1,003 research outputs found
Use of dye to distinguish salt and protein crystals under microcrystallization conditions
An improved method of screening crystal growth conditions is provided wherein molecules are crystallized from solutions containing dyes. These dyes are selectively incorporated or associated with crystals of particular character thereby rendering crystals of particular character colored and improving detection of the dyed crystals. A preferred method involves use of dyes in protein solutions overlayed by oil. Use of oil allows the use of small volumes of solution and facilitates the screening of large numbers of crystallization conditions in arrays using automated devices that dispense appropriate solutions to generate crystallization trials, overlay crystallization trials with an oil, provide appropriate conditions conducive to crystallization and enhance detection of dyed (colored) or undyed (uncolored) crystals that result
Genetic Polymorphism in Evolving Population
We present a model for evolving population which maintains genetic
polymorphism. By introducing random mutation in the model population at a
constant rate, we observe that the population does not become extinct but
survives, keeping diversity in the gene pool under abrupt environmental
changes. The model provides reasonable estimates for the proportions of
polymorphic and heterozygous loci and for the mutation rate, as observed in
nature
Tangled banks: A landscape genomic evaluation of Wallace's Riverine barrier hypothesis for three Amazon plant species
Wallace's Riverine Barrier hypothesis is one of the earliest biogeographic explanations for Amazon speciation, but it has rarely been tested in plants. In this study, we used three woody Amazonian plant species to evaluate Wallace's Hypothesis using tools of landscape genomics. We generated unlinked single‐nucleotide polymorphism (SNP) data from the nuclear genomes of 234 individuals (78 for each plant species) across 13 sampling sites along the Rio Branco, Brazil, for Amphirrhox longifolia (8,075 SNPs), Psychotria lupulina (9,501 SNPs) and Passiflora spinosa (14,536 SNPs). Although significantly different migration rates were estimated between species, the population structure data do not support the hypothesis that the Rio Branco—an allopatric barrier for primates and birds—is a significant genetic barrier for Amphirrhox longifolia, Passiflora spinosa or Psychotria lupulina. Overall, we demonstrated that medium‐ sized rivers in the Amazon Basin, such as the Rio Branco, are permeable barriers to gene flow for animal‐dispersed and animal‐pollinated plant species.National Science Foundation, NASAFundação de Amparo à Pesquisa do Estado de São Paulo, Grant/Award Number: 2013/12633‐8, 2015/07141‐4, 2017/02302‐5 and 2012/50260‐6; Conselho Nacional de Desenvolvimento Científico e Tecnológico, Grant/Award Number: 310871/2017‐4; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Grant/Award Number: 88881.064974/2014‐01; National Science Foundation, Grant/Award Number: FESD 1338694 and DEB 1240869; Universidade de São PauloPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148338/1/Nazareno2019.pdf85Description of Nazareno2019.pdf : Main articl
Modeling, Simulation, and Experiments of Coating Growth on Nanofibers
This work is a comparison of modeling and simulation results with experiments for an integrated experimental/modeling investigation of a procedure to coat nanofibers and core-clad nanostructures with thin film materials using plasma enhanced physical vapor deposition. In the experimental effort, electrospun polymer nanofibers are coated with metallic materials under different operating conditions to observe changes in the coating morphology. The modeling effort focuses on linking simple models at the reactor level, nanofiber level and atomic level to form a comprehensive model. The comprehensive model leads to the definition of an evolution equation for the coating free surface around an isolated nanofiber. This evolution equation was previously derived and solved under conditions of a nearly circular coating, with a concentration field that was only radially dependent and that was independent of the location of the coating free surface. These assumptions permitted the development of analytical expressions for the concentration field. The present work does not impose the above-mentioned conditions and considers numerical simulations of the concentration field that couple with level set simulations of the evolution equation for the coating free surface. Further, the cases of coating an isolated fiber as well as a multiple fiber mat are considered. Simulation results are compared with experimental results as the reactor pressure and power, as well as the nanofiber mat porosity, are varied. (C) 2008 American Institute of Physics
Nurses\u27 Alumnae Association Bulletin - Volume 17 Number 1
Alumnae Notes
Committee Reports
Digest of Alumnae Association Meetings
Greetings from Miss Childs
Greetings from the Educational Director
Greetings from the President
Graduation Awards - 1951
Jefferson\u27s New Hospital Addition
Marriages
Necrology
Neurosurgery Department
New Arrivals New Drugs
Notes on the Cause of Leukemia
Nursing Staff
Saul Among the Prophets
Staff Activities, 1951-1952
Students\u27 Corner
The Hospital Pharmacy
The Student Nurse Association of Pennsylvania
White Haven and Barton Memorial Division
Extrauterine listeriosis in the gravid mouse influences embryonic growth and development
Gravid mice and other rodents inoculated with Listeria monocytogenes typically fail to clear an intrauterine infection and either succumb or expel their intrauterine contents. We took advantage of this property to investigate the effects of an extrauterine infection on parameters of pregnancy success. Pregnant mice were selected for our study if they showed no clinical signs of listeriosis following oral inoculation at 7.5 gestational days (gd), and had no detectable intrauterine colony forming units (cfu) at near term (18.5 gd). The range of oral doses employed was 10(6)-10(8) cfu per mouse for two listerial serotype strains (4nonb and 1/2a). At all doses, inoculation resulted in a decrease in average near-term (18.5 gd) fetal weight per litter compared to sham inoculated controls. Additionally, embryonic death (indicated by intrauterine resorptions) was exhibited by some inoculated mice but was absent in all sham inoculated animals. In parallel experiments designed to detect possible loss of placental function, gravid uteruses were examined histopathologically and microbiologically 96 h after oral inoculation. Placental lesions were associated with high (> 10(6)), but not low (< 10(2)) or absent intrauterine cfu. In vitro, mouse embryonic trophoblasts were indistinguishable from mouse enterocytes in terms of their sensitivity to listerial exposure. A model consistent with our observations is one in which products (host or bacterial) generated during an acute infection enter embryos transplacentally and influences embryonic survival and slows normal growth in utero
Conservation Efforts for Pinus maximinoi in Mesoamerica and Its Potential as a Hybrid with Pinus taeda in South America
Seed samples were collected from 25 populations of Pinus maximinoi from Guerrero, Mexico to central Nicaragua and established in provenance tests in Brazil, Colombia and South Africa by the CAMCORE Cooperative. The trials were assessed for volume production at 3, 5 and 8 years of age. Subsets of 13 and 5 provenances were assessed using RAPD and allozyme markers, respectively, to determine patterns of genetic diversity and mating systems in natural stands. RAPD analyses indicated significant differences among provenances in percent polymorphism and observed heterozygosity. Geographical location of the population in Mesoamerica greatly influenced genetic diversity, with populations from Mexico and Guatemala exhibiting more diversity than those from Honduras and Nicaragua. Observed heterozygosity patterns detected in the RAPD analysis correlated reasonably well with provenance performance in Brazil (r = 0.53, p = 0.06), Colombia (r = 0.48, p = 0.10) and South Africa (r = 0.43, p = 0.14). Allozyme assessment showed P. maximinoi to be polymorphic for 22 of the 25 loci analyzed with an average of 2.86 alleles per polymorphic locus. There was also evidence of inbreeding in the P. maximinoi populations. Provenances selected in trials for good volume production were generally the most genetically diverse based on biochemical and molecular marker assessment. Because of this relationship and the socio-economic needs of local people, in situ conservation programs for P. maximinoi in Mesoamerica should be based on securing the gene resources of populations that performed the best in well-replicated, international field trials. Pinus maximinoi has grown much faster than P. taeda in field trials established subtropical areas of Brazil through 14 years of age. Its juvenile wood properties are as good as or better than P. taeda. Specifically, its juvenile wood has a lower latewood percentage than found for the southern pines in the region, resulting in greater wood uniformity and stability. Hybrid crosses between P. taeda and P. maximinoi appear to be successful. The presentation discusses the opportunities of using P. maximinoi either as a pure species or as a hybrid with P. taeda in subtropical regions of South America. Sound conservation efforts now will ensure that breeding material is available in the future.Papers and abstracts from the 27th Southern Forest Tree Improvement Conference held at Oklahoma State University in Stillwater, Oklahoma on June 24-27, 2003
Patterns of isozyme variation in relation to population size, isolation, and phytogeographic history in royal catchfly
The distribution of genetic variation within and among plant populations is influenced by both contemporary and historical factors. I used isozyme analysis of band phenotypes to examine genetic structure in the rare prairie forb Silene regia. Relationships between current-day population size, isolation, and phenotypic variation were assessed for 18 populations in two regions with differing postglacial history. Western populations from unglaciated southern Missouri and Arkansas were more genetically diverse based on the Shannon-Weaver index (H) and a polymorphic index than were more eastern populations. These differences may be due to loss of variation with repeated founding of new populations in previously glaciated sites in Indiana and Ohio. Within the western region, population size was not significantly correlated with genetic variation. In the east, size was correlated with Shannon-Weaver diversity. There was no relationship between variation and isolation in either region, but eastern populations were slightly more differentiated. Greater among-population differentiation and the demonstrated connection between population size and variation in the eastern sites may reflect lower levels of interpopulation gene flow in the fragmented remnant prairies of Indiana and Ohio
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