MONEY ILLUSION, GORMAN AND LAU

Any demand equation satisfying Lau’s (1982) Fundamental Theorem of Exact Aggregation and 0° homogeneity in prices and income will have a Gorman (1981) functional form for each income term. This property does not depend on symmetry or adding up. The implications of this result are illustrated by an extensive example.Demand, exact aggregation, functional form, homogeneity

Isolation of Human Antigen-Specific Antibodies from Memory B-Cells Nearly Two Years Post Vaccination

Isolation and production of therapeutic human monoclonal antibodies (mAbs) traditionally utilizes a handful of techniques including antibody engineering, phage display, hybridoma generation from transgenic mice or EBV immortalization of B-cells. Over the past decade a new approach has emerged that attempts to extract antigen-specific memory B-cells from the peripheral blood of individuals vaccinated or infected with the target. Initial attempts focused on culturing B-cells and inducing differentiation to plasmablasts for analysis of antibody-antigen specificity, but results were largely mixed due to difficult culture conditions and/or rarity of target cells. With advancing technology in cell sorting, single antigen-specific memory B-cells can be identified and sorted with fluorescently labeled antigens. This method has produced virus-specific mAbs from HIV-infected patients and tetanus-specific mAbs within weeks after Tdap immunization. Many other studies claim to have found antigen-specific mAbs months to years after immunization or clearance of an infection; however, these studies fail to provide direct evidence of antibody specificity by cloning and expressing the mAbs from B-cells. Here we report the efficient isolation of tetanus-specific mAbs from a subject Td-immunized almost two years prior to blood draw. Initially, the total B-cell population was isolated from peripheral blood mononuclear cells enriched by negative selection, then stained to identify tetanus-specific memory B-cells. These cells were individually sorted and PCR was performed to amplify heavy and light chain variable regions of the B-cell’s antibody mRNA. After sequencing, 15 of 42 samples produced both heavy and light chain antibody sequence and 11 mAbs were cloned and transiently expressed. ELISA analysis indicated 5 of the 11 mAbs bound the Hc protein fragment of tetanus toxin and 3 were specific for Hc. We plan to extend this initial success to additional targets and longer gaps between vaccination and B-cell isolation to identify functional therapeutic human antibodies

Analysis of sFlt Isoforms as Biomarkers for the Development of Preeclampsia

Preeclampsia is a multi-system disorder characterized by hypertension, edema and proteinuria affecting between 5-10% of pregnancies. A subset of cases progress to severe preeclampsia with exacerbated hypertension/proteinuria and evidence of nervous system, liver and/or kidney dysfunction, in addition to fetal growth restriction. Soluble fms-like tyrosine kinase-1 (sFlt) is minimally expressed in many tissues, including the placenta, and is a circulating antagonist to vascular endothelial growth factor. With progression of pregnancy, sFlt levels significantly rise, especially in women who develop preeclampsia. Diagnostic tests to predict preeclampsia in pregnant women are limited and current tests measure total sFlt in relationship to placental growth factor with varying sensitivity and specificity. We hypothesized that a pregnancy-specific splice variant of sFlt (sFlt1-14), almost exclusively expressed by the placenta, would serve as an improved serum biomarker for the development of preeclampsia. Monoclonal antibodies (mAbs) were developed that specifically bind the two predominant isoforms of sFlt (sFlt1 and sFlt1-14) by hybridoma generation from wild type mice immunized with c-terminal peptides of the two isoforms. Western blot, ELISA and affinity analysis indicated the mAbs were specific for sFlt1 or sFlt1-14 splice variants and recognized these proteins in biological fluids (amniotic fluid or serum). A quantitative capture ELISA was developed whereby total sFlt in biological fluid is captured by a unique human mAb and specific levels of sFlt1 or sFlt1-14 are detected by their respective mouse mAb, followed by anti-murine secondary antibody development. Using recombinant sFlt1 or sFlt1-14 as standards, these endogenous proteins were quantified in commercially available third trimester human pregnant sera. Future studies will measure these isoforms in sera prospectively collected from women with known outcomes of a healthy pregnancy or preeclampsia and the ability of absolute quantitation of the isoform(s) or a ratio of the two to predict the likely onset and severity of preeclampsia will be evaluated

Development of an Additively Manufactured Capacitive Humidity Sensor for the International Space Station

The ability to measure humidity on the International Space Station and other long-duration spaceflight missions is a crucial part of the onboard systems. For example, the Environmental Control and Life Support System (ECLSS) needs to know the amount of humidity in the air to make decisions about whether it should spend power to run the dehumidifier systems to attempt to reclaim that water. Other issues can arise if the humidity reaches too high of levels and condensation builds up on electrical components. With that in mind, it is vital that the spacecraft keeps spare sensors on board or has the ability to manufacture new sensors on demand. An additively manufactured sensor would be additionally beneficial because it would save space onboard that would normally be taken up by spares, save money from costly resupply missions, and allow the sensor to be constantly updated with the most effective design. This Technical Memorandum outlines a development process carried out to design, manufacture, and test an additively manufactured humidity sensor

Shear viscosity of a crosslinked polymer melt

We investigate the static shear viscosity on the sol side of the vulcanization transition within a minimal mesoscopic model for the Rouse-dynamics of a randomly crosslinked melt of phantom polymers. We derive an exact relation between the viscosity and the resistances measured in a corresponding random resistor network. This enables us to calculate the viscosity exactly for an ensemble of crosslinks without correlations. The viscosity diverges logarithmically as the critical point is approached. For a more realistic ensemble of crosslinks amenable to the scaling description of percolation, we prove the scaling relation $k=\phi-\beta$ between the critical exponent $k$ of the viscosity, the thermal exponent $\beta$ associated with the gel fraction and the crossover exponent $\phi$ of a random resistor network.Comment: 8 pages, uses Europhysics Letters style; Revisions: results extende

Prevalence and Predictors of Household Food Insecurity among Adult/Youth Dyads at the Initiation of the iCook 4-H Two-Year Obesity Prevention Study

Objective: Determine food insecurity prevalence and predictors among adult/youth dyads enrolled in a childhood obesity prevention study (iCook 4-H).Methods: The iCook 4-H intervention was designed for youth (9-10 years old) and their adult main meals preparer to cook, eat, and play together. Although not an inclusion criteria, diverse, low income, and/or rural families were the target during recruitment. At baseline, adults completed surveys on food insecurity, socioeconomic and demographic characteristics and youth anthropometrics were collected with body mass index (BMI) calculated. Descriptive statistics were computed and chi-square analysis was conducted to test differences between potential predictors and food insecurity. Binomial logistic regression was used to assess the relationship between food insecurity and its predictors.Results: Thirty-four percent of households (n=71 of 206) were food insecure. Youth were primarily white (69.9%) and normal weight (58.3%). Adults were also primarily white (74.8%), overweight or obese (67.9%), married (68.9%), not participating in government assistance programs (57.8%), and held no college degree (55.3%). Based on the logistic regression model, households with a non-white youth (OR=13.53; 95% CI=3.33, 55.05), an adult without a college degree (OR=5.62; 95% CI=2.01, 15.73), and government assistance program participation (OR=5.63; 95% CI=2.63, 12.07) were significantly associated with household food insecurity. However, there was no significant association with BMI found (youth p=0.167; adult p=0.179).Conclusion: Consistent with previous findings, household food insecurity status was associated with youth race, adult education, and government assistance program participation. In contrast, no relationship between BMI and food insecurity status was observed in this study, which warrants further investigation