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A fundamental problem that confronts peer-to-peer applications is to efficiently locate the node that stores a particular data item. This paper presents Chord, a distributed lookup protocol that addresses this problem. Chord provides support for just one operation: given a key, it maps the key onto a node. Data location can be easily implemented on top of Chord by associating a key with each data item, and storing the key/data item pair at the node to which the key maps. Chord adapts efficiently as nodes join and leave the system, and can answer queries even if the system is continuously changing. Results from theoretical analysis, simulations, and experiments show that Chord is scalable, with communication cost and the state maintained by each node scaling logarithmically with the number of Chord nodes.

We analyze the dynamics of part motion for a novel type of planar parts feeder consisting of a longitudinally vibrating flat plate and a part placed on its surface. For each vibration cycle, the plate's velocity is held positive (forward motion) for a longer time than it is held negative (backward motion). This type of asymmetric vibration combined with the nonlinear nature of Coulomb friction causes the part to accelerate along a straight line to a terminal velocity called the "feed rate". The average force exerted by the plate on the part is shown to be proportional to the latter's deviation from the feed rate. In other words, the part behaves as if it were immersed in a forward moving viscous fluid. Expressions for the feed rate and viscosity constants are derived with respect to various physical and control parameters. Rigid-body dynamic simulation results are shown to be in good agreement with the analysis.

Abstract A new expression system containing the Salmonella enterica prpBCDE promoter (P prpB ) responsible for expression of the propionate catabolic genes ( prp BCDE ) and prpR encoding the positive regulator of this promoter has been developed and tested. The main features of the expression system compared to those based on the bacteriophage T7 promoter are low background expression and high induced expression in Escherichia coli strains BL21, BL21(DE3), MG1655, and W3110. In addition, propionate is an inexpensive, simple‐to‐use, nontoxic inducer that is attractive for large‐scale protein production. Hence, this new system is highly complementary to the widely used T7 promoter‐driven expression systems. © 2005 Wiley Periodicals, Inc.

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Policy Points: For accountable care organizations (ACOs) to be successful they need to change the behavior of their physicians. To stimulate this change, a broad range of motivators are being used, including ways to see a greater impact on patients (social purpose) and opportunities to be a more effective physician (mastery), in addition to personal financial incentives. From our analysis of case studies, it does not appear that the full range of motivators is being deployed by ACOs, which suggests an opportunity to develop more sophisticated and wider‐ranging portfolios of motivators for greater impact. Context There are approximately 800 accountable care organizations (ACOs) in the United States. In order to achieve the ACO goals of reduced cost, improved outcomes of care, and better population health, it is critical to change how physicians within ACOs deliver care. While knowledge of ACO development and evolution is growing, relatively little is known about the motivational drivers that are being used to effect change among participating physicians. Methods We synthesized 9 well‐established and empirically tested theories of motivation into an overarching framework of 6 motivator domains. This framework was then used to explore the types of motivators that leaders use to stimulate change within 4 case study ACOs. We explored the organizational characteristics, strategies, and motivators for changing physicians’ behaviors through in‐depth interviews and document review. Findings The case study ACOs more strongly emphasized nonfinancial motivators for changing physician behavior than financial incentives. These motivators included mastery and social purpose, which were used frequently across all case study sites. Overall, the ACO case studies illustrated variability across all motivational domains. While there was evidence of changing motivators as a result of the ACO, the case study ACOs found it difficult to comprehensively change the use of motivators, in part due to dispersed managerial attention and the complexity and diversity of programs and contracts that fragmented efforts to improve. Conclusions Motivating behavior change within ACOs goes beyond financial incentives. ACOs are using a broad range of motivators, including creating ways to make a greater impact on patients and opportunities to be a more effective physician. Overall, it does not appear that ACOs are deploying the full range of available motivators. This suggests an opportunity to develop more sophisticated and wider‐ranging portfolios of motivators to drive behavior change.

Accountable care organizations (ACOs) have incentives to meet quality and cost targets to share in any resulting savings. Achieving these goals will require ACOs to engage more actively with patients and their families. The extent to which ACOs do so is currently unknown. Using mixed methods, including a national survey, phone interviews, and site-visits, we examine the extent to which ACOs actively engage patients and their families, explore challenges involved, and consider approaches for dealing with those challenges. Results indicate that greater ACO use of patient activation and engagement (PAE) activities at the point-of-care may be related to positive perceptions among ACO leaders of the impact of PAE investments on ACO costs, quality, and outcomes of care. We identify a number of important practices associated with greater PAE, including high-level leadership commitment, goal-setting supported by adequate resources, extensive provider training, use of interdisciplinary care teams, and frequent monitoring and reporting on progress.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of monomeric ruthenium hydroxo complexes (PMe3)4Ru(R)(OH) (R = H, Me) and a unique dimeric ruthenium hydroxo-water complex [trans-Ru(H)(OH)(DMPE)2.cntdot.H2O]2Melinda J. Burn, Michael G. Fickes, John F. Hartwig, Frederick J. Hollander, and Robert G. BergmanCite this: J. Am. Chem. Soc. 1993, 115, 13, 5875–5876Publication Date (Print):June 1, 1993Publication History Published online1 May 2002Published inissue 1 June 1993https://pubs.acs.org/doi/10.1021/ja00066a086https://doi.org/10.1021/ja00066a086research-articleACS PublicationsRequest reuse permissionsArticle Views606Altmetric-Citations84LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (2)»Supporting Information Supporting Information Get e-Alerts

Skin is a metabolically active tissue and contains sebaceous glands which synthesize sebum. Sebum is a complex lipid mixture that is excreted on the skin surface and consists of of triacylglycerols, diacylglycerols, free fatty acids (which together account for 50–60% of its composition), wax esters (20–30%), squalene (10–16%), and cholesterol esters (2–4%). Acne is a skin disorder with multifactorial pathogenesis and sebum production is considered one of the main contributors. However, the metabolic pathways regulating human sebum lipid composition and production are not well understood. The goal of this study was to determine the contribution of de novo fatty acid synthesis (DNL) to sebum production in healthy humans utilizing heavy water labelling and mass isotopomer distribution analysis (MIDA). Female and male volunteers were recruited by advertisement (18–35 years). Subjects received loading doses of 2 H 2 O totaling 480 mL of 70% 2 H 2 O, divided into 8 doses of 60 mL each and subjects continued to take a daily oral 2 H 2 O dose (60 ml of 70% 2 H 2 O) until Day 21. Subjects returned for outpatient visits on days 0, 2, 4, 7, 11, 14 and 21. At all outpatient visits, plasma samples were collected to determine body water 2 H 2 O. Sebum samples were also collected using Sebu‐Test Strip (CuDerm Corp., Dallas TX) from both cheeks and forehead for the measurement of DNL. Saliva sample were collected at home on Day 1 and 3 for body water 2 H 2 O enrichment. Total lipids were extracted with hexane from sebum samples. Total fatty acids were then trans‐esterified to fatty acid methyl esters, in preparation for gas chromatographic/mass spectrometric (GC/MS) analysis. The proportion of tissue palmitate derived from DNL (i.e., made “new” from acetyl‐CoA precursors) was calculated by MIDA, as described previously. The body water enrichments were stable and on average 0.98 ± 0.37% (n=10, Days 2 through 21). Fractional DNL contribution to sebum palmitate rose to an average (SD) of 83.6 % (24%) in forehead sebum, 83.5 % (18%) in left cheek sebum and 82.7 % (18%) in right cheek sebum after 21 days of 2 H 2 O labeling (n=10 subjects). DNL contribution to total palmitate was similar in sebum collected from the three different collection sites. Sapeinic acid, a non‐essential fatty acid exclusive to sebum, showed a similar contribution from DNL, ruling out contribution to palmitate from non‐sebocyte sources as the explanation for high DNL contribution.. The fractional replacement rate of newly synthesized palmitate in sebum lipids was on average 26 % per day, which translates into a half life of 3 days and an average plateau of 87 % (n=10 subjects, n=3 collection sites). No significant differences between collection sites were observed for any kinetic parameter. Contribution of DNL to sebum palmitate was significantly greater compared to the contribution of DNL to VLDL‐TG palmitate (~23%), indicating that sebum palmitate is mostly synthesized within the sebaceous gland rather than imported from blood lipoproteins. Conclusions the main source of sebum palmitate is DNL in healthy subjects; sebum palmitate is locally synthesized in the sebaceous gland; the replacement rate of sebum palmitate is 27% per day. These findings suggest than local modulation of DNL in sebocytes is important in oil production in skin and inhibition of local DNL may represent a therapeutic target in acne. Support or Funding Information KineMed, Inc. Pfizer Inc.

: Fracture by the progressive growth of incipient flaws under cyclically varying loads, i.e., by fatigue, must now be considered as the principal cause of in-service failures of engineering structures and components, whether associated with mechanical sliding and friction (fretting fatigue), rolling contact, aggressive environments (corrosion fatigue), or elevated temperatures (creep-fatigue). Of particular importance are the early stages of fatigue damage, involving the initial extension of microcracks and their subsequent growth at very low velocities, as these processes tend to dominate overall lifetime. This has been reflected by trends in fatigue research over the past five years, which have focused largely on so-called 'small cracks,' of dimensions comparable with the scale of microstructure or local plasticity, and on crack growth in the near-threshold regime, i.e., at stress intensities approaching the fatigue threshold below which cracks are presumed dormant. In addition, associated mechanistic studies have highlighted the critical role of crack tip shielding in fatigue, which arises predominantly from crack closure and deflection, and this has proved to be important in modeling aspects of environmentally-assisted cracking and behavior under variable amplitude loads, and in rationalizing the classical stress/strain-life and defect-tolerant design approaches. The series of international conferences 'Fatigue '87 covered a wide range of diverse views of the fundamental and applied aspects of fatigue. This included questions of cyclic deformation, crack initiation and propagation, small cracks, crack closure, variable amplitude effects, and environmentally-influenced behavior.