1,142 research outputs found

    Dialkylcarbamoyl chloride (DACC)-coated dressings in the management and prevention of wound infection: A systematic review

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    Objective: Dialkylcarbomoyl chloride (DACC)-coated dressings (Leukomed Sorbact and Cutimed Sorbact) irreversibly bind bacteria at the wound surface that are then removed when the dressing is changed. They are a recent addition to the wound care professional's armamentarium and have been used in a variety of acute and chronic wounds. This systematic review aims to assess the evidence supporting the use of DACC-coated dressings in the clinical environment. Method: We included all reports of the clinical use of DACC-coated dressings in relation to wound infection. Medline, Embase, CENTRAL and CINAHL databases were searched to September 2016 for studies evaluating the role of DACC-coated dressings in preventing or managing wound infections. Results: We identified 17 studies with a total of 3408 patients which were included in this review. The DACC-coating was suggested to reduce postoperative surgical site infection rates and result in chronic wounds that subjectively looked cleaner and had less bacterial load on microbiological assessments. Conclusion: Existing evidence for DACC-coated dressings in managing chronic wounds or as a surgical site infection (SSI) prophylaxis is limited but encouraging with evidence in support of DACC-coated dressings preventing and treating infection without adverse effects

    EMC and Polarized EMC Effects in Nuclei

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    We determine nuclear structure functions and quark distributions for 7^7Li, 11^{11}B, 15^{15}N and 27^{27}Al. For the nucleon bound state we solve the covariant quark-diquark equations in a confining Nambu--Jona-Lasinio model, which yields excellent results for the free nucleon structure functions. The nucleus is described using a relativistic shell model, including mean scalar and vector fields that couple to the quarks in the nucleon. The nuclear structure functions are then obtained as a convolution of the structure function of the bound nucleon with the light-cone nucleon distributions. We find that we are readily able to reproduce the EMC effect in finite nuclei and confirm earlier nuclear matter studies that found a large polarized EMC effect.Comment: 8 pages, 9 figure

    Asymptotic Giant Branch Variables in the Galaxy and the Local Group

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    AGB variables, particularly the large amplitude Mira type, are a vital step on the distance scale ladder. They will prove particularly important in the era of space telescopes and extremely large ground-based telescopes with adaptive optics, which will be optimized for infrared observing. Our current understanding of the distances to these stars is reviewed with particular emphasis on improvements that came from Hipparcos as well as on recent work on Local Group galaxies. In addition to providing the essential calibration for extragalactic distances Gaia may also provide unprecedented insight into the poorly understood mass-loss process itself.Comment: Accepted for publication in Astrophysics and Space Science. From a presentation at the conference "The Fundamental Cosmic Distance Scale: State of the Art and Gaia Perspective, Naples May 2011. 8 Pages, 9 Figure

    Potential energy threshold for nano-hillock formation by impact of slow highly charged ions on a CaF2_2(111) surface

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    We investigate the formation of nano-sized hillocks on the (111) surface of CaF2_2 single crystals by impact of slow highly charged ions. Atomic force microscopy reveals a surprisingly sharp and well-defined threshold of potential energy carried into the collision of about 14 keV for hillock formation. Estimates of the energy density deposited suggest that the threshold is linked to a solid-liquid phase transition (``melting'') on the nanoscale. With increasing potential energy, both the basal diameter and the height of the hillocks increase. The present results reveal a remarkable similarity between the present predominantly potential-energy driven process and track formation by the thermal spike of swift (\sim GeV) heavy ions.Comment: 10 pages, 2 figure

    Masses of ground and excited-state hadrons

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    We present the first Dyson-Schwinger equation calculation of the light hadron spectrum that simultaneously correlates the masses of meson and baryon ground- and excited-states within a single framework. At the core of our analysis is a symmetry-preserving treatment of a vector-vector contact interaction. In comparison with relevant quantities the root-mean-square-relative-error/degree-of freedom is 13%. Notable amongst our results is agreement between the computed baryon masses and the bare masses employed in modern dynamical coupled-channels models of pion-nucleon reactions. Our analysis provides insight into numerous aspects of baryon structure; e.g., relationships between the nucleon and Delta masses and those of the dressed-quark and diquark correlations they contain.Comment: 25 pages, 7 figures, 4 table

    Race and sex differences in dropout from the STRRIDE trials

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    Purpose: To determine if race and sex differences exist in determinants and timing of dropout among individuals enrolled in an exercise and/or caloric restriction intervention. Methods: A total of 947 adults with dyslipidemia (STRRIDE I, STRRIDE AT/RT) or prediabetes (STRRIDE-PD) were randomized to either inactive control or to 1 of 10 exercise interventions, ranging from doses of 8–23 kcal/kg/week, intensities of 50%–75% (Formula presented.) peak, and durations of 6–8 months. Two groups included resistance training, and one included a dietary intervention (7% weight loss goal). Dropout was defined as an individual withdrawn from the study, with the reasons for dropout aggregated into determinant categories. Timing of dropout was defined as the last session attended and aggregated into phases (i.e., “ramp” period to allow gradual adaptation to exercise prescription). Utilizing descriptive statistics, percentages were generated according to categories of determinants and timing of dropout to describe the proportion of individuals who fell within each category. Results: Black men and women were more likely to be lost to follow-up (Black men: 31.3% and Black women: 19.6%), or dropout due to work responsibilities (15.6% and 12.5%), “change of mind” (12.5% and 8.9%), transportation issues (6.3% and 3.6%), or reported lack of motivation (6.3% and 3.6%). Women in general noted lack of time more often than men as a reason for dropout (White women: 22.4% and Black women: 22.1%). Regardless of race and sex, most participants dropped out during the ramp period of the exercise intervention; with Black women (50%) and White men (37.1%) having the highest dropout rate during this period. Conclusion: These findings emphasize the importance of targeted retention strategies when aiming to address race and sex differences that exist in determinants and timing of dropout among individuals enrolled in an exercise and/or caloric restriction intervention

    Evidence of Final-State Suppression of High-p_T Hadrons in Au + Au Collisions Using d + Au Measurements at RHIC

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    Transverse momentum spectra of charged hadrons with pT<{p_{T} <} 6 GeV/c have been measured near mid-rapidity (0.2 <η<< \eta < 1.4) by the PHOBOS experiment at RHIC in Au + Au and d + Au collisions at sNN=200GeV{\sqrt{s_{_{NN}}} = \rm {200 GeV}}. The spectra for different collision centralities are compared to p+pˉ{p + \bar{p}} collisions at the same energy. The resulting nuclear modification factor for central Au + Au collisions shows evidence of strong suppression of charged hadrons in the high-pTp_{T} region (>2{>2} GeV/c). In contrast, the d + Au nuclear modification factor exhibits no suppression of the high-pTp_{T} yields. These measurements suggest a large energy loss of the high-pTp_{T} particles in the highly interacting medium created in the central Au + Au collisions. The lack of suppression in d + Au collisions suggests that it is unlikely that initial state effects can explain the suppression in the central Au + Au collisions.Comment: 3 pages, 4 figures, International Europhysics Conference on High Energy Physics EPS (July 17th-23rd 2003) in Aachen, German

    The effect of twisted magnetic field on the resonant absorption of MHD waves in coronal loops

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    The standing quasi modes in a cylindrical incompressible flux tube with magnetic twist that undergoes a radial density structuring is considered in ideal magnetohydrodynamics (MHD). The radial structuring is assumed to be a linearly varying density profile. Using the relevant connection formulae, the dispersion relation for the MHD waves is derived and solved numerically to obtain both the frequencies and damping rates of the fundamental and first-overtone modes of both the kink (m=1) and fluting (m=2,3) waves. It was found that a magnetic twist will increase the frequencies, damping rates and the ratio of the oscillation frequency to the damping rate of these modes. The period ratio P_1/P_2 of the fundamental and its first-overtone surface waves for kink (m=1) and fluting (m=2,3) modes is lower than 2 (the value for an untwisted loop) in the presence of twisted magnetic field. For the kink modes, particularly, the magnetic twists B_{\phi}/B_z=0.0065 and 0.0255 can achieve deviations from 2 of the same order of magnitude as in the observations. Furthermore, for the fundamental kink body waves, the frequency bandwidth increases with increasing the magnetic twist.Comment: 18 pages, 9 figure

    Excitation of standing kink oscillations in coronal loops

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    In this work we review the efforts that have been done to study the excitation of the standing fast kink body mode in coronal loops. We mainly focus on the time-dependent problem, which is appropriate to describe flare or CME induced kink oscillations. The analytical and numerical studies in slab and cylindrical loop geometries are reviewed. We discuss the results from very simple one-dimensional models to more realistic (but still simple) loop configurations. We emphasise how the results of the initial value problem complement the eigenmode calculations. The possible damping mechanisms of the kink oscillations are also discussed

    Cowries in the archaeology of West Africa: the present picture

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    Despite the perceived importance of cowrie shells as indicators of long-distance connections in the West African past, their distribution and consumption patterns in archaeological contexts remain surprisingly underexplored, a gap that is only partly explicable by the sparse distribution of archaeological sites within the sub-continent. General writings on the timeline of importation of cowries into West Africa often fail to take into account the latest archaeological evidence and rely instead on accounts drawn from historical or ethnographic documents. This paper is based on a first-hand assessment of over 4500 shells from 78 sites across West Africa, examining chronology, shell species and processes of modification to assess what distribution patterns can tell us about the history of importation and usage of cowries. These first-hand analyses are paralleled by a consideration of published materials. We re-examine the default assumption that two distinct routes of entry existed — one overland from North Africa before the fifteenth century, another coming into use from the time sea links were established with the East African coast and becoming predominant by the middle of the nineteenth century. We focus on the eastern part of West Africa, where the importance of imported cowries to local communities in relatively recent periods is well known and from where we have a good archaeological sample. The conclusion is that on suitably large assemblages shell size can be an indication of provenance and that, while the present archaeological picture seems largely to confirm historical sources, much of this may be due to the discrepancy in archaeological data available from the Sahara/Sahel zone compared to the more forested regions of the sub-continent. Future archaeological work will clarify this matter
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