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51.
Replacement of the tracheal conduit remains an unresolved problem. The microporous material expanded polytetrafluorethylene (ePTFE) is suitable for tracheal reconstruction. The aim of our study was to improve the limited mechanical properties of this material by incorporating reinforcement elements and to examine the influence of these elements on host incorporation and epithelialization. In so dours ePTFE prostheses were reinforced with lonomer cement and porous high density polyethylene (pHDPE) rings and implanted into the neck muscle of miniature pigs. One of these prostheses was epithelialized by a cell seeding technique and was thus placed into a tracheal defect. Results were examined grossly by endoscopy and than by light and scanning electron microscopy. The shapes of both types of prostheses showed a high stability. The reinforcement elements did not impair bioincorporation or the ability to epithelialize. In vivo interposition of an incorporated and epithelialized prosthesis to a host led to cell differentiation. The improved biomechanical properties of the prostheses waid and the reproducible formation of epitheliums are important advances in the solution of effectively correcting tracheal defects.  相似文献   
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The ignition and oxidation of oxetane have been studied in a single-pulse shock tube under reflected shock wave conditions and also in a jet-stirred reactor (JSR). These experiments cover a wide range of conditions: 1–10 atm, 0.5 ≤ φ ≤ 2.0, 800–1780 K. The ignition delays of oxetane measured in a shock tube have been used to propose an overall dependence of ignition delay time on the concentrations of each component in the gas as: τ = 10−13.5 exp(13389/T5)[C3H6O]−0.36[O2]−0.59[Ar]0.088 (units: seconds, moles per cubic decimeters, and Kelvin). Concentration profiles of the reactants, intermediates, and products of the oxidation of oxetane were measured in a JSR. A numerical model, consisting of a detailed kinetic reaction mechanism with 423 reactions (most of them reversible) of 63 species describes the ignition of oxetane in reflected shock waves and its oxidation in a jet-stirred reactor. Fairly good agreement between the observations and the model was obtained. The major reaction paths have been identified through detailed kinetic modeling.  相似文献   
53.
Employee loyalty affects company performance, competitiveness and ultimately the bottom line. Today, the old employment contract is null and void. Employee loyalty cannot be taken for granted; it must be fostered and cultivated. The new employment contract encourages participative decision making, career development, pay for productivity and flexible benefits.  相似文献   
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Electrospinning of fibrous scaffolds containing nano-hydroxyapatite (nHAp) embedded in a matrix of functional biomacromolecules offers an attractive route to mimicking the natural bone tissue architecture. Functional fibrous substrates will support cell attachment, proliferation and differentiation, while the role of HAp is to induce cells to secrete extracellular matrix (ECM) for mineralization to form bone. Electrospinning of biomaterials composed of polyhydroxybutyrate-co-(3-hydroxyvalerate) with 2% valerate fraction (PHBV), nano-hydroxyapatite (nHAp), and Bombyx mori silk fibroin essence (SF), Mw = 90KDa, has been achieved for nHAp and SF solution concentrations of 2 (w/vol) % each and 5 (w/vol) % each. The structure and properties of the nanocomposite fibrous membranes were investigated by means of Scanning Electron Microscopy in combination with Energy Dispersive X-Ray Analysis (SEM/EDX), Fourier Transformed Infrared Spectroscopy (FT-IR), uniaxial tensile and compressive mechanical testing, degradation tests and in vitro bioactivity tests. SEM images showed smooth, uniform and continuous fibre deposition with no bead formation, and fibre diameters of between 10 and 15 μm. EDX and FT-IR confirmed the presence of nHAp and SF. After one month in deionised water, tests showed less than 2% weight loss with the samples retaining their fibrous morphology, confirming that this material biodegrades slowly. After 28 days of immersion in Simulated Body Fluid (SBF) an apatite layer was visible on the surface of the fibres, proving their bioactivity. Preliminary in vitro biological assessment showed that after 1 and 3 days in culture, cells were attached to the fibres, retaining their morphology while presenting a flattened appearance and elongated shape on the surface of fibres. Young's modulus was found to increase from 0.7 kPa (± 0.33 kPa) for electrospun samples of PHBV only to 1.4 kPa (± 0.54 kPa) for samples with 2 (w/vol) % each of nHAp and SF. Samples prepared with 5 (w/vol) % each of nHAp and SF did not show a similar improvement.  相似文献   
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Policy makers and decision makers are struggling to recognize the needs of shattered communities in the wake of unimaginable devastation. Professional psychology is providing some of the answers as it examines the consequences of disaster. The authors, 6 U.S. Public Health Service commissioned officers, describe their experiences in this new arena. Working at the federal, state, and local levels of government during the national response to the Hurricane Katrina disaster, the authors strive to identify high-value practice areas and define new roles for professional psychologists. The authors suggest that traditional crisis and trauma interventions are expanding to include nontraditional population-based and macrosystems-level interventions. Such roles are explored in narrative form, providing professional and personal insight into the impact that psychologists can have on decision makers who recognize their value and position them effectively. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
58.
Participatory action research (PAR) has been heralded as an important research methodology to address issues of research relevance, community involvement, democracy, emancipation and liberation. Increasingly, nurse researchers are turning to PAR as a method of choice. Although nursing interest in PAR is expanding little is known about how to successfully involve the community in research. This article attends to this dearth of information by presenting the results of a study investigating the significant elements of community involvement in PAR. Through the use of qualitative research methods, five themes emerged that describe the community participation process: (a) planning for participation, (b) the structural components of community participation, (c) living the philosophy, (d) enhancing the credibility, and (e) the type of leadership required to facilitate community participation. It is hoped that by sharing these results others may consider the knowledge gleaned from this project as they plan and proceed with the challenges and rewards inherent in PAR.  相似文献   
59.
In this study, a combined enrichment/real-time PCR method for the rapid detection of Salmonella on fresh meat carcasses, was designed, developed and validated in-house following requirements outlined in ISO 16140:2003. The method included an 18 h non-selective enrichment in buffered peptone water (BPW) and a 6 h selective enrichment in Rappaport Vasilliadis Soya (RVS) broth, based on the traditional culture method, ISO 6579:2002. The real-time PCR assay included an internal amplification control (IAC), was 100% specific and was sensitive to one cell equivalent. The alternative method was validated against the traditional culture method and relative accuracy of 94.9%, sensitivity of 94.7% and specificity of 100% were determined using 150 fresh meat carcass swabs. This alternative method had a detection limit of 1–10 CFU/100 cm2 for fresh meat carcass swabs and was performed in 26 h. Following further inter-laboratory studies, this alternative method could be suitable for implementation in testing laboratories for the analysis of carcass swabs.  相似文献   
60.
The objective of this study was the development of DNA and RNA real-time PCR methods for detection of food-borne Salmonella sp. as rapid alternatives to the traditional cultural method (ISO 6579, 2004) in fresh meat carcasses and processed meat samples. These PCR methods were based on the hilA sequence, with primers and hybridisation probes designed against this gene target. The primers and probes were evaluated for their efficiency and dynamic range and subsequently the specificity of the assay was tested using 106 Salmonella enterica subspecies enterica strains and 30 non-salmonellae strains. An internal amplification control (IAC) was also developed for incorporation. The optimum copy number of IAC was determined to be 500 copies per reaction. A complementary enrichment protocol was adapted from the existing standard ISO 6579:2004 and consisted of enrichment in Buffered Peptone Water (BPW) 22 ± 2 h and a second selective enrichment for 6 h in Rappaport Vassiliadis with Soya (RVS). The DNA and RNA-based real-time PCR protocols, were applied to meat samples inoculated with Salmonella enterica subspecies enterica strains, including swabs from meat carcasses and minced beef samples which were heat treated or frozen. The developed methods have the potential as useful alternatives to the standard ISO 6579:2004 method for the detection of Salmonella enterica subspecies enterica on carcass swabs and raw meat using hilA as a target. The DNA assay is a useful tool for the screening of meat samples in the abattoir within 3 days of slaughter or in a food production process and the RNA-based assay has the potential to detect viable Salmonella enterica subspecies enterica in ready-to-eat products.  相似文献   
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