870 research outputs found

    Application of response surface techniques to helicopter rotor blade optimization procedure

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    In multidisciplinary optimization problems, response surface techniques can be used to replace the complex analyses that define the objective function and/or constraints with simple functions, typically polynomials. In this work a response surface is applied to the design optimization of a helicopter rotor blade. In previous work, this problem has been formulated with a multilevel approach. Here, the response surface takes advantage of this decomposition and is used to replace the lower level, a structural optimization of the blade. Problems that were encountered and important considerations in applying the response surface are discussed. Preliminary results are also presented that illustrate the benefits of using the response surface

    Smartphone-Based Microscope for Pathogen Detection

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    Vibrio cholerae is a water and food borne bacteria that causes cholera, a severe acute diarrheal disease, when ingested and when left untreated, can cause patient death within hours. Currently there is a lack of both sensitive and rapid portable detection technologies of V. cholerae for testing water and food samples. Combining nucleic acid amplification and particle diffusometry present an alternative detection method for V. cholerae in under 30 minutes, but the process requires an expensive laboratory microscope. In this work, we develop a smartphone-based microscope to detect V. cholerae DNA in environmental water samples using particle diffusometry. A modular iPhone case is designed with a detachable cartridge and an integrated ball lens to image a microfluidic sample slide. This sample slide is essential for performing the DNA amplification assay and contains the microparticles necessary for imaging and particle diffusometry measurements. The ball lenses to image these particles have diameters of 1.0, 0.79, and 0.5 millimeters and are tested in conjunction with the iPhone 6 camera to determine optimal magnification and focal length. We demonstrate the ability to detect the Brownian motion of 1.0 micrometer particles using a 0.5 millimeter ball lens with brightfield imaging. This field-portable imaging platform provides the capability to perform rapid detection of V. cholerae in the field, and in the future, can be applied toward detecting other diseases at the point of care

    ‘It Brings Light to What You Really Put into Your Body’: A Focus Group Study of Reactions to Messages about Nicotine Reduction in Cigarettes

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    Objective: In 2017, the U.S. Food and Drug Administration (FDA) announced a proposed regulation to lower nicotine in cigarettes to minimally addictive levels to help smokers quit. We sought to explore effective message strategies communicating about nicotine reduction in cigarettes across the different key audiences that the regulation is most likely to influence. Methods: We designed four types of messages: efficacy messages, risk messages, a message about alternative sources of nicotine, and a compensation message. Sixteen virtual focus groups were conducted in Atlanta and San Francisco in April-May 2020. Data were analyzed in NVivo 12.0 using a thematic analysis approach. Findings: Exclusive smokers were receptive to both efficacy messages and risk messages. Dual users were the only group that was open to resorting to alternative sources of nicotine. Former smokers were critical of these messages as promoting the new kinds of cigarettes and potentially encouraging initiation and relapse of smoking. Nonsmokers felt that efficacy messages downplayed the risks of smoking and did not scare people away from smoking. Presenting information that very low nicotine cigarettes (VLNCs) still contain harmful chemicals made smokers question continued smoking in the absence of nicotine and view VLNCs as harmful. Conclusions: Messages communicating about nicotine reduction in cigarettes might help to motivate smokers to quit and can correct the misperceptions that VLNCs are less harmful. The FDA should consider specific target audiences and use different messages that complement each other in communicating about this regulation

    Loop corrections for Kaluza-Klein AdS amplitudes

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    Recently we conjectured the four-point amplitude of graviton multiplets in AdS5×S5{\rm AdS}_5 \times {\rm S}^5 at one loop by exploiting the operator product expansion of N=4\mathcal{N}=4 super Yang-Mills theory. Here we give the first extension of those results to include Kaluza-Klein modes, obtaining the amplitude for two graviton multiplets and two states of the first KK mode. Our method again relies on resolving the large N degeneracy among a family of long double-trace operators, for which we obtain explicit formulas for the leading anomalous dimensions. Having constructed the one-loop amplitude we are able to obtain a formula for the one-loop corrections to the anomalous dimensions of all twist five double-trace operators.Comment: 37 pages. One ancillary file containing data on the correlator

    Early Epstein-Barr Virus Genomic Diversity and Convergence toward the B95.8 Genome in Primary Infection

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    Over 90% of the world\u27s population is persistently infected with Epstein-Barr virus. While EBV does not cause disease in most individuals, it is the common cause of acute infectious mononucleosis (AIM) and has been associated with several cancers and autoimmune diseases, highlighting a need for a preventive vaccine. At present, very few primary, circulating EBV genomes have been sequenced directly from infected individuals. While low levels of diversity and low viral evolution rates have been predicted for double-stranded DNA (dsDNA) viruses, recent studies have demonstrated appreciable diversity in common dsDNA pathogens (e.g., cytomegalovirus). Here, we report 40 full-length EBV genome sequences obtained from matched oral wash and B cell fractions from a cohort of 10 AIM patients. Both intra- and interpatient diversity were observed across the length of the entire viral genome. Diversity was most pronounced in viral genes required for establishing latent infection and persistence, with appreciable levels of diversity also detected in structural genes, including envelope glycoproteins. Interestingly, intrapatient diversity declined significantly over time (P \u3c 0.01), and this was particularly evident on comparison of viral genomes sequenced from B cell fractions in early primary infection and convalescence (P \u3c 0.001). B cell-associated viral genomes were observed to converge, becoming nearly identical to the B95.8 reference genome over time (Spearman rank-order correlation test; r = -0.5589, P = 0.0264). The reduction in diversity was most marked in the EBV latency genes. In summary, our data suggest independent convergence of diverse viral genome sequences toward a reference-like strain within a relatively short period following primary EBV infection. IMPORTANCE Identification of viral proteins with low variability and high immunogenicity is important for the development of a protective vaccine. Knowledge of genome diversity within circulating viral populations is a key step in this process, as is the expansion of intrahost genomic variation during infection. We report full-length EBV genomes sequenced from the blood and oral wash of 10 individuals early in primary infection and during convalescence. Our data demonstrate considerable diversity within the pool of circulating EBV strains, as well as within individual patients. Overall viral diversity decreased from early to persistent infection, particularly in latently infected B cells, which serve as the viral reservoir. Reduction in B cell-associated viral genome diversity coincided with a convergence toward a reference-like EBV genotype. Greater convergence positively correlated with time after infection, suggesting that the reference-like genome is the result of selection

    High Epstein-Barr Virus Load and Genomic Diversity Are Associated with Generation of gp350-Specific Neutralizing Antibodies following Acute Infectious Mononucleosis

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    The Epstein-Barr virus (EBV) gp350 glycoprotein interacts with the cellular receptor to mediate viral entry and is thought to be the major target for neutralizing antibodies. To better understand the role of EBV-specific antibodies in the control of viral replication and the evolution of sequence diversity, we measured EBV gp350-specific antibody responses and sequenced the gp350 gene in samples obtained from individuals experiencing primary EBV infection (acute infectious mononucleosis [AIM]) and again 6 months later (during convalescence [CONV]). EBV gp350-specific IgG was detected in the sera of 17 (71%) of 24 individuals at the time of AIM and all 24 (100%) individuals during CONV; binding antibody titers increased from AIM through CONV, reaching levels equivalent to those in age-matched, chronically infected individuals. Antibody-dependent cell-mediated phagocytosis (ADCP) was rarely detected during AIM (4 of 24 individuals; 17%) but was commonly detected during CONV (19 of 24 individuals; 79%). The majority (83%) of samples taken during AIM neutralized infection of primary B cells; all samples obtained at 6 months postdiagnosis neutralized EBV infection of cultured and primary target cells. Deep sequencing revealed interpatient gp350 sequence variation but conservation of the CR2-binding site. The levels of gp350-specific neutralizing activity directly correlated with higher peripheral blood EBV DNA levels during AIM and a greater evolution of diversity in gp350 nucleotide sequences from AIM to CONV. In summary, we conclude that the viral load and EBV gp350 diversity during early infection are associated with the development of neutralizing antibody responses following AIM. IMPORTANCE: Antibodies against viral surface proteins can blunt the spread of viral infection by coating viral particles, mediating uptake by immune cells, or blocking interaction with host cell receptors, making them a desirable component of a sterilizing vaccine. The EBV surface protein gp350 is a major target for antibodies. We report the detection of EBV gp350-specific antibodies capable of neutralizing EBV infection in vitro The majority of gp350-directed vaccines focus on glycoproteins from lab-adapted strains, which may poorly reflect primary viral envelope diversity. We report some of the first primary gp350 sequences, noting that the gp350 host receptor binding site is remarkably stable across patients and time. However, changes in overall gene diversity were detectable during infection. Patients with higher peripheral blood viral loads in primary infection and greater changes in viral diversity generated more efficient antibodies. Our findings provide insight into the generation of functional antibodies, necessary for vaccine development

    Using Genetic Technologies To Reduce, Rather Than Widen, Health Disparities

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    Evidence shows that both biological and nonbiological factors contribute to health disparities. Genetics, in particular, plays a part in how common diseases manifest themselves. Today, unprecedented advances in genetically based diagnoses and treatments provide opportunities for personalized medicine. However, disadvantaged groups may lack access to these advances, and treatments based on research on non-Hispanic whites might not be generalizable to members of minority groups. Unless genetic technologies become universally accessible, existing disparities could be widened. Addressing this issue will require integrated strategies, including expanding genetic research, improving genetic literacy, and enhancing access to genetic technologies among minority populations in a way that avoids harms such as stigmatization

    The Iowa Homemaker vol.17, no.7

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    Beauty from Beauty by Peggy Schenk, page 1 Through Masculine Eyes by Jim Henderson and E. L. Anderson, page 2 Use Angles and Lights for Snappy Shots by Jane Helser, page 4 Faces in Focus by Gaynold Carroll and Harriett Graves, page 5 New Style Loves by Sally, page 6 Beds for Beauty by Ruth Dahlberg, page 7 Gems in Pottery by Katherine Taube, page 8 Room for Improvement by Leah Scott, page 9 What’s New in Home Economics edited by Marjorie Pettinger, page 10 In the Still of the Night by Helen Greene, page 12 Short but Sweet by Harriet Beyer, page 13 Dessert Course, a poem by Ronny Ronningen, page 14 Controlled Curves by Gertrude E. Hendriks, page 14 First Ladies by Ruth Sawin, page 15 Complaints of Shopworn Clerks by Ruth Dahlberg, page 16 Behind Bright Jackets, page 18 Alumnae News by Faithe Danielson, page 19 Lamp Light by Mary Bush, page 20 To Whom It May Concern, a poem by Ronny Ronningen, page 20 Heart to Heart by the editor, page 2
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