test.

RESULTS

The frequencies of MBP VNTR genotypes (AA, AB and BB) were 47%, 42% and 11% among patients, and 45%, 43% and 12% in control subjects, respectively. HLA-DRB1*1501 allele was more frequent among patients than healthy individuals (OR=1.65, P=0.0045). The frequency of allele A and genotype A/A was significantly higher among HLA-DRB1*1501 positive patients (61% and 32%) than controls (46% and 19%) (OR=1.88, P=0.0013; A/A vs. B/B: OR=5.09, P=0.0004). The two-locus analysis of the interaction between the MBP VNTR polymorphism and the HLA-DRB1 allele showed that the HLADRB1* 1501/A haplotype was more frequent among MS patients than the healthy controls.

CONCLUSION

The interaction between the HLA-DRB1*1501 allele and MBP gene may be considered as a predisposing factor in the development and pathogenesis of MS in the case of gene-gene interaction.

Ultra-wideband high-speed Mach-Zehnder switch based on hybrid plasmonic waveguides

In this paper, the distinctive dispersion characteristic of hybrid plasmonic waveguides is exploited for designing ultra-wideband directional couplers. It is shown that by using optimized geometrical dimensions for hybrid plasmonic waveguides, nearly wavelength-independent directional couplers can be achieved. These broadband directional couplers are then used to design Mach-Zehnder-interferometer-based switches. Our simulation results show the ultra-wide bandwidth of ∼260  nm for the proposed hybrid plasmonic-waveguide-based switch. Further investigation of the proposed Mach-Zehnder switch confirms that because of the strong light confinement in the hybrid plasmonic waveguide structure, the switching time, power consumption, and overall footprint of the device can be significantly improved compared to silicon-ridge-waveguide-based Mach-Zehnder switches. For the Mach-Zehnder switch designed by using the optimized directional coupler, the switching time is found to be less than one picosecond, while the power consumption, V_πL_π figure of merit, and active length of the device are ∼61  fJ/bit, 85  V×μm, and 30 μm, respectively.

Long-term treatment of chronic migraine with OnabotulinumtoxinA: efficacy, quality of life and tolerability in a real-life setting

Botulinum toxin was shown to be effective in treatment of chronic migraine. We wanted to explore its efficacy and tolerability in chronic application under real-life conditions. For this, 27 consecutive patients (age 45.6 ± 10.8 years, 25 females, 2 males) received altogether 176 injection series (IS) with 189.7 ± 45.8MU onabotulinumtoxinA (Botox(®)) according to the PREEMPT scheme. During the study period altogether 6.5 ± 2.9 (min 4, max 13) IS were applied per patient (total treatment time of 73.1 ± 36.9 weeks). 96 % of the patients reported benefit. Monthly headache days were reduced from 18.9 ± 3.9 to 8.7 ± 4.5 (p < 0.001, -53.7 %), migraine days from 16.8 ± 4.9 to 7.4 ± 4.6 (p < 0.001, -55.1 %), autonomic days from 8.6 ± 7.5 to 2.7 ± 4.2 (p < 0.001, -71.9 %) and medication days from 14.2 ± 4.6 to 8.3 ± 4.2 (p < 0.001, -71.1 %). Health-related quality of life improved by 0.6-1.5 standard deviations (SD) (Short Form Health Survey), migraine-related quality of life by 1.4-2.0 SD (Migraine-Specific Quality of Life Questionnaire) and by 1.9 SD (Headache Impact Test), depression by 1.1 SD (Beck Depression Inventory). Subjective global clinical improvement was 2.6 ± 0.6 (Global Clinical Improvement Scale). All improvements were stable throughout the entire study period. Adverse effects were infrequent, mild and transient. Botulinum toxin provides highly effective and safe long-term treatment of chronic migraine.

Lower motor neuron involvement in ALS assessed by motor unit number index (MUNIX): Long-term changes and reproducibility

OBJECTIVE

Motor unit number estimation (MUNE) techniques such as motor unit number index (MUNIX) have been used to quantify lower motor neuron loss and disease progression in amyotrophic lateral sclerosis (ALS). We investigated the consistency of reproducibility of MUNIX in 30 ALS-patients during the course of the disorder.

METHODS

MUNIX was recorded in abductor pollicis brevis and tibialis anterior muscles bilaterally in ALS-patients by two measurements at the first and at one follow-up visit and once in healthy controls. Intra-rater reproducibility was evaluated by three statistical methods: interclass correlation coefficient (ICC), correlation coefficient analysis (CCA), and coefficient of variation (CV).

RESULTS

We found significant correlation between the first and second measurement of MUNIX in all tested muscles and at the follow-up visit (r⩾0.891, p<0.01) and good statistically significant reproducibility of MUNIX in all four measured muscles at the follow-up visit (ICC⩾0.946, p<0.01). The CV of MUNIX at the follow-up visit ranged from 13.90% to 32.95%.

CONCLUSIONS

This study shows good consistency of reproducibility of MUNIX in the course of ALS.

SIGNIFICANCE

This study suggests that MUNIX can be used to track the progression of the disorder both in clinical routine and in treatment trials.

Interferon-gamma gene polymorphism in Iranian patients with multiple sclerosis

Interferon- gamma (IFN- gamma) is an important immune regulator and inflammatory cytokine which is implicated in the pathogenesis of multiple sclerosis (MS). A single nucleotide polymorphism, T to A, at position +874 in the first intron has previously been shown. This polymorphism is associated with IFN- gamma production level. To study the effect of this polymorphism on susceptibility to multiple sclerosis, we screened genomic DNA samples from clinically definite MS patients and their unaffected first-degree relatives as controls, using sequence-specific primers (PCR-SSP). The results indicated that MS patients showed a lower TT (21.2% vs. 30.3%) and higher AA (21.2% vs. 12.1%) genotypes compared to controls, although there were statistically no differences in the IFN- gamma genotype distribution between these two groups. Thus, our data indicate that there is no association between IFN- gamma +874 polymorphism and MS susceptibility or severity of the disease.

Unilateral hypoglossal nerve palsy: as the only presentation of tuberculosis

Tuberculous spondylitis is not an uncommon disease of the spine. Near one percent of all cases of spinal tuberculosis (TB) involves craniocervical junction. Hypoglossal nerve palsy is not an uncommon neurological finding, but isolated involvement of the hypoglossal nerve is rare and limited to case reports or small case series. Here, we report a case of craniocervical junction tuberculosis presenting with unilateral hypoglossal nerve palsy. Case is a 41-year-old woman with neck and suboccipital pain since one month and unilateral right hypoglossal nerve palsy since one week. All laboratory tests were unremarkable except raised ESR level. Involvement of C1-C2 and hypoglossal canal were demonstrated by CT scan of craniocervical junction. Tissue diagnosis of TB was established by open biopsy of the craniocervical junction.

HLA-DRB1*1501 intensifies the impact of IL-6 promoter polymorphism on the susceptibility to multiple sclerosis in an Iranian population

Background: The multifunctional cytokine interleukin-6 (IL-6) is involved in inflammatory processes in the central nervous system. It is well documented that amount of IL-6 is increased in serum, cerebrospinal fluid and central nervous system lesions of patients with multiple sclerosis. A single nucleotide polymorphism at position -174 in the IL-6 gene promotor appears to influence IL-6 expression. Recently, several researchers have focused on HLA-DRB alleles, specifically HLA-DRB1*1501, as a potential risk allele in the pathogenesis of multiple sclerosis.

Objective: To investigate the possible influence of IL-6/-174 polymorphisms on susceptibility to multiple sclerosis and its integration with HLA-DRB1*1501. Genomic DNA was extracted from whole blood of 345 patients with multiple sclerosis and 426 control subjects.

Method: The SSP-PCR method was used to determine genotypes and Fisher’s exact test was applied to determine differences between groups. HLA-DRB1*1501 was observed more frequently among multiple sclerosis patients compared with healthy subjects (45% and 34%, respectively; OR = 1.6, 95% CI = 1.2—2.2, p = 0.0018). At the IL-6/-174 position, the G allele had higher frequency among multiple sclerosis patients compared with controls (77% and 70%, respectively; OR = 1.4, 95% CI = 1.1—1.8, p = 0.0038). This difference was more significant among HLA-DRB1*1501-positive patients and controls (81% and 67%, respectively; OR = 1.9, 95% CI = 1.5—2.5, p < 0.0001).

Results: Our results have shown that the G allele at the IL-6/-174 promoter polymorphism may be associated with development of multiple sclerosis in this population, and may be strengthened by HLA-DRB1*1501.

Conclusions: We suggest more studies to confirm these results in other populations.