Showing papers by "Northwestern University published in 2006"
TL;DR: The bottom-up chemical approach of tuning the graphene sheet properties provides a path to a broad new class of graphene-based materials and their use in a variety of applications.
Abstract: The remarkable mechanical properties of carbon nanotubes arise from the exceptional strength and stiffness of the atomically thin carbon sheets (graphene) from which they are formed. In contrast, bulk graphite, a polycrystalline material, has low fracture strength and tends to suffer failure either by delamination of graphene sheets or at grain boundaries between the crystals. Now Stankovich et al. have produced an inexpensive polymer-matrix composite by separating graphene sheets from graphite and chemically tuning them. The material contains dispersed graphene sheets and offers access to a broad range of useful thermal, electrical and mechanical properties. Individual sheets of graphene can be readily incorporated into a polymer matrix, giving rise to composite materials having potentially useful electronic properties. Graphene sheets—one-atom-thick two-dimensional layers of sp2-bonded carbon—are predicted to have a range of unusual properties. Their thermal conductivity and mechanical stiffness may rival the remarkable in-plane values for graphite (∼3,000 W m-1 K-1 and 1,060 GPa, respectively); their fracture strength should be comparable to that of carbon nanotubes for similar types of defects1,2,3; and recent studies have shown that individual graphene sheets have extraordinary electronic transport properties4,5,6,7,8. One possible route to harnessing these properties for applications would be to incorporate graphene sheets in a composite material. The manufacturing of such composites requires not only that graphene sheets be produced on a sufficient scale but that they also be incorporated, and homogeneously distributed, into various matrices. Graphite, inexpensive and available in large quantity, unfortunately does not readily exfoliate to yield individual graphene sheets. Here we present a general approach for the preparation of graphene-polymer composites via complete exfoliation of graphite9 and molecular-level dispersion of individual, chemically modified graphene sheets within polymer hosts. A polystyrene–graphene composite formed by this route exhibits a percolation threshold10 of ∼0.1 volume per cent for room-temperature electrical conductivity, the lowest reported value for any carbon-based composite except for those involving carbon nanotubes11; at only 1 volume per cent, this composite has a conductivity of ∼0.1 S m-1, sufficient for many electrical applications12. Our bottom-up chemical approach of tuning the graphene sheet properties provides a path to a broad new class of graphene-based materials and their use in a variety of applications.
11,866 citations
TL;DR: In this article, stable aqueous dispersions of polymer-coated graphitic nanoplatelets can be prepared via an exfoliation/in-situ reduction of graphite oxide in the presence of poly(sodium 4-styrenesulfonate).
Abstract: For the first time, stable aqueous dispersions of polymer-coated graphitic nanoplatelets can be prepared via an exfoliation/in-situ reduction of graphite oxide in the presence of poly(sodium 4-styrenesulfonate).
2,493 citations
TL;DR: 5XFAD mice rapidly recapitulate major features of AD amyloid pathology and may be useful models of intraneuronal Aβ42-induced neurodegeneration and amyloids plaque formation.
Abstract: Mutations in the genes for amyloid precursor protein (APP) and presenilins (PS1, PS2) increase production of β-amyloid 42 (Aβ42) and cause familial Alzheimer's disease (FAD). Transgenic mice that express FAD mutant APP and PS1 overproduce Aβ42 and exhibit amyloid plaque pathology similar to that found in AD, but most transgenic models develop plaques slowly. To accelerate plaque development and investigate the effects of very high cerebral Aβ42 levels, we generated APP/PS1 double transgenic mice that coexpress five FAD mutations (5XFAD mice) and additively increase Aβ42 production. 5XFAD mice generate Aβ42 almost exclusively and rapidly accumulate massive cerebral Aβ42 levels. Amyloid deposition (and gliosis) begins at 2 months and reaches a very large burden, especially in subiculum and deep cortical layers. Intraneuronal Aβ42 accumulates in 5XFAD brain starting at 1.5 months of age (before plaques form), is aggregated (as determined by thioflavin S staining), and occurs within neuron soma and neurites. Some amyloid deposits originate within morphologically abnormal neuron soma that contain intraneuronal Aβ. Synaptic markers synaptophysin, syntaxin, and postsynaptic density-95 decrease with age in 5XFAD brain, and large pyramidal neurons in cortical layer 5 and subiculum are lost. In addition, levels of the activation subunit of cyclin-dependent kinase 5, p25, are elevated significantly at 9 months in 5XFAD brain, although an upward trend is observed by 3 months of age, before significant neurodegeneration or neuron loss. Finally, 5XFAD mice have impaired memory in the Y-maze. Thus, 5XFAD mice rapidly recapitulate major features of AD amyloid pathology and may be useful models of intraneuronal Aβ42-induced neurodegeneration and amyloid plaque formation.
2,471 citations
TL;DR: Using the scalable technique of density-gradient ultracentrifugation, isolated narrow distributions of SWNTs in which >97% are within a 0.02-nm-diameter range are isolated.
Abstract: The heterogeneity of as-synthesized single-walled carbon nanotubes (SWNTs) precludes their widespread application in electronics, optics and sensing. We report on the sorting of carbon nanotubes by diameter, bandgap and electronic type using structure-discriminating surfactants to engineer subtle differences in their buoyant densities. Using the scalable technique of density-gradient ultracentrifugation, we have isolated narrow distributions of SWNTs in which >97% are within a 0.02-nm-diameter range. Furthermore, using competing mixtures of surfactants, we have produced bulk quantities of SWNTs of predominantly a single electronic type. These materials were used to fabricate thin-film electrical devices of networked SWNTs characterized by either metallic or semiconducting behaviour.
2,219 citations
TL;DR: An integrative review of the available evidence on implicit and explicit attitude change that is guided by a distinction between associative and propositional processes is provided.
Abstract: A central theme in recent research on attitudes is the distinction between deliberate, "explicit" attitudes and automatic, "implicit" attitudes. The present article provides an integrative review of the available evidence on implicit and explicit attitude change that is guided by a distinction between associative and propositional processes. Whereas associative processes are characterized by mere activation independent of subjective truth or falsity, propositional reasoning is concerned with the validation of evaluations and beliefs. The proposed associative-propositional evaluation (APE) model makes specific assumptions about the mutual interplay of the 2 processes, implying several mechanisms that lead to symmetric or asymmetric changes in implicit and explicit attitudes. The model integrates a broad range of empirical evidence and implies several new predictions for implicit and explicit attitude change.
2,191 citations
TL;DR: In this article, a number of functionalized graphite oxides were prepared by treatment of graphite oxide (GO) with organic isocyanates, which can then be exfoliated into functionalized graphene oxide nanoplatelets that can form a stable dispersion in polar aprotic solvents.
2,103 citations
TL;DR: It is proposed that Orai1 is an essential component or regulator of the CRAC channel complex, which contains four putative transmembrane segments and is based on a novel protein that was identified in SCID patients.
Abstract: Antigen stimulation of immune cells triggers Ca2+ entry through Ca2+ release-activated Ca2+ (CRAC) channels, promoting the immune response to pathogens by activating the transcription factor NFAT. We have previously shown that cells from patients with one form of hereditary severe combined immune deficiency (SCID) syndrome are defective in store-operated Ca2+ entry and CRAC channel function. Here we identify the genetic defect in these patients, using a combination of two unbiased genome-wide approaches: a modified linkage analysis with single-nucleotide polymorphism arrays, and a Drosophila RNA interference screen designed to identify regulators of store-operated Ca2+ entry and NFAT nuclear import. Both approaches converged on a novel protein that we call Orai1, which contains four putative transmembrane segments. The SCID patients are homozygous for a single missense mutation in ORAI1, and expression of wild-type Orai1 in SCID T cells restores store-operated Ca2+ influx and the CRAC current (I(CRAC)). We propose that Orai1 is an essential component or regulator of the CRAC channel complex.
2,102 citations
TL;DR: By chemically tailoring the density of DNA bound to the surface of gold nanoparticles, a tunable gene knockdown was demonstrated and it was demonstrated that gold nanoparticle-oligonucleotide complexes are nontoxic to the cells under the conditions studied.
Abstract: We describe the use of gold nanoparticle-oligonucleotide complexes as intracellular gene regulation agents for the control of protein expression in cells. These oligonucleotide-modified nanoparticles have affinity constants for complementary nucleic acids that are higher than their unmodified oligonucleotide counterparts, are less susceptible to degradation by nuclease activity, exhibit greater than 99% cellular uptake, can introduce oligonucleotides at a higher effective concentration than conventional transfection agents, and are nontoxic to the cells under the conditions studied. By chemically tailoring the density of DNA bound to the surface of gold nanoparticles, we demonstrated a tunable gene knockdown.
1,870 citations
TL;DR: A single-molecule study of the substrate and oxidation-dependent adhesive properties of dopa is reported, in which dopa exploits a remarkable combination of high strength and chemical multifunctionality to accomplish adhesion to substrates of widely varying composition.
Abstract: The glue proteins secreted by marine mussels bind strongly to virtually all inorganic and organic surfaces in aqueous environments in which most adhesives function poorly. Studies of these functionally unique proteins have revealed the presence of the unusual amino acid 3,4-dihydroxy-L-phenylalanine (dopa), which is formed by posttranslational modification of tyrosine. However, the detailed binding mechanisms of dopa remain unknown, and the chemical basis for mussels' ability to adhere to both inorganic and organic surfaces has never been fully explained. Herein, we report a single-molecule study of the substrate and oxidation-dependent adhesive properties of dopa. Atomic force microscopy (AFM) measurements of a single dopa residue contacting a wet metal oxide surface reveal a surprisingly high strength yet fully reversible, noncovalent interaction. The magnitude of the bond dissociation energy as well as the inability to observe this interaction with tyrosine suggests that dopa is critical to adhesion and that the binding mechanism is not hydrogen bond formation. Oxidation of dopa, as occurs during curing of the secreted mussel glue, dramatically reduces the strength of the interaction to metal oxide but results in high strength irreversible covalent bond formation to an organic surface. A new picture of the interfacial adhesive role of dopa emerges from these studies, in which dopa exploits a remarkable combination of high strength and chemical multifunctionality to accomplish adhesion to substrates of widely varying composition from organic to metallic.
1,859 citations
Ohio State University1, Fred Hutchinson Cancer Research Center2, University of Cincinnati3, University of Iowa4, University of California, Davis5, University of Alabama at Birmingham6, University of Arizona7, University of Washington8, Rush University Medical Center9, Wake Forest University10, University of Nevada, Reno11, University of Texas at San Antonio12, Kaiser Permanente13, University of Pittsburgh14, University of California, Los Angeles15, Stony Brook University16, Baylor College of Medicine17, University of North Carolina at Chapel Hill18, Wayne State University19, Howard University20, George Washington University21, University of California, Irvine22, University of Tennessee Health Science Center23, Medical College of Wisconsin24, University of California, San Diego25, Rutgers University26, University of Florida27, National Institutes of Health28, Harvard University29, University of Minnesota30, University of Massachusetts Boston31, University of Miami32, Emory University33, University of Wisconsin-Madison34, Stanford University35, Northwestern University36, University at Buffalo37, Brown University38, Yeshiva University39
TL;DR: Among healthy postmenopausal women, calcium with vitamin D supplementation resulted in a small but significant improvement in hip bone density, did not significantly reduce hip fracture, and increased the risk of kidney stones.
Abstract: Background The efficacy of calcium with vitamin D supplementation for preventing hip and other fractures in healthy postmenopausal women remains equivocal. Methods We recruited 36,282 postmenopausal women, 50 to 79 years of age, who were already enrolled in a Women's Health Initiative (WHI) clinical trial. We randomly assigned participants to receive 1000 mg of elemental calcium as calcium carbonate with 400 IU of vitamin D3 daily or placebo. Fractures were ascertained for an average follow-up period of 7.0 years. Bone density was measured at three WHI centers. Results Hip bone density was 1.06 percent higher in the calcium plus vitamin D group than in the placebo group (P<0.01). Intention-to-treat analysis indicated that participants receiving calcium plus vitamin D supplementation had a hazard ratio of 0.88 for hip fracture (95 percent confidence interval, 0.72 to 1.08), 0.90 for clinical spine fracture (0.74 to 1.10), and 0.96 for total fractures (0.91 to 1.02). The risk of renal calculi increased with...
1,765 citations
TL;DR: It is recommended that the term renal osteodystrophy be used exclusively to define alterations in bone morphology associated with CKD, and the term CKD-Mineral and Bone Disorder (CKD-MBD) be used to describe a broader clinical syndrome that develops as a systemic disorder of mineral and bone metabolism due to CKD.
TL;DR: The general mechanisms of the circadian clockwork are reviewed, recent findings that elucidate tissue-specific expression patterns of the clock genes are described and the importance of circadian regulation in peripheral tissues for an organism's overall well-being is addressed.
Abstract: Mammals synchronize their circadian activity primarily to the cycles of light and darkness in the environment. This is achieved by ocular photoreception relaying signals to the suprachiasmatic nucleus (SCN) in the hypothalamus. Signals from the SCN cause the synchronization of independent circadian clocks throughout the body to appropriate phases. Signals that can entrain these peripheral clocks include humoral signals, metabolic factors, and body temperature. At the level of individual tissues, thousands of genes are brought to unique phases through the actions of a local transcription/translation-based feedback oscillator and systemic cues. In this molecular clock, the proteins CLOCK and BMAL1 cause the transcription of genes which ultimately feedback and inhibit CLOCK and BMAL1 transcriptional activity. Finally, there are also other molecular circadian oscillators which can act independently of the transcription-based clock in all species which have been tested.
TL;DR: The 5 principles suggest a framework for integrating the Big Five model of personality traits with those self-defining features of psychological individuality constructed in response to situated social tasks and the human need to make meaning in culture.
Abstract: Despite impressive advances in recent years with respect to theory and research, personality psychology has yet to articulate clearly a comprehensive framework for understanding the whole person. In an effort to achieve that aim, the current article draws on the most promising empirical and theoretical trends in personality psychology today to articulate 5 big principles for an integrative science of the whole person. Personality is conceived as (a) an individual's unique variation on the general evolutionary design for human nature, expressed as a developing pattern of (b) dispositional traits, (c) characteristic adaptations, and (d) self-defining life narratives, complexly and differentially situated (e) in culture and social context. The 5 principles suggest a framework for integrating the Big Five model of personality traits with those self-defining features of psychological individuality constructed in response to situated social tasks and the human need to make meaning in culture.
TL;DR: This work isolated nucleosome-bound sequences at high resolution from yeast and used these sequences in a new computational approach to construct and validate experimentally a nucleosom–DNA interaction model, and to predict the genome-wide organization of nucleosomes.
Abstract: Eukaryotic genomes are packaged into nucleosome particles that occlude the DNA from interacting with most DNA binding proteins. Nucleosomes have higher affinity for particular DNA sequences, reflecting the ability of the sequence to bend sharply, as required by the nucleosome structure. However, it is not known whether these sequence preferences have a significant influence on nucleosome position in vivo, and thus regulate the access of other proteins to DNA. Here we isolated nucleosome-bound sequences at high resolution from yeast and used these sequences in a new computational approach to construct and validate experimentally a nucleosome–DNA interaction model, and to predict the genome-wide organization of nucleosomes. Our results demonstrate that genomes encode an intrinsic nucleosome organization and that this intrinsic organization can explain ∼50% of the in vivo nucleosome positions. This nucleosome positioning code may facilitate specific chromosome functions including transcription factor binding, transcription initiation, and even remodelling of the nucleosomes themselves. Eukaryotic genomes do not exist in vivo as naked DNA, but in complexes known as chromatin. Chromatin contains nucleosomes, short stretches of DNA tightly wrapped around a histone protein core, which exclude most DNA binding proteins and so act as repressors. A combined computational and experimental approach has been used to determine DNA sequence preferences of nucleosomes and to predict genome-wide nucleosome organization. The yeast genome encodes an intrinsic nucleosome organization that explains about half of the in vivo nucleosome positions. Highly conserved across eukaryotes, the code directs transcription factors to their binding sites and facilitates many other specific chromosome functions. An accompanying News and Views piece discusses the role of DNA sequence and other regulators in nucleosome positioning. The cover graphic represents a stretch of chromatin including several nucleosomes. A combined computational and experimental approach is used to determine the DNA sequence preferences of nucleosomes and predict genome-wide nucleosome organization. The yeast genome encodes an intrinsic nucleosome organization, which can explain about 50% of in vivo nucleosome positions.
TL;DR: A focused and systematic review of articles that specifically address SDM reveals that there is no shared definition ofSDM and proposes a definition that integrates the extant literature base and outlines essential elements that must be present for patients and providers to engage in the process of SDM.
TL;DR: It is shown that Orai1 is a plasma membrane protein, and that CRAC channel function is sensitive to mutation of two conserved acidic residues in the transmembrane segments, which reduces Ca2+ influx, increases current carried by monovalent cations, and renders the channel permeable to Cs+.
Abstract: Stimulation of immune cells causes depletion of Ca2+ from endoplasmic reticulum (ER) stores, thereby triggering sustained Ca2+ entry through store-operated Ca2+ release-activated Ca2+ (CRAC) channels, an essential signal for lymphocyte activation and proliferation. Recent evidence indicates that activation of CRAC current is initiated by STIM proteins, which sense ER Ca2+ levels through an EF-hand located in the ER lumen and relocalize upon store depletion into puncta closely associated with the plasma membrane. We and others recently identified Drosophila Orai and human Orai1 (also called TMEM142A) as critical components of store-operated Ca2+ entry downstream of STIM. Combined overexpression of Orai and Stim in Drosophila cells, or Orai1 and STIM1 in mammalian cells, leads to a marked increase in CRAC current. However, these experiments did not establish whether Orai is an essential intracellular link between STIM and the CRAC channel, an accessory protein in the plasma membrane, or an actual pore subunit. Here we show that Orai1 is a plasma membrane protein, and that CRAC channel function is sensitive to mutation of two conserved acidic residues in the transmembrane segments. E106D and E190Q substitutions in transmembrane helices 1 and 3, respectively, diminish Ca2+ influx, increase current carried by monovalent cations, and render the channel permeable to Cs+. These changes in ion selectivity provide strong evidence that Orai1 is a pore subunit of the CRAC channel.
TL;DR: In this paper, the authors examine the different methods used in the literature and explain when the different standard errors yield the same (and correct) standard errors and when they diverge.
Abstract: In both corporate finance and asset pricing empirical work, researchers are often confronted with panel data. In these data sets, the residuals may be correlated across firms or across time, and OLS standard errors can be biased. Historically, the two literatures have used different solutions to this problem. Corporate finance has relied on clustered standard errors, while asset pricing has used the Fama-MacBeth procedure. This paper examines the different methods used in the literature and explains when the different methods yield the same (and correct) standard errors and when they diverge. The intent is to provide intuition as to why the different approaches sometimes give different answers and give researchers guidance for their use.
University of Utah1, Veterans Health Administration2, National Institutes of Health3, University of Nebraska Medical Center4, Case Western Reserve University5, Indiana University6, New York University7, Cedars-Sinai Medical Center8, University of California, San Francisco9, Presbyterian Hospital of Dallas10, University of Alabama11, University of Pennsylvania12, University of Pittsburgh13, Virginia Mason Medical Center14, University of Arizona15, Northwestern University16, University of California, Los Angeles17
TL;DR: The GAIT trial as discussed by the authors evaluated the efficacy and safety of glucosamine and chondroitin sulfate as a treatment for knee pain from osteoarthritis in 1583 patients.
Abstract: Background Glucosamine and chondroitin sulfate are used to treat osteoarthritis. The multicenter, double-blind, placebo- and celecoxib-controlled Glucosamine/chondroitin Arthritis Intervention Trial (GAIT) evaluated their efficacy and safety as a treatment for knee pain from osteoarthritis. Methods We randomly assigned 1583 patients with symptomatic knee osteoarthritis to receive 1500 mg of glucosamine daily, 1200 mg of chondroitin sulfate daily, both glucosamine and chondroitin sulfate, 200 mg of celecoxib daily, or placebo for 24 weeks. Up to 4000 mg of acetaminophen daily was allowed as rescue analgesia. Assignment was stratified according to the severity of knee pain (mild [N=1229] vs. moderate to severe [N=354]). The primary outcome measure was a 20 percent decrease in knee pain from baseline to week 24. Results The mean age of the patients was 59 years, and 64 percent were women. Overall, glucosamine and chondroitin sulfate were not significantly better than placebo in reducing knee pain by 20 perce...
TL;DR: The absence of established risk factors at 50 years of age is associated with very low lifetime risk for CVD and markedly longer survival, which should promote efforts aimed at preventing development of risk factors in young individuals.
Abstract: Background Lifetime risk for atherosclerotic cardiovascular disease (CVD) has not previously been estimated, and the effect of risk factor burden on lifetime risk is unknown. Methods and results We included all Framingham Heart Study participants who were free of CVD (myocardial infarction, coronary insufficiency, angina, stroke, claudication) at 50 years of age. Lifetime risks to 95 years of age were estimated for men and women, with death free of CVD as a competing event. We followed up 3564 men and 4362 women for 111,777 person-years; 1757 had CVD events and 1641 died free of CVD. At 50 years of age, lifetime risks were 51.7% (95% CI, 49.3 to 54.2) for men and 39.2% (95% CI, 37.0 to 41.4) for women, with median survivals of 30 and 36 years, respectively. With more adverse levels of single risk factors, lifetime risks increased and median survivals decreased. Compared with participants with > or =2 major risk factors, those with optimal levels had substantially lower lifetime risks (5.2% versus 68.9% in men, 8.2% versus 50.2% in women) and markedly longer median survivals (>39 versus 28 years in men, >39 versus 31 years in women). Conclusions The absence of established risk factors at 50 years of age is associated with very low lifetime risk for CVD and markedly longer survival. These results should promote efforts aimed at preventing development of risk factors in young individuals. Given the high lifetime risks and lower survival in those with intermediate or high risk factor burden at 50 years of age, these data may be useful in communicating risks and supporting intensive preventive therapy.
TL;DR: Computer-assisted testing, which selects items from a bank of possible items according to a baseline-predicted reading ability and responses to previous questions, should allow more accurate measurement of indiidual capacity without increasing the time required to complete testing.
Abstract: Health literacy is a complicated construct that depends on individual capacity to communicate and the demands posed by society and the health care system. More comprehensive tests are needed to understand the gap between capacities and current demands to help guide efforts to educate children and adults about health issues and to develop health-related information that more of the general public can understand. For research, new instruments are needed that will measure individuals reading fluency more precisely without posing an undue response burden. Computer-assisted testing, which selects items from a bank of possible items according to a baseline-predicted reading ability and responses to previous questions, should allow more accurate measurement of indiidual capacity without increasing the time required to complete testing. It remains unclear whether it is possible to develop an accurate, practical “screening” test to identify individuals with limited health literacy. Even if this goal is achieved, it remains unclear whether it is better to screen patients or to adopt “universal precautions” to avoid miscommunication by using plain language in all oral and written communication and confirming understanding with all patients by having them repeat back their understanding of their diagnosis and treatment plan. George Bernard Shaw said, “The main problem with communication is the assumption that it has occurred.” This is a universal truth that transcends reading ability.
TL;DR: Evidence suggests that transformed cells use ROS signals to drive proliferation and other events required for tumor progression, making them vulnerable to chemotherapeutic agents that further augment ROS generation or that weaken antioxidant defenses of the cell.
TL;DR: This article found that firms with access to the public bond markets, as measured by having a debt rating, have significantly more leverage than firms without a rating, even after controlling for firm characteristics that determine observed capital structure and instrumenting for the possible endogeneity of having a rating.
Abstract: Prior work on leverage implicitly assumes capital availability depends solely on firm characteristics. However, market frictions that make capital structure relevant may also be associated with a firm's source of capital. Examining this intuition, we find firms that have access to the public bond markets, as measured by having a debt rating, have significantly more leverage. Although firms with a rating are fundamentally different, these differences do not explain our findings. Even after controlling for firm characteristics that determine observed capital structure, and instrumenting for the possible endogeneity of having a rating, firms with access have 35% more debt. Copyright 2006, Oxford University Press.
TL;DR: In this paper, the response of U.S., German and British stock, bond and foreign exchange markets to real-time macroeconomic news is characterized using a unique high-frequency futures dataset.
TL;DR: N nanoparticles up to 250 nm in diameter were found have approximately 2 orders of magnitude higher DNA loading than smaller (13-30 nm) nanoparticles, a consequence of their larger surface area.
Abstract: We have investigated the variables that influence DNA coverage on gold nanoparticles. The effects of salt concentration, spacer composition, nanoparticle size, and degree of sonication have been evaluated. Maximum loading was obtained by salt aging the nanoparticles to ∼0.7 M NaCl in the presence of DNA containing a poly(ethylene glycol) spacer. In addition, DNA loading was substantially increased by sonicating the nanoparticles during the surface loading process. Last, nanoparticles up to 250 nm in diameter were found have ∼2 orders of magnitude higher DNA loading than smaller (13−30 nm) nanoparticles, a consequence of their larger surface area. Stable large particles are attractive for a variety of biodiagnostic assays.
TL;DR: In Experiment 3, high-power participants were less accurate than control participants in determining other people's emotion expressions; these results suggest a power-induced impediment to experiencing empathy.
Abstract: Four experiments and a correlational study explored the relationship between power and perspective taking. In Experiment 1, participants primed with high power were more likely than those primed with low power to draw an E on their forehead in a self-oriented direction, demonstrating less of an inclination to spontaneously adopt another person's visual perspective. In Experiments 2a and 2b, high-power participants were less likely than low-power participants to take into account that other people did not possess their privileged knowledge, a result suggesting that power leads individuals to anchor too heavily on their own vantage point, insufficiently adjusting to others' perspectives. In Experiment 3, high-power participants were less accurate than control participants in determining other people's emotion expressions; these results suggest a power-induced impediment to experiencing empathy. An additional study found a negative relationship between individual difference measures of power and perspective taking. Across these studies, power was associated with a reduced tendency to comprehend how other people see, think, and feel.
01 Jan 2006
TL;DR: The package provides crossover techniques between algorithmic options as well as automatic selection of options and settings, and it is effective for the following special cases: unconstrained optimization, nonlinear systems of equations, least squares, and linear and quadratic programming.
Abstract: This paper describes Knitro 5.0, a C-package for nonlinear optimization that combines complementary approaches to nonlinear optimization to achieve robust performance over a wide range of application requirements. The package is designed for solving large-scale, smooth nonlinear programming problems, and it is also effective for the following special cases: unconstrained optimization, nonlinear systems of equations, least squares, and linear and quadratic programming. Various algorithmic options are available, including two interior methods and an active-set method. The package provides crossover techniques between algorithmic options as well as automatic selection of options and settings.
TL;DR: Multichannel customer management is the design, deployment, coordination, and evaluation of channels through which firms and customers interact, with the goal of enhancing customer value through ef... as discussed by the authors.
Abstract: Multichannel customer management is the design, deployment, coordination, and evaluation of channels through which firms and customers interact, with the goal of enhancing customer value through ef...
Memorial Hospital of South Bend1, Howard University2, Northwestern University3, George Washington University4, Harvard University5, Stanford University6, Yeshiva University7, University of Pittsburgh8, Fred Hutchinson Cancer Research Center9, University of California, San Diego10, Rutgers University11, University of Alabama at Birmingham12, University of Florida13, University of Minnesota14, Ohio State University15, University of Massachusetts Medical School16, University of Miami17, Emory University18, University of California, Davis19, National Institutes of Health20, University of Wisconsin-Madison21, University of Iowa22, Kaiser Permanente23, University at Buffalo24, Wake Forest University25, Pfizer26, Brown University27, University of Arizona28, Rush University Medical Center29, University of Nevada, Reno30, University of Texas at San Antonio31, University of California, Los Angeles32, University of Cincinnati33, Stony Brook University34, Baylor College of Medicine35, University of North Carolina at Chapel Hill36, Wayne State University37, University of California, Irvine38, University of Tennessee Health Science Center39, Medical College of Wisconsin40
TL;DR: A dietary intervention that reduced total fat intake and increased intakes of vegetables, fruits, and grains did not significantly reduce the risk of CHD, stroke, or CVD in postmenopausal women and achieved only modest effects on CVD risk factors, suggesting that more focused diet and lifestyle interventions may be needed to improve risk factors and reduce CVDrisk.
Abstract: ContextMultiple epidemiologic studies and some trials have linked diet with cardiovascular disease (CVD) prevention, but long-term intervention data are needed.ObjectiveTo test the hypothesis that a dietary intervention, intended to be low in fat and high in vegetables, fruits, and grains to reduce cancer, would reduce CVD risk.Design, Setting, and ParticipantsRandomized controlled trial of 48 835 postmenopausal women aged 50 to 79 years, of diverse backgrounds and ethnicities, who participated in the Women's Health Initiative Dietary Modification Trial. Women were randomly assigned to an intervention (19 541 [40%]) or comparison group (29 294 [60%]) in a free-living setting. Study enrollment occurred between 1993 and 1998 in 40 US clinical centers; mean follow-up in this analysis was 8.1 years.InterventionIntensive behavior modification in group and individual sessions designed to reduce total fat intake to 20% of calories and increase intakes of vegetables/fruits to 5 servings/d and grains to at least 6 servings/d. The comparison group received diet-related education materials.Main Outcome MeasuresFatal and nonfatal coronary heart disease (CHD), fatal and nonfatal stroke, and CVD (composite of CHD and stroke).ResultsBy year 6, mean fat intake decreased by 8.2% of energy intake in the intervention vs the comparison group, with small decreases in saturated (2.9%), monounsaturated (3.3%), and polyunsaturated (1.5%) fat; increases occurred in intakes of vegetables/fruits (1.1 servings/d) and grains (0.5 serving/d). Low-density lipoprotein cholesterol levels, diastolic blood pressure, and factor VIIc levels were significantly reduced by 3.55 mg/dL, 0.31 mm Hg, and 4.29%, respectively; levels of high-density lipoprotein cholesterol, triglycerides, glucose, and insulin did not significantly differ in the intervention vs comparison groups. The numbers who developed CHD, stroke, and CVD (annualized incidence rates) were 1000 (0.63%), 434 (0.28%), and 1357 (0.86%) in the intervention and 1549 (0.65%), 642 (0.27%), and 2088 (0.88%) in the comparison group. The diet had no significant effects on incidence of CHD (hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.90-1.06), stroke (HR, 1.02; 95% CI, 0.90-1.15), or CVD (HR, 0.98; 95% CI, 0.92-1.05). Excluding participants with baseline CVD (3.4%), the HRs (95% CIs) for CHD and stroke were 0.94 (0.86-1.02) and 1.02 (0.90-1.17), respectively. Trends toward greater reductions in CHD risk were observed in those with lower intakes of saturated fat or trans fat or higher intakes of vegetables/fruits.ConclusionsOver a mean of 8.1 years, a dietary intervention that reduced total fat intake and increased intakes of vegetables, fruits, and grains did not significantly reduce the risk of CHD, stroke, or CVD in postmenopausal women and achieved only modest effects on CVD risk factors, suggesting that more focused diet and lifestyle interventions may be needed to improve risk factors and reduce CVD risk.Clinical Trials RegistrationClinicalTrials.gov Identifier: NCT00000611
TL;DR: An interior-point method for nonlinear programming that enjoys the flexibility of switching between a line search method that computes steps by factoring the primal-dual equations and a trust region method that uses a conjugate gradient iteration.
Abstract: An interior-point method for nonlinear programming is presented It enjoys the flexibility of switching between a line search method that computes steps by factoring the primal-dual equations and a trust region method that uses a conjugate gradient iteration Steps computed by direct factorization are always tried first, but if they are deemed ineffective, a trust region iteration that guarantees progress toward stationarity is invoked To demonstrate its effectiveness, the algorithm is implemented in the Knitro [6,28] software package and is extensively tested on a wide selection of test problems
TL;DR: Keltner et al. as discussed by the authors found that individuals with a higher generalized sense of power and those primed with a high-power mind-set were more optimistic in their perceptions of risk.
Abstract: Five studies investigated the hypotheses that the sense of power increases optimism in perceiving risks and leads to more risky behavior. In Studies 1 and 2, individuals with a higher generalized sense of power and those primed with a high-power mind-set were more optimistic in their perceptions of risk. Study 3 primed the concept of power nonconsciously and found that both power and gain/loss frame had independent effects on risk preferences. In Study 4, those primed with a high-power mind-set were more likely to act in a risk-seeking fashion (i.e., engage in unprotected sex). In Study 5, individuals with a higher sense of power in a face-to-face negotiation took more risks by divulging their interests. The effects of power on risk-taking were mediated by optimistic risk perceptions and not by selfefficacy beliefs. Further, these effects were attenuated when the high-power individual felt a sense of responsibility. Copyright # 2006 John Wiley & Sons, Ltd. Power fascinates. People spend an inordinate amount of time attending to, thinking about, and discussing the thoughts and behaviors of powerful and prestigious individuals—be they heads of state, CEOs, or prominent members of their local church, club, or community (Chance, 1967; Fiske, 1993; Hall, 1984; Keltner & Robinson, 1997). Though typically viewed as frivolous and the province of gossip and gawking, this interest in powerholders is often important and useful. On a practical level, understanding the minds of those with power helps people appreciate how their leaders make decisions—decisions that impact people’s own lives. The behaviors of the powerful have inordinate pull, in that their actions have greater impact and matter more compared to those without power. On a theoretical level, understanding powerholders’ behavior can also provide a window into human nature more broadly; for only when people possess power do some of their deepest desires and motivations reveal themselves in the light of day. Research on the possession of power has shown that power affects diverse psychological processes, from stereotyping (Fiske, 1993) to styles of dress (Pfeffer, 1992). To help integrate these disparate findings, a recent theory proposed that power influences the relative activation of two broad and fundamental behavioral systems: the behavioral approach and inhibition systems (Keltner, Gruenfeld, & Anderson, 2003). As we discuss below, these two behavioral systems help individuals pursue