634 research outputs found
Regulating the Regulators: The Impact of FDA Regulation on Corporations\u27 First Amendment Rights, 39 J. Marshall L. Rev. 95 (2005)
Succenturiate Placental Lobe Abruption: a placental pathology complicating a dangerous delivery
The development of a placenta is a complex process that occurs without a clinically significant issue in most pregnancies. At times, however, the process develops in a way that isolates an island of placental tissue away from the main body, connected only by unprotected vasculature within the amniotic membranes. The vessels of this succenturiate lobe of the placenta are vulnerable both to compression or laceration, threatening the antepartum period with poor weight gain or the peripartum period with fetal distress, hemorrhage or retained products of conception. A majority of the time, this pathology is undiagnosed until recognized innocuously following delivery of the placenta. A placental abruption is a premature separation of the placenta from the uterus that can result in painful bleeding and fetal distress. This increased distress of mother or baby from continued blood loss usually necessitates delivery either vaginally, if stability is maintained, or by cesarean if it isn’t. The amount of distress correlates to where and how much of the placenta is affected. While succenturiate lobes of the placenta and placental abruptions are not routinely associated with each other, the abruption of only the succenturiate lobe of the placenta in this instance minimized the severity to the fetus, by allowing the main body of the placenta to remain intact. As the bleeding coagulated at the lobe, maternal well-being was maintained allowing enough time to complete a vaginal delivery
Local wood demand, land cover change and the state of Albany thicket on an urban commonage in the Eastern Cape, South Africa
Understanding the rates and causes of land-use change is crucial in identifying solutions, especially in sensitive landscapes and ecosystems, as well as in places undergoing rapid political, socioeconomic or ecological change. Despite considerable concern at the rate of transformation and degradation of the biodiversity-rich Albany Thicket biome in South Africa, most knowledge is gleaned from private commercial lands and state conservation areas. In comparison, there is limited work in communal areas where land uses include biomass extraction, especially for firewood and construction timber. We used aerial photographs to analyze land use and cover change in the high- and low-use zones of an urban commonage and an adjacent protected area over almost six decades, which included a major political transition. Field sampling was undertaken to characterize the current state of the vegetation and soils of the commonage and protected area and to determine the supply and demand for firewood and construction timber. Between the 1950s and 1980s, there was a clear increase in woody vegetation cover, which was reversed after the political transition in the mid-1990s. However, current woody plant standing stocks and sustainable annual production rates are well above current firewood demand, suggesting other probable causes for the decline in woody plant cover. The fragmentation of woody plant cover is paralleled by increases in grassy areas and bare ground, an increase in soil compaction, and decreases in soil moisture, carbon, and nutrients
Enhanced immunogenicity of a functional enzyme by T cell epitope modification
BACKGROUND: T helper epitopes are necessary for the induction of high titers of antigen-specific IgG antibodies. We are interested in the epitope modification of intact proteins as a method to enhance their immunogenicity for the generation of recombinant protein-based vaccines. RESULTS: Hartley strain guinea pig T cell epitopes were mapped for two related bacterial proteases. Two T cell epitopes were found in one of the proteases, while a comparatively reduced immunogenicity protease had no detectable T cell epitopes. A T cell epitope sequence homologous to the immunogenic protease was created in the less immunogenic protease by changing a single amino acid. Proliferative responses to the whole protein parent enzyme were two-fold higher in splenocyte cultures from variant-immunized animals. We found that the single amino acid change in the variant resulted in a protein immunogen that induced higher titers of antigen-specific IgG antibody at low doses and at early time points during the immunization protocol. The serum from parent- and variant-immunized guinea pigs cross-reacted at both the protein and the peptide level. Finally, animals primed to the variant but boosted with the parent enzyme had higher levels of antigen-specific IgG than animals immunized with the parent enzyme alone. CONCLUSIONS: With a single amino acid change we have introduced a T cell epitope into a comparatively low-immunogenic enzyme and have increased its immunogenicity while retaining the enzyme's original proteolytic function. The ability to immunomodulate proteins while leaving their function intact has important implication for the development of recombinant vaccines and protein-based therapeutics
Quantum Rotor Engines
This chapter presents autonomous quantum engines that generate work in the
form of directed motion for a rotor. We first formulate a prototypical
clock-driven model in a time-dependent framework and demonstrate how it can be
translated into an autonomous engine with the introduction of a planar rotor
degree of freedom. The rotor plays both the roles of internal engine clock and
of work repository. Using the example of a single-qubit piston engine, the
thermodynamic performance is then reviewed. We evaluate the extractable work in
terms of ergotropy, the kinetic energy associated to net directed rotation, as
well as the intrinsic work based on the exerted torque under autonomous
operation; and we compare them with the actual energy output to an external
dissipative load. The chapter closes with a quantum-classical comparison of the
engine's dynamics. For the single-qubit piston example, we propose two
alternative representations of the qubit in an entirely classical framework:
(i) a coin flip model and (ii) a classical magnet moment, showing subtle
differences between the quantum and classical descriptions.Comment: Chapter of the upcoming book "Thermodynamics in the Quantum Regime -
Recent Progress and Outlook
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