697 research outputs found
Multivalent Recognition of Peptides by Modular Self-Assembled Receptors
Developing nontraditional approaches to the synthesis and characterization of multivalent compounds is critical to our efforts to study and interface with biological systems and to build new noncovalent materials. This paper demonstrates a biomimetic approach to the construction of discrete, modular, multivalent receptors via molecular self-assembly in aqueous solution. Scaffolds presenting 1â3 viologen groups recruit a respective 1â3 copies of the synthetic host, cucurbit[8]uril, in a noncooperative manner and with a consistent equilibrium association constant (Ka) value of 2 Ă 106 Mâ1 per binding site. The assembled mono-, di-, and trivalent receptors bind to their cognate target peptides containing 1â3 Trp residues with Ka values in the range 1.7 Ă 104â4.7 Ă 106 Mâ1 and in predetermined mono- or multivalent binding modes with 31â280-fold enhancements in affinity and additive enthalpies due to multivalency. The extent of valency was determined directly by measuring the visible charge-transfer absorptivity due to the viologenâindole pair. The predictable behavior of this system and its ease of synthesis and analysis make it well suited to serve as a model for multivalent binding and for the multivalent recognition of peptides by design
Life table analysis of Diaphorina citri (Hemiptera: Psyllidae) infesting sweet orange (Citrus sinensis) in SĂŁo Paulo
An ecological life table for eggs and nymphs of Diaphorina citri Kuwayama (Hemiptera:
Psyllidae) was constructed with data obtained from orange orchards (Citrus sinensis Osbeck) in 2 regions of the State of SĂŁo Paulo, over 4 generations in the period from XI-2006
to V-2007, comprising spring, summer, and fall seasons. Young growing shoots with D. citri
eggs present were identifed, and live individuals were counted until adult emergence. No
predatory arthropods were observed in association with D. citri eggs and nymphs during
the study. The mean parasitism of fourth- and ffth-instar nymphs by Tamarixia radiata
Waterston (Hymenoptera: Eulophidae) was 2.3%. The durations of the eggâadult period
were similar among the 4 generations, ranging from 18.0 to 24.7 d (at mean temperatures
ranging from 21.6 to 26.0 °C) and followed the temperature requirement models obtained
in the laboratory for D. citri. However, survival from the egg to the adult stage for the same
period varied considerably from 1.7 to 21.4%; the highest mortalities were observed in the
egg and small nymphal (frst- to thirdinstar) stages, which were considered to be key phases
for population growth of the pest.Uma tabela de vida ecolĂłgica foi construĂda para ovos e ninfas de Diaphorina citri Kuwayama (Hemiptera: Psyllidae) com dados obtidos em pomares de laranja (Citrus sinensis Osbeck) em 2 regiĂ”es do estado de SĂŁo Paulo, com 4 geraçÔes, no perĂodo de novembro de 2006
a maio de 2007, compreendendo as estaçÔes de primavera, verão e outono. Ramos jovens
em crescimento com a presença de ovos de D. citri foram identificados e os indivĂduos vivos
foram contados atĂ© a emergĂȘncia dos adultos. Nenhum predador foi observado associado a
ovos e ninfas de D. citri durante o estudo. A taxa média de parasitismo de ninfas de quarto
e quinto Ănstares por Tamarixia radiata Waterson (Hymenoptera: Eulophidae) foi de 2.3%.
A duração do perĂodo de ovo a adulto foi semelhante entre as quatro geraçÔes, variando de
18.0 a 24.7 dias (com temperaturas médias de 21.6 a 26.0 °C) e seguiram os modelos de
exigencias térmicas obtidas em laboratório para D. citri. Todavia, a sobrevivencia de ovo
atĂ© o estĂĄgio adulto variou consideravelmente para o mesmo perĂodo, de 1.7 a 21.4%, sendo
que as maiores mortalidades foram observadas nos estĂĄgios de ovos e ninfas pequenas (de
primeiro a terceiro Ănstares), as quais foram consideradas fases chaves para o crescimento
populacional desta praga.info:eu-repo/semantics/publishedVersio
The validity of using ICD-9 codes and pharmacy records to identify patients with chronic obstructive pulmonary disease
Background: Administrative data is often used to identify patients with chronic obstructive pulmonary disease (COPD), yet the validity of this approach is unclear. We sought to develop a predictive model utilizing administrative data to accurately identify patients with COPD.
Methods: Sequential logistic regression models were constructed using 9573 patients with postbronchodilator spirometry at two Veterans Affairs medical centers (2003-2007). COPD was defined as: 1) FEV1/FVC <0.70, and 2) FEV1/FVC < lower limits of normal. Model inputs included age, outpatient or inpatient COPD-related ICD-9 codes, and the number of metered does inhalers (MDI) prescribed over the one year prior to and one year post spirometry. Model performance was assessed using standard criteria.
Results: 4564 of 9573 patients (47.7%) had an FEV1/FVC < 0.70. The presence of â„1 outpatient COPD visit had a sensitivity of 76% and specificity of 67%; the AUC was 0.75 (95% CI 0.74-0.76). Adding the use of albuterol MDI increased the AUC of this model to 0.76 (95% CI 0.75-0.77) while the addition of ipratropium bromide MDI increased the AUC to 0.77 (95% CI 0.76-0.78). The best performing model included: â„6 albuterol MDI, â„3 ipratropium MDI, â„1 outpatient ICD-9 code, â„1 inpatient ICD-9 code, and age, achieving an AUC of 0.79 (95% CI 0.78-0.80).
Conclusion: Commonly used definitions of COPD in observational studies misclassify the majority of patients as having COPD. Using multiple diagnostic codes in combination with pharmacy data improves the ability to accurately identify patients with COPD.Department of Veterans Affairs, Health Services Research and Development (DHA), American Lung Association (CI- 51755-N) awarded to DHA, the American Thoracic Society Fellow Career Development AwardPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/84155/1/Cooke - ICD9 validity in COPD.pd
Example of function optimization via hybrid computation
Iterative techniques for function optimization have been considered extensivezy for use in all-digital computation. Relatively little has been done to take advantage of the much higher integration speed of hybrid computation systems. This paper demonstrates application of one simple procedure in a hybrid envi ronment and compares the results to those obtained by an efficient digital procedure. Even though a much more efficient procedure was used on the digital, time-saving factors between 8 and 2 were obtained via the simpler hybrid implementation. Since the dollar cost of the hybrid is much less than that of the digital, the hybrid has a large advantage per solution.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68324/2/10.1177_003754977302100204.pd
The brain tumor experience from the relatives' perspective
Article describes the clinical optimization of uptake parameters of Boronophenylalanin
Collective Flow from the Intranuclear Cascade Model
The phenomenon of collective flow in relativistic heavy ion collisions is
studied using the hadronic cascade model ARC. Direct comparison is made to data
gathered at the Bevalac, for Au+Au at GeV/c. In contrast to the
standard lore about the cascade model, collective flow is well described
quantitatively without the need for explicit mean field terms to simulate the
nuclear equation of state. Pion collective flow is in the opposite direction to
nucleon flow as is that of anti-nucleons and other produced particles. Pion and
nucleon flow are predicted at AGS energies also, where, in light of the higher
baryon densities achieved, we speculate that equation of state effects may be
observable.Comment: 9 pages, 2 figures include
Delays Associated with Elementary Processes in Nuclear Reaction Simulations
Scatterings, particularly those involving resonances, and other elementary
processes do not happen instantaneously. In the context of semiclassical
nuclear reaction simulations, we consider delays associated with an interaction
for incident quantum wave-packets. As a consequence, we express delays
associated with elementary processes in terms of elements of the scattering
matrix and phase shifts for elastic scattering. We show that, to within the
second order in density, the simulation must account for delays in scattering
consistently with the mean field in order to properly model thermodynamic
properties such as pressure and free-energy density. The delays associated with
nucleon-nucleon and pion-nucleon scattering in free space are analysed with
their nontrivial energy dependence. Finally, an example of s-channel scattering
of massless partons is studied, and scattering schemes in nuclear reaction
simulations are investigated in the context of scattering delays.Comment: 45 pages, 5 uuencoded Postscript figure
Recommended from our members
Electromagnetic Decay of Giant Resonances
Coincidence experiments were done to investigate the photon and neutron emission from the giant resonance regions of /sup 208/Pb and /sup 90/Zr using the ORNL Spin Spectrometer, a 72-segment NaI detector system. We have determined the total gamma-decay probability, the ground-state gamma branching ratio, and the branching ratios to a number of low-lying states as a function of excitation energy in /sup 208/Pb to approx.15 MeV. Similar data were also obtained on /sup 90/Zr. The total yield of ground-state E2 gamma radiation in /sup 208/Pb and the comparative absence of such radiation in /sup 90/Zr can only be understood if decay of compound (damped) states is considered. Other observations in /sup 208/Pb include the absence of a significant branch from the giant quadrupole resonance (GQR) to the 3/sup -/ state at 2.6 MeV, a strong branch to a 3/sup -/ state at 4.97 MeV from the same region, and transitions to various 1/sup -/ states between 5 to 7 MeV from the E* approx. 14 MeV region (EO resonance)
An interdisciplinary intervention for older Taiwanese patients after surgery for hip fracture improves health-related quality of life
Abstract Background The effects of intervention programs on health-related quality of life (HRQOL) of patients with hip fracture have not been well studied. We hypothesized that older patients with hip fracture who received our interdisciplinary intervention program would have better HRQOL than those who did not. Methods A randomized experimental design was used. Older patients with hip fracture (N = 162), 60 to 98 years old, from a medical center in northern Taiwan were randomly assigned to an experimental (n = 80) or control (n = 82) group. HRQOL was measured by the SF-36 Taiwan version at 1, 3, 6, and 12 months after discharge. Results The experimental group had significantly better overall outcomes in bodily pain (β = 9.38, p = 0.002), vitality (β = 9.40, p < 0.001), mental health (β = 8.16, p = 0.004), physical function (β = 16.01, p < 0.001), and role physical (β = 22.66, p < 0.001) than the control group at any time point during the first year after discharge. Physical-related health outcomes (physical functioning, role physical, and vitality) had larger treatment effects than emotional/mental- and social functioning-related health outcomes. Conclusions This interdisciplinary intervention program may improve health outcomes of elders with hip fracture. Our results may provide a reference for health care providers in countries using similar programs with Chinese/Taiwanese immigrant populations. Trial registration NCT01052636http://deepblue.lib.umich.edu/bitstream/2027.42/78259/1/1471-2474-11-225.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78259/2/1471-2474-11-225.pdfPeer Reviewe
Quantum Tunneling in Nuclear Fusion
Recent theoretical advances in the study of heavy ion fusion reactions below
the Coulomb barrier are reviewed. Particular emphasis is given to new ways of
analyzing data, such as studying barrier distributions; new approaches to
channel coupling, such as the path integral and Green function formalisms; and
alternative methods to describe nuclear structure effects, such as those using
the Interacting Boson Model. The roles of nucleon transfer, asymmetry effects,
higher-order couplings, and shape-phase transitions are elucidated. The current
status of the fusion of unstable nuclei and very massive systems are briefly
discussed.Comment: To appear in the January 1998 issue of Reviews of Modern Physics. 13
Figures (postscript file for Figure 6 is not available; a hard copy can be
requested from the authors). Full text and figures are also available at
http://nucth.physics.wisc.edu/preprints
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