1,118 research outputs found
Extreme Precision Antenna Reflector Study Results
Thermal and mechanical distortion degrade the RF performance of antennas. The complexity of future communications antennas requires accurate, dimensionally stable antenna reflectors and structures built from materials other than those currently used. The advantages and disadvantages of using carbon fibers in an epoxy matrix are reviewed as well as current reflector fabrications technology and adjustment. The manufacturing sequence and coefficient of thermal expansion of carbon fiber/borosilicate glass composites is described. The construction of a parabolic reflector from this material and the assembling of both reflector and antenna are described. A 3M-aperture-diameter carbon/glass reflector that can be used as a subassembly for large reflectors is depicted. The deployment sequence for a 10.5M-aperture-diameter antenna, final reflector adjustment, and the deployment sequence for large reflectors are also illustrated
What Can Congress Do: The Second Amendment versus the Commerce and Equal Protection Clauses
This research project explores the Second Amendment debate through the lens of Congress\u27s power to enact legislation. It evaluates whether or not Congress has power through the Commerce Clause and/or Equal Protection Clause to create gun control legislation, placing these rights and powers in conversation with Second Amendment rights. This paper provides a legal groundwork for gun control, using case briefs, law reviews, and Supreme Court rulings. It analyzes the implications of precedent on the legal response to potential future legislation regarding gun control. With this framework, a response to case history will provide a legal argument for why Congress can, and should, pursue reasonable gun control regulations. My thesis statement is that Congress, by powers enumerated in Article I, Section 8 of the Constitution (the Commerce Clause), and to protect rights laid out to citizens in the Equal Protection Clause of the Fourteenth Amendment, can constitutionally enact federal gun control legislation in America. This project is significant because it provides a specific and actionable legal outline for federal gun control
Calculation of posterior chamber intraocular lens (IOL) size and dioptric power for use in pet rabbits undergoing phacoemulsification
Bacterial Transposons containing Markers for Fungal Gene Disruption
We have constructed 2 tn5-containing plasmids, pLH1 and pLH3, specialized towards mutagenesis of genes from fungi which are auxotrophic for arginine or sensitive to hygromycin (such as the filamentous fungi Aspergillus nidulans and Magnaporthe grisea.) These plasmids are also a useful means of integrating additional marker genes in the plasmid backbone
A Common Variant Associated with Dyslexia Reduces Expression of the KIAA0319 Gene
Numerous genetic association studies have implicated the KIAA0319 gene on human chromosome 6p22 in dyslexia susceptibility. The causative variant(s) remains unknown but may modulate gene expression, given that (1) a dyslexia-associated haplotype has been implicated in the reduced expression of KIAA0319, and (2) the strongest association has been found for the region spanning exon 1 of KIAA0319. Here, we test the hypothesis that variant(s) responsible for reduced KIAA0319 expression resides on the risk haplotype close to the gene's transcription start site. We identified seven single-nucleotide polymorphisms on the risk haplotype immediately upstream of KIAA0319 and determined that three of these are strongly associated with multiple reading-related traits. Using luciferase-expressing constructs containing the KIAA0319 upstream region, we characterized the minimal promoter and additional putative transcriptional regulator regions. This revealed that the minor allele of rs9461045, which shows the strongest association with dyslexia in our sample (max p-value = 0.0001), confers reduced luciferase expression in both neuronal and non-neuronal cell lines. Additionally, we found that the presence of this rs9461045 dyslexia-associated allele creates a nuclear protein-binding site, likely for the transcriptional silencer OCT-1. Knocking down OCT-1 expression in the neuronal cell line SHSY5Y using an siRNA restores KIAA0319 expression from the risk haplotype to nearly that seen from the non-risk haplotype. Our study thus pinpoints a common variant as altering the function of a dyslexia candidate gene and provides an illustrative example of the strategic approach needed to dissect the molecular basis of complex genetic traits
Effect and Distribution of Contrast Medium after Injection into the Anterior Suprachoroidal Space in Ex Vivo Eyes
PURPOSE: To determine the effects and posterior distribution of injections made into the anterior suprachoroidal space (SCS). METHODS: The anterior SCS of adult porcine and canine ex vivo eyes was cannulated. Latex injections and high frequency ultrasound (50 MHz) was used to image the effect and distension of the SCS. Flow characteristics and percentage maximal distribution of microbubble contrast injection into the SCS were assessed by 2D and 3D ultrasound. RESULTS: Mean (SD) distension of the SCS with PBS increased from 1.57 (0.48) mm after injection of 250 μL to 3.28 (0.57) mm with 1000 μL PBS. Eyes injected at physiologic IOP had no significant difference in SCS distension. In real-time 2D ultrasound, the contrast agent flowed from the injection site to the opposite ventral anterior SCS and the posterior SCS. Contrast arrived at the opposite and posterior SCS 7.8 (4.6) and 7.7 (4.6) seconds after injection, respectively. In sagittal images, contrast was visible in 24.0%to 27.2% of the SCS; in 10 of 12 eyes, contrast reached the posterior pole of the eye. In 3D images, contrast medium occupied 39.0% to 52.1% of the entire SCS. CONCLUSIONS: These results suggest that the SCS can expand, in a dose-dependent manner, to accommodate various volumes of fluid and that it is possible to image the SCS with ultrasound contrast. The authors' hypothesis that a single anterior SCS injection can reach the ocular posterior segment was supported. Further development of SCS injections for treatment of the ocular posterior segment is warranted
Equine infectious keratitis in Finland : Associated microbial isolates and susceptibility profiles
Objective To retrospectively describe laboratory findings, treatment, and outcome associated with equine infectious keratitis in Finland. Animals and procedures Medical records of horses diagnosed with infectious keratitis in University of Helsinki Equine Hospital from January 2007 to June 2018 were reviewed. Results Forty-seven cases were included. Keratomycosis was diagnosed in 27 eyes and bacterial keratitis in 20 eyes. Aspergillus flavus was the most frequent fungal isolate (9/17, 53%), followed by Cylindrocarpon sp. (3/17, 18%) and Aspergillus fumigatus (2/17, 12%). Susceptibility was tested for 10/11 Aspergillus sp. isolates; all were susceptible to voriconazole while only two were susceptible to amphotericin B. Cylindrocarpon sp. isolates were resistant to both agents. Streptococcus equi subsp. zooepidemicus was the most frequent bacterial isolate (9/19, 47%), followed by other streptococci (4/19, 21%). All 13 Streptococcus sp. isolates were susceptible to penicillin, and all tested isolates (n = 11) were also susceptible to chloramphenicol. Mean duration of medical treatment was longer in fungal keratitis (38 days) than in bacterial keratitis (25 days) (P <.001). Twenty-six of the eyes underwent globe-sparing surgery in addition to medical therapy. Recovery was achieved in 66% (31/47) of all cases and in 59% (16/27) and 75% (15/20) (P = .264) of cases with keratomycosis and bacterial keratitis, respectively. Conclusions Although Aspergillus sp. and S zooepidemicus were the most frequently encountered isolates, cytology, culture, and susceptibility testing are essential to differentiate bacterial and fungal keratitis and guide the clinician to choose the most efficient treatment.Peer reviewe
Esomeprazole for the treatment of erosive esophagitis in children: an international, multicenter, randomized, parallel-group, double-blind (for dose) study
<p>Abstract</p> <p>Background</p> <p>Acid suppression with a proton pump inhibitor is standard treatment for gastroesophageal reflux disease and erosive esophagitis in adults and increasingly is becoming first-line therapy for children aged 1-17 years. We evaluated endoscopic healing of erosive esophagitis with esomeprazole in young children with gastroesophageal reflux disease and described esophageal histology.</p> <p>Methods</p> <p>Children aged 1-11 years with endoscopically or histologically confirmed gastroesophageal reflux disease were randomized to esomeprazole 5 or 10 mg daily (< 20 kg) or 10 or 20 mg daily (≥ 20 kg) for 8 weeks. Patients with erosive esophagitis underwent an endoscopy after 8 weeks to assess healing of erosions.</p> <p>Results</p> <p>Of 109 patients, 49% had erosive esophagitis and 51% had histologic evidence of reflux esophagitis without erosive esophagitis. Of the 45 patients who had erosive esophagitis and underwent follow-up endoscopy, 89% experienced erosion resolution. Dilation of intercellular space was reported in 24% of patients with histologic examination.</p> <p>Conclusions</p> <p>Esomeprazole (0.2-1.0 mg/kg) effectively heals macroscopic and microscopic erosive esophagitis in this pediatric population with gastroesophageal reflux disease. Dilation of intercellular space may be an important histologic marker of erosive esophagitis in children.</p> <p>Trial Registration</p> <p>D9614C00097; ClinicalTrials.gov identifier NCT00228527.</p
Arbitration between model-free and model-based control is not affected by transient changes in tonic serotonin levels
Background: Serotonin has been suggested to modulate decision-making by influencing the arbitration between model-based and model-free control. Disruptions in these control mechanisms are involved in mental disorders such as drug dependence or obsessive-compulsive disorder. While previous reports indicate that lower brain serotonin levels reduce model-based control, it remains unknown whether increases in serotonergic availability might thus increase model-based control. Moreover, the mediating neural mechanisms have not been studied yet. Aim: The first aim of this study was to investigate whether increased/decreased tonic serotonin levels affect the arbitration between model-free and model-based control. Second, we aimed to identify the underlying neural processes. Methods: We employed a sequential two-stage Markov decision-task and measured brain responses during functional magnetic resonance imaging in 98 participants in a randomized, double-blind cross-over within-subject design. To investigate the influence of serotonin on the balance between model-free and model-based control, we used a tryptophan intervention with three intervention levels (loading, balanced, depletion). We hypothesized that model-based behaviour would increase with higher serotonin levels. Results: We found evidence that neither model-free nor model-based control were affected by changes in tonic serotonin levels. Furthermore, our tryptophan intervention did not elicit relevant changes in Blood-Oxygenation-Level Dependent activity
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