Buckling effects in AlN monolayers: Shifting and enhancing optical characteristics from the UV to the near visible light range

The structural, electronic, and optical properties of flat and buckled AlN monolayers are investigated using first-principles approaches. The band gap of a flat AlN monolayer is changed from an indirect one to a direct one, when the planar buckling increases, primarily due to diminishing sp$^2$ overlapping and bond symmetry breaking in the conversion to sp$^3$ bonds. The sp$^3$ hybridization thus results in a stronger $\sigma\text{-}\pi$ bond rather than a $\sigma\text{-}\sigma$ covalent bond. The calculations of the phonon band structure indicates that the buckled AlN monolayers are structurally and dynamically stable. The optical properties, such as the dielectric function, the refractive index, and the optical conductivity of an AlN monolayer are evaluated for both flat systems and those impacted with planar buckling. The flat AlN monolayer has outstanding optical characteristics in the Deep-UV and absorbs more effectively in the UV spectrum due to its large band gap. The results reveal that optical aspects are enhanced along different directions of light polarization, with a considerable shift in the optical spectrum from Deep-UV into the visible range. Additionally, depending on the polarization direction of the incoming light, increased planar buckling enhances the optical conductivity in both the visible and the Deep-UV domains. The ability to modify the optical and electronic properties of these essential 2D materials using planar buckling technique opens up new technological possibilities, particularly for optoelectronic devices.Comment: RevTeX - pdfLaTeX, 9 pages with 7 included pdf figure

Clinical Findings in Isolated Bulbar Amyotrophic Lateral Sclerosis

Background: Isolated bulbar amyotrophic lateral sclerosis (IBALS) is a regional variant of amyotrophic lateral sclerosis (ALS) with weakness restricted to the bulbar muscles for at least 2 years, and slower progression than generalized ALS. Bulbar-onset generalized ALS, by contrast, typically has a more rapid progression than limb-onset ALS.Objective: To characterize patients with IBALS and compare them to patients with isolated bulbar disease at presentation who progress to generalized ALS.Methods: We performed a retrospective chart review of patients seen in our ALS specialty clinic at the University of Kansas Medical Center between 2001-2011. Results: Of 543 patients seen in the ALS clinic, 150 presented with bulbar symptoms at disease onset: 28 (18.7%) had bulbar signs and no evidence of extremity involvement on exam or electrodiagnostic testing at their initial visit; and 14 (9.3%) had weakness restricted to the bulbar muscles after 2 years of follow up (IBALS). IBALS patients were 57.1% male, with a mean age of symptom onset of 60.8 years (range 39-77 years). The mean disease duration was 3.1 years (range of 2-8 years), with 50% mortality at a mean follow up of 3.5 years. Minimal denervation changes were seen in at least one limb in 6 subjects (42.9%). Other clinical features included: 4 subjects (28.6%) had cognitive impairment, 4 (28.6%) had pseudo-bulbar affect, and 5 subjects (35.7%) had impaired eye movements on smooth pursuit.Conclusion: Isolatred bulbar ALS IBALS is an identifiable restricted regional ALS pattern if there is no clinical limb weakness 2 years after symptom onset. It may have a slower progression from typical ALS. The biologic factors that account for the IBALS restricted pattern are unknown

Role of planar buckling on the electronic, thermal, and optical properties of Germagraphene nanosheets

We report the electronic, the thermal, and the optical properties of a Germagraphene (GeC) monolayer taking into account buckling effects. The relatively wide direct band gap of a flat GeC nanosheet can be changed by tuning the planar buckling. A GeC monolayer has an sp$^2$ hybridization in which the contribution of an $s$-orbital is half of the contribution of a $p$-orbital leading to stronger $\sigma\text{-}\sigma$ bonds compared to the $\sigma\text{-}\pi$ bonds. Increasing the planar buckling, the contribution of an $s$-orbital is decreased while the contribution of a $p$-orbital is increased resulting in a sp$^3$-hybridization in which the $\sigma\text{-}\pi$ bond becomes stronger than the $\sigma\text{-}\sigma$ bond. As a result, the band gap of a buckled GeC is reduced and thus the thermal and the optical properties are significantly modified. We find that the heat capacity of the buckled GeC is decreased at low values of planar buckling, which is caused by the anticrossing of the optical and the acoustic phonon modes affecting phonon scattering processes. The resulting optical properties, such as the dielectric function, the refractive index, the electron energy loss spectra, the absorption, and the optical conductivity show that a buckled GeC nanosheet has increased optical activities in the visible light region compared to a flat GeC. The optical conductivity is red shifted from the near ultraviolet to the visible light region, when the planar buckling is increased. We can thus confirm that the buckling can be seen as another parameter to improve GeC monolayers for optoelectronic devices.Comment: RevTeX - pdfLaTeX, 10 pages with 12 included pdf figure

CIDP Diagnostic Criteria and Response to Treatment

AbstractIntroduction: Diagnostic criteria for CIDP have been proven useful for clinical trials. However, use of these criteria in clinics has been limited by time constraints and unknown usefulness in predicting outcomes. Methods: A retrospective chart review of CIDP patients at the University of Kansas seen between 2008 and 2014 was performed. We determined the diagnostic criteria fulfilled by each patient and assessed treatment responses. A positive response was defined by improvement sensory or motor examination as determined by a neuromuscular physician.Results: There were 38 total patients included in the study. The response rate to IVIG in patients who fulfilled EFNS/PNS criteria was 20/22 (90.1%). Among patients who fulfilled AAN criteria, 8/9 (88.9%) responded positively to IVIG. Slightly lower response rates were seen in patients fulfilling INCAT criteria and Saperstein criteria at 10/15 (66.7%) and 12/17 (70.6%), respectively.Discussion: EFNS/PNS and AAN criteria can similarly predict IVIG treatment response

Timing of Decremental Response During Repetitive Nerve Stimulation in Myasthenia Gravis

Background: A decrement >10% detected during repetitive nerve stimulation (RNS) is supportive of considering a diagnosis of myasthenia gravis (MG). Several studies have found that most of this decrement is seen between 4 to 6 min post-exercise. However, there are not available studies analyzing if shorter timing would be sufficient.   Objective: The objective of this study was to evaluate if RNS up to 2 min post-exercise is sufficient to detect a decrement response >10%. Methods: We performed a retrospective chart review study of patients referred to our neuromuscular clinic at The University of Kansas Medical Center with symptoms suggestive of MG from 2013 to 2017. Results: A total of 76 patients with MG and 100 controls were identified.  A significant decrement was detected in 95% of MG patients with abnormal RNS within 2 minutes post-exercise. Conclusion: RNS up to 2 min post-exercise might be sufficient to detect a significant decrement in MG patients.&nbsp

Amyloid Myopathy as an Inclusion Body Myositis Mimic

Introduction: Amyloid myopathy is a rare presentation of systemic amyloidosis. Amyloid myopathy can be initially misdiagnosed as sporadic inclusion body myositis (IBM). Methods: We report 4 cases of amyloid myopathy clinically mimicking inclusion body myositis and initially thought to be phenotypically IBM by neuromuscular experts. Results: Case 1 is an 81-year-old woman who presented with distal arm and proximal leg asymmetric weakness (myopathy pattern 4). Case 2 is a 76-year-old man with primary systemic amyloidosis who presented with myopathy pattern 4 and progressive dysphagia for four years. Case 3 is an 82-year-old man with progressive myopathy pattern 4 weakness and swallowing difficulty. Case 4 is a 62-year-old man with progressive bilateral finger flexor weakness. Muscle biopsies in all 4 cases showed perivascular amyloid deposits Discussion: Amyloid myopathy may be clinically indistinguishable from IBM. Muscle biopsy is of critical importance in the evaluation of patients suspected to have IBM

A Bayesian comparative effectiveness trial in action: developing a platform for multisite study adaptive randomization

A grant from the One-University Open Access Fund at the University of Kansas was used to defray the author's publication fees in this Open Access journal. The Open Access Fund, administered by librarians from the KU, KU Law, and KUMC libraries, is made possible by contributions from the offices of KU Provost, KU Vice Chancellor for Research & Graduate Studies, and KUMC Vice Chancellor for Research. For more information about the Open Access Fund, please see http://library.kumc.edu/authors-fund.xml.Background In the last few decades, the number of trials using Bayesian methods has grown rapidly. Publications prior to 1990 included only three clinical trials that used Bayesian methods, but that number quickly jumped to 19 in the 1990s and to 99 from 2000 to 2012. While this literature provides many examples of Bayesian Adaptive Designs (BAD), none of the papers that are available walks the reader through the detailed process of conducting a BAD. This paper fills that gap by describing the BAD process used for one comparative effectiveness trial (Patient Assisted Intervention for Neuropathy: Comparison of Treatment in Real Life Situations) that can be generalized for use by others. A BAD was chosen with efficiency in mind. Response-adaptive randomization allows the potential for substantially smaller sample sizes, and can provide faster conclusions about which treatment or treatments are most effective. An Internet-based electronic data capture tool, which features a randomization module, facilitated data capture across study sites and an in-house computation software program was developed to implement the response-adaptive randomization. Results A process for adapting randomization with minimal interruption to study sites was developed. A new randomization table can be generated quickly and can be seamlessly integrated in the data capture tool with minimal interruption to study sites. Conclusion This manuscript is the first to detail the technical process used to evaluate a multisite comparative effectiveness trial using adaptive randomization. An important opportunity for the application of Bayesian trials is in comparative effectiveness trials. The specific case study presented in this paper can be used as a model for conducting future clinical trials using a combination of statistical software and a web-based application. Trial registration ClinicalTrials.gov Identifier: NCT02260388, registered on 6 October 201