991 resultados para solid lipid nanoparticle


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Audit report on the Rathbun Area Solid Waste Commission for the year ended June 30, 2011

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Cytomegalovirus (CMV) remains one of the most common infections after solid organ transplantation, resulting in significant morbidity, graft loss, and occasional mortality. Management of CMV varies considerably among transplant centers. A panel of experts on CMV and solid organ transplant was convened by The Infectious Diseases Section of The Transplantation Society to develop evidence and expert opinion-based consensus guidelines on CMV management including diagnostics, immunology, prevention, treatment, drug resistance, and pediatric issues.

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It has been recently shown (Seddiki, N., B. Santner-Nanan, J. Martinson, J. Zaunders, S. Sasson, A. Landay, M. Solomon, W. Selby, S.I. Alexander, R. Nanan, et al. 2006. J. Exp. Med. 203:1693-1700.) that the expression of interleukin (IL) 7 receptor (R) alpha discriminates between two distinct CD4 T cell populations, both characterized by the expression of CD25, i.e. CD4 regulatory T (T reg) cells and activated CD4 T cells. T reg cells express low levels of IL-7Ralpha, whereas activated CD4 T cells are characterized by the expression of IL-7Ralpha(high). We have investigated the distribution of these two CD4 T cell populations in 36 subjects after liver and kidney transplantation and in 45 healthy subjects. According to a previous study (Demirkiran, A., A. Kok, J. Kwekkeboom, H.J. Metselaar, H.W. Tilanus, and L.J. van der Laan. 2005. Transplant. Proc. 37:1194-1196.), we observed that the T reg CD25(+)CD45RO(+)IL-7Ralpha(low) cell population was reduced in transplant recipients (P < 0.00001). Interestingly, the CD4(+)CD25(+)CD45RO(+)IL-7Ralpha(high) cell population was significantly increased in stable transplant recipients compared with healthy subjects (P < 0.00001), and the expansion of this cell population was even greater in patients with documented humoral chronic rejection compared with stable transplant recipients (P < 0.0001). The expanded CD4(+)CD25(+)CD45RO(+)IL-7Ralpha(high) cell population contained allospecific CD4 T cells and secreted effector cytokines such as tumor necrosis factor alpha and interferon gamma, thus potentially contributing to the mechanisms of chronic rejection. More importantly, CD4(+)IL-7Ralpha(+)and CD25(+)IL-7Ralpha(+) cells were part of the T cell population infiltrating the allograft of patients with a documented diagnosis of chronic humoral rejection. These results indicate that the CD4(+)CD25(+)IL-7Ralpha(+) cell population may represent a valuable, sensitive, and specific marker to monitor allospecific CD4 T cell responses both in blood and in tissues after organ transplantation.

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We present a numerical study of classical particles diffusing on a solid surface. The particles motion is modeled by an underdamped Langevin equation with ordinary thermal noise. The particle-surface interaction is described by a periodic or a random two-dimensional potential. The model leads to a rich variety of different transport regimes, some of which correspond to anomalous diffusion such as has recently been observed in experiments and Monte Carlo simulations. We show that this anomalous behavior is controlled by the friction coefficient and stress that it emerges naturally in a system described by ordinary canonical Maxwell-Boltzmann statistics.

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A mechanism of extraction of tubular membranes from a lipid vesicle is presented. A concentration gradient of anchoring amphiphilic polymers generates tubes from budlike vesicle protrusions. We explain this mechanism in the framework of the Canham-Helfrich model. The energy profile is analytically calculated and a tube with a fixed length, corresponding to an energy minimum, is obtained in a certain regime of parameters. Further, using a phase-field model, we corroborate these results numerically. We obtain the growth of tubes when a polymer source is added, and the budlike shape after removal of the polymer source, in accordance with recent experimental results.

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We present a numerical and partially analytical study of classical particles obeying a Langevin equation that describes diffusion on a surface modeled by a two-dimensional potential. The potential may be either periodic or random. Depending on the potential and the damping, we observe superdiffusion, large-step diffusion, diffusion, and subdiffusion. Superdiffusive behavior is associated with low damping and is in most cases transient, albeit often long. Subdiffusive behavior is associated with highly damped particles in random potentials. In some cases subdiffusive behavior persists over our entire simulation and may be characterized as metastable. In any case, we stress that this rich variety of behaviors emerges naturally from an ordinary Langevin equation for a system described by ordinary canonical Maxwell-Boltzmann statistics.

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Audit report on the Wayne-Ringgold-Decatur County Solid Waste Management Commission for the year ended June 30, 2011

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BACKGROUND: High sugar and fat intakes are known to increase intrahepatocellular lipids (IHCLs) and to cause insulin resistance. High protein intake may facilitate weight loss and improve glucose homeostasis in insulin-resistant patients, but its effects on IHCLs remain unknown. OBJECTIVE: The aim was to assess the effect of high protein intake on high-fat diet-induced IHCL accumulation and insulin sensitivity in healthy young men. DESIGN: Ten volunteers were studied in a crossover design after 4 d of either a hypercaloric high-fat (HF) diet; a hypercaloric high-fat, high-protein (HFHP) diet; or a control, isocaloric (control) diet. IHCLs were measured by (1)H-magnetic resonance spectroscopy, fasting metabolism was measured by indirect calorimetry, insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp, and plasma concentrations were measured by enzyme-linked immunosorbent assay and gas chromatography-mass spectrometry; expression of key lipogenic genes was assessed in subcutaneous adipose tissue biopsy specimens. RESULTS: The HF diet increased IHCLs by 90 +/- 26% and plasma tissue-type plasminogen activator inhibitor-1 (tPAI-1) by 54 +/- 11% (P < 0.02 for both) and inhibited plasma free fatty acids by 26 +/- 11% and beta-hydroxybutyrate by 61 +/- 27% (P < 0.05 for both). The HFHP diet blunted the increase in IHCLs and normalized plasma beta-hydroxybutyrate and tPAI-1 concentrations. Insulin sensitivity was not altered, whereas the expression of sterol regulatory element-binding protein-1c and key lipogenic genes increased with the HF and HFHP diets (P < 0.02). Bile acid concentrations remained unchanged after the HF diet but increased by 50 +/- 24% after the HFHP diet (P = 0.14). CONCLUSIONS: Protein intake significantly blunts the effects of an HF diet on IHCLs and tPAI-1 through effects presumably exerted at the level of the liver. Protein-induced increases in bile acid concentrations may be involved. This trial was registered at www.clinicaltrials.gov as NCT00523562.

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The effects of flow induced by a random acceleration field (g-jitter) are considered in two related situations that are of interest for microgravity fluid experiments: the random motion of isolated buoyant particles, and diffusion driven coarsening of a solid-liquid mixture. We start by analyzing in detail actual accelerometer data gathered during a recent microgravity mission, and obtain the values of the parameters defining a previously introduced stochastic model of this acceleration field. The diffusive motion of a single solid particle suspended in an incompressible fluid that is subjected to such random accelerations is considered, and mean squared velocities and effective diffusion coefficients are explicitly given. We next study the flow induced by an ensemble of such particles, and show the existence of a hydrodynamically induced attraction between pairs of particles at distances large compared with their radii, and repulsion at short distances. Finally, a mean field analysis is used to estimate the effect of g-jitter on diffusion controlled coarsening of a solid-liquid mixture. Corrections to classical coarsening rates due to the induced fluid motion are calculated, and estimates are given for coarsening of Sn-rich particles in a Sn-Pb eutectic fluid, an experiment to be conducted in microgravity in the near future.

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Audit report on the Pocahontas County Solid Waste Commission for the year ended June 30, 2011

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Background Addressing the risks of nanoparticles requires knowledge about their hazards, which is generated progressively, but also about occupational exposure and liberation into the environment. However, currently such information is not systematically collected, therefore the risk assessment of this exposure or liberation lacks quantitative data. In 2006 a targeted telephone survey among Swiss companies (1) showed the usage of nanoparticles in a few selected companies but did not provide data to extrapolate on the totality of the Swiss workforce. The goal of this study was to evaluate in a representative way the current prevalence and level of nanoparticle usage in Swiss industry, the health, safety and environment measures, and the number of potentially exposed workers. Results A representative, stratified mail survey was conducted among 1,626 clients of the Swiss National Accident Insurance Fund (SUVA). SUVA insures about 80,000 manufacturing firms, which represent 84% of all Swiss manufacturing companies. 947 companies answered the survey (58.3% response rate). Extrapolation to all Swiss manufacturing companies results in 1,309 workers (95%-confidence interval, 1,073 to 1,545) across the Swiss manufacturing sector being potentially exposed to nanoparticles in 586 companies (95%-CI: 145 to 1'027). This corresponds to 0.08% (95%-CI: 0.06% to 0.09%) of all Swiss manufacturing sector workers and to 0.6% (95%-CI: 0.2% to 1.1%) of companies. The industrial chemistry sector showed the highest percentage of companies using nanoparticles (21.2% of those surveyed) and a high percentage of potentially exposed workers (0.5% of workers in these companies), but many other important sectors also reported nanoparticles. Personal protection equipment was the predominant protection strategy. Only a minority applied specific environmental protection measures. Conclusions This is the first representative nationwide study on the prevalence of nanoparticle usage across a manufacturing sector. The information about the number of companies can be used for quantitative risk assessment. Furthermore it can help policy makers designing strategies to support companies in the responsible development of safer nanomaterial use. Noting the low prevalence of nanoparticle usage, there would still seem to be time to introduce necessary protection methods in a proactive and cost effective way in Swiss industry. But if the predicted "nano-revolution" becomes true, now is the time to take action.

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One of the key challenges in the field of nanoparticle (NP) analysis is in producing reliable and reproducible characterisation data for nanomaterials. This study looks at the reproducibility using a relatively new, but rapidly adopted, technique, Nanoparticle Tracking Analysis (NTA) on a range of particle sizes and materials in several different media. It describes the protocol development and presents both the data and analysis of results obtained from 12 laboratories, mostly based in Europe, who are primarily QualityNano members. QualityNano is an EU FP7 funded Research Infrastructure that integrates 28 European analytical and experimental facilities in nanotechnology, medicine and natural sciences with the goal of developing and implementing best practice and quality in all aspects of nanosafety assessment. This study looks at both the development of the protocol and how this leads to highly reproducible results amongst participants. In this study, the parameter being measured is the modal particle size.

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During episodes of trauma carnitine-free total parenteral nutrition (TPN) may result in a reduction of the total body carnitine pool, leading to a diminished rate of fat oxidation. Sixteen patients undergoing esophagectomy were equally and randomly divided and received isonitrogenous (0.2 gN/kg.day) and isocaloric (35 kcal/kg.day TPN over 11 days without and with L-carnitine supplementation (12 mg/kg.day). Compared with healthy controls, the total body carnitine pool was significantly reduced in both groups prior to the operation. Without supplementation carnitine concentrations were maintained, while daily provision of carnitine resulted in an elevation of total carnitine mainly due to an increase of the free fraction. Without supplementation the cumulative urinary carnitine losses were 11.5 +/- 6.3 mmol corresponding to 15.5% +/- 8.5% of the estimated total body carnitine pool. Patients receiving carnitine revealed a positive carnitine balance in the immediate postoperative phase, 11.1% +/- 19.0% of the infused carnitine being retained. After 11 days of treatment comparable values for respiratory quotient, plasma triglycerides, free fatty acids, ketone bodies, and cumulative nitrogen balance were observed. It is concluded that in the patient population studied here carnitine supplementation during postoperative TPN did not improve fat oxidation or nitrogen balance.

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Spherical gravitational wave (GW) detectors offer a wealth of so far unexplored possibilities to detect gravitational radiation. We find that a sphere can be used as a powerful testbed for any metric theory of gravity, not only general relativity as considered so far, by making use of a deconvolution procedure for all the electric components of the Riemann tensor. We also find that the spheres cross section is large at two frequencies, and advantageous at higher frequencies in the sense that a single antenna constitutes a real xylophone in its own. Proposed GW networks will greatly benefit from this. The main features of a two large sphere observatory are reported.

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Audit report on the Delaware County Solid Waste Disposal Commission for the year ended June 30, 2011