Radar cross-section measurements and simulation of a tethered satellite. The small expendable deployer system end-mass payload

The first Small Expendable Deployer System (SEDS-1), a tethered satellite system, was developed by NASA and launched March 29, 1993 as a secondary payload on a United State Air Force (USAF) Delta-2 launch vehicle. The SEDS-1 successfully deployed an instrumented end-mass payload (EMP) on a 20-km nonconducting tether from the second stage of the Delta 2. This paper describes the effort of NASA Langley Research Center's Antenna and Microwave Research Branch to provide assistance to the SEDS Investigators Working Group (IWG) in determining EMP dynamics by analyzing the mission radar skin track data. The radar cross section measurements taken and simulations done for this study are described and comparisons of the measured data with the simulated data for the EMP at 6 GHz are presented

Structurally Integrated Antenna Concepts for HALE UAVs

This technical memorandum describes work done in support of the Multifunctional Structures and Materials Team under the Vehicle Systems Program's ITAS (Integrated Tailored Aero Structures) Project during FY 2005. The Electromagnetics and Sensors Branch (ESB) developed three ultra lightweight antenna concepts compatible with HALE UAVs (High Altitude Long Endurance Unmanned Aerial Vehicles). ESB also developed antenna elements that minimize the interaction between elements and the vehicle to minimize the impact of wing flexure on the EM (electromagnetic) performance of the integrated array. In addition, computer models were developed to perform phase correction for antenna arrays whose elements are moving relative to each other due to wing deformations expected in HALE vehicle concepts. Development of lightweight, conformal or structurally integrated antenna elements and compensating for the impact of a lightweight, flexible structure on a large antenna array are important steps in the realization of HALE UAVs for microwave applications such as passive remote sensing and communications

Case report: Pain in anti-DPPX encephalitis

Encephalitis due to antibodies targeting dipeptidyl-peptidase-like protein 6 (DPPX), a potassium channel subunit, is rare. The illness is typically characterized by a triad of weight loss, CNS hyperexcitability and cognitive symptoms, but recent reports suggest that the clinical picture may be more heterogeneous. Here, we describe the case of a 63-year-old female who was admitted to the hospital with severe extremity pain, which had been preceded by diarrhea and weight loss. She later developed cognitive changes, and her general condition rapidly deteriorated. Extensive workup did not reveal gastrointestinal illness or underlying malignancies. MRI of the brain was normal. Analyses of blood and cerebrospinal fluid showed normal cell counts but high titres of DPPX antibodies in blood and cerebrospinal fluid. The patient was treated with intravenous methylprednisolone followed by rituximab. At 1-year follow-up, she was without pain and had completely recovered. In this case, DPPX-associated autoimmune encephalitis was dominated by severe extremity pain, illustrating that sensory symptoms may be one of the main complaints in these patients. It is important for clinicians to be aware of the heterogeneous clinical picture in this serious condition, since correct diagnosis and treatment with immunosuppressants are associated with favorable prognosis

An assessment of the potential of continuous-wave ranging for measuring the distance to a highly reflective, infinite sheet

The feasibility of a continuous-wave, distance-measuring technique for measuring the distance from a spacecraft antenna to a highly ionized plasma surface is examined. The reflection coefficient angle is computed for several aperture models. It is concluded that aperture size and the presence of a nonablating dielectric cover over the antenna are critical factors

Paraneoplastic and Other Autoimmune Encephalitides: Antineuronal Antibodies, T Lymphocytes, and Questions of Pathogenesis

Autoimmune and paraneoplastic encephalitides represent an increasingly recognized cause of devastating human illness as well as an emerging area of neurological injury associated with immune checkpoint inhibitors. Two groups of antibodies have been detected in affected patients. Antibodies in the first group are directed against neuronal cell surface membrane proteins and are exemplified by antibodies directed against the N-methyl-D-aspartate receptor (anti-NMDAR), found in patients with autoimmune encephalitis, and antibodies directed against the leucine-rich glioma-inactivated 1 protein (anti-LGI1), associated with faciobrachial dystonic seizures and limbic encephalitis. Antibodies in this group produce non-lethal neuronal dysfunction, and their associated conditions often respond to treatment. Antibodies in the second group, as exemplified by anti-Yo antibody, found in patients with rapidly progressive cerebellar syndrome, and anti-Hu antibody, associated with encephalomyelitis, react with intracellular neuronal antigens. These antibodies are characteristically found in patients with underlying malignancy, and neurological impairment is the result of neuronal death. Within the last few years, major advances have been made in understanding the pathogenesis of neurological disorders associated with antibodies against neuronal cell surface antigens. In contrast, the events that lead to neuronal death in conditions associated with antibodies directed against intracellular antigens, such as anti-Yo and anti-Hu, remain poorly understood, and the respective roles of antibodies and T lymphocytes in causing neuronal injury have not been defined in an animal model. In this review, we discuss current knowledge of these two groups of antibodies in terms of their discovery, how they arise, the interaction of both types of antibodies with their molecular targets, and the attempts that have been made to reproduce human neuronal injury in tissue culture models and experimental animals. We then discuss the emerging area of autoimmune neuronal injury associated with immune checkpoint inhibitors and the implications of current research for the treatment of affected patients.publishedVersio

The application of reliability methods in the design of stiffened FRP composite panels for marine vessels

The use of composite laminate materials has increased rapidly in recent years due to their excellent strength to weight ratio and resistance to corrosion. In the construction of marine vessels, stiffened plates are the most commonly used structural elements, forming the deck, bottom hull, side shells and bulkheads. This paper presents the use of a stochastic approach to the design of stiffened marine composite panels as part of a current research programme into developing stochastic methods for composite ship structures, accounting for variations in material properties, geometric indices and processing techniques, from the component level to the full system level. An analytical model for the solution of a stiffened isotropic plate using a grillage analogy is extended by the use of equivalent elastic properties for composite modelling. This methodology is applied in a reliability analysis of an isotropic (steel) stiffened plate before the final application for a reliability analysis for a FRP composite stiffened plate

Ribosome Distribution in HeLa Cells during the Cell Cycle

In this study, we employed a surface-specific antibody against the large ribosome subunit to investigate the distribution of ribosomes in cells during the cell cycle. The antibody, anti-L7n, was raised against an expansion segment (ES) peptide from the large subunit ribosomal protein L7, and its ribosome-surface specificity was evident from the positive immuno-reactivity of ribosome particles and the detection of 60 S immune-complex formation by an immuno-electron microscopy. Using immunofluorescent staining, we have microscopically revealed that ribosomes are dispersed in the cytoplasm of cells throughout all phases of the cell cycle, except at the G2 phase where ribosomes show a tendency to gather toward the nuclear envelope. The finding in G2 cells was confirmed by electron microscopy using a morphometric assay and paired t test. Furthermore, further observations have shown that ribosomes are not distributed immune-fluorescently with nuclear envelope markers including the nuclear pore complex, the integral membrane protein gp210, the inner membrane protein lamin B2, and the endoplasm reticulum membrane during cell division we propose that the mechanism associated with ribosome segregation into daughter cells could be independent of the processes of disassembly and reassembly of the nuclear envelope

Annexin A2 Binds RNA and Reduces the Frameshifting Efficiency of Infectious Bronchitis Virus

Annexin A2 (ANXA2) is a protein implicated in diverse cellular functions, including exocytosis, DNA synthesis and cell proliferation. It was recently proposed to be involved in RNA metabolism because it was shown to associate with some cellular mRNA. Here, we identified ANXA2 as a RNA binding protein (RBP) that binds IBV (Infectious Bronchitis Virus) pseudoknot RNA. We first confirmed the binding of ANXA2 to IBV pseudoknot RNA by ultraviolet crosslinking and showed its binding to RNA pseudoknot with ANXA2 protein in vitro and in the cells. Since the RNA pseudoknot located in the frameshifting region of IBV was used as bait for cellular RBPs, we tested whether ANXA2 could regulate the frameshfting of IBV pseudoknot RNA by dual luciferase assay. Overexpression of ANXA2 significantly reduced the frameshifting efficiency from IBV pseudoknot RNA and knockdown of the protein strikingly increased the frameshifting efficiency. The results suggest that ANXA2 is a cellular RBP that can modulate the frameshifting efficiency of viral RNA, enabling it to act as an anti-viral cellular protein, and hinting at roles in RNA metabolism for other cellular mRNAs

Multicentre comparison of a diagnostic assay: Aquaporin-4 antibodies in neuromyelitis optica

Objective Antibodies to cell surface central nervous system proteins help to diagnose conditions which often respond to immunotherapies. The assessment of antibody assays needs to reflect their clinical utility. We report the results of a multicentre study of aquaporin (AQP) 4 antibody (AQP4-Ab) assays in neuromyelitis optica spectrum disorders (NMOSD). Methods Coded samples from patients with neuromyelitis optica (NMO) or NMOSD (101) and controls (92) were tested at 15 European diagnostic centres using 21 assays including live (n=3) or fixed cell-based assays (n=10), flow cytometry (n=4), immunohistochemistry (n=3) and ELISA (n=1). Results Results of tests on 92 controls identified 12assays as highly specific (0-1 false-positive results). 32 samples from 50 (64%) NMO sera and 34 from 51 (67%) NMOSD sera were positive on at least two of the 12 highly specific assays, leaving 35 patients with seronegative NMO/spectrum disorder (SD). On the basis of a combination of clinical phenotype and the highly specific assays, 66 AQP4-Ab seropositive samples were used to establish the sensitivities (51.5-100%) of all 21 assays. The specificities (85.8-100%) were based on 92 control samples and 35 seronegative NMO/SD patient samples. Conclusions The cell-based assays were most sensitive and specific overall, but immunohistochemistry or flow cytometry could be equally accurate in specialist centres. Since patients with AQP4-Ab negative NMO/SD require different management, the use of both appropriate control samples and defined seronegative NMOSD samples is essential to evaluate these assays in a clinically meaningful way. The process described here can be applied to the evaluation of other antibody assays in the newly evolving field of autoimmune neurology

Recombinant humanised anti-HER2/neu antibody (Herceptin®) induces cellular death of glioblastomas

Glioblastoma multiforme (GBM) remains the most devastating primary tumour in neuro-oncology. Targeting of the human epithelial receptor type 2 (HER2)-neu receptor by specific antibodies is a recent well-established therapy for breast tumours. Human epithelial receptor type 2/neu is a transmembrane tyrosine/kinase receptor that appears to be important for the regulation of cancer growth. Human epithelial receptor type 2/neu is not expressed in the adult central nervous system, but its expression increases with the degree of astrocytoma anaplasia. The specificity of HER2/neu for tumoral astrocytomas leads us to study in vitro treatment of GBM with anti-HER2/neu antibody. We used human GBM cell lines expressing HER2/neu (A172 express HER2/neu more than U251MG) or not (U87MG) and monoclonal humanised antibody against HER2/neu (Herceptin®). Human epithelial receptor type 2/neu expression was measured by immunohistochemistry and flow cytometry. Direct antibody effect, complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity were evaluated by different cytometric assays. We have shown, for the first time, the ability of anti-HER2/neu antibodies to induce apoptosis and cellular-dependent cytotoxicity of HER2/neu-expressing GBM cell lines. The results decreased from A172 to U251 and were negative for U87MG, in accordance with the decreasing density of HER2/neu receptors