3,012 research outputs found

    Biomolecule-directed assembly of nanoscale building blocks studied via lattice Monte Carlo simulation

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    We perform lattice Monte Carlo simulations to study the self-assembly of functionalized inorganic nanoscale building blocks using recognitive biomolecule linkers. We develop a minimal coarse-grained lattice model for the nanoscale building block (NBB) and the recognitive linkers. Using this model, we explore the influence of the size ratio of linker length to NBB diameter on the assembly process and the structural properties of the resulting aggregates, including the spatial distribution of NBBs and aggregate topology. We find the constant-kernel Smoluchowski theory of diffusion-limited cluster–cluster aggregation describes the aggregation kinetics for certain size ratios. © 2004 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70812/2/JCPSA6-121-8-3919-1.pd

    High-sensitivity troponin T and C-reactive protein have different prognostic values in hemo- and peritoneal dialysis populations : a cohort study

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    Background--Dialysis patients have an exceedingly high mortality rate. Biomarkers may be useful tools in risk stratification of this population. We evaluated the prognostic value of high-sensitivity cardiac troponin T (hs-cTnT) and CRP (C-reactive protein) in predicting adverse outcomes in stable hemodialysis and peritoneal dialysis (PD) patients. Variability in hs-cTnT was also examined. Methods and Results--A retrospective cohort study included 574 dialysis patients (hemodialysis 347, PD 227). Outcomes examined included mortality and major adverse cardiovascular events, with median follow-up of 3.5 years. hs-cTnT was an independent predictor of both outcomes in hemodialysis and PD patients. Increased risk only became significant when hs-cTnT reached quintile 3 ( > 49 ng/L). Area under the receiver operating curve analysis showed that the addition of hs-cTnT to clinical parameters significantly improved its prognostic performance for mortality in PD patients (P=0.002). CRP was an independent predictor of both outcomes in PD patients only. Only CRP in the highest quintile ( > 16.8 mg/L) was associated with increased risk. hs-cTnT remained relatively stable for the whole follow-up period for hemodialysis patients, whereas for PD patients, hs-cTnT increased by 23.63% in year 2 and 29.13% in year 3 compared with baseline (P < 0.001). Conclusions--hs-cTnT and CRP are useful tools in predicting mortality and major adverse cardiovascular events in hemodialysis and PD patients. Given that hs-cTnT levels increase over time in PD patients, interval monitoring may be valuable for risk assessment. In contrast, hs-cTnT in hemodialysis patients has little interval change and progress monitoring is not indicated

    Primary care providers\u27 perspectives on online weight-loss programs: a big wish list

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    BACKGROUND: Integrating online weight-loss programs into the primary care setting could yield substantial public health benefit. Little is known about primary care providers\u27 perspectives on online weight-loss programs. OBJECTIVE: To assess primary care providers\u27 perspectives on online weight-loss programs. METHODS: We conducted focus group discussions with providers in family medicine, internal medicine, and combined internal medicine/pediatrics in Texas and Pennsylvania, USA. Open-ended questions addressed their experience with and attitudes toward online weight-loss programs; useful characteristics of existing online weight-loss programs; barriers to referring patients to online weight-loss programs; and preferred characteristics of an ideal online weight-loss program. Transcripts were analyzed with the grounded theory approach to identify major themes. RESULTS: A total of 44 primary care providers participated in 9 focus groups. The mean age was 45 (SD 9) years. Providers had limited experience with structured online weight-loss programs and were uncertain about their safety and efficacy. They thought motivated, younger patients would be more likely than others to respond to an online weight-loss program. According to primary care providers, an ideal online weight-loss program would provide-at no cost to the patient-a structured curriculum addressing motivation, psychological issues, and problem solving; tools for tracking diet, exercise, and weight loss; and peer support monitored by experts. Primary care providers were interested in receiving reports about patients from the online weight-loss programs, but were concerned about the time required to review and act on the reports. CONCLUSIONS: Primary care providers have high expectations for how online weight-loss programs should deliver services to patients and fit into the clinical workflow. Efforts to integrate online weight-loss programs into the primary care setting should address efficacy and safety of online weight-loss programs in clinic-based populations; acceptable methods of sending reports to primary care providers about their patients\u27 progress; and elimination or reduction of costs to patients

    Microscopic Realization of the Kerr/CFT Correspondence

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    Supersymmetric M/string compactifications to five dimensions contain BPS black string solutions with magnetic graviphoton charge P and near-horizon geometries which are quotients of AdS_3 x S^2. The holographic duals are typically known 2D CFTs with central charges c_L=c_R=6P^3 for large P. These same 5D compactifications also contain non-BPS but extreme Kerr-Newman black hole solutions with SU(2)_L spin J_L and electric graviphoton charge Q obeying Q^3 \leq J_L^2. It is shown that in the maximally charged limit Q^3 -> J_L^2, the near-horizon geometry coincides precisely with the right-moving temperature T_R=0 limit of the black string with magnetic charge P=J_L^{1/3}. The known dual of the latter is identified as the c_L=c_R=6J_L CFT predicted by the Kerr/CFT correspondence. Moreover, at linear order away from maximality, one finds a T_R \neq 0 quotient of the AdS_3 factor of the black string solution and the associated thermal CFT entropy reproduces the linearly sub-maximal Kerr-Newman entropy. Beyond linear order, for general Q^3<J_L^2, one has a finite-temperature quotient of a warped deformation of the magnetic string geometry. The corresponding dual deformation of the magnetic string CFT potentially supplies, for the general case, the c_L=c_R=6J_L CFT predicted by Kerr/CFT.Comment: 18 pages, no figure
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