376 research outputs found
Applications of Allyl and Alkenyl Zirconocenes and Progress Toward the Total Synthesisof Tuberostemonone
This dissertation describes the development of several novel chemical reactions employing allyl and alkenyl zirconocenes. These diverse nucleophiles were employed in thesynthesis of a variety of biologically and chemically important molecules. Initially, allyl zirconocenes were employed for the addition to imines, thereby providing rapid access tofunctionalized homoallylic amines. We were later able to employ alkenyl zirconocenes in both the construction of C-glycosidic bonds and the addition to chiral imines. The power of thesetransformations was realized by a rapid and stereoselective synthesis of an immunostimulant agent and its analogs. Biological evaluation of these compounds showed encouraging activity against malaria. Small molecule radioprotectant agents have also been developed and show promising potential for therapeutic use. Finally, we were able to install key stereocenters of the Stemona alkaloid tuberostemonone
An Empirical Study of Judicial Review of Agency Interpretations of Agency Rules
In this essay, Pierce and Weiss report the results of a study of judicial review of agency interpretations of agency rules. Prior studies found that, while courts at all levels uphold about 70% of agency actions, the Supreme Court upholds 91% of agency interpretations of agency rules. Pierce and Weiss find that lower courts do not confer this type of super deference on agency interpretations of agency rules. District courts and circuit courts uphold 76% of such agency actions. That is within the range of the findings of prior studies of judicial review of other types of agency actions and much lower than the rate at which the Supreme Court upholds agency interpretations of agency rules. Pierce and Weiss also find no evidence that judges are influenced by their political or ideological preferences when they review agency interpretations of agency rules. That finding is consistent with the findings of a prior study of judicial review of agency findings of fact, but it is inconsistent with the findings of several studies of judicial review of agency interpretations of agency-administered statutes and of judicial review of agency policy decisions
The Greenest Solar Power? Life Cycle Assessment Of Foam-Based Flexible Floatovoltaics
This study presents a life cycle analysis (LCA) of a 10 MW foam-based floatovoltaics (FPV) plant installed on Lake Mead, Nevada, U.S. A material inventory of the flexible crystalline silicon (c-Si)-based module involved massing and determination of material composition of the module\u27s encapsulation layers with ATR/FTR spectroscopy and electron microscopy. The LCA was performed using SimaPro and the results were interpreted in terms of cumulative energy demands, energy payback time, global warming potential, GHG emissions, and water footprint including negative values for reduced evaporation. A sensitivity analysis was performed on the lifetime of the modules and the foam-based racking. The results show that the 30 year lifetime foam-based FPV system has one of the lowest energy payback times (1.3 years) and the lowest GHG emissions to energy ratio (11 kg CO2 eq per MW h) in c-Si solar PV technologies reported to date. In addition, the foam-based FPV system also had 5 times less water footprint (21.5 m3 per MW h) as compared to a conventional pontoon-based FPV (110 m3 per MW h). The lifetime of the foam-based racking does not affect the result, while the lifetime of the modules has a significant effect on the lifecycle impacts of the foam-based FPV plant. Foam-based FPV has a net positive impact on the environment for CO2 emissions and energy consumption if its lifetime is above 7.4 years and the technology has the potential to become the greenest c-Si-based solar PV technology if the lifetime of the modules can be guaranteed for at least 26.6 years. Future work is needed to determine the lifetimes of these systems and expand them
AN ASSAY OF GRAFT-HOST INTERACTIONS ACROSS STRONG AND WEAK HISTOCOMPATIBILITY BARRIERS IN MICE
1. A new assay of graft-host interactions has been presented. It consists of the early finding of liver infiltrates in responsive and unresponsive homologous recipients 1 to 3 days after the intravenous injection of competent lymphoid tissue in the mouse. 2. Evidence is presented that infiltrates are of donor origin, and are influenced by a homologous antigenic environment. They can be quantitatively increased by preimmunization of donor to recipient and decreased by preimmunization of recipient to donor. Furthermore, they are present in lethally x-irradiated or neonatally thymectomized unresponsive recipients after intravenous injection of competent homologous spleen cells. 3. Splenomegaly, which also occurs in this early period, is a product of both donor and host-specific immune reactivity together with a small non-specific component of host reactivity. 4. A comparison, of the responsiveness of lymphoid tissue from different strains to the same transplantation antigens is presented, together with the observation of differences in the reactivity of reciprocal donor-recipient injection combinations to each other. 5. Graft-host interactions with this model can be demonstrated in donor-host strain combinations isogenic at the H-2 locus without preimmunization of the donor. Differences in reactivity of reciprocal donor-recipient combinations of lymphoid tissue injections to each other can be detected in this group as well as in the groups differing at the strong H-2 locus
Food Habits of Sympatric Pitvipers from the West Gulf Coastal Plain, USA
Widespread species that occupy multiple communities exhibit geographic variation in their natural history due to the ecological context of the local community. An animal’s food habitats are a central component to understanding its natural history and ecological role within its community—information that is critical to understanding resource needs of a species, mechanisms of species coexistence, and energy flow in food webs (Litvaitis 2000; Schalk et al. 2014). This information is also crucial for predicting the response of populations to changes in resource availability and, if necessary, inform mitigation strategies (Holycross and Mackessy 2002
Recommended from our members
#MeToo in EM: A Multicenter Survey of Academic Emergency Medicine Faculty on Their Experiences with Gender Discrimination and Sexual Harassment
Introduction: Gender-based discrimination and sexual harassment of female physicians are well documented. The #MeToo movement has brought renewed attention to these problems. This study examined academic emergency physicians’ experiences with workplace gender discrimination and sexual harassment.Methods: We conducted a cross-sectional survey of a convenience sample of emergency medicine (EM) faculty across six programs. Survey items included the following: the Overt Gender Discrimination at Work (OGDW) Scale; the frequency and source of experienced and observed discrimination; and whether subjects had encountered unwanted sexual behaviors by a work superior or colleague in their careers. For the latter question, we asked subjects to characterize the behaviors and whether those experiences had a negative effect on their self-confidence and career advancement. We made group comparisons using t-tests or chi-square analyses, and evaluated relationships between gender and physicians’ experiences using correlation analyses.Results: A total of 141 out of 352 (40.1%) subjects completed at least a portion of the survey. Women reported higher mean OGDW scores than men (15.4 vs 10.2; 95% confidence interval [CI], 3.6–6.8). Female faculty were also more likely to report having experienced gender-based discriminatory treatment than male faculty (62.7% vs 12.5%; 95% CI, 35.1%-65.4%), although male and female faculty were equally likely to report having observed gender-based discriminatory treatment of another physician (64.7% vs 56.3%; 95% CI, 8.6%-25.5%). The three most frequent sources of experienced or observed gender-based discriminatory treatment were patients, consulting or admitting physicians, and nursing staff. The majority of women reported having encountered unwanted sexual behaviors in their careers, with a significantly greater proportion of women reporting them compared to men (52.9% vs 26.2%, 95% CI, 9.9%-43.4%). The majority of unwanted behaviors were sexist remarks and sexual advances. Of those respondents who encountered these unwanted behaviors, 22.9% and 12.5% reported at least somewhat negative effects on their self-confidence and career advancement.Conclusion: Female EM faculty perceived more gender-based discrimination in their workplaces than their male counterparts. The majority of female and approximately a quarter of male EM faculty encountered unwanted sexual behaviors in their careers.
Pediatric Germ Cell Tumors: A Developmental Perspective
Germ cell tumors (GCTs) arising in infants, children, and adolescents present a set of special challenges. GCTs make up about 3% of malignancies in children aged 0–18 and nearly 15% of cancers in adolescents. Epidemiologic and molecular evidence suggests that GCTs in young children likely represent a distinct biologic group as compared to GCTs of older adolescents and adults. Despite this difference, pediatric GCTs are typically treated with cisplatin-based multiagent regimens similar to those used in adults. There is evidence that children are particularly vulnerable to late effects of conventional therapy, including ototoxicity, pulmonary abnormalities, and secondary malignancies, motivating the search for molecular targets for novel therapies. Evidence is accumulating that the genes and mechanisms controlling normal germ cell development are particularly relevant to the understanding of germ cell tumorigenesis. Perturbations in the epigenetic program of germ cell differentiation, with resulting effects on the regulation of pluripotency, may contribute to the marked histologic variability of GCTs. Perturbations in the KIT receptor signaling pathway have been identified via next-generation sequencing studies and in genome-wide association studies of testicular cancer susceptibility. Here, we review these and other biological insights that may fuel further translational and clinical research in childhood GCTs
- …